CN113070899A

CN113070899A - Variable-rigidity flexible manipulator

Info

Publication number: CN113070899A
Application number: CN202110354163.XA
Authority: CN
Inventors: 蒋林祥; 贺磊盈; 武传宇
Original assignee: Zhejiang University of Technology ZJUT
Current assignee: Zhejiang University of Technology ZJUT; Zhejiang Sci Tech University ZSTU; Zhejiang University of Science and Technology ZUST
Priority date: 2021-04-01
Filing date: 2021-04-01
Publication date: 2021-07-06

Abstract

The invention relates to the field of manipulators. The variable-rigidity flexible manipulator can adjust the rigidity of the manipulator in a certain range or at different grabbing stages to adapt to different grabbing objects, and ensures that enough grabbing force is provided to better grab objects. The technical scheme is as follows: the utility model provides a become flexible manipulator of rigidity which characterized in that: the manipulator comprises a motor and a base which are arranged on a mounting rack, at least two flexible fingers which are respectively connected to the base through variable stiffness components, and a tendon rope connected between the flexible fingers and the base; the number of the motors is consistent with that of the flexible fingers, and the corresponding flexible fingers are driven one by one through the corresponding tendon ropes; the rigidity changing component is communicated with an external power source.

Description

Variable-rigidity flexible manipulator

Technical Field

The invention relates to the field of manipulators, in particular to a variable-rigidity flexible manipulator.

Background

With the continuous progress of robotics and automatic control techniques, robots have been widely used in various aspects of human society. In extreme and dangerous engineering environments where humans are not involved, robots provide great convenience to humans. The mechanical arm is a main actuator for robot operation, and a plurality of rigid mechanical arms with good performance are available in the market at present, but the mechanical arms still have a plurality of defects, such as difficulty in grabbing objects which are easy to damage and deform, and the like. In recent years, a plurality of flexible manipulators appear in academia, and rigid parts of the traditional rigid manipulator are replaced by flexible organic polymers so as to overcome the defects of the traditional manipulator in a specific application scene. The flexible manipulator can be better attached to the object when grabbing the object, the structure of the object is not easy to damage, and great advantages are also provided when grabbing irregular objects. However, due to the elasticity of the joints of the flexible manipulator, the holding force is limited, so that the application range is limited, and the object may be thrown out when the object is grabbed and the object is subjected to acceleration and deceleration movement with large acceleration. In order to solve the problem, a flexible manipulator with variable rigidity is urgently needed to be invented, and the flexible manipulator not only can be suitable for grabbing various objects, but also can be locked by force after grabbing the objects.

Disclosure of Invention

The invention aims to overcome the defects in the background technology, and provides a variable-rigidity flexible manipulator, which can adjust the rigidity of the manipulator within a certain range or at different grabbing stages to adapt to different grabbing objects, so that enough grabbing force is ensured, and the objects can be better grabbed.

The technical scheme of the invention is as follows:

the utility model provides a become flexible manipulator of rigidity which characterized in that: the manipulator comprises a motor and a base which are arranged on a mounting rack, at least two flexible fingers which are respectively connected to the base through variable stiffness components, and a tendon rope connected between the flexible fingers and the base; the number of the motors is consistent with that of the flexible fingers, and the corresponding flexible fingers are driven one by one through the corresponding tendon ropes; the rigidity changing component is communicated with an external power source.

The variable stiffness component consists of an elastic part and a controllable part which are attached side by side into a whole; the elastic part is made of elastic material;

the controllable part is an elastic film bag filled with magnetic powder, a coil which can be connected with a power supply is arranged in the film bag, and the power supply is a power supply; or comprises a sealed film bag, particles arranged in the film bag and a port which is manufactured on the wall of the film bag and is communicated with a vacuum pump through an air pipe; the power source is a power source or a vacuum pump.

The flexible finger comprises a finger root which is connected with the base through a variable stiffness part and is of a hollow structure, and a fingertip which is connected with the finger root through another variable stiffness part.

A round hole is formed in the center of the side face of the finger root; one end of the tendon rope is fixed with the finger tip, and the other end of the tendon rope extends into the round hole of the finger root, bypasses the pulley on the wall part of the inner cavity of the finger root and the pulley on the base and then is downwards wound on the turntable at the shaft end of the motor.

The motor is a servo motor, a stepping motor or a steering engine.

The elastic material is one of elastic silica gel and rubber.

The particles are one of glass balls and sand.

The invention has the beneficial effects that:

according to the variable-rigidity flexible manipulator provided by the invention, the motor rotates to drive the tendon rope, so that the flexible finger bends to realize the grabbing of an object. When the rigidity is required to be changed, the coil in the controllable part is electrified, so that the magnetic powder is attached to the coil, the rigidity of the flexible finger is increased, and the holding force of the flexible finger is changed; or the rigidity of the flexible finger rigidity changing component is controlled by the negative pressure degree realized by the external vacuum pump, so that the rigidity of the flexible finger is changed; the driving mode is safe, the man-machine interaction is strong, and the adaptability and the load capacity of the manipulator are ensured; the overall rigidity of the manipulator can be adjusted according to different grabbing objects, so that sufficient grabbing force is guaranteed, the load capacity of the manipulator is improved, and grabbing of fragile and deformable objects can be completed; the rigidity can be adjusted at different grabbing stages, and the stability and the reliability of the grabbing process are improved.

Drawings

FIG. 1 is a schematic overall axial view of an embodiment of the present invention.

Fig. 2 is a schematic top view of the present invention.

Fig. 3 is a schematic view of a single finger structure in the present invention.

Fig. 4 is a schematic view of the winding structure of the tendon rope of the present invention.

Fig. 5 is one of the structural diagrams of the variable stiffness member in the present invention.

Fig. 6 is a second structural schematic diagram of the variable stiffness component of the present invention.

Detailed Description

The technical scheme of the invention is clearly and completely described below by combining the attached drawings in the embodiment of the invention.

The variable-rigidity flexible manipulator shown in fig. 1 and 2 comprises a mounting frame 5, a base 3, a motor 6, a fingertip 1, a finger root 2, a variable-rigidity component 7, a pulley 9 and a tendon rope 11.

The base 3 is arranged on a mounting frame 5 through a connecting part 4 (preferably, a copper column is riveted or bolted);

the mounting frame 5 is designed for facilitating the integration of the mechanical arm and the industrial mechanical arm and being easy to mount on other mechanical arms for use; the motor 6 is arranged on the mounting frame 5 and used for controlling the flexible fingers;

the flexible fingers are arranged on the edge of the base 3; the flexible finger consists of a fingertip 1 and a finger root 2, the fingertip and the finger root are connected by a variable stiffness part 7, and the finger root 2 and the base 3 are also connected by the variable stiffness part 7; the flexible fingers can be two fingers, three fingers or even multiple fingers, and the two fingers are adopted in the embodiment and are oppositely arranged, so that the two fingers can grab the same object together.

As shown in fig. 3, the contact surface 8 of the fingertip 1 and the base 2 is soft (elastic part), and can be made of silica gel, or can be made of flexible materials such as rubber, and can adapt to irregular objects and is beneficial to grabbing fragile objects. The surface may also incorporate pressure sensors for measuring and feeding back the grasping pressure. The finger tip and the finger root of the flexible finger root are both prior art.

As shown in fig. 4, the same side of the fingertip 1 and the base 2 is provided with a round hole, the upper end of the tendon rope 11 extends into the round hole of the fingertip and is fixed with the fingertip (the round hole can be replaced by a convex nail on the fingertip, and the upper end of the tendon rope is fastened on the convex nail), the lower end of the tendon rope extends into the round hole on the base, and winds on the turntable (the turntable is fixed at the motor shaft end of the motor 6) after sequentially passing around the pulley 9 on the base and the pulley on the base; the pulley 9 can be rotatably arranged in the middle of the wall of the finger root inner cavity, so that the friction force of the tendon rope can be obviously reduced;

the variable stiffness part 7 is composed of two parts which are attached side by side into a whole, one part is an elastic part 7.1 and can be made of elastic silica gel, rubber or other elastic materials, and the other part is a controllable part 7.2. The controllable part can have the following two structures;

as shown in fig. 5, an elastic film is made into a bag shape (preferably a high polymer film bag), magnetic powder 7.3 with a proper amount (preferably between two thirds and three fourths of the space in the bag) is filled in the bag, and a coil 7.4 is arranged in the film bag; when the coil is electrified, a magnetic field is formed, the magnetic powder is magnetized under the action of the magnetic field to form a magnetic powder chain, the rigidity is increased through the bonding force and the friction force between the magnetic powder chains, and when the current disappears, the magnetic powder is in a free loose state, so that the rigidity is reduced.

Another is as shown in fig. 6, the elastic film is made into a bag shape (preferably a high molecular film bag), a proper amount of particulate matter 7.6 (preferably between two thirds and three fourths of the space in the bag) is filled in the bag, and a port 7.5 of the wall part of the film bag is connected with a vacuum pump through an air pipe; the degree of vacuum pumping through the vacuum pump can control the magnitude of negative pressure in the elastic film, and the friction force between particles and between the elastic film and the particles is changed, so that the rigidity of the whole rigidity-variable component is adjusted. The particles can be glass balls, sand and other granular objects.

As can be seen from the figure: the variable stiffness part is in a strip shape, and the elastic part and the controllable part are also in a strip shape which is arranged side by side and is adhered into a whole; when the variable-rigidity part is connected (preferably adhered by adhesive) with two objects (such as fingertips and finger roots), two ends of the elastic part are respectively connected with the two objects, and two ends of the controllable part are also respectively connected with the two objects.

The gas pipe, vacuum pump and conducting wire are omitted in the figure.

The working principle of the invention is as follows:

the initial state of the invention is shown in fig. 1; when the manipulator is in work, the motor 6 rotates to drive the tendon rope 11, the fingertip 1 and the finger root 2 of the flexible finger and the finger root 2 and the base 3 are connected through the elastic rigidity-changing component 7, when the flexible finger is pulled, the flexible finger can bend inwards, when the surface 8 of the finger is completely attached to a grabbed object, the binding force and the friction force between the magnetic powder 7.3 in the rigidity-changing component 7 are changed by adjusting external voltage (or the friction force between the particulate matters 7.6 in the controllable part 7.2 is changed by adjusting the negative pressure of the vacuum pump), the rigidity of the whole manipulator is finally changed, the rigidity of the manipulator is increased, the grabbing force of the manipulator is improved, and the manipulator has good adaptability and load capacity. When releasing the object, firstly, the voltage of the coil is cut off (or the vacuum pump is closed), and then the motor is rotated reversely; because the variable stiffness part has elasticity, the flexible finger can restore to the original shape under the action of the elasticity to release the grabbed object.

The variable-rigidity soft manipulator provided by the invention greatly improves the load capacity of the manipulator on the basis of a common soft manipulator, can adjust the rigidity of the manipulator within a certain range, and can greatly widen the application field of the soft manipulator.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that various changes in the embodiments and modifications thereof may be made, and equivalents may be substituted for elements thereof; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. The utility model provides a become flexible manipulator of rigidity which characterized in that: the manipulator comprises a motor (6) and a base (3) which are arranged on a mounting rack (5), at least two flexible fingers which are respectively connected to the base through variable stiffness components (7), and tendon ropes (11) connected between the flexible fingers and the base; the number of the motors is consistent with that of the flexible fingers, and the corresponding flexible fingers are driven one by one through the corresponding tendon ropes; the rigidity changing component is communicated with an external power source.

2. The variable stiffness soft robot of claim 1, wherein: the variable stiffness component consists of an elastic part (7.1) and a controllable part (7.2) which are attached side by side into a whole; the elastic part is made of elastic material;

the controllable part is an elastic film bag filled with magnetic powder, and a coil which can be connected with a power supply is arranged in the film bag; or comprises a sealed film bag, particles (7.6) arranged in the film bag and a port (7.5) which is made on the wall of the film bag and is communicated with a vacuum pump through an air pipe; the power source is a power source or a vacuum pump.

3. The variable stiffness soft robot of claim 2, wherein: the flexible finger comprises a finger root (2) which is connected with the base through a variable stiffness part and is of a hollow structure, and a fingertip (1) which is connected with the finger root through another variable stiffness part.

4. The variable stiffness soft robot of claim 3, wherein: a round hole is formed in the center of the side face of the finger root; one end of the tendon rope is fixed with a fingertip; the other end of the tendon rope extends into the round hole of the finger root, and winds downwards on the turntable at the shaft end of the motor after passing through the pulley (9) on the inner cavity wall of the finger root and the pulley on the base.

5. The variable stiffness soft robot of claim 4, wherein: the elastic material is one of elastic silica gel and rubber.

6. The variable stiffness soft robot of claim 5, wherein: the motor is a servo motor, a stepping motor or a steering engine.

7. The variable stiffness soft robot of claim 6, wherein: the particles are one of glass balls and sand.