CN111730583A - Two-degree-of-freedom asymmetric parallel rotating mechanism - Google Patents

Abstract

The invention discloses a two-degree-of-freedom asymmetric parallel rotating mechanism, comprising a first connecting rod, a second connecting rod connected with the first connecting rod through a first rotating pair, and a second connecting rod connecting with the second connecting rod through the second rotating pair A third link, a ball joint pair, a ball rod connected to the ball joint pair, a universal pair connected between the other end of the ball rod and the third link, used to provide the second link The driving force makes the second connecting rod rotate relative to the first connecting rod around the first rotation axis, and the first driving assembly for providing the driving force to the ball joint pair makes the third connecting rod rotate relative to the first connecting rod. A second drive assembly that rotates the two links about a second axis of rotation. The present invention can be applied to the mechanical arm of the robot to realize two-degree-of-freedom rotational drive. The mechanism of the present invention can fix the driving components on the front rod or the base, which can greatly reduce the quality of the rear mechanism and reduce the front The power of the drive components, so that the entire manipulator structure can be made more compact and flexible.

Description

Two-degree-of-freedom asymmetric parallel rotating mechanism

technical field

The invention relates to the field of robots, in particular to a two-degree-of-freedom asymmetric parallel rotation mechanism.

Background technique

According to the number of kinematic chains, the kinematic mechanism can be divided into series mechanism and parallel mechanism. The series mechanism refers to the sequential connection of several basic rods with a single degree of freedom. The output motion of each front rod is the input of the rear rod, and there is only one kinematic chain between the base and the end effector. The open-loop mechanism A parallel mechanism is a closed-loop mechanism in which a designated platform (base) and a moving platform (end effector) are connected through at least two independent kinematic chains, the mechanism has two or more degrees of freedom, and is driven in parallel .

Both series and parallel mechanisms have their own advantages and disadvantages.

The tandem mechanism has the advantages of large working space, simple structure and mature control algorithm, and is currently widely used in industrial robotic arms and other fields. However, each single-degree-of-freedom rod of the series mechanism must be equipped with driving components, such as motors, electric cylinders, hydraulic cylinders or hydraulic motors. load, but also the weight from the corresponding drive components. Considering that the mass of the drive components is often relatively large, they will generate a large centrifugal load when the robot works, and as a result, more powerful pre-drive components are required, which consumes more energy. Moreover, in order to ensure sufficient strength and rigidity, the structure of the serial manipulator is often designed to be very "stout", and the entire robot is relatively heavy. The parallel mechanism has the following advantages: no cumulative error, high precision; compact structure, high rigidity, and large bearing capacity.

Many of the rotating drive mechanisms used in manipulators now either have the disadvantage of using the structure of serial manipulators, which makes the structure appear very "sturdy", or there is a need for power due to the installation of the drive components on the rear mechanism. Disadvantages of larger front-drive components.

So now a more reliable solution is needed.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a two-degree-of-freedom asymmetric parallel rotation mechanism in view of the above-mentioned deficiencies in the prior art.

In order to solve the above-mentioned technical problems, the technical solution adopted in the present invention is: a two-degree-of-freedom asymmetric parallel rotating mechanism, comprising a first connecting rod, a second connecting rod connected to the first connecting rod through a first rotating pair, The third link connected with the second link through the second rotation pair, the ball joint pair, the ball rod connected with the ball joint pair, the other end of the ball rod and the third link a universal joint between the two, a first drive assembly for providing a driving force to the second link to make the second link rotate relative to the first link around the first rotation axis, and a first drive assembly for driving the ball The hinge pair provides a driving force to make the third connecting rod rotate relative to the second connecting rod about a second driving assembly about the second rotation axis;

The first rotation axis and the second rotation axis are not parallel, so that the third link can perform attitude adjustment in two rotation directions.

Preferably, the universal pair is replaced by a ball joint pair.

Preferably, the positions of the ball joint pair and the universal joint pair at both ends of the club are reversed.

Preferably, the first rotating pair includes a first rotating shaft rotatably connecting the second connecting rod to the front end of the first connecting rod;

The second rotating pair includes a second rotating shaft rotatably connecting the third connecting rod to the front end of the second connecting rod;

The axes of the first rotating shaft and the second rotating shaft are not parallel.

Preferably, the first drive assembly includes a crank-rocker mechanism disposed on the first connecting rod and a first motor drivably connected to the input end of the crank-rocker mechanism. The output end is connected with the second connecting rod.

Preferably, the first motor is fixed on the first connecting rod, and the crank-rocker mechanism includes a first crank drivingly connected with the output shaft of the first motor and rotating with the first crank The connected first rocker, the other end of the first rocker is rotatably connected with the second link.

Preferably, the second drive assembly includes a double crank mechanism disposed on the first connecting rod and a second motor drivably connected to the input end of the double crank mechanism, and the output end of the double crank mechanism is connected to the double crank mechanism. The spherical hinge pair is connected.

Preferably, the second motor is fixed on the first connecting rod, and the double crank mechanism includes a rear crank that is drivingly connected to the output shaft of the second motor, and a third crank that is rotatably connected to the rear crank. two rockers, a front crank whose first end is rotatably connected to the front end of the first connecting rod and whose second end is rotatably connected to the second rocker;

The spherical hinge pair includes a spherical hinge seat fixed on the second end of the front crank and a spherical hinge connected to the spherical hinge seat;

The universal joint includes a universal joint connecting the spherical hinge and the third link.

Preferably, the first drive assembly includes a first linear actuator rotatably connected to the first link, the output rod of the first linear actuator and the second link Swivel connection.

Preferably, the second drive assembly includes a second linear actuator rotatably connected to the first link, the first end is rotatably connected to the front end of the first link, and the second end is rotatably connected to the first link. a second crank connected to the output rod of the second linear actuator in rotation;

The ball rod is connected with the second end of the second crank through the ball joint pair.

The beneficial effects of the present invention are as follows: the present invention proposes a two-degree-of-freedom asymmetric parallel rotating drive mechanism, which can be applied to the robotic arm of a robot to realize two-degree-of-freedom rotational drive, and the mechanism of the present invention can fix the drive components on the On the front rod or base, the mass of the rear mechanism can be greatly reduced, and the power of the front drive part can be reduced, so that the entire mechanical arm structure can be made more compact and flexible.

Description of drawings

Fig. 1 is the principle schematic diagram of the two-degree-of-freedom asymmetric parallel rotation mechanism of the present invention;

2 is a schematic structural diagram of a two-degree-of-freedom asymmetric parallel rotation mechanism in Embodiment 1 of the present invention;

3 is a schematic structural diagram of another angle of the two-degree-of-freedom asymmetric parallel rotation mechanism in Embodiment 1 of the present invention;

4 is a schematic structural diagram of another angle of the two-degree-of-freedom asymmetric parallel rotation mechanism in Embodiment 1 of the present invention;

5 is a schematic structural diagram of a two-degree-of-freedom asymmetric parallel rotation mechanism in Embodiment 2 of the present invention.

Description of reference numbers:

1—first connecting rod; 2—first rotating pair; 3—second connecting rod; 4—second rotating pair; 5—third connecting rod; 6—ball hinge pair; 7—ball lever; 8—universal Vice; 9—first drive assembly; 10—second drive assembly; 60—spherical hinge seat; 61—spherical hinge; 90—crank rocker mechanism; 91—first motor; 92—first crank; 93—first Rocker; 94—first linear actuator; 100—double crank mechanism; 101—second motor; 102—rear crank; 103—second rocker; 104—front crank; 105—second linear actuator ; 106—Second crank.

Detailed ways

The present invention will be further described in detail below with reference to the embodiments, so that those skilled in the art can implement according to the description.

It should be understood that terms such as "having", "comprising" and "including" as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

As shown in FIG. 1 , a two-degree-of-freedom asymmetric parallel rotating mechanism in this embodiment includes a first connecting rod (L _i-1 ), which is connected to the first connecting rod through a first rotating pair (R ₁ ). The second connecting rod (L _i ), the third connecting rod (L _i+1 ) connected with the second connecting rod through the second rotating pair (R ₂ ), the spherical joint pair (or spherical pair, S) , a ball rod (1) connected with the ball joint pair, a universal pair (also called a Hooke pair, U) connected between the other end of the ball rod and the third connecting rod, used for pairing The second link provides a driving force (torque M in FIG. 1 ) to rotate the second link relative to the first link around a first axis of rotation and a first drive assembly for driving the ball. The hinge pair provides a driving force (the force F in FIG. 1 ) to make the third connecting rod rotate relative to the second connecting rod about a second driving assembly about the second rotation axis;

Wherein, the first rotation axis and the second rotation axis are not parallel, and the rotation angle of the first rotation pair (R ₁ ) and the position of the ball joint pair (S) can be controlled by the torque M and the force F respectively. The rod (L _i+1 ) realizes the attitude adjustment of two rotation angles in space.

In another embodiment, the universal pair can be replaced with a ball joint pair, that is, both ends of the ball shaft can be ball joint pairs.

In another embodiment, the positions of the ball joint pair and the universal joint pair at both ends of the club are reversed.

The above is the general idea of the present invention, and more specific embodiments are provided below to further describe the present invention in detail.

Example 1

2-4, in this embodiment, the first rotating pair includes a first rotating shaft rotatably connecting the second connecting rod to the front end of the first connecting rod;

The second rotating pair includes a second rotating shaft rotatably connecting the third connecting rod to the front end of the second connecting rod;

The axes of the first rotating shaft and the second rotating shaft are not parallel. In this embodiment, the axes of the first rotating shaft and the second rotating shaft are perpendicular to each other.

Wherein, the first drive assembly includes a crank-rocker mechanism disposed on the first connecting rod and a first motor drivably connected to the input end of the crank-rocker mechanism, and the output end of the crank-rocker mechanism connected with the second link. Further, the first motor is fixed on the first connecting rod, and the crank-rocker mechanism includes a first crank that is drivingly connected to the output shaft of the first motor and that is rotatably connected to the first crank The other end of the first rocker is rotatably connected with the second link.

Wherein, the second drive assembly includes a double crank mechanism disposed on the first connecting rod and a second motor drivingly connected with the input end of the double crank mechanism, and the output end of the double crank mechanism is connected to the double crank mechanism. Ball joint connection. Further, the second motor is fixed on the first connecting rod, and the double crank mechanism includes a rear crank that is drivingly connected to the output shaft of the second motor, and a second crank that is rotatably connected to the rear crank. a rocker, a front crank having a first end rotatably connected to the front end of the first connecting rod and a second end rotatably connected to the second rocker;

The spherical hinge pair includes a spherical hinge seat fixed on the second end of the front crank and a spherical hinge connected to the spherical hinge seat;

The universal joint includes a universal joint connecting the spherical hinge and the third link.

In a preferred embodiment, both the first motor and the second motor are equipped with a reducer.

2 and 3, the first motor rotates, and the crank-rocker mechanism can drive the second connecting rod to rotate relative to the first connecting rod in the pitch direction; the second motor rotates, through the double crank mechanism, the ball joint pair, the universal joint The transmission can drive the third link to rotate relative to the second link, and by controlling the rotation angles of the two motors, the pitch and rotation angle of the third link in space can be controlled.

The present invention is mainly applied to the mechanical arm of the robot to realize two-degree-of-freedom rotational drive, and the two motors can be arranged on the front rod (the first link), or can be arranged on the front link for installing and connecting the first link. On the base, by moving the setting position of the motor with larger mass forward (away from the end of the robot arm), the mass of the rear mechanism (closer to the end of the robot arm) can be greatly reduced, reducing the power of the front drive components , which can make the whole manipulator structure more compact and flexible.

Example 2

Referring to FIG. 5 , the main difference between this embodiment and Embodiment 1 is that the motor in the drive assembly is replaced with a linear actuator, specifically: in this embodiment, the first drive assembly includes a rotatable connection on the The first linear actuator on the first link, the output rod of the first linear actuator is rotatably connected with the second link.

The second drive assembly includes a second linear actuator rotatably connected to the first link, a first end is rotatably connected to the front end of the first link, and a second end is connected to the second straight line The output rod of the actuator rotates the connected second crank;

The ball rod is connected with the second end of the second crank through the ball joint pair.

The first and second linear actuators can be selected from hydraulic cylinders, air cylinders or electric cylinders.

The output rod of the first linear actuator is telescopic, which can drive the second connecting rod to rotate relative to the first connecting rod in the pitch direction; the output rod of the second linear actuator is telescopic, through the double crank mechanism, ball joint pair, universal The transmission of the joint can drive the third link to perform a rotary motion relative to the second link. By controlling the elongation of the two linear actuators, the pitch and rotation angle of the third link in space can be controlled.

Although the embodiment of the present invention has been disclosed as above, it is not limited to the application listed in the description and the embodiment, and it can be applied to various fields suitable for the present invention. For those skilled in the art, it can be easily Therefore, the invention is not limited to the specific details without departing from the general concept defined by the appended claims and the scope of equivalents.

Claims (10)

1. A two-degree-of-freedom asymmetric parallel rotation mechanism, characterized in that it comprises a first link, a second link connected to the first link through a first rotation pair, and a second link connected to the first link through a second rotation pair. A third link connected with the second link, a ball joint pair, a ball rod connected with the ball joint pair, a universal pair connected between the other end of the ball rod and the third link, used for A first drive assembly for providing a driving force to the second link to rotate the second link relative to the first link around a first rotation axis, and a first drive assembly for providing a driving force to the ball joint pair to make the A second drive assembly for the third link to rotate relative to the second link around the second axis of rotation; The first rotation axis and the second rotation axis are not parallel, so that the third link can perform attitude adjustment in two rotation directions. 2 . The two-degree-of-freedom asymmetric parallel rotation mechanism according to claim 1 , wherein the universal pair is replaced by a ball joint pair. 3 . 3 . The two-degree-of-freedom asymmetric parallel rotation mechanism according to claim 1 , wherein the positions of the ball joint pair and the universal joint pair at both ends of the ball bar are reversed. 4 . 4 . The two-degree-of-freedom asymmetric parallel rotation mechanism according to claim 1 , wherein the first rotation pair comprises a second link rotatably connected to the front end of the first link. 5 . a rotating shaft; The second rotating pair includes a second rotating shaft rotatably connecting the third connecting rod to the front end of the second connecting rod; The axes of the first rotating shaft and the second rotating shaft are not parallel. 5 . The two-degree-of-freedom asymmetric parallel rotation mechanism according to claim 4 , wherein the first driving assembly comprises a crank-rocker mechanism arranged on the first connecting rod and a crank-rocker mechanism connected with the crank-rocker mechanism. 6 . The input end of the mechanism drives the connected first motor, and the output end of the crank-rocker mechanism is connected with the second connecting rod. 6 . The two-degree-of-freedom asymmetric parallel rotation mechanism according to claim 5 , wherein the first motor is fixed on the first connecting rod, and the crank-rocker mechanism includes a connection with the first connecting rod. 7 . The output shaft of the motor is drivingly connected to a first crank and a first rocker rotatably connected to the first crank, and the other end of the first rocker is rotatably connected to the second connecting rod. 7 . The two-degree-of-freedom asymmetric parallel rotation mechanism according to claim 6 , wherein the second drive assembly comprises a double crank mechanism arranged on the first connecting rod and a double crank mechanism connected to the double crank mechanism. 8 . The input end drives the connected second motor, and the output end of the double crank mechanism is connected with the ball joint pair. 8 . The two-degree-of-freedom asymmetric parallel rotation mechanism according to claim 7 , wherein the second motor is fixed on the first connecting rod, and the double crank mechanism includes a connection with the second motor. 9 . The output shaft is drivingly connected to the rear crank, the second rocker is rotatably connected to the rear crank, the first end is rotatably connected to the front end of the first connecting rod, and the second end is rotatably connected to the second rocker front crank; The spherical hinge pair includes a spherical hinge seat fixed on the second end of the front crank and a spherical hinge connected to the spherical hinge seat; The universal joint includes a universal joint connecting the spherical hinge and the third link. 9 . The two-degree-of-freedom asymmetric parallel rotation mechanism according to claim 4 , wherein the first drive assembly comprises a first linear actuator rotatably connected to the first link, so the The output rod of the first linear actuator is rotatably connected with the second connecting rod. 10 . The two-degree-of-freedom asymmetric parallel rotation mechanism according to claim 9 , wherein the second drive assembly comprises a second linear actuator rotatably connected to the first link, a first a second crank whose end is rotatably connected with the front end of the first connecting rod and whose second end is rotatably connected with the output rod of the second linear actuator; The ball rod is connected with the second end of the second crank through the ball joint pair.

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