CN107650141A - A kind of joint of mechanical arm - Google Patents

Abstract

The present invention relates to the field of mechanical arm technology, in particular to a mechanical arm joint, which includes an input assembly, an output assembly, a brake assembly, a harmonic reducer and a multi-turn absolute encoder; the input assembly includes a hollow shaft motor and a hollow input shaft, the hollow input shaft is fixedly connected with the rotor of the hollow shaft motor; the output assembly includes an output flange and a hollow output shaft, the hollow output shaft is fixedly connected with the output flange; the hollow output shaft It is installed in the shaft cavity of the hollow input shaft, and relative rotation can occur between the hollow output shaft and the hollow input shaft; the hollow input shaft is fixedly connected with the wave generator of the harmonic reducer, and the output flange It is fixedly connected with the rigid wheel of the harmonic reducer; the multi-turn absolute encoder is used to detect the multi-turn absolute angle value of the hollow input shaft; the brake assembly is fixed on the hollow input shaft. The complexity of the structure is reduced, which is beneficial to reduce the cost.

Description

A mechanical arm joint

technical field

The invention relates to the technical field of mechanical arms, in particular to a mechanical arm joint.

Background technique

The traditional robotic arm is composed of the upper arm of a human being. In order to ensure that the robotic arm has six degrees of freedom in space, the number of active joints is generally six, and generally all of them are rotational joints. The structure of the modular joints in the existing modular manipulators is too complicated, which makes the joints themselves larger in size and higher in cost.

Contents of the invention

The object of the present invention is to provide a mechanical arm joint to solve the technical problem in the prior art that the structure of the modular joint is too complicated, which makes the cost of the joint relatively high.

The invention provides a mechanical arm joint, including an input assembly, an output assembly, a brake assembly, a harmonic reducer and a multi-turn absolute encoder;

The input assembly includes a hollow shaft motor and a hollow input shaft, and the hollow input shaft is fixedly connected to the rotor of the hollow shaft motor;

The output assembly includes an output flange and a hollow output shaft, and the hollow output shaft is fixedly connected to the output flange;

The hollow output shaft is passed through the shaft cavity of the hollow input shaft, and relative rotation can occur between the hollow output shaft and the hollow input shaft;

The hollow input shaft is fixedly connected to the wave generator of the harmonic reducer, and the output flange is fixedly connected to the rigid wheel of the harmonic reducer;

The multi-turn absolute encoder is used to detect the multi-turn absolute angle value of the hollow input shaft; the brake assembly is fixed on the hollow input shaft.

Further, it also includes a parallel shaft assembly, the parallel shaft assembly includes a parallel shaft, a synchronous belt and two synchronous wheels, the axis of the parallel shaft is parallel to the axis of the hollow input shaft, and the hollow input shaft is fixed on There is a first synchronous wheel, a second synchronous wheel is fixed on the parallel shaft, and the first synchronous wheel and the second synchronous wheel are driven by the synchronous belt;

The multi-turn absolute encoder is arranged at the shaft end of the parallel shaft.

Further, the multi-turn absolute encoder includes a single-chip microcomputer circuit, a permanent magnet, at least one magnetic angle sensor and at least two Wiegand sensors;

The permanent magnet is installed on the parallel shaft and rotates with the rotation of the object to be measured;

The at least one magnetic angle sensor is arranged around the permanent magnet to detect the single-turn absolute angle value of the object to be measured;

The at least two Wiegand sensors are arranged around the permanent magnet, and when the permanent magnet rotates, the magnetic field along the sensitive axis direction of each Wiegand sensor is periodically switched, so that the Wiegand sensor outputting electrical signal pulses, the electrical signal pulses dividing the circumference of the permanent magnet into multiple angular intervals;

The output ends of the at least one magnetic angle sensor and the at least two Wiegand sensors are respectively connected to the single-chip circuit, so that the single-chip circuit can determine the value to be tested according to the single-turn absolute angle value and the electrical signal pulse. The absolute angular value of the object's multiturn.

Further, the sensitive axes of the at least two Wiegand sensors are arranged radially of the rotation circle of the permanent magnet, or arranged tangentially to the rotation circle of the permanent magnet, or tangential to the rotation circle of the permanent magnet. It is set at a preset angle, or placed on a different plane from the tangent of the permanent magnet rotation circle.

Further, the at least two Wiegand sensors are arranged around the permanent magnet at different sensitive axis radial angles or different plane angles.

Further, there are two magnetic angle sensors.

Further, the brake assembly includes a brake block and an electromagnet with an iron core; the brake block is fixed on the hollow input shaft, and the iron core can move along the electromagnet for controlling the The brake pads provide a stop.

Further, a magnetic isolation soft iron is provided on one side of the brake block, and an elastic washer is provided between the brake block and the magnetic isolation soft iron.

Further, it also includes a casing, the flexible spline of the harmonic reducer is fixedly connected to the casing; the output flange is connected to the wave generator through a first bearing; the hollow input shaft sleeve is provided with a second A bearing, the second bearing is connected to the housing through a bearing frame.

Further, a backup power supply is also included for providing backup power to the multi-turn absolute encoder encoder.

Compared with prior art, the beneficial effect of the present invention is:

The mechanical arm joint provided by the present invention includes an input assembly, an output assembly, a brake assembly, a harmonic reducer and a multi-turn absolute encoder; the input assembly includes a hollow shaft motor and a hollow input shaft, and the hollow input shaft and the hollow The rotor of the shaft motor is fixedly connected; the output assembly includes an output flange and a hollow output shaft, and the hollow output shaft is fixedly connected to the output flange; the hollow output shaft is passed through the shaft cavity of the hollow input shaft, And relative rotation can occur between the hollow output shaft and the hollow input shaft; the hollow input shaft is fixedly connected to the wave generator of the harmonic reducer, and the output flange is fixedly connected to the rigid wheel of the harmonic reducer; The multi-turn absolute encoder is used to detect the multi-turn absolute angle value of the hollow input shaft; the brake assembly is fixed on the hollow input shaft. The hollow output shaft and the output flange are separated, which reduces the difficulty of processing and thus reduces the cost; in addition, the hollow cavity of the hollow output shaft can be used for cables to pass through, which optimizes the circuit layout and facilitates the optimization of the structure. To sum up, the mechanical arm joint provided by the present invention reduces the complexity of the structure and is beneficial to reduce the cost.

Description of drawings

In order to more clearly illustrate the specific implementation of the present invention or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings that need to be used in the specific implementation or description of the prior art. Obviously, the accompanying drawings in the following description The drawings show some implementations of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative work.

Fig. 1 is a schematic diagram of the structure of the mechanical arm joint provided by the embodiment of the present invention when the end cap is not installed;

Figure 2 is an enlarged schematic view of part A of Figure 1;

Fig. 3 is a schematic structural view of the mechanical arm joint provided by the embodiment of the present invention when the end cap is installed;

Figure 4 is an enlarged schematic view of part B of Figure 3

Fig. 5 is a structural schematic diagram of a hollow output shaft and an output flange according to an embodiment of the present invention;

Fig. 6 is a structural schematic diagram of a hollow input shaft and a brake assembly according to an embodiment of the present invention;

Fig. 7 is a structural schematic diagram of the transmission relationship between the hollow input shaft and the parallel shaft according to the embodiment of the present invention;

Fig. 8 is a structural schematic diagram of the tangential arrangement of the sensitive axes of two Wiegand sensors along the rotation circle of the permanent magnet in an embodiment of the present invention;

Fig. 9 is a structural schematic diagram of two Wiegand sensor sensitive axes arranged radially along the permanent magnet rotation circle in an embodiment of the present invention;

Fig. 10 is a schematic structural diagram of three Wiegand sensor sensitive axes arranged tangentially along the permanent magnet rotation circle in an embodiment of the present invention;

Fig. 11 is a structural schematic diagram of a magnetic angle sensor and two Wiegand sensors fixed on a drive circuit board in an embodiment of the present invention;

Fig. 12 is a schematic diagram of another angle structure of the magnetic angle sensor and two Wiegand sensors arranged along the rotation circle of the annular permanent magnet in the embodiment of the present invention;

Fig. 13 is a schematic diagram of the structure of two Wiegand sensors arranged at different plane angles along the rotation circle of the annular permanent magnet in the embodiment of the present invention.

Reference signs: 100-hollow input shaft; 101-rotor; 102-stator; 103-hollow output shaft; 104-output flange; 105-wave generator; 106-rigid wheel; 107-flexible wheel; 108-shell; 109-end cover; 110-parallel shaft; 111-synchronous belt; 112-first synchronous wheel; 113-second synchronous wheel; 114-drive circuit board; ; 118-sensitive shaft; 119-electromagnet; 120-brake block; 121-block foot; The second retaining ring; 127-elastic washer; 128-the first bearing; 129-the second bearing.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Apparently, the described embodiments are some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" etc. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, or in a specific orientation. construction and operation, therefore, should not be construed as limiting the invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and should not be construed as indicating or implying relative importance.

As shown in Figures 1 to 4, the embodiment of the present invention provides a mechanical arm joint, including an input assembly, an output assembly, a brake assembly, a harmonic reducer and a multi-turn absolute encoder; the input assembly includes a hollow shaft motor and The hollow input shaft 100 is fixedly connected to the rotor 101 of the hollow shaft motor; the output assembly includes a hollow output shaft 103 and an output flange 104, and the hollow output shaft 103 is fixedly connected to the output flange 104; the hollow output shaft 103 is pierced In the shaft cavity of the hollow input shaft 100 , relative rotation can occur between the hollow output shaft 103 and the hollow input shaft 100 . The mechanical arm joint also includes a harmonic reducer, wherein the hollow input shaft 100 is fixedly connected to the wave generator 105 of the harmonic reducer, and the output flange 104 is fixedly connected to the rigid wheel 106 of the harmonic generator; the hollow output shaft 103 has A hollow cavity extending along its own axis.

The multi-turn absolute encoder is used to detect the multi-turn absolute angle value of the hollow input shaft 100; the brake assembly is fixed on the hollow input shaft.

Preferably, the material of the hollow output shaft 103 is nylon or carbon fiber, which has high temperature resistance and is not easy to wear non-metal. The mechanical arm joint also includes a casing 108, the stator 102 of the hollow shaft motor is fixedly connected with the casing 108, and the stator 102 can be connected with the casing 108 by gluing or by screws; the hollow input shaft 100 and the rotor of the hollow shaft motor 101 can be connected by glue or nuts. When the rotor 101 of the hollow shaft motor rotates, the hollow input shaft 100 rotates together with the rotor 101 . One end of the hollow output shaft 103 is threadedly connected to the output flange 104, that is, one end of the hollow output shaft 103 is threadedly connected to the shaft hole of the output flange 104. In order to strengthen the fixing strength, the hollow output shaft 103 and the output flange 104 can be The fixation is strengthened by gluing; the axis of the output flange 104 coincides with the axis of the hollow output shaft 103 . Since the hollow output shaft 103 is made of non-metallic material, and the inner surface of the hollow cavity of the hollow output shaft 103 is smooth, when the cable passes through the hollow cavity of the hollow output shaft 103, the distance between the cable and the hollow output shaft 103 can be greatly reduced. The coefficient of friction can reduce the abrasion of cables, and make the layout of each part of the joint tidy, which is more conducive to improving the structural layout.

In addition, the output flange 104 is made of aluminum alloy, which can greatly reduce the cost and processing difficulty. The flexible spline 107 of the harmonic reducer is fixedly connected to the casing 108, specifically the flexible spline 107 is fixedly connected to the casing 108 by screws, the rigid spline 106 is fixedly connected to the output flange 104 by screws, and the flexible spline 107 and the rigid spline 106 are crossed by a cross Roller bearing drive connection. The hollow input shaft 100 is sheathed on the outer surface of the hollow output shaft 103 , and the hollow input shaft 100 and the hollow output shaft 103 are arranged coaxially.

When working, the rotor 101 of the hollow shaft motor drives the hollow input shaft 100 to rotate, and the hollow input shaft 100 drives the wave generator 105 of the harmonic reducer to rotate, and then realizes deceleration through the flexible spline 107 and rigid spline 106, and through the output flange 104 outputs rotation, that is to say, the input speed of the hollow input shaft 100 is greater than the output speed of the output flange 104; while the output flange 104 rotates, it drives the hollow output shaft 103 to rotate together.

The hollow output shaft 103 and the output flange 104 provided by the embodiment of the present invention are separated, which reduces the difficulty of processing and thus reduces the cost; in addition, the hollow cavity of the hollow output shaft 103 can be passed through by cables, which optimizes the circuit layout. To sum up, the mechanical arm joint provided by the embodiment of the present invention reduces the complexity of the structure and is beneficial to reduce the cost.

In this embodiment, the output flange 104 is connected to the wave generator 105 through the first bearing 128. Specifically, the inner ring of the first bearing 128 is connected to the output flange 104, and the outer ring of the first bearing 128 is connected to the wave generator 105. , the wave generator 105 is fixedly connected with the hollow input shaft 100 . The hollow input shaft 100 is sheathed with a second bearing 129 , specifically, the inner ring of the second bearing 129 is fixedly connected with the hollow input shaft 100 , and the outer ring of the second bearing 129 is fixedly connected with the casing 108 through a bearing fixing frame. Preferably, the first bearing 128 and the second shaft 129 are deep groove ball bearings; the two bearings are located between the output flange 104 and the hollow shaft motor, which can save space and cost; and, the wave generator 105 and the hollow input The shaft 100 is fixedly connected, and the two bearings can provide two stable support points for the hollow input shaft 100, and can offset the bending moment exerted on the hollow input shaft 100 by the magnetic force generated by the hollow shaft motor, and at the same time realize the wave generator 105 and Relative rotation between the output flanges 104.

In this embodiment, the high-precision output on the low-speed side is realized through the harmonic reducer, and the multi-turn absolute value encoder is installed on the high-speed side of the joint to detect the multi-turn absolute angle value of the hollow input shaft 100 to simplify the joint structure.

As shown in Fig. 1, Fig. 3 and Fig. 7, in this embodiment, the multi-turn absolute value encoder indirectly obtains the number of rotations and the angle value of the hollow input shaft 100 by detecting the parallel shaft assembly, specifically, the parallel shaft The assembly includes a parallel shaft 110 and a synchronous belt 111, the axis of the parallel shaft 110 is parallel to the axis of the hollow input shaft 100, the first synchronous wheel 112 is fixed on the hollow input shaft 100, and the second synchronous wheel 113 is fixed on the parallel shaft 110, The first synchronous wheel 112 and the second synchronous wheel 113 are driven by a synchronous belt 111 .

In the optional solution of this embodiment, the diameter of the pitch circle of the first synchronous wheel 112 is the same as the diameter of the pitch circle of the second synchronous wheel 113, and the number of teeth of the first synchronous wheel 112 is the same as that of the second synchronous wheel 113. The number of teeth is the same. In this way, when the hollow input shaft 100 rotates, it will drive the first synchronous wheel 112 to rotate, the first synchronous wheel 112 and the second synchronous wheel 113 rotate synchronously through the synchronous belt 111, and the rotation of the second synchronous wheel 113 drives the parallel shaft 110 to rotate synchronously , and the parallel shaft 110 will synchronously reflect the running condition of the hollow input shaft 100 . Since there is no transmission gap in the synchronous belt 111, and the diameters of the pitch circles of the first synchronous wheel 112 and the second synchronous wheel 113 are the same, and the number of teeth is equal, therefore, this transmission mode will rotate the hollow input shaft 100 by 1:1. Synchronously transmitted to the parallel shaft 110, the rotation parameters of the parallel shaft 110 are the same as the rotation parameters of the hollow input shaft 100, by directly measuring the rotation parameters of the parallel shaft 110, the rotation parameters of the hollow input shaft 100 can be obtained, so that these parameters can be changed Control accordingly.

Further, as shown in Figures 1 and 3, the mechanical arm joint also includes a drive circuit board 114, which is used to control the hollow shaft motor and control the multi-turn absolute encoder to maintain the normal operation of the entire joint; the parallel shaft 110 passes through two Three coaxial third bearings 124 arranged at intervals are installed on the fixed frame 115, so that the parallel shaft can rotate around its own axis. Specifically, the parallel shaft 110 is connected with the inner rings of the two third bearings 124, and the two third bearings The outer ring of the bearing 124 is connected with the fixing frame 115 to form a stable structure. When the parallel shaft 110 rotates, the fixed frame 115 does not move; the fixed frame 115 is fixed on the drive circuit board 114 by screws, and the parallel shaft assembly is arranged on the left side of the hollow shaft motor, that is, the hollow shaft motor is located between the parallel shaft assembly and the output flange 104 between. Preferably, the joint of the mechanical arm further includes an end cover 109, and the end cover 109 cooperates with the housing 108 to protect the joint.

In this embodiment, as shown in Figures 8-13, the multi-turn absolute encoder includes a single-chip circuit, a permanent magnet 116, a magnetic angle sensor 125 and a plurality of Wiegand sensors 117, wherein the single-chip circuit is printed on the drive circuit board 114 , the magnetic angle sensor 125 and a plurality of Wiegand sensors 117 are connected with the single-chip microcomputer circuit. The permanent magnet 116 is installed on the parallel shaft 110 and rotates with the rotation of the parallel shaft 110, and the geometric center of the permanent magnet 116 is located on the axis of the parallel shaft 110, the magnetic angle sensor 125 is arranged on one side of the permanent magnet 116, and bonded Or be welded on the drive circuit board 114, of course, the magnetic angle sensor 125 can also be arranged above the end face of the permanent magnet 116 at intervals, the parallel shaft 110 rotates one circle, and the magnetic angle sensor 125 can provide a single circle in a circle through the periodically changing magnetic field. The absolute angle value of one turn, the direction of the magnetic field along the sensitive axis direction of each Wiegand sensor 117 is periodically switched, and the single-chip circuit determines the absolute angle value of multiple turns of the parallel axis 110 according to the absolute angle value of a single turn and the electrical signal pulse.

In the embodiment of the present invention, a single-turn absolute encoder is realized based on the principle of the magnetic angle sensor 125. The Wiegand sensor 117 can send an electric pulse when the magnetic field is reversed when the power is cut off, and the electric pulse can wake up the single-chip circuit. Specifically, the single-chip microcomputer can judge the new interval information according to: first, which Wiegand sensor sent a pulse; second, the original interval information, and accumulate and memorize the multi-turn information, and then sleep again, waiting for the next An electrical pulse wakes it up. Therefore, the single-chip circuit can be completely closed during standby, which greatly reduces the standby power consumption of the multi-turn absolute value encoder, thereby prolonging the standby time and reducing the cost of the multi-turn absolute value encoder. The function of counting laps for a long time can also be realized by relying on the backup battery for power supply when the power is cut off. Moreover, the present invention divides a circle into several intervals through at least two Wiegand sensors 117 at a certain angle to each other, and can accurately determine the number of rotations of the object to be measured in combination with the interval value, and then combines the single-turn angle value to obtain The current absolute position avoids the jump of the angle when crossing the circle, and then can realize the position detection of multi-turn rotation with simple structure and high reliability at a lower cost.

The Wiegand sensor 117 is used to detect the number of turns, combined with the single-turn angle value obtained by the above-mentioned magnetic angle sensor, to obtain multi-turn absolute position information. The working principle of the Wiegand sensor is that the magnetic bistable functional alloy material in the sensor is excited by an external magnetic field, and the magnetization direction is instantly reversed, thereby inducing an electrical signal in the detection coil to realize magnetoelectric conversion. The Wiegand sensor does not need an external power supply, it can send out electric pulses by itself, and the output signal amplitude has nothing to do with the changing speed of the magnetic field, which can realize "zero speed" sensing. Trigger the polarity of the magnetic field to change for a week, and the sensor outputs two pulse electrical signals, one positive and one negative. The positions of the positive pulse signal and the negative pulse signal are symmetrical about the center of the circle, forming 180 degrees. The signal period is the alternating period of the magnetic field.

Preferably, as shown in FIGS. 8-13 , the permanent magnet 116 is a permanent magnet with N poles and S poles arranged symmetrically. More preferably, the permanent magnet 116 is an annular permanent magnet with an N pole and an S pole arranged symmetrically, so that the cable passes through the hollow output shaft 103 and passes through the annular permanent magnet. Wherein, the annular permanent magnet includes an annular permanent magnet, a square annular permanent magnet or a hexagonal annular permanent magnet and the like.

In the embodiment of the present invention, as shown in FIG. 8 , the sensitive axes 118 of the two Wiegand sensors 117 are arranged tangentially along the rotation circle of the permanent magnet 116 , or along the radial direction of the rotation circle of the permanent magnet 101 as shown in FIG. 9 . Or, as shown in FIG. 12, it is set at a preset angle with the tangential direction of the permanent magnet 116 rotation circle, or as shown in FIG. Specifically, two (or three, or more, such as N) Wiegand sensors 201 are placed around the rotating permanent magnet 101, forming a certain angle with each other, and can be evenly or unevenly distributed along the circumference. The invention is not specifically limited to this.

In practical applications, when the permanent magnet 116 is laid out, it is necessary to ensure that when the permanent magnet 116 rotates, the magnetic field along the direction of the sensitive axis 118 of the Wiegand sensor undergoes periodic direction switching. At the moment of direction switching, the Wiegand sensor 117 sends out electric pulse. The sensitive shaft 118 of the Wiegand sensor can be placed radially along the rotation circle of the permanent magnet 116, also can be placed along the tangential direction, can also be placed at a certain angle with the tangential direction, and can also be placed on a different plane from the tangent line. Several Wiegand sensors 117 It can also be placed with different sensitive axis radial angles and different plane angles.

It should be noted that the radial angle of the sensitive axis is the angle between the sensitive axis 118 and the line connecting the geometric center of the Wiegand sensor to the axis of the magnet.

In this embodiment, the mechanical arm joint also includes an MCU, a signal conditioner and a memory, and the memory is a ferroelectric memory FRAM; the signal conditioner, memory, magnetic angle sensor, and Wiegand sensor 117 are respectively electrically connected to the MCU. The MCU is used to detect the power of the backup power supply, and when the backup power supply is in a low power state, the power charging function is turned on. The MCU is also used to monitor the power-off status of the external power supply. When the external power supply is powered off, the currently recorded rotation circle value is written into a ferroelectric memory chip (FRAM). When the external power supply is powered off, if the multi-turn absolute encoder generates a rotational angular displacement, the cumulative calculation of the number of rotational turns is performed through the MCU, the signal conditioner, the memory and the Wiegand sensor 117 .

In this embodiment, the mechanical arm joint also includes a backup power supply as a backup power supply for providing backup power to the multi-turn absolute encoder. Preferably, the backup power source is a rechargeable button battery. In this embodiment, the power source selection chip is used to select the power source. In a specific embodiment, the power source selection chip is implemented by a MAX6326 chip.

Referring to Fig. 1, Fig. 3 and Fig. 6, in this embodiment, the mechanical arm joint also includes a brake assembly, and the brake assembly includes a brake block 120 and an electromagnet 119; the brake block 120 is fixed on the hollow input shaft 100, and the electromagnetic The iron 119 is used to stop the brake lining 120 . The brake assembly is located between the parallel shaft assembly and the hollow shaft motor.

The brake of the traditional locking structure will in turn produce a relatively external force impact on the harmonic reducer. Over time, the harmonic reducer will wear out in advance and reduce the service life. In order to avoid this from happening, preferably, the brake assembly also includes The elastic washer 127 , the magnetic isolation soft iron 123 , the first retaining ring 122 and the second retaining ring 126 . The first retaining ring 122, the brake block 120, the elastic washer 127, the magnetic isolation soft iron 123 and the second retaining ring 126 are installed on the hollow input shaft 100 in sequence, and form a non-locking connection, that is, when the external force is less than the threshold , under the action of the elastic washer 127, the brake block 120 rotates and stops synchronously with the magnetically isolated soft iron 123 and the hollow input shaft 100; when the external force is greater than the threshold value, the brake block 120 can perform a certain rotation relative to the hollow input shaft 100 , which acts as a buffer.

Wherein, the threshold value refers to the frictional force between the elastic washer 127 , the brake pad 120 and the magnetic isolation soft iron 123 . Preferably, the elastic washer 127 is a three-peak washer.

In addition, the magnetic isolation soft iron 123 is also used to isolate the magnetic field generated by other components such as the motor, so as to avoid affecting the multi-turn absolute encoder.

When the mechanical arm joint is working normally, the electromagnet 119 is in the power-on state, and the electromagnet 119 makes its iron core and the brake block 120 stagger, so that the brake block 120 can run without hindrance; Or when working abnormally, the electromagnet 119 is in a power-off state. After the electromagnet 119 is powered off, the iron core moves relative to the electromagnet and contacts the brake pad 120, hindering the operation of the brake pad 120, thereby achieving the purpose of braking.

In the embodiment of the present invention, six retaining feet 121 are evenly distributed in the circumferential direction of the brake block 120. When braking, the iron core extends between any two retaining feet 121 to prevent the rotation of the hollow input shaft 100. At this time From the start of the brake to the completion of the brake, the stopper can be rotated by a maximum of 60 degrees to stop, which can improve the overall sensitivity of the brake and the amount of movement of the entire mechanical arm joint after braking.

In another optional embodiment, in order to improve the accuracy of the magnetic angle sensor 125, two magnetic angle sensors 125 can be arranged around the permanent magnet 116 at a certain angle to each other, and the measured values of the two magnetic angle sensors 125 can be adjusted to a certain extent. Calibration fusion computation.

It should be noted that the calibration and fusion of the two magnetic angle sensors 125 is a mature technology, so details will not be described here.

In another optional embodiment, the multi-turn absolute encoder includes two permanent magnets 116, and the two permanent magnets 116 are N-pole and S-pole symmetrical, and one or two magnetic angle sensors 125 correspond to one permanent magnet 116 , the Wiegand sensor 117 corresponds to another permanent magnet 116 .

Specifically, the two permanent magnets 116 are arranged at intervals along the axial direction of the parallel shaft 110 to avoid magnetic field interference between the two permanent magnets 116 , and the two permanent magnets 11 rotate together with the parallel shaft 110 .

To sum up, the manipulator joint provided by this embodiment only uses a multi-turn absolute encoder on the high-speed side, and relies on the harmonic reducer to achieve high-precision output on the low-speed side, so that it can use a lower-precision, lower-cost The encoder achieves the same precision as the original, and simplifies the joint structure.

Finally, it should be noted that: the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present invention are included in the protection scope of the present invention. Furthermore, those skilled in the art will understand that although some embodiments described herein include some features included in other embodiments but not others, combinations of features from different embodiments are meant to be within the scope of the invention. and form different embodiments. For example, in the following claims, any of the claimed embodiments may be used in any combination.

Claims (10)

1. a kind of joint of mechanical arm, it is characterised in that including input module, output precision, brake assemblies, harmonic speed reducer and more Enclose absolute value encoder；

The input module includes hollow shaft motor and hollow input shaft, and the hollow input shaft turns with the hollow shaft motor Son is fixedly connected；

The output precision includes output flange and hollow output shaft, and the hollow output shaft is fixed with the output flange to be connected Connect；

The hollow output shaft is arranged in the axocoel of the hollow input shaft, and the hollow output shaft and the hollow input It can be relatively rotated between axle；

The hollow input shaft is fixedly connected with the wave producer of the harmonic speed reducer, and the output flange subtracts with the harmonic wave The firm gear of fast device is fixedly connected；

The multi-turn absolute value encoder is used for the multiturn absolute angle value for detecting the hollow input shaft；The brake assemblies are consolidated It is scheduled on the hollow input shaft.

2. joint of mechanical arm according to claim 1, it is characterised in that also including parallel shaft assembly, the parallel axes group Part includes parallel axes, timing belt and two synchronizing wheels, and the axis of the parallel axes is parallel with the axis of the hollow input shaft, The first synchronizing wheel is fixed with the hollow input shaft, the second synchronizing wheel, first synchronizing wheel are fixed with the parallel axes Pass through the toothed belt transmission with second synchronizing wheel；

The multi-turn absolute value encoder is arranged at the axial end of the parallel axes.

3. joint of mechanical arm according to claim 2, it is characterised in that the multi-turn absolute value encoder includes single-chip microcomputer Circuit, permanent magnet, at least one magnetic deviation sensor and at least two Wiegand sensors；

The permanent magnet is installed on the parallel axes and rotated with the rotation of the parallel axes；

At least one magnetic deviation sensor is arranged at around the permanent magnet, to detect the individual pen absolute angle of object to be measured Value；

At least two Wiegand sensor is arranged on around the permanent magnet, and during permanent magnet rotation, along each Wei The direction switching of the magnetic field generating period of the sensitive direction of principal axis of root sensor, the Wiegand sensor output telecommunications is set to feel the pulse The circumference of the permanent magnet is divided into multiple angular intervals by punching, the electric signal pulse；

The output end of at least one magnetic deviation sensor and at least two Wiegand sensors connects with the single chip circuit respectively Connect, so that the single chip circuit determines the object to be measured according to the individual pen absolute angle angle value and the electric signal pulse Multiturn absolute angle value.

4. joint of mechanical arm according to claim 3, it is characterised in that the sensitive axes of at least two Wiegand sensor Being radially arranged along the permanent magnet rotation round, or along the tangentially-arranged of the permanent magnet rotation round, or with it is described forever Magnet rotation round is tangentially set in predetermined angle, or is placed with the tangent line antarafacial of the permanent magnet rotation round.

5. joint of mechanical arm according to claim 3, it is characterised in that at least two Wiegand sensor is with different quick Sense Axial and radial angle or antarafacial angle are arranged on around the permanent magnet.

6. joint of mechanical arm according to claim 3, it is characterised in that the magnetic deviation sensor is two.

7. joint of mechanical arm according to claim 1, it is characterised in that the brake assemblies include brake catch and had The electromagnet of iron core；The brake catch is fixed on the hollow input shaft, and the iron core can move along the electromagnet, For carrying out backstop to the brake catch.

8. joint of mechanical arm according to claim 7, it is characterised in that the side of the brake catch is provided with soft every magnetic Iron, described it is provided with the brake catch and between magnetic soft iron elastic washer.

9. joint of mechanical arm according to claim 1, it is characterised in that also including shell, the harmonic speed reducer it is soft Wheel is fixedly connected with the shell；The output flange is connected by clutch shaft bearing with the wave producer；The hollow input Axle sleeve is provided with second bearing, and the second bearing passes through bearing bracket stand and the cage connection.

10. joint of mechanical arm according to claim 1, it is characterised in that also including stand-by power supply, for the multi-turn Absolute value encoder provides non-firm power.