A bidirectional rotary imitating wrist joint soft driver based on kresling paper folding

Abstract

The application discloses a bidirectional rotation imitating wrist joint soft driver based on Kresling paper folding, which comprises a body structure, a driving system and a control system; the body structure comprises a paper folding type air bag, an upper end plate and a base; the paper folding type air bag is arranged between the upper end plate and the base, and the three are sealingly connected. The paper folding type air bag based on the bistable Kresling paper folding structure actively switches among three stable states under the joint action of the driving system and the control system. The driving system can adopt two mixed driving modes of air driving and motor string driving and air driving and shape memory alloy wire driving. The control system controls the motor, the shape memory alloy wire and the air pressure of the air bag, so that the driver can realize bidirectional rotation function. The driver has the characteristics of simple system, fast response and low cost and can be widely applied to the field of space soft capture robots.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of space soft capture robots, in particular to a bidirectional rotation imitative wrist joint soft driver based on Kresling origami. BACKGROUND

[0002] The Kresling origami structure has bistable characteristics, can realize fast transition from one initial stable state to another stable state, and the structure rotates and presses down in the stable state transition process. However, the traditional Kresling structure generally has an initial state that is not a vertical prism state, and often has an initial rotation angle, so it can only realize unidirectional rotation. SUMMARY

[0003] The purpose of the present application is to provide a bidirectional rotation imitative wrist joint soft driver based on Kresling origami, which realizes bidirectional rotation deformation through a hybrid driving mode.

[0004] The purpose of the present application is realized by the following technical scheme:

[0005] A bidirectional rotation imitative wrist joint soft driver based on a bistable Kresling origami structure, comprising a driving system, a control system and a body structure; the driving system is connected with the body structure; the control system realizes control of the driving system through programming; the driving scheme of the driving system includes hybrid driving of pneumatic driving and motor cable driving, and hybrid driving of pneumatic driving and shape memory alloy wire driving.

[0006] In the technical solution, further, the body structure is composed of a paper-folding type air bag, an upper end plate and a base; the paper-folding type air bag is shaped as a regular hexagonal prism shell structure, the top surface is sealed, the bottom surface is open, and the material is silica gel, which is processed by 3D printing silica gel complex mold; the paper-folding type air bag is provided with crease areas at the positions of the diagonal lines and four sides of the rectangular side surface, the crease areas are thin in thickness, and can be folded along the creases; the paper-folding type air bag is arranged between the upper end plate and the base, and the three are sealingly connected; the upper end plate is shaped as a regular hexagon, the material is acrylic, and six protruding ear plates are arranged at the six end points, and two small holes are arranged on each protruding ear plate; the base is a double-layer disc structure, the material is acrylic, a gas hole is arranged at the center of the upper disc, and the lower disc is an annular structure; the upper disc and the lower disc are fixedly connected through twelve cylinders, and six groups of small holes are uniformly distributed around the edges of the two discs; six small holes are arranged in the inner and outer circles of the upper disc, for the shape memory alloy wires or traction ropes to pass through; six small holes are arranged in the inner and outer circles of the lower disc, for the shape memory alloy wires to pass through and be fixed; six cylinders are arranged in the inner and outer circles of the twelve cylinders, for the shape memory alloy wires to be wound, so as to increase the deformation stroke of the shape memory alloy wires; three shape memory alloy wires passing through the small holes in the inner circle of the upper end plate and the upper disc are wound around the inner circle cylinders for one turn; similarly, three shape memory alloy wires passing through the small holes in the outer circle of the upper end plate and the upper disc are wound around the outer circle cylinders for one turn; two separation pieces are arranged on each cylinder, for separating different shape memory alloy wires and preventing the shape memory alloy wires from interfering with each other.

[0007] Further, when the driver adopts a hybrid drive and control of motor rope drive and pneumatic drive, the motor is arranged on the lower disc and is distributed directly below the six protruding ear plates of the upper end plate, the number is six, and three motors are arranged in each group for controlling the driver to rotate in the clockwise direction and the counterclockwise direction; one end of the traction rope is fixed to the small hole of the protruding ear plate of the upper end plate, and the other end passes through the small hole on the upper disc along the diagonal line direction of the paper-folding type air bag and is fixed to the corresponding motor shaft disc; the traction ropes for controlling the driver to rotate in the clockwise direction and the counterclockwise direction are connected with the small holes in the outer circle, and vice versa; the motors are connected with the power supply in series, different motor groups are powered by the single-chip microcomputer to control the rotation direction of the driver; the gas hole at the center of the upper disc is connected with the air pump through an air pipe, the air pipe is provided with the electromagnetic valve, and the single-chip microcomputer controls the electromagnetic valve, so as to control the air pressure of the paper-folding type air bag.

[0008] Further, the driver adopts a hybrid drive and control of shape memory alloy wire drive and pneumatic drive: the shape memory alloy wire is six in total, one end is fixed to the small hole of the protruding ear plate of the upper end plate, the other end is along the diagonal direction of the origami air bag, passes through the small hole on the upper layer disc, winds around the cylinder for one circle and is fixedly connected with the small hole on the lower layer disc; the shape memory alloy wire of the control driver rotating clockwise or counterclockwise is connected with the small hole of the outer circle and winds around the outer circle cylinder, and vice versa; the shape memory alloy wires are connected in series with the power supply, and different shape memory alloy wires are powered by the single-chip microcomputer to control the rotating direction of the driver; the air hole in the center of the upper layer disc is connected with the air pump through the air pipe, the electromagnetic valve is arranged on the air pipe, and the single-chip microcomputer controls the electromagnetic valve, so as to control the air pressure of the origami air bag.

[0009] Further, the method for realizing the clockwise rotation and then counterclockwise rotation of the driver by using the driving system comprises the following steps:

[0010] Step 1. At the initial moment, the driver is in the first steady state, and the origami air bag is subjected to air extraction operation;

[0011] Step 2. The motor set or shape memory alloy wire for rotating the control driver in the clockwise direction is powered, and the traction rope or shape memory alloy wire is tightened and contracted, at this time, the driver has a tendency to rotate in the clockwise direction;

[0012] Step 3. The air pump controls the origami air bag to continue air extraction, and the driver continues to rotate in the predetermined direction until the driver is completely folded to reach the second steady state;

[0013] Step 4. The origami air bag is inflated, the power supply and motor are controlled to make the traction rope or shape memory alloy wire return to the initial state, at this time, the driver returns to the first steady state;

[0014] Step 5. The motor set or shape memory alloy wire for rotating the control driver in the counterclockwise direction is powered, at this time, the driver has a tendency to rotate in the counterclockwise direction;

[0015] Step 6. The above step 3 is repeated until the driver is completely folded to reach the third steady state, and then step 4 is repeated, and the driver returns to the first steady state.

[0016] The driver has three steady states, including the initial state (the first steady state), the state of rotating in the clockwise direction to completely fold the origami air bag (the second steady state), and the state of rotating in the counterclockwise direction to completely fold the origami air bag (the third steady state). The driver has a bidirectional rotation function, and the driver can rotate from the first steady state to the second steady state in the clockwise direction, or rotate from the initial state to the second steady state in the counterclockwise direction.

[0017] The present application has the advantages of:

[0018] The device can realize the axial bidirectional rotation of the wrist joint type, and the driving mode can adopt the hybrid driving of the motor rope driving and the pneumatic driving, or the hybrid driving of the shape memory alloy wire driving and the pneumatic driving. The device has the multi-stable state characteristics, can realize the bidirectional rotation from one stable state to another stable state, and has the fast extension and contraction characteristics. The device has simple structure and simple preparation process, and can be applied to the space soft capture robot. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is the assembly drawing of the bidirectional rotation wrist joint type soft driver driving system and the body structure of the present application;

[0020] Figure 2 is the assembly drawing of the body structure;

[0021] Figure 3 is the structure drawing of the origami type air bag;

[0022] Figure 4 is the structure drawing of the upper end plate;

[0023] Figure 5 is the structure drawing of the base;

[0024] In the drawing, 1 is an origami type air bag, 2 is an upper end plate, 3 is a base, 4-1 is a shape memory alloy wire, 4-2 is a traction rope, 5 is an upper layer disc, 6 is a cylinder, 7 is a lower layer disc, and 8 is a separation piece. DETAILED DESCRIPTION

[0025] The device of the present application will be described in detail below with reference to the accompanying drawings.

[0026] The present application designs a bidirectional rotation wrist joint type soft driver device based on Kresling origami. The device has the bidirectional rotation function and has the multi-stable state characteristics.

[0027] Figure 1 is the assembly drawing of the bidirectional rotation wrist joint type soft driver driving system and the body structure, which details the assembly mode of the driver structure. The driver includes a body structure, a driving system and a control system; the body structure is composed of an origami type air bag 1, an upper end plate 2 and a base 3; the origami type air bag 1 is arranged between the upper end plate 2 and the base 3, and the three are sealingly connected; the driving system is connected with the body structure, and adopts the hybrid driving mode of the air driving and the motor rope driving or the air driving and the shape memory alloy wire driving to drive the body structure; the control system is used for controlling the driving system, so that the whole driver realizes the fast extension and contraction deformation.

[0028] When the driving system adopts the hybrid driving of motor wire driving and pneumatic driving, the traction wire 4-2 is connected with the motor axis disc located on the lower disc. The driving system comprises a motor, a gas pump and the traction wire 4-2, and the control system comprises a single-chip microcomputer, a power supply and an electromagnetic valve. The motor is arranged on the lower disc 7 and is distributed directly below the six protruding ear plates of the upper end plate 2, and the number of the motors is six. Three motors in each group are used to control the driving device to rotate in the clockwise direction and the counterclockwise direction respectively. The traction wire 4-2 is six in number, one end of which is fixed to the small hole of the protruding ear plate of the upper end plate 2, and the other end thereof is fixed to the corresponding motor axis disc along the diagonal direction of the origami air bag 1 and passes through the small hole on the upper disc 5. The traction wire 4-2 for controlling the driving device to rotate in the clockwise direction and the counterclockwise direction is connected with the small hole of the outer ring, and vice versa. The motor is connected with the power supply in series, and the different motor groups are powered by the single-chip microcomputer to control the rotating direction of the driving device. The upper disc 5 is connected with the gas pump through the gas pipe, and the gas pipe is provided with the electromagnetic valve. The single-chip microcomputer controls the electromagnetic valve, so as to control the air pressure of the origami air bag 1.

[0029] When the driving system adopts the hybrid driving of shape memory alloy wire driving and pneumatic driving, the shape memory alloy wire 4-1 is wound on the cylinder. The driving system comprises a gas pump and the shape memory alloy wire 4-1, and the control system comprises a single-chip microcomputer, a power supply and an electromagnetic valve. The shape memory alloy wire 4-1 is six in number, one end of which is fixed to the small hole of the protruding ear plate of the upper end plate 2, and the other end thereof is fixed to the small hole on the lower disc 7 after being wound on the cylinder 6 for one turn and passing through the small hole on the upper disc 5 along the diagonal direction of the origami air bag 1. Three shape memory alloy wires 4-1 passing through the small holes on the inner ring of the upper end plate 2 and the upper disc 5 are wound on the inner ring cylinder 6 for one turn. Similarly, three shape memory alloy wires 4-1 passing through the small holes on the outer ring of the upper end plate 2 and the upper disc 5 are wound on the outer ring cylinder 6 for one turn. Two partition plates 8 are arranged on each cylinder 6 to separate the different shape memory alloy wires 4-1 and prevent the shape memory alloy wires 4-1 from interfering with each other. The shape memory alloy wire 4-1 for controlling the driving device to rotate in the clockwise direction and the counterclockwise direction is connected with the small hole on the outer ring and wound on the outer ring cylinder, and vice versa. The shape memory alloy wire 4-1 is connected with the power supply in series, and the different shape memory alloy wires 4-1 are powered by the single-chip microcomputer to control the rotating direction of the driving device. The gas hole in the center of the upper disc 5 is connected with the gas pump through the gas pipe, and the gas pipe is provided with the electromagnetic valve. The single-chip microcomputer controls the electromagnetic valve, so as to control the air pressure of the origami air bag 1.

[0030] The gas hole in the center of the upper disc of the base 3 of the driving device body structure is connected with the gas pump through the gas pipe, so that the load can be applied to the driving device.

[0031] Figure 2 is the assembly drawing of the body structure, which describes the assembly method of the driver body structure in detail.

[0032] wherein the opening edge of the origami-type airbag 1 is sealed downwardly connected with the base 3 to prevent air leakage of the driver structure.

[0033] wherein the six vertices of the upper end plate 2, the six endpoints of the origami-type airbag 1, and the small holes on the disc of the base 3 are uniformly corresponding.

[0034] Figure 3 is the structure drawing of the origami-type airbag, which shows the multi-stable structure mode of the origami-type airbag 1 based on the kresling origami structure in detail.

[0035] Figure 4 is the upper end plate 2, wherein the twelve small holes are used to connect the shape memory alloy wire 4-1 or the traction rope 4-2.

[0036] Figure 5 is the base 3, including the upper disc 5, the cylinder 6, and the lower disc 7, which are used to fix the motor, the traction rope 4-2, and the shape memory alloy wire 4-1.

[0037] The cylinder 6 is fixed between the upper disc 5 and the lower disc 7, which can be used to wind the shape memory alloy wire 4-1.

[0038] When the driver rotates downwardly, the control system and the driving system complete the electrical connection through the signal line. When the control driver rotates clockwise, the control pump performs the air extraction operation on the origami-type airbag 1, so that the origami-type airbag 1 has the tendency to concave inward along the crease. The control system applies voltage to the group of motors or the shape memory alloy wire 4-1 that controls the clockwise rotation of the driver, so that the traction rope 4-2 or the driving shape memory alloy wire 4-1 is tightened and contracted, so that the driver has the tendency to rotate clockwise. The driving system drives the pump to continuously extract air on the origami-type airbag 1, so as to realize the rotation and downward displacement of the driver. When the longitudinal displacement of the driver reaches the maximum and is located in the second stable state, stop the air extraction operation and inflate the origami-type airbag 1, and at the same time control the power supply and the motor to make the traction rope 4-2 or the shape memory alloy wire 4-1 return to the relaxed state, so that the driver body structure and the driving system return to the initial state. When the control driver rotates counterclockwise, repeat the above steps, and only apply voltage to the group of motors or the shape memory alloy wire 4-1 that controls the counterclockwise rotation of the driver, so as to realize the counterclockwise rotation of the driver, and finally the driver returns to the initial state.

Claims

1. A bidirectional rotational wrist joint-like soft actuator based on Kresling origami, characterized in that: The actuator has a bidirectional rotation function; the actuator includes a main body structure, a drive system and a control system; the main body structure includes an origami-type airbag (1), an upper end plate (2) and a base (3); the origami-type airbag (1) is located between the upper end plate (2) and the base (3), and the three are sealed together; the origami-type airbag (1) is based on a bistable Kresling origami structure design and has three stable states, including the initial state, the state of rotating clockwise to the state of the origami-type airbag (1) being completely folded, and the state of rotating counterclockwise to the state of the origami-type airbag (1) being completely folded; the drive system is connected to the main body structure and uses a hybrid drive method of air drive and motor rope drive or air drive and shape memory alloy wire drive to drive the main body structure; the control system is used to control the drive system, so that the entire actuator can achieve rapid extension and contraction deformation.

2. The bidirectional rotational wrist joint-like soft actuator based on Kresling origami according to claim 1, characterized in that, The origami-type airbag (1) is a regular hexagonal prism shell structure with a sealed top surface and an open bottom surface, and is made of silicone rubber. The origami-type airbag (1) has crease areas on the diagonal and four sides of the rectangle on its side. The crease areas are thin and can be folded along the creases. The upper plate (2) is a regular hexagon and is made of acrylic. It has protruding ear plates at the six ends, and each protruding ear plate has two small holes. The base (3) is a double-layer disc structure made of acrylic. The upper disc (5) has an air hole in the center, and the lower disc (7) is a ring structure. The upper disc (5) and the lower disc (7) are fixedly connected by twelve cylinders (6). Six sets of small holes are evenly distributed around the edges of the two discs.

3. The bidirectional rotational wrist joint-like soft actuator based on Kresling origami according to claim 2, characterized in that: When the driver adopts a hybrid drive and control system of air drive and motor rope drive, the drive system includes a motor, an air pump and traction ropes (4-2), and the control system includes a microcontroller, a power supply and a solenoid valve; the motors are placed on the lower disc (7) and distributed directly below the six protruding ear plates of the upper end plate (2), with a total of six motors, three motors spaced apart as a group, respectively used to control the driver to rotate in the clockwise and counterclockwise directions; there are six traction ropes (4-2), one end of which is fixed to the small hole of the protruding ear plate of the upper end plate (2), and the other end runs along the origami-shaped airbag (1). Diagonally, the small holes on the upper disc (5) are passed through and fixed to the corresponding motor shaft disc; the traction rope (4-2) used to control the clockwise / counterclockwise rotation of the driver is connected to the small holes on the outer ring, and vice versa; the motor is connected to the power supply in series, and the microcontroller powers different motor groups to control the rotation direction of the driver; the air hole in the center of the upper disc (5) is connected to the air pump through the air pipe, and the solenoid valve is provided on the air pipe. The microcontroller controls the solenoid valve to control the air pressure of the origami-type airbag (1).

4. The bidirectional rotational wrist joint-like soft actuator based on Kresling origami according to claim 2, characterized in that: When the actuator adopts a hybrid drive and control system of air drive and shape memory alloy wire drive, the drive system includes an air pump and shape memory alloy wire (4-1), and the control system includes a microcontroller, a power supply and a solenoid valve; the twelve cylinders (6) are arranged in two inner and outer rings; each cylinder (6) has two separators to separate the shape memory alloy wires (4-1) from each other and prevent two adjacent shape memory alloy wires (4-1) from interfering with each other; there are six shape memory alloy wires (4-1) in total, one end of which is fixed to the small hole of the ear plate protruding from the upper end plate (2), and the other end passes through the small hole on the upper disc (5) along the diagonal direction of the origami-shaped airbag (1). The hole, after being wound around the cylinder (6) once, is fixedly connected to the small hole on the lower disk (7); the shape memory alloy wire (4-1) that controls the clockwise / counterclockwise rotation of the driver is connected to the small hole on the outer ring and wound around the outer ring cylinder, and vice versa, it is connected to the small hole on the inner ring and wound around the inner ring cylinder; the shape memory alloy wire (4-1) is connected to the power supply in series, and the microcontroller powers different shape memory alloy wires (4-1) to control the rotation direction of the driver; the air hole in the center of the upper disk (5) is connected to the air pump through the air pipe, and the solenoid valve is provided on the air pipe. The microcontroller controls the solenoid valve to control the air pressure of the origami-type airbag (1).

5. The bidirectional rotational wrist joint-like soft actuator based on Kresling origami according to claim 3 or 4, characterized in that: The method for using the drive system to make the driver rotate clockwise first and then counterclockwise specifically includes the following steps: Step 1. At the initial moment, the driver is in the first steady state, and the air pump is controlled to perform air extraction operation on the origami-type airbag (1); Step 2. Power is applied to the motor unit or shape memory alloy wire that controls the driver to rotate clockwise, and the traction rope (4-2) or shape memory alloy wire (4-1) is tightened and contracted. At this time, the driver has the tendency to rotate clockwise. Step 3. Control the air pump to continuously pump air into the folding paper-type airbag (1), and the driver continues to rotate in the predetermined direction until the driver is fully folded and reaches the second steady state; Step 4. Inflate the origami-type airbag (1), control the power supply and motor to return the traction rope (4-2) or shape memory alloy wire (4-1) to the initial state, at which point the actuator returns to the first steady state; Step 5. Next, energize the motor assembly or shape memory alloy wire (4-1) that controls the driver to rotate counterclockwise. At this time, the driver has the tendency to rotate in the counterclockwise direction. Step 6. Repeat the operation of step 3 until the driver is completely folded and reaches the third steady state; then repeat the operation of step 4 to return the driver to the first steady state.

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