CN111283707A - Two-finger self-adaptive manipulator with rigid and flexible integration - Google Patents

Abstract

The invention relates to a rigid-flexible fused two-finger self-adaptive manipulator, which comprises: the motor base (2) is symmetrically provided with a pair of mounting seats (21); the linear motor (1) is connected to the lower part of the motor base (2), and the driving end of the linear motor is connected to the mounting hole of the motor base (2) and is positioned between the pair of mounting bases (21); a differential mechanism (3); the parallel connecting rod mechanism (4) comprises two pulley connecting rods (41) which are arranged in parallel, one end of each pulley connecting rod (41) is rotatably connected with the mounting seat (21), and the other end of each pulley connecting rod is rotatably connected with a fingertip (44); and the lower end of the pulley connecting rod (41) at the inner side in the parallel connecting rod mechanism (4) is connected with a semicircular pulley (411), and the semicircular pulley (411) is connected with a pair of reeds close to one side of the semicircular pulley. The rigid-flexible fused two-finger adaptive manipulator provided by the invention has a single-input and double-output function, so that adaptive grabbing can be realized through one driver.

Description

A rigid-flexible two-finger adaptive manipulator

technical field

The invention relates to a manipulator, in particular to a rigid-flexible two-finger adaptive manipulator.

Background technique

The existing adaptive manipulators mainly have the following types:

(1) Full-drive adaptive manipulator, that is, each joint of the manipulator is driven by a driver, which can move independently of each other. The number of drivers used by the manipulator in this driving mode is as many as dozens.

Although this kind of manipulator has full functions and strong adaptability, the complexity of its own structure and the diversity of the objects to be grasped bring a great amount of calculation to the grasping planning of the manipulator. On the other hand, the cost of these manipulators is very expensive due to the numerous drives and various sensing and detection units. In general, although the fully-driven adaptive manipulator can theoretically solve the adaptive grasping problem well, it is not ideal in terms of technology and cost in practical industrial applications.

(2) Under-actuated manipulator, compared with full-drive manipulator, the number of actuators used in this manipulator is less than the number of joints, and the excess degrees of freedom are not controlled by the central controller, but are controlled by the constraints generated when grasping objects .

At present, the fingers of the vast majority of underactuated manipulators use complex underactuated structures, and each finger uses at least one actuator. Therefore, a multi-axis controller is still needed to plan the coordinated movement between fingers, which is still complex and cost-effective, and is difficult to be widely used in small and medium-sized enterprises.

SUMMARY OF THE INVENTION

In order to solve the above technical problems, the purpose of the present invention is to provide a manipulator with a simple structure, a large grasping stroke, and a single driver that can realize self-adaptive grasping without additional displacement or force sensor, and is structurally Combines the high precision of a flexible mechanism with the high stiffness and long-stroke motion characteristics of a rigid mechanism.

The technical scheme of the present invention is as follows:

A rigid-flexible two-finger adaptive manipulator, characterized by comprising:

a motor frame (2), on which a pair of mounting seats (21) are symmetrically arranged;

a linear motor (1), connected to the bottom of the motor base (2), the drive end of which is connected to the mounting hole of the motor base (2) and is located between a pair of mounting bases (21);

The differential mechanism (3) includes a bracket (31), the lower end of the bracket (31) is connected to the driving end of the linear motor (1), the main body structure is "H" shape, the middle part of the main body structure is connected by a flexible hinge ( 301) is connected with a motor shaft connecting plate (32);

A pair of reeds are respectively connected on the connecting plates on the left and right sides of the "H" shape, wherein each pair of reeds is located on a straight diagonal line of the connecting plate, and the connection diagonals of the two pairs of reeds intersect;

A parallel link mechanism (4), comprising two pulley links (41) arranged in parallel, one end of the pulley links (41) is rotatably connected to the mounting seat (21) and the other end is rotatably connected to a fingertip (44) ; And the lower end of the pulley link (41) on the inner side of the parallel link mechanism (4) is connected with a semicircular pulley (411), and the semicircular pulley (411) is connected to a pair of springs close to one side thereof. piece.

Further, the lower end of the bracket (31) is an "L"-shaped motor shaft connecting plate (32), on which is connected a motor shaft pressing plate (33), and the driving end of the linear motor (1) is squeezed and fixed on the motor. in the light hole formed by the shaft pressing plate (33) and the motor shaft connecting plate (32).

Further, a motor casing (5) is provided outside the linear motor (1), and the upper part of the motor casing (5) is connected to the casing of the motor base (2).

Further, an electrical interface (51) is also provided on the motor cover (5).

Further, each of the reeds includes a flat surface portion and a curved surface portion at the end of the surface portion, and the curved surface portion is connected to the semi-circular pulley (411).

By means of the above scheme, the present invention has at least the following advantages:

The rigid-flexible two-finger self-adaptive manipulator proposed by the present invention adopts a compact flexible differential mechanism and has the function of single input and double output. Therefore, self-adaptive grasping can be realized through one driver, and the self-adaptation is reduced. Manipulator cost and control strategies.

Compared with the traditional complex planetary gear differential mechanism, the flexible differential mechanism designed by the present invention improves the compactness of the mechanism, and the unique elasticity of the flexible mechanism enables it to automatically return to the equilibrium position after deformation;

The finger structure adopts a parallelogram linkage mechanism, so that the fingertip can produce a larger range of motion, and the manipulator based on this mechanism can adapt to objects with a larger size range;

The manipulator designed by the present invention has the function of automatic centering, that is, the movements of the two fingers are synchronized when the movement of each finger is not restricted;

The self-adaptive manipulator designed by the invention can adapt to the size change and position error of the parts when grasping the object;

Each finger of the self-adaptive manipulator designed by the present invention has only one degree of freedom, and the adaptability when grasping objects comes from the coordinated movement between the two fingers, rather than the under-actuated mechanism of the fingers. complexity, ease of maintenance, and improved reliability.

The above description is only an overview of the technical solution of the present invention. In order to understand the technical means of the present invention more clearly and implement it according to the content of the description, the following detailed description is given with the preferred embodiments of the present invention and the accompanying drawings.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings that need to be used in the embodiments. It should be regarded as a limitation of the scope, and for those of ordinary skill in the art, other related drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is the three-dimensional structure schematic diagram of the present invention;

Fig. 2 is the three-dimensional structure schematic diagram of the differential mechanism of the present invention;

Fig. 3 is the three-dimensional structure schematic diagram of the finger mechanism of the present invention;

Fig. 4 is the three-dimensional structure schematic diagram of the pulley connecting rod of the present invention;

Fig. 5 is the exploded schematic diagram of the motor frame of the present invention;

6 is a schematic diagram of the bending force of the stent of the present invention;

Fig. 7 is the principle diagram of the parallel linkage mechanism of the present invention;

8 is a simplified schematic diagram of the motion of the present invention;

9 is a schematic diagram of the synchronous movement of two fingers according to the present invention;

10 is a schematic diagram of the present invention to eliminate errors;

Fig. 11 is the three-dimensional structure diagram of the stent of the present invention;

In the picture:

1-Linear motor;

2-motor base; 21-mounting seat; 22-first mounting screw; 23-second mounting screw;

3-differential mechanism; 301-flexible hinge; 31-bracket; 311-reed mount; 312-press; 313-first screw; 32-motor shaft connecting plate; 33-motor shaft pressure plate; 331-second screw; 34-first reed; 35-second reed; 36-third reed; 37-fourth reed;

4-parallel link mechanism; 41- pulley link; 411-semi-circular pulley; 42-first pin; 43-first retaining ring; 44-fingertip; 45-second pin; 46-second retaining ring;

5- motor cover; 51- electrical interface; 52- transfer interface;

100 - parts;

200-fixture; 201-part centerline; 202-manipulator centerline.

Detailed ways

The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments. The following examples are intended to illustrate the present invention, but not to limit the scope of the present invention.

The rigid-flexible two-finger adaptive manipulator described in a preferred embodiment of the present invention is mainly composed of three parts: a differential mechanism 3 , a parallel link mechanism 4, and a driving device. The driving device is a linear motor 1, a motor base 2 is connected to the linear motor 1, a parallel link mechanism 4 is symmetrically arranged on the motor base 2, and two fingertips 44 are respectively installed on a finger mechanism of a parallel connection mechanism 4. , a differential mechanism 3 is also installed above the motor base 2 , and the differential mechanism 3 is connected to the parallel link mechanism 4 . Through the up and down movement of the linear motor 1, the movement of the driving bracket 31 is realized, thereby driving the parallel connection mechanism 4 to drive the fingertips 44 to clamp.

Referring to FIGS. 1-7 , in the present invention, a motor base 2 is connected to the upper part of the driving end of the linear motor 1 , and a motor cover 5 is connected to the outside of the housing of the linear motor 1 . The motor base 2 includes a square frame mechanism, and a circular mounting hole is arranged on the frame mechanism. The circular mounting hole is used to install the driving end of the linear motor 1. On the front of the frame mechanism The linear motor 1 is connected to the linear motor 1 through four first installation screws 22, and the motor cover 5 is connected to the four sides of the frame mechanism through eight second installation screws 23. The bottom of the motor housing 5 is also provided with a switch port 52 , and the switch port 52 is used to connect external devices. An electrical interface 51 connected to the outside is provided on the side of the motor housing 5 for power supply and control of the motor.

The differential mechanism 3 is connected to the driving end of the linear motor 1. Specifically, the differential mechanism 3 includes a bracket 31. The bracket 31 itself includes an "H"-shaped main structure. Two reed mounts 311, the reed mounts 311 are mounted on a pair of diagonal corners of the mounting plate on one mounting plate, and the reed mounts 311 are also mounted on the other mounting plate to the one of the mounting plate On the opposite corners, the connecting lines of the installed two pairs of opposite corners cross. The main structure is connected to the lower motor shaft connecting plate 32 through a flexible hinge 301 . The flexible hinge 301 connects the main structure and the motor shaft connecting plate 32, which is equivalent to forming a notch flexible hinge on the bracket 31, allowing the upper and lower parts of the fingertip to generate high-precision relative rotation under the action of external torque. The flexible hinge 301 rotates with a single degree of freedom, and is very rigid in other directions. The motor shaft connecting plate 32 is "L" shaped, and the motor shaft connecting plate 32 is connected to the motor shaft pressing plate 33 by screws, and the motor shaft pressing plate 33 clamps the motor shaft of the linear motor 1. A first reed 34 , a second reed 35 , a third reed 36 , and a fourth reed 37 are respectively connected to the four reed mounting bases 311 , and the springs are pressed by the motor shaft connecting plate 312 during the specific connection. The pieces are then fixedly connected by the first screws 313 . The thickness of the first reed 34, the second reed 35, the third reed 36, and the fourth reed 37 are very small, and due to their own geometric characteristics, they have a very large stiffness along the length of the reed, but along the width The bending stiffness in the direction is very small, and the reed includes a flat part and a curved part connecting the flat part. The flat part is connected to the reed mounting seat 311 through the pressing piece 312 and the first screw 313, and the curved part is bent to the outside. .

A pair of mounting seats 21 are also symmetrically arranged on the motor base 2, and the two finger mechanisms of the parallel link mechanism 4 are respectively rotated and mounted on the mounting seats 21. The specific finger mechanism includes two pulley links 41. The pulley link 41 The lower part of the pulley connecting rod 41 is installed on the mounting seat 21 through the second pin shaft 45, the upper part of the pulley connecting rod 41 is installed on the fingertip through the first pin shaft 42, and the end of the second pin shaft 45 is provided with a second retaining ring 46. The end of a pin shaft 42 is provided with a first retaining ring 43 . After the installation is completed, the pulley link 41 , the motor base 21 and the fingertip 44 form a parallelogram structure. A semi-circular pulley 411 is also connected to the lower part of a pulley link 41 on the inner side, and two sets of mounting holes are provided on it, and each set is connected to the curved surface of a reed. Therefore, when the semicircular pulley 411 rotates at a small angle θ, it is enlarged and transformed into the translation x of the fingertip 44 through the parallelogram structure, which ensures the parallel grasping function of the manipulator. It is not difficult to see that each finger of the manipulator has only one joint, that is, the rotation joint of the parallelogram.

The working principle of the present invention is as follows:

Referring to FIG. 8 , when the driver is pulled downward, the second reed 35 and the fourth reed 37 pull the pulley to rotate, the fingers are closed, and the first reed 34 and the third reed 36 are basically free from force. The front reed in the front view of FIG. 2 is represented by a thick solid line in FIG. 8 , and the rear reed is represented by a thick dashed line. It can be seen from the schematic diagram after the two fingers move synchronously in Fig. 9 that when the fingers of the manipulator do not touch the object, the two fingers move synchronously, which has the function of automatic centering. In addition, the flexible hinge 301 does not undergo rotational deformation, the length of the second reed 35 and the fourth reed 37 on the pulley is shortened, and the first reed 34 and the third reed 36 are included on the pulley. On the other hand, when the driver pushes upward, the first reed 34 and the third reed 36 pull the fingers to open.

Referring to FIG. 10 , when grabbing a part 100 installed in a fixture 200 and the center line 201 of the part 100 has a position error Δ relative to the center line 202 of the manipulator, under the action of the differential mechanism 3, the right finger touches first The object stops moving, and then the left finger touches the object. The rotation angles of the pulleys on both sides are different (θ1<θ2), and the flexible hinge 301 is inclined and deformed. The deformation amount is only related to the size of the position error and has nothing to do with the specific size of the part.

The present invention has the following advantages:

The rigid-flexible two-finger self-adaptive manipulator proposed by the present invention adopts a compact flexible differential mechanism and has the function of single input and double output. Therefore, self-adaptive grasping can be realized through one driver, and the self-adaptation is reduced. Manipulator cost and control strategies.

Compared with the traditional complex planetary gear differential mechanism, the flexible differential mechanism designed by the present invention improves the compactness of the mechanism, and the unique elasticity of the flexible mechanism enables it to automatically return to the equilibrium position after deformation;

The finger structure adopts a parallelogram linkage mechanism, so that the fingertip can produce a larger range of motion, and the manipulator based on this mechanism can adapt to objects with a larger size range;

The manipulator designed by the present invention has the function of automatic centering, that is, the movements of the two fingers are synchronized when the movement of each finger is not restricted;

The self-adaptive manipulator designed by the invention can adapt to the size change and position error of the parts when grasping the object;

Each finger of the self-adaptive manipulator designed by the present invention has only one degree of freedom, and the adaptability when grasping objects comes from the coordinated movement between the two fingers, rather than the under-actuated mechanism of the fingers. complexity, ease of maintenance, and improved reliability.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. It should be pointed out that for those skilled in the art, some improvements can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims (5)

1. a rigid-flexible two-finger adaptive manipulator, characterized in that, comprising: a motor frame (2), on which a pair of mounting seats (21) are symmetrically arranged; a linear motor (1), connected to the bottom of the motor base (2), the drive end of which is connected to the mounting hole of the motor base (2) and is located between a pair of mounting bases (21); The differential mechanism (3) includes a bracket (31), the lower end of the bracket (31) is connected to the driving end of the linear motor (1), the main body structure is "H" shape, the middle part of the main body structure is connected by a flexible hinge ( 301) is connected with a motor shaft connecting plate (32); A pair of reeds are respectively connected on the connecting plates on the left and right sides of the "H" shape, wherein each pair of reeds is located on a straight diagonal line of the connecting plate, and the connection diagonals of the two pairs of reeds intersect; A parallel link mechanism (4), comprising two pulley links (41) arranged in parallel, one end of the pulley links (41) is rotatably connected to the mounting seat (21) and the other end is rotatably connected to a fingertip (44) ; And the lower end of the pulley link (41) on the inner side of the parallel link mechanism (4) is connected with a semicircular pulley (411), and the semicircular pulley (411) is connected to a pair of springs close to one side thereof. piece. 2. The rigid-flexible two-finger adaptive manipulator according to claim 1, characterized in that: the lower end of the bracket (31) is an "L"-shaped motor shaft connecting plate (32), on which is connected a motor shaft pressing plate ( 33), the driving end of the linear motor (1) is squeezed and fixed in the light hole formed by the motor shaft pressing plate (33) and the motor shaft connecting plate (32). 3. The rigid-flexible two-finger adaptive manipulator according to claim 1, wherein the linear motor (1) is further provided with a motor cover (5), and the motor cover (5) is provided with a motor cover (5). The upper part is connected to the housing of the motor frame (2). 4. The rigid-flexible two-finger adaptive manipulator according to claim 3, characterized in that: the motor cover (5) is further provided with an electrical interface (51). 5. The rigid-flexible two-finger adaptive manipulator according to claim 1, wherein each of the reeds comprises a flat surface portion and a curved surface portion at the end of the surface portion, and the curved surface portion is connected to the semicircle on the pulley (411).

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