The application claims priority of an exoskeleton driver and a driving state monitoring method of China patent application CN 2020102424530 which is filed on 3 months and 31 days in 2020 and priority of a parallel elastic driving device, a serial-parallel elastic driving device and an exoskeleton of China patent application CN2021103293593 which is filed on 28 days in 2021, wherein the two priority China patent applications are fully incorporated by reference.
Disclosure of Invention
The invention aims to provide a parallel elastic driver of a power-assisted exoskeleton and a control method thereof, which partially solve or alleviate the defects in the prior art, realize the separation of a driving mechanism and an actuating mechanism, and simultaneously reduce the system dead weight of the power-assisted exoskeleton, thereby reducing the negative influence of the dead weight of the exoskeleton on the walking gait of a wearer.
In order to solve the technical problems, the invention adopts the following technical scheme:
In a first aspect, the invention provides a parallel elastic driver of a power-assisted exoskeleton, comprising a driving mechanism for providing power assistance, a stay wire mechanism for transmitting the power assistance to at least one actuating mechanism of the power-assisted exoskeleton, and an elastic mechanism for providing recovery force for the stay wire mechanism to tighten stay wires in the stay wire mechanism when the driving mechanism stops providing power assistance, wherein the elastic power mechanism is arranged at an input end of the stay wire mechanism in parallel with the driving mechanism.
In some exemplary embodiments, the drive mechanism includes a motor.
In some exemplary embodiments, the wire pulling mechanism comprises a wire pulling mechanism for transmitting the power assistance and a winch for winding the wire pulling mechanism, wherein the winch is connected with the motor in a synchronous rotation mode, the fixed end of the wire pulling mechanism is fixed on the winch, and at least one force output end of the wire pulling mechanism is connected with the at least one actuating mechanism.
In some exemplary embodiments, the parallel elastic driver further comprises a clutch locking mechanism arranged between two adjacent actuating mechanisms, wherein the clutch locking mechanism is respectively connected with the two actuating mechanisms through a pull wire in the pull wire mechanism, when a boosted joint of a wearer is in a straightened state or is close to the straightened state, the clutch locking mechanism is in an engaged state, so that the power assistance output by the driving mechanism is transmitted to the two actuating mechanisms connected with the clutch locking mechanism through the pull wire mechanism, and when the boosted joint is in a bending state, the clutch locking mechanism is in an unengaged state, so that the power assistance output by the driving mechanism is transmitted to the actuating mechanism close to the driving mechanism through the pull wire mechanism.
In some exemplary embodiments, the elastic mechanism includes an elastic energy storage member mounted on the wire pulling mechanism and configured to store energy when the power mechanism provides assistance to the wire pulling mechanism and to release energy to provide the recovery force to the wire pulling mechanism when the power mechanism ceases to provide assistance to the wire pulling mechanism.
In some exemplary embodiments, the elastic energy storage member is a coil spring, an outer ear of which is fixed to the wire pulling mechanism, and an inner ear of which is fixed to a rotation shaft of the coil spring.
In some exemplary embodiments, the stay wire in the stay wire mechanism is divided into three branches through three stay wire channels in the power-assisted exoskeleton, wherein two branches are symmetrically arranged on the left side and the right side of the corresponding power-assisted joint mechanism in the power-assisted exoskeleton, and the other branch is arranged right in front of or right behind the power-assisted joint mechanism.
In some exemplary embodiments, the stay wire in the stay wire mechanism is divided into two branches by two stay wire channels in the power-assisted exoskeleton, and the two branches are symmetrically arranged at the left side and the right side of the corresponding power-assisted joint mechanism in the power-assisted exoskeleton.
In a second aspect, the invention provides a parallel elastic driver without motion damping in a power-assisted exoskeleton, comprising a driving mechanism for providing power assistance, a wire pulling mechanism for transmitting the power assistance to at least one actuator in the power-assisted exoskeleton, an elastic mechanism for providing a recovery force to the wire pulling mechanism to tighten a wire pulled in the wire pulling mechanism when the driving mechanism stops providing power assistance, and a centrifugal clutch, wherein the driving mechanism and the elastic mechanism are connected in parallel at an input end of the wire pulling mechanism, the centrifugal clutch is arranged between the driving mechanism and the wire pulling mechanism, and connects the driving mechanism with the wire pulling mechanism when the driving mechanism provides power assistance, and disconnects the driving mechanism from the wire pulling mechanism when the driving mechanism stops providing power assistance, and the elastic mechanism provides the recovery force to the wire pulling mechanism. Wherein the drive mechanism comprises a motor.
In some exemplary embodiments, the centrifugal clutch comprises at least one pawl, at least one elastic reset piece, a pawl seat and a ratchet wheel, wherein the pawl seat is connected with the motor in a synchronous rotation mode, the ratchet wheel is connected with a winch in the wire pulling mechanism in a synchronous rotation mode, at least one pawl is uniformly distributed on the pawl seat in a mode of rotating relative to the pawl seat, the first end of the elastic reset piece is fixed on the pawl seat, the second end of the elastic reset piece is connected with the pawl, when the motor provides assistance, the motor drives the pawl seat to synchronously rotate, the pawl expands outwards in a direction away from the central axis of the pawl seat under the action of centrifugal force and gradually engages with the ratchet wheel, so that the motor is connected with the wire pulling mechanism, and when the motor stops assistance, the pawl gathers along a direction close to the central axis of the pawl seat and gradually breaks away from the ratchet wheel under the action of the elastic reset piece, so that the motor is disconnected from the wire pulling mechanism.
In some exemplary embodiments, the centrifugal clutch further includes a synchronizing gear disposed at a center of the pawl holder, and accordingly, one side of each of the pawls, which corresponds to the synchronizing gear, is provided with an incomplete gear that is engageable with the synchronizing gear, and at least one of the pawls rotates in synchronization when the pawl rotates about the rotation axis.
In some exemplary embodiments, the centrifugal clutch further includes at least one pawl stop disposed on the pawl seat for limiting a maximum angle of rotation of the pawl in a direction away from a center of the pawl seat.
In a third aspect, the invention provides a series-parallel elastic driver of a power-assisted exoskeleton, comprising a driving mechanism for providing power assistance, a pulling wire mechanism for transmitting the power assistance to at least one actuating mechanism of the power-assisted exoskeleton, an elastic mechanism for providing recovery force to the pulling wire mechanism when the driving mechanism stops providing the power assistance, and an elastic buffer component for providing buffer to the pulling wire mechanism, wherein the driving mechanism and the elastic mechanism are connected in parallel at an input end of the pulling wire mechanism, a centrifugal clutch is arranged between the driving mechanism and the pulling wire mechanism, the elastic buffer component is connected in series at an input end/output end of the pulling wire mechanism, the centrifugal clutch is meshed when the driving mechanism provides the power assistance, so as to connect the driving mechanism with the pulling wire mechanism, and the impact force caused by the centrifugal clutch meshing moment is relieved by the elastic buffer component, and the centrifugal clutch is disconnected from the driving mechanism and the pulling wire mechanism when the driving mechanism stops providing the power assistance, and the recovery force is provided to the pulling wire mechanism by the elastic mechanism.
In a fourth aspect, the present invention provides a power-assisted exoskeleton comprising at least one actuator, and any one of the above drives, wherein an output of the drive is connected to an input of the at least one actuator.
The fifth aspect of the present invention provides a method for controlling a driver of a power-assisted exoskeleton, wherein the driver is any one of the drivers described above, and the method specifically includes the steps of acquiring and identifying a current working state of the driver, where the working state includes preparation and power assistance;
If the working state of the driver is identified to be ready, acquiring the current joint expansion angular speed and joint bending angle of the power-assisted joint mechanism in the power-assisted exoskeleton;
judging whether the power-assisted joint mechanism needs power assistance or not according to the joint stretching angular speed, the joint bending angle, a preset stretching threshold angle and a failure threshold angle;
If assistance is required, the current working state of the driver is set to an assistance state from a preparation state, and the output torque of the driver is set to a preset threshold T ref.
In some exemplary embodiments, the control method further includes the steps of:
if the working state of the driver is recognized as power assistance, the current knee joint bending angle, the knee joint stretching angular speed or the knee joint bending angular speed of the power assistance joint mechanism is obtained;
judging whether the power assisting needs to be canceled currently according to the knee joint bending angle and a preset failure threshold angle, or the knee joint stretching angular speed and a preset maximum stretching angular speed, or the knee joint bending angular speed and a preset bending threshold angular speed, if so, setting the current working state of the driver into a follow-up state from a power assisting state, and setting the output torque of the driver to 0.
In some exemplary embodiments, the operating state of the driver further comprises a follower, and correspondingly, the control method further comprises the steps of:
if the working state of the driver is identified to be follow-up, acquiring the current joint bending angle and the current joint bending angular speed of the power-assisted joint mechanism;
Judging whether the power assistance is needed at present according to the joint bending angle, the joint bending angular speed, a preset power assistance threshold angle and a preset bending threshold angular speed, if so, setting the current working state of the driver from a follow-up state to a preparation state, and setting the output torque of the driver to 0.
The technical scheme of the invention is that the parallel elastic driver is combined with the flexible transmission mechanism of the wire tube and the exoskeleton rigid actuating mechanism of the joint part. The wire winch is fixedly mounted at the output end of the motor, the wire pipe fixing seat is fixedly mounted on a peripheral shell of the motor, the end of the wire is arranged at a wire end mounting groove arranged on the wire winch, a coil spring is mounted in the wire winch, the outer ear of the coil spring is arranged in an outer ear mounting groove of the wire winch, and the inner ear of the coil spring is fixed with the peripheral shell of the motor through a straight groove on a central shaft end cover.
As the preferred technical scheme, the spool fixing base includes spool fixed body, set up the spool through-hole on the spool fixed body, spool fixed body with the one side of motor contact sets up spool fixed wall, wire capstan passes through the spool through-hole is installed the output of motor, spool fixed wall downside is provided with wire outlet slot, the center pin end cover with the cooperation of spool fixed wall is sealed, is used for the protection the wire capstan.
As an optimized technical scheme, the steel wire winch comprises a steel wire winch body, wherein a mounting hole is formed in the middle of the steel wire winch body, the steel wire winch body is connected with the output end of the motor through the mounting hole, a steel wire winch wall is arranged on one surface of the steel wire winch body, and a steel wire end mounting groove for mounting the steel wire end and an outer ear mounting groove for mounting the outer ear of the coil spring are mounted on the steel wire winch wall;
the wire winch also comprises a coil spring end cover, wherein the coil spring end cover is closed by being matched with the wire winch wall and is used for protecting the coil spring.
As the preferable technical scheme, a plurality of threaded holes are formed in the upper end of the wire winch wall, a plurality of end cover mounting holes are correspondingly formed in the coil spring end cover, and a plurality of bolts penetrate through the plurality of mounting holes to be matched with the plurality of threaded holes so as to fixedly mount the coil spring end cover on the wire winch wall.
As an optimal technical scheme, a plurality of central shaft end cover mounting grooves are periodically formed in the wire tube fixing wall, and the central shaft end cover is matched with the mounting grooves through a plurality of mounting blocks on the central shaft end cover to seal and protect the wire winch.
As an preferable technical scheme, a wire pipe is installed corresponding to the wire outlet groove.
As an optimal technical scheme, an elasticity fine tuning knob is arranged in the steel wire appearance groove.
The driving state detection method of the parallel elastic driver comprises the following steps of:
if the knee joint angle is greater than the power-assisted threshold angle and the knee joint bending angular velocity is greater than the bending threshold angular velocity, judging that the driving state is ready, wherein the motor moment=0;
If the knee joint stretching angular velocity is greater than the stretching threshold angular velocity and the knee joint angle is greater than the failure threshold angle, judging that the driving state is power assisting, wherein the motor moment=T ref;
if the knee joint angle < failure threshold angle or knee joint extension angular velocity > maximum extension angular velocity or knee joint flexion angular velocity > flexion threshold angular velocity, the driving state is judged to be follow-up, and the motor torque=0.
Further, after judging the driving state, judging whether the user modifies Tref or each threshold parameter;
if yes, judging whether the system is abnormal or not after adjusting the related threshold value;
if not, directly judging whether the system is abnormal;
if the system is abnormal, restarting or alarming;
If the system is not abnormal, the driving state is continuously judged according to the mode.
The technical scheme of the invention is that the exoskeleton driver is characterized by comprising a motor and an elastic mechanism, wherein the motor and the elastic mechanism are connected with a first end of a steel wire in a parallel mode and apply tension to the steel wire, a second end of the steel wire is connected with a knee assisting joint mechanism through a steel wire tube mechanism, and the exoskeleton driver is arranged at a position of a waist of a wearer and above when in use.
As a preferable technical scheme, the elastic mechanism is a coil spring.
As a preferable technical scheme, the third end of the steel wire is connected with the ankle assisting joint mechanism through the steel wire tube mechanism.
As a preferable technical scheme, a clutch locking mechanism is arranged between the second end and the third end of the steel wire, when the knee joint of a wearer is in an upright state or a nearly upright state in use, the clutch locking mechanism is in an engaged state, so that the tensile force applied by the exoskeleton driver is transmitted to the ankle assisting joint mechanism, and when the knee joint of the wearer is in a bending state, the clutch locking mechanism is in a separated state, and the transmission of the tensile force applied by the exoskeleton driver to the ankle assisting joint mechanism is cut off.
As a preferred technical solution, the second end of the steel wire passes through the knee-assisted joint mechanism through at least three steel wire channels located in the knee-assisted joint mechanism, wherein the at least three steel wire channels include a left rotating shaft located at the left side of the knee joint of the wearer, a right rotating shaft located at the right side of the knee joint of the wearer, and a front steel wire sliding slot located at the front face of the knee joint of the wearer.
As the preferable technical scheme, the steel wire is coiled at the power-assisted joint pulley of the knee power-assisted joint mechanism for a plurality of times through the movable pulley mechanism, so that the transmission ratio of the steel wire from the exoskeleton driver to the knee power-assisted joint mechanism is changed, and the power-assisted torque amplification at the knee power-assisted joint mechanism is realized.
The invention has the beneficial effects that:
According to the invention, the driving mechanism and the elastic mechanism are arranged in parallel at the input end of the wire pulling mechanism, so that the power assistance provided by the driving mechanism and/or the recovery force provided by the elastic mechanism can be transmitted to at least one executing mechanism through the wire pulling mechanism, and the separation of the driver and the executing mechanism in the power assistance exoskeleton is realized, so that the device with a certain weight, such as the driving mechanism, a winch, a battery control system and the like in the wire pulling mechanism, can be arranged at the waist or above the waist of a wearer, and the problems that in the prior art, the wearer feels heavy in device and even the freedom of movement of the wearer is limited due to the fact that the driving motor is directly arranged on the executing mechanism are avoided; in addition, the parallel elastic driver realizes that one driver drives a plurality of execution mechanisms, avoids the negative influence of the increase of the dead weight of the power-assisted exoskeleton system caused by the installation of one driving mechanism for each execution mechanism in the prior art, thereby affecting the walking gait of a wearer, namely the parallel elastic driver has simpler structure, reduces the self system of the power-assisted exoskeleton, reduces the negative influence of the dead weight of an exoskeleton device on the walking gait of the lower limb of the wearer, and further improves the user experience of the wearer.
On the other hand, the invention connects an elastic mechanism in parallel with the driving mechanism at the input end of the wire pulling mechanism, so that when the driving mechanism works (namely, provides assistance), the driving mechanism (such as a motor) and the elastic mechanism (such as a coil spring) simultaneously pull the wire pulling mechanism (such as a steel wire or a braiding belt) to transmit assistance to each actuating mechanism (such as a knee assistance joint mechanism and an ankle assistance joint mechanism) in the assistance exoskeleton, and when the driving mechanism stops working (namely, stops providing assistance, such as a battery is exhausted or intentionally stops the motor), the elastic mechanism provides recovery force for the wire pulling mechanism to tighten the wire pulling, namely, under the action of the elastic mechanism, the wire pulling mechanism is always in a tight state even if a wearer wears the assistance exoskeleton, thereby avoiding the risk of mechanical failure and even safety accident caused by mutual winding of the wire pulling at a winch (or a stranded wire disc) due to the fact that the wire pulling is in a free and loose state.
In addition, the invention can transmit the assistance generated by the exoskeleton driver to a plurality of actuating mechanisms (such as knee assistance joint mechanisms and ankle assistance joint mechanisms) in the exoskeleton through the wire tube mechanism, so that one driving mechanism can assist more than one place, for example, when the knee joint of the thigh of a wearer is large (for example, when the wearer is on a step), the assistance generated by the exoskeleton driver mainly acts on the knee assistance joint mechanism (at the moment, the assistance requirement of the knee joint is large and the assistance requirement of the ankle joint is small), but as the knee joint of the thigh gradually returns to be upright (the assistance requirement of the knee joint is reduced and the assistance requirement of the ankle joint is increased), the assistance generated by the exoskeleton driver gradually moves downwards from the knee joint to the ankle joint, and the assistance provided for the ankle joint is gradually increased.
Furthermore, the driver of the invention is also provided with a clutch locking mechanism between two adjacent execution mechanisms, and the clutch locking mechanism is connected with the two execution mechanisms through a stay wire, so that the power assisting can be better distributed between the two execution mechanisms, and the power assisting efficiency of the driver is further improved. For example, a clutch locking mechanism is added between the knee-assisted joint mechanism and the ankle-assisted joint mechanism, when the knee joint is bent to a large extent, the clutch locking mechanism can be made to enter a separated state (or an unlocked state or an unengaged state), so that the pulling force of the pulling wire mechanism stops transmitting assistance to the ankle-assisted joint mechanism (namely, an actuating mechanism far away from the driver), the assistance generated by the exoskeleton driver is concentrated at the knee-assisted joint mechanism to help a wearer to climb a step or a slope, and when the knee joint is bent to a certain extent, the clutch locking mechanism is made to enter an engaged state (or a locked state or an engaged state) again, so that the pulling wire mechanism can transmit assistance to the knee-assisted joint mechanism and also can transmit assistance to the ankle-assisted joint mechanism, and assistance to the knee joint and the ankle joint is realized. In other words, by adding the clutch mechanism, the assistance force can be better distributed between the knee joint and the ankle joint, and the assistance efficiency of the exoskeleton driver for providing assistance force to the lower limb is improved.
According to the parallel driver without motion damping, the centrifugal clutch is arranged between the driving mechanism and the stay wire mechanism, when the driving mechanism provides assistance, the driving mechanism is connected with the stay wire mechanism through the centrifugal clutch, and when the driving mechanism stops providing assistance, the driving mechanism is disconnected from the stay wire mechanism through the centrifugal clutch, so that the problem that a wearer feels continuous motion damping when wearing assistance exoskeleton to move (and no assistance is provided) when the driving mechanism stops providing assistance is avoided, and the smoothness of free motion of corresponding joints of the wearer is further ensured when no assistance is needed.
According to the serial-parallel driver, the elastic buffer component is connected in series with the input end/output end of the wire pulling mechanism, so that impact force caused by centrifugal clutch engagement moment is relieved, the trend of variation of force assisting force for a limb of a wearer is smoother, and impact abrasion of pawls during engagement of the centrifugal clutch is relieved.
Detailed Description
The following description of the technical solutions in the embodiments of the present invention will be clear and complete, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that all directional indicators (such as up, down, left, right, front, and rear are used in the embodiments of the present invention) are merely for explaining the relative positional relationship, movement conditions, and the like between the components in a certain specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicators are changed accordingly.
Furthermore, descriptions such as those referred to as "first," "second," and the like, are provided for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implying an order of magnitude of the indicated technical features in the present disclosure. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
Noun paraphrasing:
"drive mechanism" as used herein refers to a mechanism, such as a motor, that is capable of providing assistance to at least one actuator in an assistance exoskeleton.
"Elastic power mechanism" as used herein refers to an elastic mechanism, such as a wrap spring, that provides a retraction force to a pull wire mechanism in the power assist exoskeleton that transmits power assist when the drive mechanism ceases to provide power assist, to tighten a pull wire in the pull wire mechanism.
An "actuator" is used herein to refer to a mechanism that performs a corresponding action or performs a corresponding function upon actuation of a drive mechanism, e.g., a mechanism for assisting a wearer's joint, and that moves upon actuation of the drive mechanism, such as, in particular, a knee joint, ankle joint, hip joint, etc., in an assisting exoskeleton device.
Parallel connection means that the output ends of the force (e.g. the assisting force or the recovering force) of the driving mechanism and the elastic mechanism are connected with the input end of the wire pulling mechanism so as to provide a certain acting force (e.g. the assisting force or the recovering force) for the wire pulling in the wire pulling mechanism. For example, when the motor works, the motor and the coil spring simultaneously pull the stay wire to apply assistance to the knee assistance joint mechanism and the ankle assistance joint mechanism, and when the motor stops working (such as the battery is exhausted or the motor stops working intentionally), the coil spring still can pull the stay wire, so that the stay wire is always in a tight state in the operation of the exoskeleton mechanism, the stay wire is prevented from being in a free and loose state, the risk of mechanical failure caused by the mutual winding of the stay wire at the winch is caused, and the occurrence probability of safety accidents is greatly reduced.
"Stay" means herein various mechanisms for transmitting assistance/tension, such as wire or tube-like steel wires, ropes, or wire-like, or ribbon-like or strip-like braids, etc.
The spool refers herein to a pipe which is wrapped or sleeved outside the stay wire, the two ends of the spool are fixed, the spool is incompressible, and the spool provides a motion path for the stay wire so as to realize power/tension transmission.
"Input" means herein the end of each component that receives a force, also referred to as a force input. For example, the end of the power assistance output by the driving mechanism is received by the wire pulling mechanism, or one end of the recovery force generated/output by the elastic mechanism is received by the wire pulling mechanism, or the end of the power assistance transmitted by the wire pulling mechanism is received by the actuating mechanism.
"Output" means, in this context, the end of each component that outputs a force, also referred to as the force output. For example, the end of the wire pulling mechanism that is connected to the actuator outputs the assistance provided by the drive mechanism to the input of the actuator (i.e., the end that receives the assistance).
The initial state refers to the natural state of each component under the condition of no external force or external interference. For example, the initial state of the motor refers to a state when the motor is not energized, or is not rotating. As another example, the initial state of the centrifugal clutch is a state in which the motor does not rotate the pawl seat and (i) the pawl is not outwardly expanded by centrifugal force, or (ii) is moved toward the center of the pawl seat by the elastic restoring member (in this case, the elastic restoring member is in a pre-tightening state of factory) as shown in fig. 9c and 9 d. For another example, the initial state of the elastic mechanism refers to a state in which the coil spring is not tightened by being driven by a capstan or a wire, and is not loosened by being subjected to other external forces.
In order to ensure that the wires in the wire pulling mechanism are in a tight state (i.e. a tightened state) even without providing assistance to the actuator, thereby avoiding the risk of mechanical failure caused by the wires being entangled with each other, the present invention provides a parallel elastic driver 12 comprising:
a driving mechanism for providing an assistance force,
A wire pulling mechanism for transmitting the power assistance provided by the driving mechanism to at least one actuating mechanism, and
An elastic mechanism for providing a recovering force to the wire pulling mechanism to tighten the wire pulling in the wire pulling mechanism when the driving mechanism stops providing the assisting force, wherein,
The elastic mechanism and the driving mechanism are arranged at the input end of the wire pulling mechanism in parallel (namely, the force output end of the elastic mechanism and the force output end of the driving mechanism are connected with the force input end of the wire pulling mechanism).
In some embodiments, the drive mechanism includes a motor 1, for example, a pseudo-direct drive torque motor.
In some embodiments, see fig. 2a and 2b, the wire pulling mechanism comprises a wire pulling 4 for transmitting the power of the driving mechanism, and a winch 2 for winding the wire pulling 4, wherein the winch 2 is connected in synchronous rotation with the motor 1 (e.g. the winch 2 is fixed on the output end 6 of the torque motor, see fig. 1a and 1 b), the fixed end of the wire pulling 4 is fixed on the winch 2 (e.g. the fixed end 41 of the wire pulling 4 is placed in the end mounting groove 201 on the winch 2), and the end (or force output end) of the wire pulling 4 is connected with the actuator.
In some embodiments, referring to FIGS. 2a and 2b, the elastic mechanism includes an elastic energy storage member mounted on the wire pulling mechanism, the elastic energy storage member stores energy when the driving mechanism (e.g., torque motor) provides assistance to the wire pulling mechanism, and releases energy to provide a recovery force to the wire pulling mechanism when the driving mechanism (e.g., torque motor) ceases to provide assistance to the wire pulling mechanism. Specifically, the elastic energy storage member may employ a coil spring 5, an outer ear 501 of which is fixed to the wire pulling mechanism (for example, the outer ear 501 of the coil spring 5 is fixed to the outer ear mounting groove 202 of the capstan 2), an inner ear 502 of which is fixed to a rotation shaft of the coil spring 5 (for example, by providing a coil spring cover 7, and the coil spring cover 7 may be fixed to a spool fixing seat 3 in the wire pulling mechanism by a fixing member such as a bolt, and a center shaft is provided on one side thereof corresponding to the coil spring 5, which is a rotation shaft when the coil spring 5 is contracted or relaxed, and a straight groove 701 for fixing the inner ear 502 of the coil spring 5 is provided on the center shaft, see fig. 1 b).
In particular, the direction of the coil spring 5 and the wire outlet of the winch 2 are required to be consistent with the winding direction of the wire 4, so that when the driving mechanism provides power for the wire pulling mechanism, and the wire pulling mechanism pulls out the wire pulling 4, the coil spring 5 is tightened, namely the coil spring 5 stores energy, and when the driving mechanism stops providing power, the coil spring 5 releases energy, and provides recovery force for the winch 2 in the wire pulling mechanism, so that even if the driving mechanism is in an inactive state, the wire pulling 4 can be automatically wound back on the winch 2 under the action of the coil spring 5 after the corresponding joint (namely the actuating mechanism) bends and stretches, and is always in a tight state (namely the tightened state).
Of course, the installation position of the elastic mechanism can be adjusted according to actual needs, and the elastic mechanism can be installed on a motor, only needs to be connected in parallel with the motor, and can realize the following technical functions that when the driving mechanism stops working (namely stopping boosting; for example, the battery is exhausted or the motor is stopped intentionally), the driving mechanism can still pull the stay wire, so that the stay wire in the stay wire mechanism is in a tight state (namely, a tightening state) in the operation of the exoskeleton mechanism, and the stay wire (for example, a steel wire or a woven belt) is prevented from being in a free loose state.
The invention will now be further described with reference to specific embodiments and accompanying drawings.
Example 1 parallel elastic drives
Referring to fig. 1 a-4, the embodiment of the invention provides a parallel elastic driver, which comprises a motor 1, a wire winch 2, a wire tube fixing seat 3 and a wire 4, wherein the wire winch 2 is fixedly arranged at an output end 6 of the motor 1, the wire tube fixing seat 3 is fixedly arranged on a peripheral shell of the motor 1, the end of the wire 4 is arranged at a wire end mounting groove 201 arranged on the wire winch 2, a coil spring 5 is arranged in the wire winch 2, an outer ear 501 of the coil spring 5 is arranged in an outer ear mounting groove 202 of the wire winch 2, and a central inner ear 502 of the coil spring 5 is fixed with the peripheral shell of the motor 1 through a straight groove 701 arranged on a rotating shaft arranged at the central position of a central shaft end cover 7.
In the embodiment of the invention, the wire winch 2 is fixed at the output end 6 of the motor 1, the wire tube fixing seat 3 is fixed on the outer shell of the periphery of the motor 1, the aluminum end of the wire 4 is arranged at the wire end mounting groove 201 on the wire winch 2, the coil spring 5 is arranged in the wire winch 2, the outer ear 501 of the coil spring 5 is arranged in the outer ear mounting groove 202 of the wire winch 2, and the central inner ear 502 of the coil spring 5 is fixed with the outer shell of the motor 1 through the straight groove 701 on the central shaft end cover 7. The end cap of the coil spring 5 is assembled with the wire winch 2, and serves as both the outer cap of the coil spring 5 and the outer wall of the wire groove.
The wire 4 is wound around the wire winch 2 several turns before use, so that the driver has enough redundant wire to be pulled out when the assisted joint mechanism (or the assisted joint of the wearer) is bent. Meanwhile, attention should be paid to the direction of the coil spring 5 and the selection of the reel outlet to be consistent with the winding direction of the wire 4, and when the wire 4 is pulled out of the wire reel 2, the coil spring 5 tightens and accumulates energy. Thus, even if the motor 1 is in an inactive state, the wire 4 is automatically wound back onto the wire capstan 2 by the coil spring 5 after the joint is bent and stretched, and is always in a tensed state.
Referring to fig. 5a, in order to fully utilize the unidirectional power assisting requirement of the lower limb joint of the wearer (carrying the load 11), the exoskeleton driver 12 may employ a pseudo-direct-drive torque motor (including a planetary gear train reducer with a 6:1 reduction ratio), and the parallel coil spring mechanism is wound with a flexible wire together, and the wire tension is flexibly transmitted to the knee joint of the exoskeleton through the wire tube mechanism (i.e. the wire pulling mechanism 13), so as to realize the separate design of the driver and the actuator (i.e. the driver is not directly arranged at the knee joint of the exoskeleton). The driver, the winch, the battery, the control system and the like with larger mass are arranged above the waist of the wearer, so that the system dead weight of the exoskeleton at the limb position is reduced. Specifically, the parallel elastic driver 12 is mounted on the lumbar region, and the wire is connected to the knee joint wire booster 15 (i.e., actuator) via a wire tube transmission mechanism.
In addition, the technical scheme can efficiently transmit the torque of the exoskeleton driver to the exoskeleton joint with the rigid executing mechanism through the flexible transmission mechanism of the wire tube. The spool pulley and binding device of the rigid mechanism further converts the torque of the exoskeleton driver into the torque of the exoskeleton joint mechanism (e.g., knee-assisted joint mechanism, ankle-assisted joint mechanism) and acts on the adjacent limb of the wearer's corresponding joint with high efficiency, thereby achieving high efficiency assistance. In addition, the technical scheme can realize the assistance of simultaneously driving more than two exoskeleton joint mechanisms (for example, two knee assistance joint mechanisms and two ankle assistance joint mechanisms of two legs) by a single motor.
In some embodiments, please continue to refer to fig. 3, the spool fixing base 3 includes a spool fixing body 301, a spool through hole 302 is formed in the spool fixing body 301, a spool fixing wall 303 is disposed on a surface of the spool fixing body 301, which contacts the motor 1, the wire winch 2 is mounted at an output end of the motor 1 through the spool through hole 302, a wire outlet groove 304 is disposed on a lower side of the spool fixing wall 303, and the central shaft end cover 7 is sealed with the spool fixing wall 303 in a matching manner, so as to protect the wire winch 2.
In some embodiments, as shown in fig. 4, the wire winch 2 includes a wire winch body 203, three mounting holes 204 are formed on the wire winch body 203 near the middle, the wire winch body 203 is connected with the output end 6 of the motor 1 through the mounting holes 204, a wire winch wall 205 is disposed on one surface of the wire winch body 203 (i.e. the wire winch wall 205 encloses a space for placing the coil spring 5), and a wire end mounting groove 201 for mounting the wire end and an outer ear mounting groove 202 for mounting the outer ear 501 of the coil spring 5 are mounted on the wire winch wall 205;
in some embodiments, a coil spring end cap 8 may also be included, the coil spring end cap 8 being cooperatively enclosed with the wire winch wall 205 for protecting the coil spring 5.
In some embodiments, the upper end of the wire winch wall 205 is provided with a plurality of threaded holes 206, the coil spring end cover 8 is correspondingly provided with a plurality of end cover mounting holes 9, and a plurality of bolts penetrate through the plurality of end cover mounting holes 9 to cooperate with the plurality of threaded holes 206 so as to fixedly mount the coil spring end cover 8 on the wire winch wall 205.
In some embodiments, a plurality of central shaft end cover mounting grooves 307 are periodically arranged on the spool fixing wall 303, and the central shaft end cover 7 is matched with the central shaft end cover mounting grooves 307 through a plurality of mounting feet 10 on the central shaft end cover 7 to seal and protect the wire winch 2.
In some embodiments, a wire conduit 305 is mounted corresponding to the wire outlet slot 304.
In some embodiments, a slack adjuster knob 306 is disposed within the wire presentation slot 304.
Referring to fig. 5b and 5d, in some embodiments of the present invention, the exoskeleton lower limb assistance mechanism comprises a driving mechanism, a thigh support 31, a shank support 36 (including a shank upper support 3601 and a shank lower support 3602), wherein the thigh support 31 and the shank support 36 are rotatably connected through a knee joint rotation shaft 21, the shank lower support is rotatably connected with an exoskeleton shoe cover 28 through an ankle joint rotation shaft 29, and the thigh support 31 and the shank support 36 can be fixed on the leg of the wearer through a thigh binding 20 and a shank binding 22, respectively.
An exoskeleton drive mechanism, battery, control circuit, etc. can be placed on the wearer's waist (back side) through waist binding 30, with parallel elastic drives located in the exoskeleton drive mechanism. Thigh wire spool 305a one end is connected on exoskeleton actuating mechanism (i.e. the first end of steel wire), and the other end is down along the thigh, stabilizes on thigh support 31 through mechanisms such as thigh spool end fixing base 32, and the rethread knee pivot 21 (i.e. the second end of steel wire can be through knee joint steel wire top cap 34 with the steel wire pressure on knee joint pivot 21, avoid the steel wire aversion), down along the shank, stabilizes on shank upper bracket 3601 through mechanisms such as the end fixing base 35 of shank spool 305b, and then fixes the steel wire end on shoe cover cantilever 27 (i.e. the third end of steel wire) downwards. Of course, if the exoskeleton actuator only needs to provide assistance to the knee assist joint mechanism (or the wearer's knee), the steel wire may be secured to, for example, the upper portion of the upper leg rest 3601 after passing through the knee joint pivot 21, in this embodiment, without the third end of the steel wire.
In some embodiments, the calf support 36 also includes a calf length adjustment mechanism 23 thereon, which allows the length of the calf support 36 to be adjusted to accommodate wearers of different heights.
Further, referring to fig. 5c, in some embodiments, since the pull wire 4 may transmit the power provided by the driving mechanism to at least one of the actuators, that is, the pull wire 4 has a plurality of force output ends (that is, a plurality of ends 42 connected to the actuators), in order to better distribute the power between the respective actuators, thereby improving the power efficiency, a clutch lock mechanism 37 may be disposed between two adjacent actuators (for example, two power-assisted joint mechanisms), and the clutch lock mechanism is connected to the two actuators through the pull wire, respectively, and when the corresponding power-assisted joint mechanism in the power-assisted exoskeleton (or the power-assisted joint of the wearer) is in a straightened state, the clutch lock mechanism 37 is in an engaged state, so that the power-assisted force outputted by the driving mechanism is transmitted to the two actuators connected to the clutch lock mechanism 37 through the pull wire mechanism, and when the power-assisted joint mechanism (or the power-assisted joint mechanism) is in a curved state, the clutch lock mechanism 37 is in an unengaged state, so that the power-assisted mechanism outputted by the pull wire is transmitted to one of the two actuators (or the closest to one of the two actuators, or the two actuators, and the closest to one of the two actuators is based on the closest relationship between the two actuators.
For example, the clutch lock mechanism 37 may be provided between the knee joint and the ankle joint so that the knee joint and the ankle joint constitute a linked joint, and/or the clutch lock mechanism 37 may be provided between the hip joint and the knee joint so that the hip joint and the knee joint constitute a linked joint.
In some embodiments, referring to fig. 5g and 5i, the clutch lock mechanism 37 includes a clutch lock base 371, a pull wire slider 372 connected to pull wires of two actuators and provided with ratchet teeth 372-1, a sliding pawl 374 engageable with the ratchet teeth on the pull wire slider 372, and a clutch push rod 373 for pushing the sliding pawl 374 to slide to engage with the pull wire slider 372, wherein the clutch push rod 373 and the pull wire slider 372 are both installed in the clutch lock base 371 in a manner of being able to slide up and down along the height direction of the clutch lock base 371, the sliding pawl 374 is installed in the clutch lock base 371 in a manner of being able to slide left and right along the width direction of the clutch lock base 371, and in an initial state (i.e., no external force is applied to the clutch push rod 373), the sliding pawl 374 is not engaged with the pull wire slider 372, so that the pull wire slider 372 can slide up and down along the height direction of the clutch lock base 371, and further the driver is provided to the two actuators, referring to fig. 5g, when the clutch push rod 373 is applied to the clutch lock base 371, the clutch push rod 37 is gradually moved to the actuator 37, and when the clutch push rod 372 is moved to the actuator 37 is gradually moved to the clutch lock mechanism.
In some embodiments, referring to fig. 5j, corresponding wire end mounting slots 3720 may be formed at two ends of the wire slider 372 to mount wire ends of wires connected to two actuators (e.g., wire end 41a of upper wire 4a near the actuator of the actuator and wire end 41b of lower wire 4b far from the actuator of the actuator), so as to connect the two actuators, i.e., the two ends of the wire slider 372 are connected to respective ends of wires connected to the two actuators.
In some embodiments, the wire slider 372 is mounted on one side, such as the right side, of the clutch lock base 371 in a manner to be slidable up and down with respect to the height direction of the clutch lock base 371. Specifically, referring to fig. 5j, a sliding block chute 3711 may be formed on the right side of the clutch locking base 371 along the height direction, and corresponding sliding block end caps 3711-1 are disposed at the upper and lower ends of the sliding block chute 3711, and a wire through hole 3711-2 through which the wire 4 can pass and a wire pipe mounting groove 3711-3 for mounting the end of the wire pipe 305 are formed on the sliding block end cap 3711-1, and of course, the height dimension of the sliding block chute 3711 is greater than the height dimension of the wire drawing slider 372, so as to provide a space for the wire drawing slider 372 to slide up and down.
In some embodiments, the sliding pawls 374 are slidably mounted on the other side, such as the left side, of the clutch lock base 371 with respect to the width direction of the clutch lock base 371. Specifically, referring to fig. 5i and 5j, a pawl slot 3712 may be formed on the left side of the clutch lock base 371 in the width direction, and the rightmost end of the pawl slot 3712 is in communication with the slide slot 3711, and at least one second elastic restoring element 376 is disposed on the slide pawl 374 near the left side (specifically, at least one elastic restoring element mounting slot 3741 for mounting the second elastic restoring element 376 is disposed in the slide pawl 374 in the width direction, a first mounting end cap 376-1 capable of sealing the pawl slot 3712 is disposed at a notch of the pawl slot 3712, and a first guide post 376-2 for mounting the second elastic restoring element 376 is disposed on the first mounting end cap 376-1 at a position corresponding to the second elastic element 376, and at least one limiting bump 3740 is disposed on the slide pawl 374.
In some embodiments, the clutch push rod 373 is also mounted on the clutch lock base 371 in such a manner as to be slidable up and down in the height direction of the clutch lock base 371. Specifically, a push rod chute 3713 penetrating the right side of the pawl chute 3712 may be formed on the clutch lock base 371 near the slider chute 3711, a first elastic restoring element 375 may be installed at the bottom of the push rod chute 3713 (specifically, a second guiding column 375-1 may be fixedly installed at the bottom of the push rod chute 3713 to seal the bottom of the push rod chute 3713 while the first elastic restoring element 375 is installed), and at least one bump chute 3730 for providing a moving path to the limit bump 3740 is provided on the clutch push rod 373, see fig. 5i and 5j.
When no external force acts on the clutch push rod 373, the first elastic restoring element 375 (e.g., a spring) installed in the clutch locking base 371 pushes the clutch push rod 373 upward, and at this time, the limit protrusion 3740 on the sliding pawl 374 is located at the first limit position of the moving path provided by the protrusion chute 3730 on the clutch push rod 373 (e.g., the leftmost side of the protrusion chute 3730, see fig. 5 g), so that the sliding pawl 374 compresses the sliding pawl 374, and the second elastic restoring element 376 (e.g., a spring) installed in the clutch locking base 371, i.e., the sliding pawl 374 is located at the unlocking position in the clutch locking base 371, thereby separating the sliding pawl 374 from the wire slider 372, and the clutch locking device is in the releasing state. In this state, the wire slider 372 can move up and down freely along the height direction of the clutch lock base 371, so that when the driver provides the assistance force, the wire 4a at the upper end of the clutch lock base 371 transmits the assistance force provided by the driver to the wire slider 372, and the assistance force is transmitted to the lower wire 4b by the wire slider 372, thereby driving the lower wire 4b to move up and down, and further transmitting the assistance force to an actuator (e.g., ankle assistance joint mechanism) connected to the lower wire 4 b.
When an external force F is applied to the clutch push rod 373, the clutch push rod 373 compresses the first elastic restoring member 375, the clutch push rod 373 slides down as a whole, so that the bump chute 3730 releases the limit bump 3740 on the sliding pawl 374 (for example, the limit bump 3740 slides rightward to a second limit position along the moving track of the bump chute 3730, such as the rightmost side, see fig. 5 h), and simultaneously, the sliding pawl 374 slides rightward to an engaged position under the action of the two second elastic restoring members 376, so that the pawl on the sliding pawl 374 is engaged with the ratchet on the wire slider 372, that is, the clutch locking mechanism is engaged/locked. After the clutch locking mechanism is engaged, the wire slider 372 cannot move upwards any more, that is, the power assistance provided by the driving mechanism is only transmitted to the actuator connected to the upper end wire 4a (i.e., the actuator close to the driver), but not transmitted to the actuator connected to the lower end wire 4b (i.e., the actuator far from the driver).
Further, referring to fig. 5h, the ratchet teeth 372-1 on the wire slider 372 are wedge-shaped, so that when the wire slider 372 is under the pulling force of the lower wire 4b, the wedge surface of the ratchet teeth 372-1 still can push the sliding pawl 374 to move toward the first limit position, such as to the left, so that the wire slider 372 can move toward the lower wire 4 b.
Of course, besides applying the external force F to the clutch push rod 373, a solenoid valve control manner may be adopted, for example, a battery valve is disposed above the clutch push rod 373, and at least one magnetic rod is embedded in the top of the clutch push rod 373, when the battery valve is energized, the polarity of the battery valve is the same as that of the magnetic rod, so as to push the magnetic rod to move away from the lower end of the battery valve, further push the clutch push rod 373 to slide downward, so that the sliding pawl moves to the locking position (or the second limit position) and gradually engages with the pull wire slider, and when the battery valve is de-energized, the clutch push rod moves upward under the action of the first elastic reset element, so as to drive the sliding pawl 374 to move to the unlocking position (or the first limit position), and further separate the sliding pawl 374 from the pawl on the pull wire slider 372, i.e. the clutch locking mechanism 37 is in an unengaged state.
Specifically, referring to fig. 5c, in some embodiments of the present invention, the clutch locking mechanism is disposed between the knee joint power-assisted joint mechanism and the ankle joint power-assisted joint mechanism (hereinafter referred to as knee power-assisted joint mechanism and ankle power-assisted joint mechanism), specifically, a clutch locking mechanism 37 is disposed between the second end (or the upper end pull wire 4 a) of the steel wire and the third end (or the lower end pull wire 4 b) of the steel wire, and when the knee joint is bent to a greater extent by the clutch locking mechanism, the clutch locking mechanism enters a separated state, and the transmission of the pulling force to the ankle power-assisted joint mechanism is stopped, so that the assistance generated by the exoskeleton driver is concentrated at the knee power-assisted joint mechanism to help the wearer to step up and climb, and when the knee joint bending degree is reduced to a certain angle, the clutch locking mechanism reenters into a joint state, and resumes the conduction of the pulling force to the ankle power-assisted joint mechanism, thereby realizing the assistance to the ankle joint. In other words, by adding the clutch locking mechanism between the tail ends of the stay wires between two adjacent actuating mechanisms, the assistance force can be better distributed between the knee joint and the ankle joint, and the assistance efficiency of the exoskeleton driver for providing assistance force for lower limbs is improved.
Still further, in some embodiments, the stay wire in the stay wire mechanism may be divided into three branches by three stay wire channels in the power-assisted exoskeleton, wherein two branches are symmetrically disposed on the left and right sides of the corresponding power-assisted joint mechanism in the power-assisted exoskeleton, and the other branch is disposed directly in front of or directly behind the power-assisted joint mechanism. Of course, the stay wire can be divided into two branches or more branches according to actual needs. Referring to fig. 5d to 5f, a knee joint assist mechanism will be described as an example.
Specifically, the knee joint mechanisms include at least three wire channels (i.e., pull wire channels) including a left side shaft 21a positioned on the left side of the wearer's knee, a right side shaft 21b positioned on the right side of the wearer's knee, and a knee wire chute 38 positioned on the front of the wearer's knee. The steel wires (or the wires 4 such as the woven belt) are divided into three paths to pass through the knee joint, when the driver 12 pulls the steel wires, the balanced assistance can be provided for the knee joint of a wearer by the steel wires of the left rotating shaft 21a and the right rotating shaft 21b, and the large assistance can be provided for the rotation of the knee joint of the wearer by the steel wires on the front surface of the knee joint. This is because the assistance from the wires on the left and right side shafts provides less assistance because of the small displacement generated during knee joint rotation, while the wires located in the knee joint front knee joint wire chute 38 of the wearer provide more assistance because of the large displacement generated during knee joint rotation. The knee joint structure comprehensively considers the power assisting magnitude (provided by the steel wires of the knee joint front knee joint steel wire sliding groove) and the power assisting balance (provided by the steel wires of the knee joint left and right side rotating shafts), and can improve the use experience of an exoskeleton mechanism wearer.
Referring to fig. 5e and 5f, in some embodiments of the present invention, the steel wire channel of the knee joint mechanism is disposed on the front side of the knee joint (including the knee joint steel wire sliding slot 38), the left and right side rotating shafts 21a, 21b of the knee joint mechanism are gear mechanisms, and the steel wire channel from the thigh support 31 to the knee joint steel wire sliding slot 38 to the calf support 36 can be covered by the cover 40 to prevent the steel wire from shifting. The steel wire is coiled at the power-assisted joint pulley 39 of the knee power-assisted joint mechanism for a plurality of times through the movable pulley mechanism, so that the transmission ratio of the steel wire from the exoskeleton driver to the knee power-assisted joint mechanism is changed, and the power-assisted torque amplification at the knee power-assisted joint mechanism is realized.
Embodiment 2 method for detecting drive State of parallel elastic drivers
Based on the parallel elastic driver, the invention also provides a driver control method of the power-assisted exoskeleton, wherein the driver is any one of the drivers, and specifically, the control method comprises the following steps:
The method comprises the steps of acquiring and identifying the current working state of the driver, wherein the working state of the driver is controlled by a controller, so that the current working state type of the driver, particularly follow-up, preparation or power assisting, can be directly acquired from the controller;
If the working state of the driver is identified to be follow-up, acquiring the current joint bending angle and joint bending angular velocity of the power-assisted joint mechanism, judging whether the power-assisted state is needed currently according to the joint bending angle and joint bending angular velocity and a preset power-assisted threshold angle and bending threshold angular velocity, and if so, setting the current working state of the driver from the follow-up state to a preparation state;
If the current working state of the driver is a preparation state, acquiring the current joint expansion angular speed and joint bending angle of the power-assisted joint mechanism, judging whether the power-assisted joint mechanism needs power assistance or not according to the joint expansion angular speed and joint bending angle of the power-assisted joint mechanism, a preset expansion threshold angle and a preset failure threshold angle;
And judging whether the power assisting needs to be canceled currently according to the knee joint bending angle and a preset failure threshold angle, or the knee joint bending angular velocity and a preset maximum extending angular velocity, or the knee joint bending angular velocity and a preset bending threshold angular velocity, if so, setting the current working state of the driver from the power assisting state to a follow-up state, and setting the output torque of the driver to 0.
In some embodiments, the operating state of the motor in the drive is controlled by the controller, and thus the current operating state can be obtained directly from the memory module of the controller and specific types, e.g., follow-up, preparation, and assist, can be identified.
The embodiment of the invention is a driving state detection method of parallel elastic drivers, please refer to fig. 6 and 7, and the driving state is determined according to the following manner:
if the knee joint angle is greater than the power-assisted threshold angle and the knee joint bending angular velocity is greater than the bending threshold angular velocity, judging that the driving state is ready, wherein the motor moment=0;
If the knee joint stretching angular velocity is greater than the stretching threshold angular velocity and the knee joint angle is greater than the failure threshold angle, judging that the driving state is power assisting, wherein the motor moment=T ref;
if the knee joint angle < failure threshold angle or knee joint extension angular velocity > maximum extension angular velocity or knee joint flexion angular velocity > flexion threshold angular velocity, the driving state is judged to be follow-up, and the motor torque=0.
Further, after judging the driving state, judging whether the user modifies Tref or each threshold parameter;
if yes, judging whether the system is abnormal or not after adjusting the related threshold value;
if not, directly judging whether the system is abnormal;
if the system is abnormal, restarting or alarming;
If the system is not abnormal, the driving state is continuously judged according to the mode.
In specific implementation, the detection method can be realized by installing a controller and monitoring the state of the motor. The flow chart is shown by referring to the figure, the motor is initialized before the start, so that the motor state is follow-up, the moment is 0, the motor gradually becomes ready in the follow-up process, then the motor is assisted, and finally the motor returns to the follow-up.
More specifically, FIG. 7 is a simplified control scheme of a knee joint assist exoskeleton mechanism in some embodiments of the present invention. The exoskeleton evaluates and judges the working state of the exoskeleton through an embedded angle sensor (angular velocity and angular acceleration obtained after difference) of the torque motor and an armature current sensor (motor output torque obtained after formula conversion). Meanwhile, the controller sets three working states of the motor, namely follow-up, preparation and power assistance.
The judging variables of the control system comprise knee joint angles (obtained by converting motor angles through a system total transmission ratio), knee joint bending angular velocities (obtained by converting motor rotation angular velocities through the system total transmission ratio), note that the knee joint bending angular velocities and knee joint stretching angular velocities are actually the same parameters, and are only opposite in movement direction, and in order to avoid the comparison of the magnitudes of sign parameters during single-parameter representation, two positive values and negative values which belong to the representation of the motor rotation angular velocities are adopted in the flow chart of fig. 7. The assist threshold angle, the failure threshold angle, the bending threshold angular velocity, the expansion threshold angular velocity, and the maximum expansion angular velocity are judgment threshold parameters set by the control system, and T ref is the output torque of the motor set by the control system during assist.
The system operation process is described as follows, after the system is started, the system is initialized, the angle of rotation of the knee joint is set to be 0 degrees, the motor state is set to be follow-up, the motor moment is set to be 0Nm, and then the system enters the main circulation. In the main cycle, firstly judging the state of a motor:
in the "follow-up" state, the motor follows the knee joint of the wearer to move arbitrarily, and when the knee joint bending angle is greater than the set power-assisted threshold angle and the knee joint bending angular velocity is greater than the set bending threshold angular velocity, it is indicated that the knee bending degree has reached the bending degree to which we want power assistance, and is still in the leg bending motion at this time, for this reason, the motor state is set to "ready", and the motor moment is set to 0Nm.
In the "ready" state, if the angular velocity of extension of the knee joint is greater than the threshold angular velocity of extension, this indicates that the knee joint has been converted from flexion to extension and the previous flexion has exceeded the set assist threshold angle (and therefore has not entered the "ready" state), the motor state is set to "assist" and the motor is caused to output the assist torque of T ref as long as the knee joint flexion angle is greater than the failure threshold angle. The failure threshold angle is a set value larger than 0 degrees and smaller than the power-assisted threshold angle, and aims to cancel power assistance in advance when the knee joint approaches to an upright state, so that the problem that the knee joint of a wearer is not completely in the upright state (the knee joint angle is slightly larger than 0) in walking gait, and the motor is always in the power-assisted state, and the knee joint of the wearer is difficult to bend the leg again to achieve the next gait is avoided.
In the "power assisted" state, the motor is continuously outputting a torque T ref to the knee joint. At this time, if the knee joint angle is smaller than the failure threshold angle, the knee joint of the wearer is close to vertical under the assistance action, and the motor assistance is canceled, and if the knee joint expansion angular speed is larger than the maximum expansion angular speed, the load of the knee joint is possibly lighter (or the exoskeleton is not correctly worn on the knee joint of the wearer and belongs to no-load movement), and the knee joint of the exoskeleton reaches the maximum expansion angular speed rapidly with the assistance of the motor assistance. This condition indicates that the human-machine coupling system is likely to be in a light load state, and such a large assistance is not required. And in order to avoid a state in which the knee joint becomes excessively stretched after reaching the erect state due to an excessively high stretching speed, the "maximum stretching angular speed" is set.
Furthermore, if the knee joint bending angular velocity is greater than the bending threshold angular velocity, it means that although the motor is assisting the knee joint of the wearer to perform the extension motion in this state, the knee joint is actually performing the bending motion, and the bending motion velocity has exceeded the bending threshold angular velocity, meaning that in this state it is likely that the wearer has changed the motion intention, and wants to further bend the leg. Under all three conditions, the motor state is reset to the "follow-up" state and the motor torque is set to 0Nm. It should be noted that if the motor state is reset to the "follow-up" state due to the knee joint bending motion in the power-assisted state, the system will determine whether the knee joint bending angle is still greater than the power-assisted threshold angle through the statement in the follow-up state in the next cycle, and if so, the motor resets to the power-assisted state not "ready". Therefore, after the wearer is assisted again, the movement intention is changed, the leg bending is continued, the motor is driven by the assistance force to prepare, and the assistance force can be provided for the knee joint in the next stretching movement.
It is worth noting that the "maximum angular extension speed" is set to determine whether the system is in a light load state, and avoid excessive extension movement caused by too high extension speed of the knee joint. However, the advanced control strategy can also be used for reversely solving the load state of the system through the difference of the angular speeds, namely the angular acceleration, and dynamically adjusting the T ref of the motor moment in each power assisting process through the change of the load state. Therefore, the system can dynamically change the maximum power-assisted torque of each gait according to different load states, and the power-assisted strategy of the exoskeleton is more intelligent.
After judging the state of the motor, the system further judges whether the user changes the T ref or each threshold parameter through the keyboard or remote control input, if so, the corresponding values of the various threshold parameters are adjusted, otherwise, the system enters the next cycle after judging the normal operation of the playing system.
If the system judges that the abnormality occurs, restarting is performed, and then the working state is re-entered.
The technical scheme provided by the invention is mainly used for solving the technical problems of most of active power-assisted exoskeleton 'too rigid' or 'too soft' in the prior art. "too rigid" means that the hydraulic push rod or the gear motor is directly placed at the joint. Although the layout can efficiently transmit the driving torque to the joints of the wearer, the swing inertia of the lower limbs of the wearer is seriously increased, the movement gait dynamics of the man-machine coupling system are deteriorated, and people feel that the joints are assisted when using the man-machine coupling system, but the exoskeleton is heavy and can more tired of the wearer. The "too flexible" means that the driver is fully arranged above the waist, and the torque of the motor is converted into the wire tension to act on each joint of the wearer in a mode of flexible binding and wire driving on the lower limbs of the wearer in a large amount. Although the layout can influence the swing inertia of the lower limbs of the wearer less, the excessively soft binding leads to excessively low equivalent rigidity of a human-computer interaction interface, the motor output torque is converted into the deformation for binding more, and the excessively large pulling force can also cause the sliding of the flexible binding on the limbs, so that the output peak value of the power assisting is obviously limited. The technical scheme adopted by the invention combines the steel wire flexible transmission mechanism and the joint rigidity actuating mechanism, is a rigid-flexible knee joint power-assisted exoskeleton, and can take the advantages of reducing the swing inertia of limbs and realizing the high-efficiency transmission of the rigid exoskeleton by the flexible exoskeleton into consideration.
In addition, considering that the steel wire is a nonlinear element capable of efficiently transmitting tensile force but not thrust force, the steel wire may be in a free and loose state under the state that the motor does not assist or does not work, and the state is not beneficial to the active exoskeleton to judge the current motion state of the joint, and the steel wire at the winding roll is possibly caused to be mutually wound to cause mechanical failure. Therefore, the present invention proposes that the applicant proposes a scheme of connecting drivers in parallel (fig. 8) with an elastic mechanism (i.e. "parallel elastic drivers"), by adding elastic elements in the mechanism, it is ensured that the wire rope can be tensioned by the elastic elements at any time, thereby avoiding the problem of system uncertainty caused by slack of the wire. Compared with a driver without an elastic mechanism (when a motor does not work, the steel wires at the joint end and the winding roll end are in a loose state) or a driver serial elastic mechanism scheme (the addition of a serial spring divides the steel wires into two sections of independent line segments, so that the complexity of a system is increased, a pressure spring is connected between the motor winding roll and a knee joint steel wire pulley in series, and the steel wires at the joint end are always in a tensioning state, but the steel wires at the winding roll end are still in a free loose state when the motor does not work), the scheme of the driver parallel elastic mechanism can enable the mechanism to always keep redundant steel wires tightly wound on the winding roll in a state that the motor does not assist or does not work, further system uncertainty caused by the flexibility of the steel wires is avoided, meanwhile, an actuating mechanism of an exoskeleton is simplified as much as possible, the influence on swing inertia of a lower limb is reduced, the motion sensitivity of a man-machine system is improved, in addition, the steel wires are pulled after the torque of the parallel elastic element and the motor are overlapped, and the peak output torque of the driver is further improved.
Example 3 centrifugal clutch based parallel spring drive without motion damping
As is well known, because the assisted joint of the human body in daily movement not only needs a small part of movement occasions with a large amount of assistance, but also needs a large amount of movement occasions without assistance, for example, the knee joint of the human body needs a large amount of assistance when the human body goes up a step and squats deeply, but the human body walks on a level road in more times, no obvious assistance is needed by the exoskeleton, and the exoskeleton is not hopefully used for bringing large damping to the walking of the wearer. However, in the above embodiment, since the capstan 2 in the wire pulling mechanism is always connected to the output end 6 of the torque motor 1 (for example, the output disc of the torque motor), i.e., the driving mechanism is directly connected to the capstan 2 in the wire pulling mechanism, the wire will also reciprocate with the torque motor 1 when no assistance is required, and at this time, since the torque motor 1 is not energized, it is converted into a damping member. That is, the joint of the wearer experiences constant motion damping when not moving with assistance. While this motion damping may allow the drive mechanism, such as a motor, to reverse the battery charge, the wearer's motion experience of wearing the power-assisted exoskeleton is more negative, i.e., has continuous motion damping, thereby reducing the wearer's motion experience.
In view of this, the present invention also provides a parallel elastic driver without motion damping in a power-assisted exoskeleton, which can avoid or alleviate the problem that a driving mechanism (such as a torque motor) is driven by a capstan in a wire pulling mechanism to generate motion damping when the parallel elastic driver is not power-assisted.
The parallel elastic driver without motion damping comprises various components in the parallel elastic driver, such as a driving mechanism, a wire pulling mechanism and an elastic mechanism, wherein the connection relation among the various components can be referred to the connection relation among the various components in the parallel elastic driver, which is not repeated herein, referring to fig. 9a and 9b, except that the parallel elastic driver without motion damping further comprises a centrifugal clutch 47 arranged between the wire pulling mechanism and the driving mechanism, when the driving mechanism (such as the torque motor 1) provides assistance force, the centrifugal clutch is engaged, so that the driving mechanism is connected with the wire pulling mechanism (such as the winch 2 in the wire pulling mechanism is synchronously and rotatably connected with the output end 6 of the torque motor 1), when the driving mechanism (such as the torque motor 1) stops providing assistance force, the centrifugal clutch 47 is released, so that the connection between the driving mechanism and the wire pulling mechanism is disconnected, the driving mechanism is prevented from being converted into a damping piece to generate motion damping, and meanwhile, the elastic mechanism provides loose force to the wire pulling mechanism, so that the wire pulling mechanism is prevented from being in a loose state, and the wire pulling mechanism is prevented from being in a free state of winding and being caused by the wire pulling mechanism.
For example, when the torque motor 1 is not power-assisted (i.e. is not powered and is not rotated), the winch 2 in the wire pulling mechanism can freely pull out and retract the wire under the action of the coil spring 5 (i.e. the elastic mechanism), and because the centrifugal clutch 47 is not engaged (i.e. is in a released state), i.e. the connection between the torque motor 1 and the winch 2 of the wire pulling mechanism is disconnected, the winch 2 is not affected by motor damping, accordingly, after the power-assisted exoskeleton is worn by a wearer, the user experience is greatly improved like a passive power-assisted joint mechanism with an elastic energy storage element (e.g. a parallel spring).
In some embodiments, the centrifugal clutch 47 includes a pawl holder 60, a ratchet 208, at least one pawl 59, and at least one elastic restoring member 58, wherein the ratchet 208 is rotatably coupled coaxially with the capstan 2 in the wire pulling mechanism (for example, the ratchet 208 may be directly fixed to the capstan 2 or a pawl groove may be directly provided on an inner circumferential surface of the capstan 2 to obtain a capstan ratchet), the pawl holder 60 is rotatably coupled synchronously with the output end 6 of the torque motor 1 (for example, the pawl holder 60 may be fixed to the output end of the torque motor 1 by a fixing member such as a screw), a first end of each elastic restoring member 58 is fixed to the pawl holder 60, a second end of each elastic restoring member 58 is coupled to the pawl 59 (i.e., each elastic restoring member 58 corresponds to one pawl 59), the at least one pawl 59 is uniformly mounted on the pawl holder 60 in a rotatable manner with respect to the pawl holder 60, and a rotation axis of each pawl 59 is not coaxial with a rotation axis/center axis of the pawl holder 60.
In this embodiment, since the rotation shaft of each pawl 59 is not coaxial with the central axis of the pawl seat 60, that is, an eccentric structure is adopted to mount the pawl 59, when the torque motor 1 provides assistance, that is, when the torque motor 1 drives the pawl seat 60 to rotate synchronously, a certain centrifugal force is generated, and when the rotation speed of the torque motor 1 reaches a certain threshold value, each pawl 59 expands outwards in a direction away from the central axis of the pawl seat 60 under the action of the centrifugal force and gradually engages with the ratchet 208, so as to connect the motor with the wire pulling mechanism, and during the outwards expansion of the pawl 59, the pawl 59 stretches the elastic restoring member 59 (in an initial state, the elastic restoring member 59 has a certain pretightening force), so that the elastic restoring member 59 stores energy, and when the torque motor 1 stops assistance, that is, when the motor stops rotating, the pawl 59 gradually breaks away from the ratchet 208 in a direction close to the central axis of the pawl seat 60 under the action of the centrifugal force, so that the pawl 59 gradually breaks away from the ratchet 208, thereby disconnecting the motor from the wire pulling mechanism.
In this embodiment, a centrifugal clutch 47 is disposed between the wire pulling mechanism and the driving mechanism, and the centrifugal clutch 47 is always in a state of releasing (i.e. not engaged) under the normal state that the motor is not energized, so that the forward and reverse movement of the winch is not affected by the damping of the motor, i.e. the wire pulling mechanism and the driving mechanism are disconnected, the driving mechanism, such as the motor, is prevented from being converted into a damping member, so that the wearer feels that the free movement of the joint is not limited, the centrifugal clutch has higher working reliability, simple structure and reduces the system cost and the control complexity, but when the motor starts to energize/start to assist, the motor is in a releasing state, so that the motor can accelerate under the condition of no load, the centrifugal clutch utilizes the accelerating rotation movement, so that the pawl opens under the centrifugal force, and locks a ratchet groove (i.e. the pawl is engaged with the ratchet) on the winch, thereby connecting the wire pulling mechanism with the driving mechanism, and transmitting the output torque of the driving mechanism to the winch of the wire pulling mechanism, so as to drive the actuator to move, thereby realizing the assisting.
The parallel elastic driver without motion damping in the embodiment not only inherits the advantages of the parallel elastic driver in the embodiment, for example, the first aspect realizes the separation of the driver and the executing mechanism, so that the driver such as a heavier driver controller, a battery and the like can be integrated to the back of a wearer through a stay wire mechanism such as a stay wire tube or a braiding belt, namely, a soft transmission form, thereby reducing the weight of the executing mechanism, further reducing the increase degree of swing inertia of limbs of the wearer, enabling the wearer to feel lighter when wearing the device, the second aspect can quickly transfer the torque of a motor to an executing end of a joint when assistance is needed, and has small assistance time delay, and the third aspect enables the stay wire such as a steel wire or a braided bag in the stay wire mechanism to always maintain a tight state when the driving mechanism is assisted and when not assisted, so as to avoid the problem of mechanical failure caused by the stay wire winding and even cause safety accidents, but also can avoid the problem that the driving mechanism (such as a motor) is converted into a winch to move along with the stay wire mechanism when the driving mechanism is not assisted, so as to cause free movement of joints of the wearer, thereby guaranteeing the free movement of the joints of the wearer, and guaranteeing the free movement of the joints when the driving mechanism is not needed.
In some embodiments, referring to fig. 9a to 9c, the pawl seat 60 is ring-shaped, and is attached to the back surface of the motor 1 and can be fixed to the output end 6 of the motor 1 by a fixing member such as a screw, so as to realize synchronous rotation connection with the motor 1, and three pawl rotating shafts 6001 are uniformly distributed on the front surface of the pawl seat 60 opposite to the back surface, away from the central axis, along the circumferential direction, and a pawl seat limiting block 6002 is disposed beside each pawl rotating shaft 6001. And a first end of each pawl 59 is provided with a corresponding rotation hole 5901 such that when the rotation hole 5901 is mated with the pawl rotation shaft 6001, the pawl 59 is rotatable about the pawl rotation shaft 6001 (i.e., the pawl 59 is rotatably mounted to the pawl seat 60 relative to the pawl seat 60), and a second end of the pawl 59 remote from the pawl rotation shaft 6001 is provided with a ratchet end face (including a front end face 5903 of a pawl tip and a second arcuate outer end face 5905) that mates with the ratchet teeth slot 208-1 on the ratchet 208. Further, the first end of the pawl 59 is further provided with a pawl limiting bump 5902 capable of being matched with a pawl limiting block 6002 of the pawl seat 60, which is close to the pawl rotating shaft 6001, so that when the pawl 59 expands outwards in a direction away from the central axis of the pawl seat 60 under the action of centrifugal force, the pawl limiting bump 5902 of each pawl 59 is matched with its corresponding pawl limiting block 6002, and at this time, the ratchet end face of the second end of the pawl 59 is also matched with a ratchet groove 208-1 of the ratchet 208, that is, the pawl 59 is meshed with the ratchet 208, see fig. 9d.
In an initial state (i.e. the pawls of the centrifugal clutch are not engaged with the ratchet teeth), three pawls 59 are circumferentially arranged along the pawl seat 60, and one pawl seat projection 6002 is spaced between adjacent pawls 59 (specifically, a front end face 5903 of a second end of one pawl 59 is attached to a first side face 6002-1 of the pawl seat stopper 6002 away from a pawl rotation axis 6001 near the pawl seat, a first end of the other pawl 59 is attached to a second side face 6002-2 of the pawl seat stopper 6002 near the pawl rotation axis 6001 near the pawl seat stopper 5902, and an envelope/boundary line formed by boundary lines of the three pawls 59 is located within an outer circle surrounding range of the annular pawl seat 60 (preferably, a second arc-shaped outer end face 5905 of the second end of the pawl 59 away from a center of the pawl seat 60, and a first arc-shaped outer end face 5906 of the pawl seat stopper 5902 away from the center of the pawl seat 60 are all inscribed with an outer circle of the pawl seat 60), see fig. 9b and 9c;
when the pawl 59 engages with the ratchet wheel 208 (i.e., the pawl 59 rotates counterclockwise about the corresponding pawl rotation axis 6001 by an angle θ and mates with the ratchet tooth slot 208-1 on the ratchet wheel 208) under centrifugal force, the inner end surface 5907 of the pawl stop tab 5902 abuts against the pawl seat stop 6002, see fig. 9d.
In this embodiment, the pawl 59 is disposed near the first end of the pawl rotation shaft 6001 and a pawl seat stopper 6002 is disposed beside the pawl rotation shaft 6001, so that the maximum angle rotated by the pawl 59 (i.e. the maximum angle rotated by the pawl 59 about the pawl rotation shaft 6001 when the pawl 59 is engaged with the ratchet 208) is defined by the pawl stop bump 5902 and the pawl seat stopper 6002.
In some embodiments, each elastic restoring member 58 is fixed at one end to the pawl seat 60 and is fixed at the other end to the pawl 59 near the pawl rotation axis 6001.
In this embodiment, the winch 2 in the wire pulling mechanism is not directly connected to the output disc 6 of the motor 1, but the centrifugal clutch 47 is connected to the output disc 6 (i.e., the output end) of the motor 1 and the input end of the wire pulling mechanism, respectively. Specifically, by providing a winch mount for mounting the winch 2, the winch mount is fixed to the main body of the motor 1, and then the winch 2 is rotatably mounted on the winch mount with respect to the winch mount. For example, the capstan mount may employ a second bearing housing 51 fixed to the main body of the motor 1, and the second bearing housing 51 is provided with a second bearing 61 that is engageable with a shoulder of the capstan 2, and the second bearing housing 51 is provided with a through hole for placing the pawl mount 60 in the centrifugal clutch in correspondence with the output disc 6 of the motor 1, so that the pawl mount 60 is mountable at the center of the second bearing housing 51 and directly connected to the output disc 6 of the motor 1 in a synchronous rotation, and the capstan 2 of the wire pulling mechanism is mounted on the second bearing housing 51 by a shoulder engagement (specifically, the second bearing 61 bearing shoulder 207 is provided on the capstan 2) and is located above the pawl mount 60.
Further, in order to protect the centrifugal clutch and capstan 2, a pawl end cap 57 may be provided on the pawl seat 60. Specifically, a plurality of mounting posts/holes for mounting the pawl end cap 57 may be provided on the pawl seat 60 so that the pawl end cap 57 may be mounted on the pawl seat 60 by fasteners such as screws or the pawl end cap 57 may be secured to the capstan 2 in the wire pulling mechanism.
In some embodiments, the capstan 2 is mounted with the above elastic mechanism on a side far from the centrifugal clutch (or above the capstan 2), specifically, the elastic mechanism includes a wrap spring mounting seat 50 and a wrap spring 5 mounted at the center of the wrap spring mounting seat 50, wherein the wrap spring mounting seat 50 is fixed on the wire stem 3, and an inner ear of the wrap spring 5 is mounted in an inner ear mounting groove provided on the capstan 2, and an outer ear is fixed in an outer ear mounting groove provided on the wrap spring mounting seat 50.
Further, the elastic mechanism further includes a coil spring end cap 8 provided on the coil spring mount 50 for protecting the coil spring 5. Specifically, the center of the coil spring end cap 8 is provided with a first bearing 55, i.e., the coil spring end cap 8 is mountable on the capstan 2 via the first bearing 55 such that the capstan 2 is rotatable relative to the yellow end cap 8.
Referring to fig. 9c, when the motor 1 rotates clockwise, the pawl 59 rotates counterclockwise about the pawl rotation axis 6001 due to centrifugal force, i.e., the pawl 59 expands outwardly in a direction gradually away from the central axis of the pawl holder 60 and gradually engages with the pawl groove 208-1 of the ratchet 208 on the capstan 2, thereby locking the motor 1 and the capstan 2, and further rotating the capstan 2 clockwise under the driving of the motor 1, at this time, the wire 4 is retracted and transmits a pulling force to the actuating end to achieve power assistance;
When the motor 1 stops rotating, under the action of the pull wire 4 during the movement of the actuating mechanism, the winch 2 rotates clockwise by a certain small angle, so that the pawl 59 is retracted into the pawl seat 60 under the tension of the elastic reset piece 58, at this time, the centrifugal clutch is disengaged, i.e. the connection between the winch 2 and the motor 1 is disconnected, and the winch 2 can rotate clockwise or anticlockwise freely along with the pull wire 4, i.e. the centrifugal clutch 47 returns to the initial state.
Referring to fig. 9e, in order to avoid the situation that the gravity of the pawls 59 expands by different degrees to each pawl 59 due to different mechanical properties of each elastic restoring member, such as tension springs, and different height positions, so that partial pawl engagement occurs and other pawls 59 are not engaged successfully, the present invention further provides another parallel elastic driver, which includes the components of the above embodiments, except that a synchronizing gear is disposed at the center of the pawl seat 60 in the centrifugal clutch of the parallel elastic driver of the present embodiment, and a first incomplete gear 76 capable of being engaged with the incomplete gear is disposed at one side of each pawl 59 corresponding to the synchronizing gear, so that when the pawl 59 rotates around its rotation axis 6001, each pawl 59 realizes synchronous motion through the corresponding first incomplete gear 76 and the synchronizing gear, thereby ensuring that all eccentric ratchet gears 59 can be engaged with the ratchet 208 at the same time.
In some embodiments, the synchromesh includes three second incomplete gears 75 circumferentially distributed thereon, and each second incomplete gear 75 corresponds to a first incomplete gear 76 on one pawl 59.
Of course, in other embodiments, the centrifugal clutch may be a multi-plate friction clutch actively controlled by a solenoid valve, or may be a passive clutch that is engaged and disengaged using physical and mechanical principles.
As described above, the parallel elastic driver in each of the above embodiments, when the driving mechanism such as the motor 1 is not operated, the centrifugal clutch 47 is not engaged, that is, the connection between the wire pulling mechanism and the driving mechanism is disconnected, so that the wire pulling 4 in the wire pulling mechanism only drives the winch 2 to rotate, at this time, the driving mechanism such as the motor 1 is not converted into a damping member, so that the forward and reverse rotation of the winch 2 can be very flexible, and the elastic mechanism such as the coil spring 5 connected in parallel with the winch 2 can retract the redundant wire at any time, while when the driving mechanism such as the motor 1 is operated, the pawl 59 in the centrifugal clutch 47 is engaged with the ratchet 208 on the winch 2 under the action of the centrifugal force, that is, the driving mechanism is connected with the wire pulling mechanism, so that the torque of the driving mechanism such as the motor 1 can be directly transferred to the winch 2, and the wire pulling is retracted into the driver, so that the transmission efficiency is high, and the corresponding time is short.
However, since the centrifugal clutch 47 is engaged by centrifugal force, that is, the centrifugal clutch 47 has a certain rotational speed for a certain time (such as a few seconds or a few milliseconds) before being engaged (or clutched), and the capstan 2 in the wire pulling mechanism is at rest or not moving with a high probability, even in the process of reverse rotation, at the moment of engaging the centrifugal clutch 47, the motor 1 and the capstan 2 are subjected to a large impact force, the impact force of the capstan 2 is further transmitted to the exoskeleton actuator, so that the limbs of the wearer feel sudden impact assistance, and the pawl tip of the centrifugal clutch 47 and the edge of the ratchet slot 208-1 of the ratchet 208 are also easy to wear under the impact action, thereby reducing the service life of the device.
In view of this, the present invention also provides a serial-parallel elastic driver, which comprises the components of the parallel elastic driver in the above embodiments, such as the centrifugal clutch 47, the wire pulling mechanism, the elastic mechanism and the driving mechanism, except that the serial-parallel elastic driver in the embodiment of the present invention further comprises an elastic buffer component connected in series with the input end (such as between the wire tube 305 and the wire tube fixing seat 3 in the wire pulling mechanism) or the output end (such as between the wire pulling end of the wire pulling mechanism and the executing mechanism);
When the driving mechanism provides power assistance, the centrifugal clutch is engaged to connect the driving mechanism with the wire pulling mechanism, and the elastic buffer part is used for relieving impact force caused by the engagement moment of the centrifugal clutch;
when the drive mechanism stops providing assistance, the centrifugal clutch disconnects the drive mechanism from the pull wire mechanism and the elastic mechanism provides the pull wire mechanism with the recovery force.
In some embodiments, the elastic buffer is a compression spring 48, specifically, referring to fig. 10, the compression spring is disposed before the pull wire 4 enters the spool 305 (for example, by disposing a compression spring accommodating groove 81 on the spool fixing seat 3), the end 80 of the spool 305 is assembled on a perforated plug that can slide along the compression direction of the compression spring 48, so that when the centrifugal clutch engagement moment suddenly applies an increased pull wire retracting moment to the winch 2 and the actuator is subjected to a larger resistance (for example, the gravitational potential energy of the wearer needs to be lifted), the pull wire 4 presses the spool 305 to compress the compression spring 48 in series, and as the compression stroke of the compression spring 48 increases, the reverse pressure of the compression spring 48 to the spool 305 also gradually increases, thereby gradually increasing the assisting moment of the actuator.
In this embodiment, the end 80 of the spool 305 is connected with the compression spring 48 in series, so that the impact force caused by the engagement moment of the centrifugal clutch is reduced, the variation trend of the assisting force for the limb of the wearer is smoother, and the impact abrasion of the pawl 59 in the centrifugal clutch 47 is reduced.
The embodiments are only used to illustrate the technical scheme of the present invention, but not to limit the technical scheme, and although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical scheme described in the foregoing embodiments may be modified or some or all technical features may be equivalently replaced, and the modification or replacement does not make the essence of the corresponding technical scheme deviate from the scope of the technical scheme of the embodiments of the present invention, and is included in the scope of the claims and the specification of the present invention.