A quicksand variable-rigidity soft gripper and its drive control system and method

Abstract

The present invention relates to a quicksand variable-rigidity soft gripper based on the pneumatic quicksand principle, and its drive control system and method. The variable-rigidity soft gripper comprises quicksand variable-rigidity flexible fingers, a particle variable-rigidity flexible palm, a flexible finger position adjustment slider, and a rigid base. The quicksand variable-rigidity flexible fingers are connected to the flexible finger position adjustment block via a through hole in the middle of the flexible finger position adjustment block. The flexible finger position adjustment block is connected to the rigid base via a cylindrical protrusion of the flexible finger position adjustment block and a slideway portion of the rigid base. The particle variable-rigidity flexible palm is connected to the rigid base via a circular through hole in the rigid base. The present invention achieves adaptive gripping of objects with complex surface morphologies and has the characteristics of low cost, simple structure, convenient control, and a single drive source.

Description

Technical Field

[0001] The present invention relates to the technical field of soft robots, and in particular to a quicksand variable-rigidity soft gripper and a drive control system and method thereof. Background Art

[0002] Traditional soft grippers mostly use a through-cavity structure, which cannot achieve autonomous control of bending, especially when faced with complex contours. The inability to change its own stiffness structure results in a low grasping success rate. The method of using particle vacuum blocking to increase stiffness has the advantages of fast response speed, simple structure, and low cost. The principle of particle blocking is to extract the air from the particle chamber so that the chamber compresses the flexible film and adheres it to the particle, forming an extrusion force between the flexible film and the particle, and between the particles, resulting in a smaller gap between the particles and thus increasing stiffness. However, in the prior art, the method of changing stiffness by particle blocking requires that the driving chamber responsible for the driving part needs to be filled with air pressure, and bending is generated by the proportional difference in wall thickness, which requires at least two air sources. Summary of the Invention

[0003] The purpose of this application is to solve at least one of the above problems and provide a quicksand variable stiffness soft clamp.

[0004] Another object of the present application is to provide a drive control system for a quicksand variable-rigidity soft gripper.

[0005] Another object of the present application is to provide a drive control method for a quicksand variable-rigidity soft gripper drive control system.

[0006] The technical solution of this application is as follows:

[0007] The present application discloses a quicksand variable stiffness soft gripper and its drive control system, comprising:

[0008] A quicksand variable-rigidity soft gripper, the main body structure of which includes: quicksand variable-rigidity flexible fingers, particle variable-rigidity flexible palms, flexible finger position adjustment sliders and a rigid base; the quicksand variable-rigidity flexible fingers and the flexible finger position adjustment block are connected via a through hole in the middle of the flexible finger position adjustment block; the flexible finger position adjustment block and the rigid base are connected via the cylindrical protrusion of the flexible finger position adjustment block and the slide portion of the rigid base; the particle variable-rigidity flexible palm and the rigid base are connected via a circular through hole in the rigid base.

[0009] Preferably, the quicksand-variable-rigidity flexible finger has a main body made of soft elastic material, and comprises three sections of pneumatic flexible units, namely: pneumatic flexible unit I, pneumatic flexible unit II and pneumatic flexible unit III, and a quicksand-variable-rigidity joint is provided between two adjacent sections of pneumatic flexible units, namely: quicksand-variable-rigidity joint I and quicksand-variable-rigidity joint II.

[0010] Preferably, the pneumatic flexible unit is a multi-layer stacked structure, including: a pneumatic chamber layer, a connecting layer, an airway layer I, and a bottom sealing layer I; the pneumatic chamber layer has three independent driving cavities for driving the flexible fingers to bend; the connecting layer has air vents connected to the pneumatic chamber, and the airway layer I has three air inlets and airways, which are connected to the connecting layer and are used to input air pressure into the driving chamber, and the bottom sealing layer I has a trapezoidal corrugated protrusion with an inclined angle, which is used to increase the friction and contact area between the flexible finger and the fingertip of the object.

[0011] Preferably, the quicksand variable stiffness joint is a multi-layer stacked structure, including: a particle filling layer, an air pore array layer, an airway layer II, and a bottom sealing layer II; the particle filling layer has two independent variable stiffness cavities for filling particles, and the variable stiffness cavities are provided with exhaust holes above the variable stiffness cavities for discharging the gas in the variable stiffness chambers when inflation stops; the air pore array layer has an air pore array for connecting the variable stiffness chambers of the particle filling layer; the airway layer II has an air inlet and an airway, and the airway is connected to the air pore array layer for inputting pressure into the variable stiffness chamber; the bottom sealing layer II has particle protrusions for forming interlocking constraints with the surface of the object to improve the grasping stability.

[0012] Preferably, the pore array layer has two pore arrays with a diameter of 1 mm; the airway layer II has two air inlets and airways; and the bottom sealing layer II has three round particle protrusions.

[0013] Preferably, the particle-variable-rigidity flexible palm is composed of an elastic film, filling particles and a cylindrical soft body with an airway, the elastic film is sealed with the cylindrical soft body to form a particle-filled chamber; the filling particles are filled in the particle-filled chamber formed by the elastic film and the cylindrical soft body, and the object is wrapped by utilizing the adaptive deformation of the elastic film; the bottom of the cylindrical soft body with an airway has a disc-shaped outer edge, the function of which is to make the elastic film and the cylindrical soft body better sealed to form a particle-filled chamber.

[0014] A drive control system for a quicksand variable-stiffness soft gripper comprises: a host computer, a slave computer, a power amplifier circuit, a stiffness control system and a pneumatic drive system; wherein the host computer generates control instructions for the stiffness control system and the pneumatic drive system respectively based on instruction information input by the user, such as driving air pressure and joint stiffness, and transmits them to the slave computer; the slave computer converts the control instructions into drive signals through the power amplifier circuit and transmits them to the stiffness control system and the pneumatic drive system respectively, thereby realizing control of the motion posture and motion stiffness of the quicksand variable-stiffness soft gripper.

[0015] Preferably, the stiffness control system is:

[0016] The power supply supplies power to each solenoid valve, solenoid valve I connects the air source and the air channel of the driving chamber I and adjusts the input air pressure; solenoid valve II connects the air source and the air channel of the driving chamber II and adjusts the input air pressure; solenoid valve III connects the air source and the air channel of the driving chamber III and adjusts the input air pressure; solenoid valve IV connects the air source and the air channel of the variable stiffness chamber I and adjusts the input air pressure; solenoid valve V connects the air source and the air channel of the variable stiffness chamber II and adjusts the input air pressure; the host computer is connected to the STM32 development control board to transmit the task instructions to the STM32 development control board, and the STM32 development control board inputs a voltage signal to each solenoid valve to control the size of the input air pressure. The air source is used to provide air pressure. One air source is divided into 5 independent air paths through the air pipe shunt, and the control valve is used to control the connection of the air path between the air inlet of each solenoid valve and the air source;

[0017] The air outlet of the solenoid valve I is connected to the airway of the variable stiffness chamber I, and the air inlet of the solenoid valve I is connected to the air source; the input line of the solenoid valve I is connected to the power supply, the analog output line is connected to the analog output port of the STM32 development control board, the ground line is connected to GND, and the output line is used to detect the output voltage;

[0018] The outlet of solenoid valve II is connected to the airway of variable stiffness chamber II, and the air inlet of solenoid valve II is connected to the air source; the input line of solenoid valve II is connected to the power supply, the analog output line is connected to the analog output port of the STM32 development control board, the ground line is connected to GND, and the output line is used to detect the output voltage;

[0019] The host computer sends instructions to the STM32 development control board to turn on the gas source, set the pressure increase or decrease through the buttons on the STM32 development control board, and transmit the air pressure to the variable stiffness chamber to realize the adjustment of the stiffness control system.

[0020] Preferably, the pneumatic drive system is:

[0021] The outlet of solenoid valve III is connected to the airway of drive chamber I, and the air inlet of solenoid valve III is connected to the air source. The input line of solenoid valve III is connected to the power supply, the analog output line is connected to the analog output port of the STM32 development control board, and the ground line is connected to GND. The output line is used to detect the output voltage;

[0022] The outlet of solenoid valve IV is connected to the airway of drive chamber II, and the air inlet of solenoid valve IV is connected to the air source. The input line of solenoid valve IV is connected to the power supply, the analog output line is connected to the analog output port of the STM32 development control board, and the ground line is connected to GND. The output line is used to detect the output voltage;

[0023] The outlet of the solenoid valve V is connected to the airway of the drive chamber III, and the air inlet of the solenoid valve V is connected to the air source. The input line of the solenoid valve V is connected to the power supply, the analog output line is connected to the analog output port of the STM32 development control board, and the ground line is connected to GND. The output line is used to detect the output voltage;

[0024] The host computer sends instructions to the STM32 development control board to turn on the air source, set the pressure increase or decrease through the buttons on the STM32 development control board, and transmit the air pressure to the drive chamber to realize the adjustment of the pneumatic drive system.

[0025] A drive control method for a quicksand variable-rigidity soft gripper drive control system, characterized by comprising the following steps:

[0026] S01. The host computer inputs task instructions to the STM32 development control board;

[0027] S02. The STM32 development control board sends a voltage signal to each solenoid valve;

[0028] S03 solenoid valve according to the voltage signal to adjust the input to each drive chamber and the variable stiffness chamber pressure;

[0029] S04. Connect the air source so that the adjusted air pressure is input into the variable stiffness chamber;

[0030] S04. Inputting positive pressure into the variable stiffness chamber according to the solenoid valve to enlarge the gap between the particles in the chamber to reduce the stiffness;

[0031] S05. Adjust the output voltage of the solenoid valve that controls the variable stiffness chamber to 0, and stop inflating the variable stiffness chamber;

[0032] S06. Due to the cessation of air pressure input, the gas in the variable stiffness chamber is discharged from the exhaust holes of the air hole array structure, the gap between the particles in the variable stiffness chamber decreases and the stiffness increases. At this point, the stiffness adjustment system task is completed.

[0033] Compared with the prior art, this application also has the following advantages:

[0034] (1) The present invention has simple control, low cost, fast response and high reliability. Traditional variable stiffness grippers generally require multiple gas sources to apply positive and negative pressures to control the drive and variable stiffness respectively. However, the stiffness structure of the variable stiffness part of the present invention is inversely proportional to the particle gap. When positive pressure is applied, the chamber expands to enlarge the gap between the particles, thereby reducing the stiffness. When the gas is stopped, the gas is discharged from the exhaust holes of the pore array structure, the chamber returns to its initial state, and the gap between the particles returns to a smaller state, thereby obtaining a higher stiffness. This variable stiffness system and the drive system share a gas source to achieve soft gripper drive and variable stiffness.

[0035] (2) This application has a high grasping posture stability. Traditional soft grippers mostly use a single cavity structure, and the bending angle and deformation cannot be precisely controlled. The quicksand variable stiffness soft gripper described in this application has two variable stiffness joints and three independently driven chambers. Each chamber can automatically control the deformation amount according to the appearance of the object, and multiple chambers cooperate to maximize the contact envelope surface, thereby improving grasping reliability and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the appearance and structure of a quicksand variable-rigidity soft gripper and its drive control system provided in this application.

[0037] Figure 2 This is a structural schematic diagram of the quicksand variable stiffness flexible finger pneumatic flexible unit I provided in this application.

[0038] Figure 3 This is a schematic structural diagram of the quicksand variable stiffness flexible finger pneumatic flexible unit II provided in this application.

[0039] Figure 4 This is a schematic structural diagram of the pneumatic flexible unit III of the quicksand variable stiffness flexible finger provided in this application.

[0040] Figure 5 Schematic diagram of the particle variable stiffness flexible palm structure provided in this application.

[0041] Figure 6 This is a schematic diagram of the structure of the flexible finger position adjustment slider provided in this application.

[0042] Figure 7 This is a schematic diagram of the rigid base structure provided in this application.

[0043] Figure 8 This is a schematic diagram of the clamp gear adjustment provided in this application.

[0044] Figure 9 This is a schematic block diagram of the structural principle of the drive control system of this application.

[0045] Figure 10 This is a schematic diagram of the circuit principle structure of this application.

[0046] Figure 11 This is a flow chart of the driving control method of this application.

[0047] Description of the reference numerals in the above drawings:

[0048] 1- Quicksand variable-stiffness flexible finger; 2- Particle variable-stiffness flexible palm; 3- Flexible finger position adjustment slider; 4- Rigid base; 5- Pneumatic flexible unit I; 6- Pneumatic flexible unit II; 7- Pneumatic flexible unit III; 8- Independent drive chamber I; 9- Independent drive chamber II; 10- Independent drive chamber III; 11- Variable-stiffness chamber I; 12- Variable-stiffness chamber II; 13- Variable-stiffness chamber I exhaust hole; 14- Variable-stiffness chamber II exhaust hole; 15- Airway of independent drive chamber III; 16- Air hole array I; 17- Air hole array II ; 18-air channel of variable stiffness chamber I; 19-air channel of variable stiffness chamber II; 20-connecting hole of driving chamber I; 21-connecting hole of driving chamber II, 22-air channel of driving chamber II; 23-air channel of driving chamber II; 24-trapezoidal texture with inclined angle; 25-air-flexible particle protrusion; 26-particle variable stiffness flexible palm air channel; 27-disc-shaped outer edge; 28-elastic film chamber; 29-through hole I; 30-handle, 31-cylindrical protrusion; 32-arc transition; 33-through hole II; 34-slide; 35-gear groove, 36-arc transition. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solutions and advantages of this application clearer and more specific, this application will be further described below with reference to the accompanying drawings and examples.

[0050] like Figure 1 As shown, the present application discloses a quicksand variable-rigidity soft gripper, comprising: a quicksand variable-rigidity flexible finger 1, a particle variable-rigidity flexible palm 2, a flexible finger position adjustment slider 3, and a rigid base 4. The quicksand variable-rigidity flexible finger 1 and the flexible finger position adjustment slider 3 are secured by compressing the flexible finger through a through-hole I of the adjustment slider, utilizing the restorative properties of the flexible material. The particle variable-rigidity flexible palm 2 and the rigid base 4 are secured by passing a cylindrical soft object through a through-hole II of the rigid base. The flexible finger position adjustment slider 3 and the rigid base are secured by the adjustment slider's cylindrical protrusions and slideways.

[0051] The quicksand-variable-rigidity flexible finger is made of a soft and elastic material, including but not limited to silicone, polydimethylsiloxane, etc.; the quicksand-variable-rigidity flexible finger comprises three sections of pneumatic flexible units, namely: pneumatic flexible unit I, pneumatic flexible unit II and pneumatic flexible unit III, and a quicksand-variable-rigidity joint is provided between two adjacent sections of pneumatic flexible units, namely: quicksand-variable-rigidity joint I and quicksand-variable-rigidity joint II.

[0052] The pneumatic flexible unit is a multi-layer stacked structure, including: a pneumatic chamber layer, a connecting layer, an airway layer I, and a bottom sealing layer I; the pneumatic chamber layer has three independent driving cavities for driving the flexible fingers to bend; the connecting layer has air vents connected to the pneumatic chamber, and the airway layer I has three air inlets and airways, which are connected to the connecting layer and are used to input air pressure into the driving chamber. The bottom sealing layer I has a trapezoidal corrugated protrusion with an inclined angle, which is used to increase the friction and contact area between the flexible finger and the fingertip of the object.

[0053] The quicksand variable-stiffness joint is a multi-layer stacked structure, comprising a particle filling layer, an air hole array layer, an airway layer II, and a bottom sealing layer II. The particle filling layer has two independent variable-stiffness cavities for filling particles, with exhaust holes above the variable-stiffness cavities for discharging gas from the variable-stiffness chambers when inflation stops. The air hole array layer has two 1mm diameter air hole arrays for connecting the variable-stiffness chambers of the particle filling layer. The airway layer II has two air inlets and airways, which communicate with the air hole array layer and are used to input pressure into the variable-stiffness chambers. The bottom sealing layer II has three circular particle protrusions that form an interlocking constraint with the surface of the object to improve grasping stability.

[0054] The quicksand variable stiffness joint reduces stiffness by inputting positive pressure into a variable stiffness chamber filled with particles with a higher initial stiffness to increase the gap between the particles in the variable stiffness chamber. When the pressure input is stopped, the gas is discharged from the exhaust holes on the variable stiffness chamber to reduce the gap between the particles and restore the joint to a high stiffness state.

[0055] The structural features of the pneumatic flexible unit and the quicksand variable stiffness joint are achieved by using processes including but not limited to shape deposition processes, 3D printing processes, etc. to realize the integrated preparation of the quicksand variable stiffness flexible fingers.

[0056] In order to improve the grasping performance, the tip driving chamber of the quicksand variable stiffness flexible finger is longer than the other two independent chambers.

[0057] Specific examples Figures 2 to 4As shown, the pneumatic flexible unit I has three independently driven chambers: 8 - drive chamber I, 9 - drive chamber II, and 10 - drive chamber III; two variable stiffness chambers: 11 - variable stiffness chamber I and 12 - variable stiffness chamber II; two groups of exhaust holes in an air hole array structure: 13 - exhaust hole I, 14 - exhaust hole II, and an air channel 15 for drive chamber III. The pneumatic flexible unit II has two groups of vent holes in an air hole array structure: 16 - vent hole I and 17 - vent hole II; an air channel 18 for variable stiffness chamber I and an air channel 19 for variable stiffness chamber II; a connecting hole 20 connecting drive chamber I and a connecting hole 21 connecting drive chamber II; an air channel 22 for drive chamber I and an air channel 23 for drive chamber II. The pneumatic flexible unit III has an angled ladder-like texture 24 and flexible granular protrusions 25. The three pneumatic flexible units are bonded and sealed by using their own flexible materials to form the quicksand variable stiffness flexible finger 1.

[0058] like Figure 5 As shown, the particle-variable stiffness flexible palm consists of an elastic film 28, filler particles, and a cylindrical soft body with an air channel. The air channel 26 connects to a particle-filled chamber. The elastic film seals with the cylindrical soft body to form the particle-filled chamber; the filler particles are filled in the particle-filled chamber formed by the elastic film and the cylindrical soft body, and the object is wrapped by the adaptive deformation of the elastic film. The bottom of the cylindrical soft body with an air channel has a disc-shaped outer edge 27, which serves to expand the elastic film's bonding area and facilitate sealing, ensuring a better seal between the elastic film and the cylindrical soft body to form the particle-filled chamber.

[0059] The flexible material of the particle-variable-rigidity flexible palm is not limited to silicone, polydimethylsiloxane, etc.; the particle material is not limited to gravel, acrylic balls, coffee powder, etc.

[0060] like Figure 6 As shown, the flexible finger position adjustment slider 3 has a through hole 129 for fixing the flexible finger; an anti-scratch handle 30 for facilitating operation of adjusting the slider position; a cylindrical protrusion 31 installed in conjunction with the slide 34; and an arc transition 32 designed to prevent scratches on the fingers.

[0061] The columnar protrusion is used to cooperate with the slide rail of the rigid base to form a slidable structure, and cooperate with the groove structure of the rigid base to lock and fix the position of the adjustment slider.

[0062] The through hole 129 for connecting the flexible fingers is used to connect with and fix the quicksand-variable-rigidity flexible fingers.

[0063] The anti-scratch handle 30 is used to safely and conveniently pick up and put down the adjustment slider. In order to prevent the fingers from being scratched by sharp edges, an arc-shaped transition is made on the handle part.

[0064] like Figure 7 As shown, the rigid base 4 has a through hole II33 for the particle variable stiffness flexible palm 2; a slide 34 installed in conjunction with the adjustment slider; a groove 35 for locking the position of the adjustment slider, with a spacing of 12 mm between the grooves; and an arc transition 36 at the groove for enabling the adjustment slider to more smoothly perform adjustment conversion operations on the slide rail and the groove.

[0065] The slide rail cooperates with the adjusting slider, and the position of the adjusting slider can be changed on the slide rail by lifting the adjusting slider.

[0066] The groove provides three grooves, i.e. three gears, to fix the position of the adjustment slider, with each gear spaced 12 mm apart. The above-mentioned slide rail cooperates with the adjustment slider position to lock with the groove to prevent the position of the flexible finger from changing during the grasping process.

[0067] The arc transition at the groove is used to enable the adjusting slider to perform adjustment conversion operations on the slide rail and in the groove more smoothly.

[0068] like Figure 8 As shown, the quicksand variable-rigidity soft gripper and its drive control system have three adjustable gears to adjust the gripping diameter. When all four quicksand variable-rigidity flexible fingers are in the outer third gear, the soft gripper's maximum gripping diameter is 188mm. When all four quicksand variable-rigidity flexible fingers are in the middle second gear, the soft gripper's maximum gripping diameter is 148mm. When all four quicksand variable-rigidity flexible fingers are in the inner first gear, the soft gripper's maximum gripping diameter is 108mm. For objects of different shapes and sizes, the gear combination can be flexibly configured as needed to improve gripping performance.

[0069] A drive control system for a quicksand variable-stiffness soft gripper comprises: a host computer, a slave computer, a power amplifier circuit, a stiffness control system and a pneumatic drive system; wherein the host computer generates control instructions for the stiffness control system and the pneumatic drive system respectively based on instruction information input by the user, such as driving air pressure and joint stiffness, and transmits them to the slave computer; the slave computer converts the control instructions into drive signals through the power amplifier circuit and transmits them to the stiffness control system and the pneumatic drive system respectively, thereby realizing control of the motion posture and motion stiffness of the quicksand variable-stiffness soft gripper.

[0070] The stiffness control system is as follows: a power supply supplies power to each solenoid valve, solenoid valve I connects the air source and the air channel of the driving chamber I and adjusts the input air pressure; solenoid valve II connects the air source and the air channel of the driving chamber II and adjusts the input air pressure; solenoid valve III connects the air source and the air channel of the driving chamber III and adjusts the input air pressure; solenoid valve IV connects the air source and the air channel of the variable stiffness chamber I and adjusts the input air pressure; solenoid valve V connects the air source and the air channel of the variable stiffness chamber II and adjusts the input air pressure; the host computer is connected to the STM32 development control board to transmit the task instruction to the STM32 development control board, and the STM32 development control board inputs a voltage signal to each solenoid valve to control the size of the input air pressure. The air source is used to provide air pressure, and one air source is divided into 5 independent air paths through the air pipe shunt, and the control valve is used to control the connection of the air path between the air inlet of each solenoid valve and the air source;

[0071] The air outlet of the solenoid valve I is connected to the airway of the variable stiffness chamber I, and the air inlet of the solenoid valve I is connected to the air source; the input line of the solenoid valve I is connected to the power supply, the analog output line is connected to the analog output port of the STM32 development control board, the ground line is connected to GND, and the output line is used to detect the output voltage;

[0072] The outlet of solenoid valve II is connected to the airway of variable stiffness chamber II, and the air inlet of solenoid valve II is connected to the air source; the input line of solenoid valve II is connected to the power supply, the analog output line is connected to the analog output port of the STM32 development control board, the ground line is connected to GND, and the output line is used to detect the output voltage;

[0073] The host computer sends instructions to the STM32 development control board to turn on the gas source, set the pressure increase or decrease through the buttons on the STM32 development control board, and transmit the air pressure to the variable stiffness chamber to realize the adjustment of the stiffness control system.

[0074] The pneumatic drive system is as follows: the outlet of the solenoid valve III is connected to the airway of the drive chamber I, the air inlet of the solenoid valve III is connected to the air source, the input line of the solenoid valve III is connected to the power supply, the analog output line is connected to the analog output port of the STM32 development control board, the ground line is connected to GND, and the output line is used to detect the output voltage;

[0075] The outlet of solenoid valve IV is connected to the airway of drive chamber II, and the air inlet of solenoid valve IV is connected to the air source. The input line of solenoid valve IV is connected to the power supply, the analog output line is connected to the analog output port of the STM32 development control board, and the ground line is connected to GND. The output line is used to detect the output voltage;

[0076] The outlet of the solenoid valve V is connected to the airway of the drive chamber III, and the air inlet of the solenoid valve V is connected to the air source. The input line of the solenoid valve V is connected to the power supply, the analog output line is connected to the analog output port of the STM32 development control board, and the ground line is connected to GND. The output line is used to detect the output voltage;

[0077] The host computer sends instructions to the STM32 development control board to turn on the air source, set the pressure increase or decrease through the buttons on the STM32 development control board, and transmit the air pressure to the drive chamber to realize the adjustment of the pneumatic drive system.

[0078] A drive control method for a quicksand variable-rigidity soft gripper drive control system, comprising the following steps:

[0079] S01. The host computer inputs task instructions to the STM32 development control board;

[0080] S02. The STM32 development control board sends a voltage signal to each solenoid valve;

[0081] S03 solenoid valve according to the voltage signal to adjust the input to each drive chamber and the variable stiffness chamber pressure;

[0082] S04. Connect the air source so that the adjusted air pressure is input into the variable stiffness chamber;

[0083] S04. Inputting positive pressure into the variable stiffness chamber according to the solenoid valve to enlarge the gap between the particles in the chamber to reduce the stiffness;

[0084] S05. Adjust the output voltage of the solenoid valve that controls the variable stiffness chamber to 0, and stop inflating the variable stiffness chamber;

[0085] S06. Due to the cessation of air pressure input, the gas in the variable stiffness chamber is discharged from the exhaust holes of the air hole array structure, the gap between the particles in the variable stiffness chamber decreases and the stiffness increases. At this point, the stiffness adjustment system task is completed.

[0086] The working process of this application is as follows:

[0087] 1. Secure the four quicksand variable-stiffness flexible fingers 1 to the flexible finger position adjustment slider 3 through the through-holes. Secure the granular variable-stiffness flexible palm 2 to the rigid base 4 through the through-holes. Mount the flexible finger position adjustment slider 3 and the rigid base 4 using cylindrical bumps 31 and slideways 34. Connect the air inlets of each solenoid valve to the air source. Connect the air outlet of solenoid valve 1 to the airway of variable-stiffness chamber 1, the air outlet of solenoid valve 2 to the airway of variable-stiffness chamber 2, the air outlet of solenoid valve 3 to the airway of drive chamber 1, the air outlet of solenoid valve 4 to the airway of drive chamber 2, and the air outlet of solenoid valve 5 to the airway of drive chamber 3.

[0088] 2. Connect the input line, signal analog line, ground line, and output line of each solenoid valve to the corresponding IO port of the STM32 development control board. Connect the STM32 development control board to the host computer. Place the soft gripper on the target object. The host computer sends task instructions to the STM32 development control board.

[0089] 3. Use the STM32 development control panel buttons to control the output of the voltage signal. The initial value is 0. The gaps between the gravel in the variable stiffness chamber are very small and have high stiffness. Connect the air source of the variable stiffness chamber and increase the output of the voltage signal by pressing the button. Solenoid valve 1 and solenoid valve 2 adjust the air pressure output to the variable stiffness chamber according to the received voltage signal. The input positive pressure expands the gaps between the gravel (the particles are not limited to gravel, coffee powder, etc., but the granular material used in this application is gravel) in the variable stiffness chamber, thereby reducing its stiffness.

[0090] 4. Connect the air source to the drive chamber and increase the output voltage signal by pressing the button. Solenoid valves 3, 4, and 5 adjust the air pressure output to the drive chamber according to the received voltage signal. The input positive pressure causes the drive chamber to expand and bend, thereby grabbing the target object.

[0091] 5. After contacting the grasping target, in order to increase the clamping force and carrying capacity, the output voltage signals of solenoid valve 1 and solenoid valve 2 are adjusted through the STM32 development control board, so that the output air pressure of solenoid valve 1 and solenoid valve 2 is adjusted to 0. The air pressure in the two sets of variable stiffness chambers will be quickly discharged from the exhaust holes of the air hole array structure. The gaps between the sand and gravel in the variable stiffness chambers will shrink sharply and return to a high stiffness state, thereby improving the carrying capacity and grasping performance.

[0092] 6. After successfully grasping the object, the STM32 development board controls the output voltage signals of solenoid valves 3, 4, and 5, gradually reducing the output air pressure of solenoid valves 3, 4, and 5 to 0, causing the soft gripper to slowly lower the target object. At this point, the grasping task is completed. For objects of different shapes and sizes, the activation drive of the drive chamber and the variable stiffness chamber can be flexibly combined according to the grasping requirements, as well as the flexible combination of different gear positions of the adjustment slider to achieve more reasonable and effective grasping.

[0093] In this application, the pneumatic flexible unit I consists of three independent, empty drive chambers, two variable-rigidity chambers for loading sand, and an air channel that drives the drive chamber at the end of the flexible finger. To improve gripping performance, the chamber at the fingertip of the three independent chambers is longer than the other two. To ensure that the sand in the variable-rigidity chambers is evenly filled with air for better fluidity and increased spacing between the sand, the air holes in the pneumatic flexible unit II are arranged with uniform and even spacing. To increase friction and contact area with objects, the striped texture of the pneumatic flexible unit III is made of a flexible material, and the angled ladder-like structure is designed to increase friction, especially for grasping small objects. To improve gripping performance, the granular protrusions at the fingertips of the pneumatic flexible unit III are made of a flexible material that is easily deformed. By contacting and deforming with the object, they wrap around it, providing support and interlocking. To improve the deformation and gripping effect of the variable-rigidity flexible fingers, the drive chamber and variable-rigidity chamber are both made of silicone.

[0094] In the description of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like, indicating positions or locations, are based on the positions or locations shown in the accompanying drawings and are intended only to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present invention, and the scope of protection of the present invention is not limited by the specific embodiments.

[0095] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A quicksand variable stiffness soft gripper, characterized in that: The main structure includes: a quicksand-variable-rigidity flexible finger, a particle-variable-rigidity flexible palm, a flexible finger position adjustment slider, and a rigid base; the quicksand-variable-rigidity flexible finger and the flexible finger position adjustment block are connected via a through hole in the middle of the flexible finger position adjustment block; the flexible finger position adjustment block and the rigid base are connected via a cylindrical protrusion of the flexible finger position adjustment block and a slide portion of the rigid base; the particle-variable-rigidity flexible palm and the rigid base are connected via a circular through hole in the rigid base; The quicksand-variable-rigidity flexible finger is made of a soft elastic material. It comprises three pneumatic flexible units, namely, pneumatic flexible unit I, pneumatic flexible unit II, and pneumatic flexible unit III. A quicksand-variable-rigidity joint is provided between two adjacent pneumatic flexible units, namely, quicksand-variable-rigidity joint I and quicksand-variable-rigidity joint II. The pneumatic flexible unit is a multi-layer stacked structure, including: a pneumatic chamber layer, a connecting layer, an airway layer I, and a bottom sealing layer I; the pneumatic chamber layer has three independent drive cavities for driving the flexible finger to bend; the connecting layer has vents connected to the pneumatic chamber, and the airway layer I has three air inlets and airways, which communicate with the connecting layer and are used to input air pressure into the drive chamber. The bottom sealing layer I has a stepped corrugated protrusion with an inclined angle to increase the friction and contact area between the flexible finger and the fingertip of the object; The quicksand variable stiffness joint is a multi-layer stacked structure, including: a particle filling layer, an air hole array layer, an airway layer II, and a bottom sealing layer II; the particle filling layer has two independent variable stiffness cavities for filling particles, and the variable stiffness cavities have exhaust holes above them for discharging the gas in the variable stiffness chambers when inflation stops; the air hole array layer has an air hole array for connecting the variable stiffness chambers of the particle filling layer; the airway layer II has an air inlet and an airway, and the airway is connected to the air hole array layer for inputting pressure into the variable stiffness chamber; the bottom sealing layer II has particle protrusions for forming an interlocking constraint with the surface of the object to improve the grasping stability; The air hole array layer has two air hole arrays with a diameter of 1 mm; the airway layer II has two air inlets and airways; the bottom sealing layer II has three round particle protrusions; The particle-variable-rigidity flexible palm consists of an elastic film, filling particles and a cylindrical soft body with an airway. The elastic film is sealed with the cylindrical soft body to form a particle-filled chamber; the filling particles are filled in the particle-filled chamber formed by the elastic film and the cylindrical soft body, and the object is wrapped by utilizing the adaptive deformation of the elastic film; the bottom of the cylindrical soft body with an airway has a disc-shaped outer edge, the function of which is to make the elastic film and the cylindrical soft body better sealed to form a particle-filled chamber.

2. A drive control system for the quicksand variable stiffness soft gripper according to claim 1, characterized in that: include: A host computer, a slave computer, a power amplifier circuit, a stiffness control system and a pneumatic drive system; wherein the host computer generates control instructions for the stiffness control system and the pneumatic drive system respectively according to the command information input by the user, such as the driving air pressure and the joint stiffness, and transmits them to the slave computer; the slave computer converts the control instructions into drive signals through the power amplifier circuit and transmits them to the stiffness control system and the pneumatic drive system respectively, thereby realizing the control of the motion posture and motion stiffness of the quicksand variable stiffness soft gripper.

3. The driving control system of the quicksand variable stiffness soft gripper according to claim 2, characterized in that: The stiffness control system is: The power supply supplies power to each solenoid valve. Solenoid valve I connects the air source to the air passage of driving chamber I and adjusts the input air pressure. Solenoid valve II connects the air source to the air passage of driving chamber II and adjusts the input air pressure. The solenoid valve III connects the air source to the air passage of the driving chamber III and adjusts the input air pressure; The solenoid valve IV connects the air source to the air passage of the variable stiffness chamber I and adjusts the input air pressure; Solenoid valve V connects the air source to the airway of variable stiffness chamber II and regulates the input air pressure. The host computer connects to the STM32 development control board and transmits task instructions to the STM32 development control board. The STM32 development control board inputs voltage signals to each solenoid valve to control the input air pressure. The air source is used to provide air pressure. One air source is divided into five independent air paths through the air pipe. The control valve is used to control the air path between each solenoid valve inlet and the air source. The air outlet of the solenoid valve I is connected to the airway of the variable stiffness chamber I, and the air inlet of the solenoid valve I is connected to the air source; the input line of the solenoid valve I is connected to the power supply, the analog output line is connected to the analog output port of the STM32 development control board, the ground line is connected to GND, and the output line is used to detect the output voltage; The outlet of solenoid valve II is connected to the airway of variable stiffness chamber II, and the air inlet of solenoid valve II is connected to the air source; the input line of solenoid valve II is connected to the power supply, the analog output line is connected to the analog output port of the STM32 development control board, the ground line is connected to GND, and the output line is used to detect the output voltage; The host computer sends instructions to the STM32 development control board to turn on the gas source, set the pressure increase or decrease through the buttons on the STM32 development control board, and transmit the air pressure to the variable stiffness chamber to realize the adjustment of the stiffness control system.

4. The driving control system of the quicksand variable stiffness soft gripper according to claim 2, characterized in that: The pneumatic drive system is: The outlet of solenoid valve III is connected to the airway of drive chamber I, and the air inlet of solenoid valve III is connected to the air source. The input line of solenoid valve III is connected to the power supply, the analog output line is connected to the analog output port of the STM32 development control board, and the ground line is connected to GND. The output line is used to detect the output voltage; The outlet of solenoid valve IV is connected to the airway of drive chamber II, and the air inlet of solenoid valve IV is connected to the air source. The input line of solenoid valve IV is connected to the power supply, the analog output line is connected to the analog output port of the STM32 development control board, and the ground line is connected to GND. The output line is used to detect the output voltage; The outlet of the solenoid valve V is connected to the airway of the drive chamber III, and the air inlet of the solenoid valve V is connected to the air source. The input line of the solenoid valve V is connected to the power supply, the analog output line is connected to the analog output port of the STM32 development control board, and the ground line is connected to GND. The output line is used to detect the output voltage; The host computer sends instructions to the STM32 development control board to turn on the air source, set the pressure increase or decrease through the buttons on the STM32 development control board, and transmit the air pressure to the drive chamber to realize the adjustment of the pneumatic drive system.

5. The driving control method of the quicksand variable stiffness soft gripper driving control system according to any one of claims 2 to 4, characterized in that: The steps include: S01. The host computer inputs task instructions to the STM32 development control board; S02. The STM32 development control board sends a voltage signal to each solenoid valve; S03 solenoid valve according to the voltage signal to adjust the input to each drive chamber and the variable stiffness chamber pressure; S04. Connect the air source so that the adjusted air pressure is input into the variable stiffness chamber; S04. Inputting positive pressure into the variable stiffness chamber according to the solenoid valve to enlarge the gap between the particles in the chamber to reduce the stiffness; S05. Adjust the output voltage of the solenoid valve that controls the variable stiffness chamber to 0, and stop inflating the variable stiffness chamber; S06. Due to the cessation of air pressure input, the gas in the variable stiffness chamber is discharged from the exhaust holes of the air hole array structure, the gap between the particles in the variable stiffness chamber decreases and the stiffness increases. At this point, the stiffness adjustment system task is completed.

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