A rigid-flexible coupling mechanical gripper based on a bistable elastic origami mechanism

Abstract

The present invention belongs to the technical field related to artificial intelligence robots, and discloses a rigid-flexible coupling mechanical gripper based on a bistable elastic origami mechanism. The mechanical gripper includes a base, a clamping claw, a trigger rope, a self-locking buckle and a self-locking connecting plate. The clamping claw is used to clamp an object. The two ends of the trigger rope are respectively connected to the clamping claws on both sides of the base. When the object falls and contacts the trigger rope, the clamping claw is triggered to close and clamp the object; one end of the self-locking buckle is connected to the self-locking connecting plate, and the other end is connected to the base. After the clamping claw is triggered, it drives the self-locking buckle to rotate and twist. When the self-locking buckle reaches the maximum deformation, the self-locking buckle releases energy and drives the clamping claw to close quickly. After closing, the self-locking clamping object is achieved by the characteristics of the mechanism. Through the present invention, the problem that the existing gripper cannot simply and simultaneously achieve self-triggered rapid clamping, self-locking after clamping, and adapt to the position offset, shape and size of the clamped object is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field related to artificial intelligence robots, and more specifically, relates to a rigid-flexible coupling mechanical gripper based on a bistable elastic origami mechanism. Background Art

[0002] In recent years, the application of industrial robots has gradually increased, and with the development of industry, automated production is a development trend, and gripping mechanisms play an important role in automated production.

[0003] Rigid gripping mechanisms grip objects with a preset force or displacement under external drive, and can output greater force and more controllable motion. However, when the gripped objects are fragile, deformable, or have unstable shapes, it is easy to cause unnecessary damage and destruction to the gripped objects, or it is difficult to adapt to objects with complex shapes.

[0004] In the existing flexible grasping mechanism, the commonly used methods to achieve flexibility include: using flexible materials to transmit external driving force, using the deformation of flexible materials to protect objects and create a certain adaptability; using under-actuated mechanisms to transmit external driving force, and using their deformation characteristics to grasp objects of different shapes and sizes. Flexible grasping mechanisms are highly flexible and have strong adaptability to objects with complex shapes, and can better realize the automated loading and unloading of workpieces, but the output force of flexible grasping mechanisms is generally too small and the position of movement is difficult to accurately control.

[0005] In addition, the flexible and rigid methods have the following disadvantages: 1) It is necessary to use manual or sensor-installed methods to determine the grasping timing, which increases the additional cost of grasping; 2) After the grasping is completed, external drive needs to continue to act to provide continuous clamping force; 3) The force for clamping and opening the gripping device is the same, which may easily result in excessive force during clamping or insufficient force to grasp the object. Summary of the invention

[0006] In response to the above defects or improvement needs of the prior art, the present invention provides a rigid-flexible coupling mechanical gripper based on a bistable elastic origami mechanism, which solves the problem that the existing grippers cannot simply and simultaneously achieve self-triggered rapid clamping, self-locking after clamping, and adapt to the position offset, shape and size of the clamped object.

[0007] To achieve the above object, according to the present invention, a rigid-flexible coupling mechanical gripper based on a bistable elastic origami mechanism is provided, the mechanical gripper comprising a base, a clamping claw, a trigger net, a self-locking connecting plate and a self-locking buckle, wherein:

[0008] The clamping jaws are arranged on both sides of the base for clamping an object, and the trigger rope is arranged above the base. The two ends of the trigger rope are respectively connected to the clamping jaws on one side and the fixed bracket on the other side to form a mesh structure. When an object falls and contacts the trigger net, the clamping jaws are triggered to close and clamp the object.

[0009] One end of the self-locking buckle is connected to the self-locking connecting plate, and the other end is connected to the base. When the clamping jaws are closed, the self-locking buckle is driven to rotate and twist. When the clamping jaws reach the maximum torsional deformation, energy is released to drive the clamping jaws to achieve self-locking and rapid closure, and self-lock to clamp the object when closed.

[0010] Further preferably, the self-locking buckle is C-shaped, and the position of one end connected to the clamp is higher than the position of one end connected to the base, so as to achieve twisting.

[0011] Further preferably, the self-locking buckle is made of spring steel with toughness.

[0012] Further preferably, the self-locking buckle is connected to the self-locking connecting plate and the base via a rotating shaft, and the self-locking buckle rotates around the rotating shaft when the self-locking buckle undergoes torsional deformation.

[0013] Further preferably, the base is in a "J" shape, and the lower end of the clamp is connected to a side plate, and the side plate and the bottom end are connected to the bottom end of the base. When the self-locking buckle is self-locking, the side plate is close to both sides of the trapezoidal base.

[0014] Further preferably, a motor and a driving rod are also provided in the gripper, and the motor drives the rod to rotate, and the driving rod drives the self-locking buckle to rotate and thereby drives the clamping claw to open.

[0015] Further preferably, the clamping claw is arc-shaped and is arranged opposite to the protrusion of the base.

[0016] Further preferably, the number of the trigger ropes is one or more.

[0017] Further preferably, fixed brackets are provided on both sides of the clamping jaw, and the trigger rope is connected to the fixed bracket and the clamping jaw to form a trigger net, so that the clamping jaws on both sides are subjected to balanced force to avoid unilateral clamping jaw triggering.

[0018] Further preferably, the middle of the clamping jaw is hollowed out, and the hollowed out part is filled with a flexible material to achieve soft contact with the clamped object.

[0019] In general, the above technical solutions conceived by the present invention have the following beneficial effects compared with the prior art:

[0020] 1. The elastic origami mechanism of the present invention, wherein the spatial link configuration formed by the side plate, the clamping claw, the self-locking connecting plate and the self-locking buckle has the ability to self-lock after the gripper is clamped by the dead point of the movement, and the spatial link configuration combined with the certain elastic deformation ability of the self-locking buckle gives the gripper the characteristics of bistable motion, thereby enabling it to quickly grasp objects and have the ability of self-triggering;

[0021] 2. The self-locking function provided by the present invention has different forces when grasping and opening. The force when grasping an object is generated by the energy when the self-locking buckle is released in a bistable state. This energy is determined by the torsional energy of the elastic plate and the energy density of the material. However, when opening, the self-locking buckle cannot deform in the torsional form when it was previously closed due to the dead point of the mechanism, and a larger resistance force is generated;

[0022] 3. The gripper provided by the present invention has the characteristic of bistable folding. With the cooperation of the trigger mechanism, this characteristic gives the gripper the ability of self-triggering rapid clamping. Bistable means that the mechanism has two states with low energy and can exist stably, and when switching between these two states, a large amount of work needs to be done on the system to cross the energy barrier between the two low energy states. After crossing the energy barrier, the rapid release of energy will lead to a faster movement speed;

[0023] 4. This device is a special form of the Miura origami mechanism. By replacing a rigid part of the Miura origami mechanism with a resilient elastic self-locking buckle, the device has both the simple analyzability of the single-degree-of-freedom motion of the origami mechanism and the bistable self-locking characteristics.

[0024] 5. The left and right sides of the clamping jaws and the self-locking mechanism used in the present invention are completely symmetrical. Under the action of the flexible rod, the object can deviate from the symmetry center of the mechanism when being clamped, and can adapt to the position offset, shape and size of the clamped object;

[0025] 6. The three characteristics of the present invention, namely, self-triggering rapid clamping, self-locking after clamping, and adapting to the position offset, shape and size of the clamped object, are embodied in a simple and compact mechanical mechanism, making the mechanism have better portability and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic structural diagram of a mechanical gripper constructed according to a preferred embodiment of the present invention;

[0027] Figure 2 is a schematic diagram of the process of a mechanical gripper grasping an object constructed according to a preferred embodiment of the present invention;

[0028] Figure 3 It is a schematic diagram of the structure constructed according to the preferred embodiment of the present invention when an attempt is made to open in reverse when self-locking;

[0029] Figure 4 is a schematic diagram of the structure constructed according to the preferred embodiment of the present invention when it is controlled to open;

[0030] Figure 5 It is a schematic diagram of the structure of a mechanical gripper constructed according to a preferred embodiment of the present invention after grasping an object.

[0031] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0032] 1-base, 2-gripping jaws, 3-self-locking connecting plate, 4-self-locking buckle, 5-trigger rope, 6-driving rod, 7-motor, 8-side plate. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0034] like Figure 1 As shown, the invention is a rigid-flexible coupling mechanical gripper based on a bistable elastic origami unit, on which three units are arranged, namely, an elastic origami unit, a trigger unit and a control unit, which cooperate to achieve the clamping and releasing of objects.

[0035] The elastic origami unit consists of three rigid plates connected in sequence by plane hinges at a certain spatial position, and an elastic plate is connected to the rigid plates at the head and tail by an axis at a certain position. The unit accumulates energy when the gripper starts to close, and after reaching the maximum energy state, it quickly releases energy and closes quickly.

[0036] The trigger unit is composed of a trigger rope connected between the left and right parts of the elastic origami unit, wherein the trigger rope is a Kevlar rope, a carbon fiber rope or a steel wire rope. When the gripper is opened, the trigger unit triggers the elastic origami unit to perform a bistable process through the triggering of an object.

[0037] The control device is composed of a driving rod and a torque motor, wherein the base of the torque motor is fixed on the bottom plate of the elastic origami unit, and the driving rod is fixed on the motor shaft of the torque motor. After the gripper clamps the object, the self-locking elastic origami unit is controlled to release the object and return it to the open state to be triggered.

[0038] Specifically, the manipulator is composed of a base 1, two groups of grippers 2, two groups of self-locking connecting plates 3, two groups of self-locking buckles 4, a trigger rope 5, two groups of side plates 8, two groups of driving rods 6 and two groups of motors 7. The side plates 8, grippers 2, self-locking connecting plates 3, and self-locking buckles 4 are elastic origami mechanisms, the trigger rope 5 is a trigger device of the mechanism, and the driving rod 6 and the motor 7 are control devices of the mechanism.

[0039] like Figure 2 As shown, the self-locking buckle 4 of the elastic origami mechanism increases its bending deformation when the clamping jaws 2 begin to close, accumulates energy, and after reaching the maximum energy state, begins to release energy due to the continued rotation of the self-locking connecting plate 3, thereby quickly closing.

[0040] refer to Figure 2 The trigger rope 5 serves as a trigger device and is stretched straight when the jaws 2 are fully opened. When the clamped object presses down on the trigger rope 5, the trigger rope 5 pulls the jaws 2 to close, causing the self-locking buckle 4 to deform and increase to a maximum energy state. Subsequently, the jaws 2 quickly release energy and close quickly, completing the self-triggering of the mechanical gripper.

[0041] refer to Figure 3 , the driving rod 6 and the motor 7 are control devices. The self-locking connecting plate 3 rotates in a large range after the clamping jaws 2 are closed. If an external force forces the clamping jaws 2 to open, the self-locking connecting plate 3 will self-lock under the joint action of the clamping jaws 2 and the twisted self-locking buckle 4 and generate a large resistance, so that the self-locking buckle 4 cannot be reversed from the twisting deformation state to the bending deformation state when the clamping jaws 2 are opened, and can only gradually increase the twisting deformation to hinder the opening of the clamping jaws 2. The self-locking effect of the mechanical gripper is achieved.

[0042] refer to Figure 4 When the motor 7 rotates the driving rod 6, it drives the self-locking buckle 4, which drives the self-locking connecting plate 3 to rotate in the opposite direction. At this time, the self-locking connecting plate 3 has no self-locking effect on the clamping jaw 2. As the motor 7 continues to rotate, the clamping jaw 2 will be driven to open, achieving the effect of controlled opening of the mechanical gripper.

[0043] refer to Figure 5 , the clamping jaws 2 are blocked and stopped when touching the object, and the deformation of the self-locking buckle 4 generates a pre-tightening force. Because the pre-tightening force exists within a certain range and the object is acted upon by two symmetrical clamping jaws 2, the object can be acted upon by two pre-tightening forces at the same time within a certain range, and can be positioned nearby, so it can adapt to the position deviation, shape and size of the object when clamping. And due to the bending deformation and torsional deformation process of the self-locking buckle 4, after clamping the object, the object cannot cause the clamping jaws 2 to open and thus achieve the self-locking effect.

[0044] Preferably, the middle of the clamp is hollowed out, and the hollow is filled with a flexible material to achieve soft contact with the clamped object. Fixed brackets are provided on both sides of the clamp, and the trigger rope is connected to the fixed bracket and the clamp to form a trigger net, so that the clamps on both sides are subjected to balanced force to avoid unilateral clamp triggering.

[0045] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A rigid-flexible coupling mechanical gripper based on a bistable elastic origami mechanism, characterized in that: The mechanical gripper includes a base (1), clamping jaws (2), a trigger rope (5), a self-locking buckle (4), and a self-locking connecting plate (3). Among them, the clamping jaws (2) are arranged on both sides of the base (1) for clamping an object. The trigger rope (5) is arranged above the base. Both ends of the trigger rope (5) are respectively connected to the clamping jaws (2) on both sides of the base. When an object falls and contacts the trigger rope, the clamping jaws are triggered to close and clamp the object; one end of the self-locking buckle (4) is connected to the self-locking connecting plate (3), and the other end is connected to the base (1). When the clamping jaws (2) close, they drive the self-locking buckle to rotate and twist. When it reaches the maximum torsional deformation, it releases energy to drive the clamping jaws to quickly close and self-lock to clamp the object.

2. A rigid-flexible coupling mechanical gripper based on a bistable elastic origami mechanism as claimed in claim 1, characterized in that: The self-locking buckle (4) is in a C shape. The position of the end connected to the self-locking connecting plate (3) of the self-locking buckle (4) is higher than the position of the end connected to the base (1), and both are connected by a rotating shaft for realizing torsion and rotation.

3. A rigid-flexible coupling mechanical gripper based on a bistable elastic origami mechanism as claimed in claim 2, characterized in that: The self-locking buckle (4) is made of spring steel with toughness.

4. A rigid-flexible coupling mechanical gripper based on a bistable elastic origami mechanism as claimed in claim 1 or 2, characterized in that: The self-locking buckle (4) is connected to the clamping jaws (2) through the self-locking connecting plate (3). The self-locking connecting plate (3) is hinged to the clamping jaws and connected to the base (1) through a rotating shaft. When the self-locking buckle undergoes torsional deformation, the self-locking connecting plate rotates around the rotating shaft and undergoes torsional deformation.

5. The rigid-flexible coupling mechanical gripper based on the bistable elastic origami mechanism according to claim 4, characterized in that: The base (1) is in a "ji" shape. The lower end of the clamping jaws (2) is connected with side plates (8). The bottom ends of the side plates are connected to the bottom end of the base. When the self-locking buckle self-locks, the side plates closely adhere to both sides of the trapezoidal base.

6. The rigid-flexible coupling mechanical gripper based on the bistable elastic origami mechanism according to claim 4, characterized in that: A motor (7) and a driving rod (6) are also arranged in the mechanical gripper. The motor drives the driving rod (6) to rotate, and the driving rod pushes the self-locking buckle to rotate, thereby driving the clamping jaws to open.

7. The rigid-flexible coupling mechanical gripper based on a bistable elastic origami mechanism according to claim 1, characterized in that: The upper part of the clamping jaws (2) is arc-shaped and is arranged opposite to the protrusion of the base.

8. The rigid-flexible coupling mechanical gripper based on the bistable elastic origami mechanism according to claim 7, characterized in that: The trigger rope (5) is one or more.

9. The rigid-flexible coupling mechanical gripper based on the bistable elastic origami mechanism according to claim 8, characterized in that: Fixed brackets are arranged on both sides of the clamping jaws (2). The trigger rope (5) is connected to the fixed brackets and the clamping jaws to form a trigger net, so that the clamping jaws on both sides are evenly stressed and unilateral clamping jaw triggering is avoided.

10. The rigid-flexible coupling mechanical gripper based on the bistable elastic origami mechanism according to claim 9, characterized in that: The middle of the clamping jaws (2) is hollowed out, and the hollowed-out part is filled with a flexible material to achieve soft contact with the grabbed object.

Images