Hydraulically-driven rigidity-variable soft gripper

Abstract

The invention relates to a hydraulically-driven variable-rigidity soft gripper which comprises flexible fingers, a fixed support, a sliding block, a gear, an upper oil pipe, a lower oil pipe, a piston driving device, a first flow divider valve, a second flow divider valve and a motor. The flexible finger is arranged at the upper end of the sliding block, the sliding block is slidably connected with the fixed support, the gear is meshed with a rack on the sliding block, the piston driving device is fixed to the lower end of the fixed support, one end of the upper oil pipe is connected with the sliding block, the other end of the upper oil pipe is connected with the second flow divider valve, and one end of the lower oil pipe is connected with the sliding block. One end of the sliding block driving motor is connected with a sliding block, the other end of the sliding block driving motor is connected with a first flow divider valve, the sliding block driving motor is connected with a sun gear in a fixed support, the sun gear is meshed with a planet gear, the planet gear is meshed with a rack, and the piston driving motor is connected with a piston driving device. The mechanical gripper is simple in structure, the gripping force of the gripper can be adjusted according to the weight of an object, fingers can be bent more easily during gripping action, and therefore lossless gripping of the object is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of soft grippers, and in particular to a hydraulically driven variable-rigidity soft gripper. Background Art

[0002] Soft grippers are made of soft, deformable materials and have higher adaptability. They can adapt to objects of various shapes, sizes and surface characteristics without the need to design specific clamps or claws. This adaptability makes soft grippers more flexible and versatile in handling different objects. Soft grippers have no sharp edges or mechanical parts, so they reduce scratches and damage to the surface of the object when in contact with the object being grasped. This makes soft grippers more suitable for fragile or surface-sensitive objects.

[0003] The existing variable stiffness soft grippers are basically driven by gas. The gripping force and bending degree of the soft hand can be controlled by controlling the air pressure of the input gas. This method will result in insufficient gripping force. Moreover, the current grippers are fixed on the base and cannot be adjusted for objects of different sizes, and the gripping range is narrow.

[0004] Therefore, in order to solve the above problems, the present invention proposes a hydraulically driven variable stiffness soft gripper, which is simple to control, has a large gripping force range, and can achieve adjustment of different finger positions. Summary of the invention

[0005] In response to the above problems, the present invention invents a hydraulically driven variable stiffness soft gripper through the design of TPMS (three-period minimal surface structure) flexible bionic layer, rigid layer, and oil-filled variable stiffness layer. The gripper has sufficient gripping stiffness and can effectively reduce the strength of finger bending while ensuring the safety of the grasped object.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A hydraulically driven variable stiffness soft gripper proposed in the present invention comprises flexible fingers, a fixed support, a slider, a gear, an upper oil pipe, a lower oil pipe, a piston drive device, a first diverter valve, a second diverter valve and a motor; the flexible fingers are arranged at the upper end of the slider, the gears are meshed with the rack on the slider, the piston drive device is fixed to the lower end of the fixed support, one end of the upper oil pipe is connected to the slider, and the other end is connected to the diverter valve 2, one end of the lower oil pipe is connected to the slider, and the other end is connected to the diverter valve 1, the slider drive motor is connected to the sun gear in the fixed support, the sun gear is meshed with the planetary gear, the planetary gear is meshed with the rack, and the motor 2 is connected to the piston drive device.

[0008] The flexible finger includes a silicone shell, a TPMS (three-period minimal surface structure) flexible bionic layer, a rigid layer, and an oil-filled variable stiffness layer, which are sequentially arranged inside the silicone shell from bottom to top; the TPMS (three-period minimal surface structure) flexible bionic layer is connected to the lower oil pipe through the internal oil passage of the slider, the other end of the lower oil pipe is connected to the diverter valve 1, the diverter valve is connected to the piston drive device, and the piston drive device is driven by a motor;

[0009] The slider is installed in the slide groove of the fixed support, the lower end of the slider is connected to the rack, the rack is meshed with the planetary gear, the planetary gear is meshed with the sun gear, the sun gear is driven by the motor, the motor drives the sun gear to rotate and drives the planetary gear to rotate, the planetary gear rotates and drives the rack to move linearly, and the rack drives the slider to move linearly, so as to realize the grasping of objects of different sizes by fingers;

[0010] The piston driving device includes two pistons, a gear, a rack, and a housing. The gear is meshed with the rack, the rack is connected to the piston, the piston is connected to a piston barrel on the housing, oil is filled in the piston barrel, the motor drives the gear to rotate, the gear drives the rack to make the piston fixed on the rack reciprocate, and the oil pushing and oil sucking actions are completed under the push of the piston. There are two oil ports on the housing, which are respectively connected to two diverter valves.

[0011] The beneficial effects of the present invention are:

[0012] 1. A sliding groove is provided on the fixed support, which enables the fingers installed on the slider to slide and adjust;

[0013] 2. The sun gear driven by the motor drives the planetary gear to rotate, and the planetary gear drives the rack on the slider to reciprocate, realizing the stable sliding of the slider;

[0014] 3. The piston drive device can realize the actions of oil absorption and oil filling at the same time. When the oil filling variable stiffness layer is filled with oil, the finger is bent, and when the oil is absorbed, the TPMS (three-period minimal surface structure) flexible bionic layer is contracted, thereby reducing the bending strength of the finger for a more stable grasping;

[0015] 4. When the fingers grasp an object, the TPMS (three-periodic minimal surface structure) flexible bionic layer can better fit the surface of the object based on the deformation ability of the TPMS structure, thereby realizing the bionic grasping of the object. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of a hydraulically driven variable-rigidity soft gripper proposed by the present invention.

[0017] Figure 2 yes Figure 1 Schematic diagram of the internal structure of the middle fixed support;

[0018] Figure 3 yes Figure 1 Schematic diagram of the cross-sectional structure of the flexible finger;

[0019] Figure 4 yes Figure 1 Schematic diagram of the structure of the piston drive device;

[0020] Figure 5 yes Figure 4 Schematic diagram of the piston structure.

[0021] The figure numbers are as follows: 1-fixed support; 2-slider drive motor; 3-diverter valve No. 1; 4-reducer; 5-piston drive motor; 6-diverter valve No. 2; 7-planetary gear; 8-slider; 9-oil pipe; 10-sun gear; 20-piston drive device; 21-rack; 22-gear; 23-guide pin; 24-piston; 30-flexible finger; 31-oil-filled variable stiffness layer; 32-rigid body; 33-pin; 34-TPMS structure; 35-rubber ball; 36-oil port No. 1; 37-oil port No. 2. DETAILED DESCRIPTION

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] It should be noted that in the description of the present invention, it should be noted that the terms "upper", "lower", "top", "bottom", "one end", "the other end", "left", "right", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not mean that the device or element must have a specific orientation, be constructed and operated in a specific orientation.

[0024] See attached Figure 1-5, a specific structure of a hydraulically driven variable stiffness soft gripper proposed in the present invention is given. The soft gripper includes a fixed support 1, a slider drive motor 2, a first diverter valve 3, a reducer 4, a piston drive motor 5, a second diverter valve 6, a planetary gear 7, a slider 8, an oil pipe 9, a sun gear 10, a piston drive device 20, a rack 21, a gear 22, a guide pin 23, a piston 24, a flexible finger 30, an oil-filled variable stiffness layer 31, a rigid body 32, a pin 33, a TPMS bionic structure layer 34, a rubber ball 35, a first oil port 36, and a second oil port 37. In this embodiment, three sliders 10 are evenly installed on the upper end of the fixed support 1, and three flexible fingers 30 are installed on the slider. An oil passage is arranged inside the slider and is connected to the No. 1 oil port 36 and the No. 2 oil port 37 respectively. The two oil passage ends at the rear ends of the three sliders are connected to the No. 2 diverter valve 7 and the No. 1 diverter valve 3 respectively through oil pipes. The No. 2 diverter valve 7 is connected to the piston drive device 20 through an oil pipe, and the No. 1 diverter valve 3 is connected to the piston drive device 20 through an oil pipe. The fixed support 1 has a sun gear 9 connected to the slider drive motor 2 inside. The sun gear 9 is meshed with the planetary gear 6, and the planetary gear 6 is meshed with the rack on the slider 10. The slider drive motor 2 drives the sun gear 9 to rotate, and the sun gear 9 drives the planetary gear 6 to rotate in the opposite direction. The planetary gear 6 drives the slider to do linear motion, thereby playing a role in adjusting the diameter of the object grasped by the gripper.

[0025] The piston driving device 20 includes a rack 21, a gear 22, a piston 23 and a flexible finger 30. One end of the rack 21 is connected to the piston 23, and the other end is connected to the guide pin shaft 23. The gear 22 drives the two pistons to perform opposite linear motions through the reducer 4 and the piston driving motor 5. When the piston pushes the hydraulic oil to move, it produces a dual effect of oil filling and oil absorption. The piston driving device 20 causes the oil-filled variable stiffness layer 31 and the TPMS bionic structure layer 34 in the flexible finger 30 to expand or absorb oil and compress. When the oil-filled variable stiffness layer 31 is expanded by oil, the soft gripper bends under the action of expansion, and the TPMS bionic structure layer 34 absorbs oil and compresses. Under the action of contraction, the bending strength of the soft gripper is reduced. The rubber ball 35 located on the TPMS bionic structure layer 34 gradually protrudes under the action of contraction. When grasping an object, the TPMS bionic structure layer 34 can fit closely with the surface of the grasped object to achieve bionic grasping of the object. At the same time, the rubber ball 35 plays a role in increasing friction.

[0026] The embodiments described above are merely descriptions of preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A hydraulically driven variable stiffness soft gripper, characterized in that: The soft gripper includes a fixed support, a slider, a gear, an oil pipe, a piston drive device, a No. 1 diverter valve, a No. 2 diverter valve, a slider drive motor, a piston drive click, a flexible finger, a sun gear, a planetary gear, and a rack; the flexible finger is arranged at the upper end of the slider, the gear is meshed with the rack on the slider, the piston drive device is fixed to the lower end of the fixed support, one end of the upper oil pipe is connected to the slider, and the other end is connected to the diverter valve 2, one end of the lower oil pipe is connected to the slider, and the other end is connected to the diverter valve 1, the slider drive motor is connected to the sun gear in the fixed support, the sun gear is meshed with the planetary gear, the planetary gear is meshed with the rack, and the motor 2 is connected to the piston drive device; The flexible finger includes a silicone shell, a TPMS (three-period minimal surface structure) flexible bionic layer, a rigid layer, and an oil-filled variable stiffness layer, which are sequentially arranged inside the silicone shell from bottom to top; the TPMS (three-period minimal surface structure) flexible bionic layer is connected to an oil pipe through an oil passage inside a slider, the other end of the oil pipe is connected to a No. 1 diverter valve, the diverter valve is connected to a piston drive device, and the piston drive device is driven by a motor; the oil-filled variable stiffness layer is connected to an oil pipe through another oil passage inside a slider, the other end of the oil pipe is connected to a No. 2 diverter valve, the diverter valve is connected to a piston drive device, and the piston drive device is driven by a motor; The slider is installed in the slide groove of the fixed support, the lower end of the slider is connected to the rack, the rack is meshed with the planetary gear, the planetary gear is meshed with the sun gear, the sun gear is driven by the slider driving motor, the motor drives the sun gear to rotate, driving the planetary gear to rotate, the planetary gear rotation drives the rack to move linearly, and the rack drives the slider to move linearly, so as to realize the grasping of objects of different sizes by fingers.

2. The piston driving device includes two pistons, a gear, a rack, and a guide pin shaft. The gear is meshed with the rack. One end of the rack is connected to the piston, and the other end is connected to the guide pin shaft. The motor drives the gear to rotate, and the gear drives the rack to make the piston fixed on the rack reciprocate. Under the push of the piston, the oil pushing and oil sucking actions are completed. There are two oil ports on the box body, which are respectively connected to the No. 1 and No. 2 diverter valves.

3. The hydraulically driven variable stiffness soft gripper according to claim 1, characterized in that: The internal structure includes a TPMS (three-period minimal surface structure) flexible bionic layer, a rigid layer, and an oil-filled variable stiffness layer, and each layer is not interconnected.

4. The hydraulically driven variable stiffness soft gripper according to claim 1, characterized in that: The sun gear, planetary gear and slider are installed in the fixed support. The slider is installed in the slide groove of the fixed support. The lower end of the slider is connected to the rack. The rack is meshed with the planetary gear. The planetary gear is meshed with the sun gear. The sun gear is driven by a motor. The motor drives the sun gear to rotate and drives the planetary gear to rotate. The rotation of the planetary gear drives the rack to move linearly. The rack drives the slider to move linearly, so as to realize the grasping of objects of different sizes by fingers.

5. The hydraulically driven variable stiffness soft gripper according to claim 1, characterized in that: In the piston driving device, the gear is meshed with the rack, and the rack is fixedly connected with the piston.

6. The hydraulically driven variable stiffness soft gripper according to claim 1, characterized in that: The TPMS (three-periodic minimal surface structure) flexible bionic layer inside the finger is a primitive (P) structure, which is made of silicone 3D printing. This structure has a large deformation and resilience, and can fit the surface of the grasped object to the greatest extent, achieving bionic grasping.

7. The hydraulically driven variable stiffness soft gripper according to claim 1, characterized in that: The finger has dual effects of grabbing the oil-filled variable stiffness layer to expand and the TPMS (three-period minimal surface structure) flexible bionic layer to contract under the action of the piston driving device.

Images