A variable stiffness soft manipulator with multiple grasping modes

Abstract

The invention discloses a variable stiffness soft manipulator with multiple grasping modes, which solves the shortcomings of the existing variable stiffness soft manipulator, such as complex structure, cumbersome preparation process, interference in stiffness adjustment and deformation, and single grasping mode. Three variable stiffness soft fingers of the same size are alternately arranged on the front and rear sides of the base, a spring driving mechanism for adjusting the stiffness of the proximal joints of the variable stiffness soft fingers is arranged on the left side of the base, and a spring driving mechanism for adjusting the stiffness of the distal joints of the variable stiffness soft fingers and a driving mechanism for driving the finger body are arranged on the right side. The output end of the servo in the spring driving mechanism and the output end of the driving motor are both equipped with a driving shaft, and one end of the driving cable of the spring driving mechanism is connected to the driving shaft, and the other end is connected to the spring. The driving cable of the finger body passes through the reserved cavity in the finger in a U-shaped arrangement, and is finally fixed on the driving shaft of the driving motor to drive the finger body.

Description

Technical Field

[0001] The invention relates to the technical field of soft robots, and in particular to a variable-rigidity soft manipulator with multiple grasping modes. Background Art

[0002] At present, robotics technology has a wide range of applications in daily production and life. Among them, the manipulator is the end effector for the robot to interact with the external environment. The development of related research is of great significance to the automated production industry. The soft manipulator can adapt to different working environments and maintain flexible movement, effectively avoiding the shortcomings of the poor environmental adaptability of the rigid manipulator. Thanks to the advantages of the manufacturing materials of the soft manipulator, it has good ductility and flexibility, and can well protect the personal safety of the operator when working in a small space. However, the soft manipulator itself is soft and easy to deform, resulting in its shortcomings such as poor stiffness performance, low load capacity, simple grasping mode and insufficient control stability. Therefore, a variable stiffness soft manipulator with multiple grasping modes is developed, which takes into account the adjustable stiffness performance, large load capacity and adjustable grasping mode performance, and can increase the overall performance and application range of the soft manipulator. Most of the existing soft manipulators adopt a single joint structure, with a relatively single grasping mode and poor adaptability. The variable stiffness function is realized by using an additional variable stiffness mechanism, such as filling control method, which uses the method of increasing friction to adjust the stiffness; using smart materials as the stiffness adjustment mechanism, and heating it to convert the stiffness to high and low. The above variable stiffness method has high control requirements, low power density and contains rigid components, which affects the compliance of the soft manipulator.

[0003] In summary, the existing variable stiffness soft manipulators have the disadvantages of a single grasping mode, high requirements for the preparation process, and poor structural compactness. Summary of the invention

[0004] In order to solve the problems of the variable stiffness soft manipulator in the prior art having a single grasping mode, high requirements for the preparation process and poor structural compactness, the purpose of the present invention is to overcome the shortcomings of the existing technology and provide a variable stiffness soft manipulator with multiple grasping modes, which has the advantages of rich grasping modes, easy manufacturing and compact structure.

[0005] In order to achieve the above invention purpose, the present invention adopts the following technical solution:

[0006] A variable stiffness soft manipulator with multiple grasping modes comprises a variable stiffness soft finger and a base; three variable stiffness soft fingers are alternately arranged on the front and rear sides of the base, the proximal root of each variable stiffness soft finger is directly connected to the base, each variable stiffness soft finger comprises three flexible knuckles and two joints, the working surface of the variable stiffness soft finger faces the left and right inward bending direction of the finger, and the back of the variable stiffness soft finger faces the opposite direction of the left and right inward bending of the finger;

[0007] In each variable-stiffness soft finger, a proximal joint spring driving mechanism and a distal joint spring driving mechanism are also arranged on the back side near the variable-stiffness soft finger to form a variable-stiffness control system; the proximal joint spring driving mechanism is arranged on the left side of the base, and the distal joint spring driving mechanism and the finger body driving mechanism are arranged on the right side of the base; the proximal joint spring driving mechanism includes a finger proximal joint spring, a first driving cable, and a first servo, one end of the first driving cable is connected to the end of the proximal joint spring, and the other end is connected to the first driving shaft of the output end of the first servo; the distal joint spring driving mechanism includes a finger distal joint spring, a second driving cable, and a second servo, one end of the second driving cable is connected to the end of the finger distal joint spring, and the other end is connected to the second driving shaft of the output end of the second servo; the body stiffness of the variable-stiffness soft finger is controlled by each servo;

[0008] In each variable stiffness soft finger, a finger body driving mechanism is also arranged near the working surface of the variable stiffness soft finger. The finger body driving mechanism includes a third driving cable. The third driving cable is arranged in a U-shaped manner. After passing through each section of the flexible knuckles of the finger body, the end is connected to the third driving shaft of the driving motor; the driving motor is used to control the bending angle of the proximal joint and the distal joint of the finger to achieve the grasping or releasing action of the variable stiffness soft finger; the target object is operated in multiple grasping modes through the coordinated work of the variable stiffness control system and the finger body driving mechanism. The driving cable of the finger body of the present invention passes through the reserved cavity in the finger through the U-shaped arrangement, and is finally fixed on the driving shaft of the driving motor to drive the finger body.

[0009] Furthermore, the variable-rigidity soft finger includes three sections of flexible knuckles, a rigid skeleton, a proximal joint spring, a distal joint spring and a drive cable; a spring slide groove is provided in the rigid skeleton to facilitate length adjustment of the spring.

[0010] Furthermore, the material of the three sections of flexible knuckles is the rubber-like material Agilus30, and the material of the rigid skeleton is VeroPure White.

[0011] Furthermore, the Polyjet 3D printing method is used to simultaneously deposit and print the two materials.

[0012] Furthermore, the proximal joint spring drive mechanism includes a proximal joint spring, a first drive cable, a first drive shaft, and a first servo; the distal joint spring drive mechanism includes a distal joint spring, a second drive cable, a second drive shaft, and a second servo; wherein the two sets of drive mechanisms have exactly the same composition and working mode, the spring is installed in the spring slide groove of the rigid frame, one end of the drive cable is connected to the end of the spring, and the other end is connected to the drive shaft of the corresponding servo.

[0013] Furthermore, the finger body driving mechanism includes a third driving cable, a driving motor and a third driving shaft; the third driving cable is arranged in a U-shape to pass through the finger knuckles, and its end is wrapped around the third driving shaft. The third driving shaft is installed at the output end of the driving motor, and the fixed part of the driving motor is installed on the base.

[0014] Furthermore, when in use, the servo of the spring drive mechanism and the finger body drive motor are connected to an external power source, and the length of the spring at the finger joint is adjusted by controlling the rotation of the first servo and the second servo, and then the drive cable is driven to contract by controlling the rotation of the drive motor, so that the variable stiffness soft finger is bent to achieve the corresponding grasping action. When the finger joint bends and gradually approaches the target angle, the spring stretch length and the drive cable contraction length are further adjusted to make the variable stiffness soft finger reach the predetermined bending angle and stiffness, thereby realizing the variable stiffness function of the soft manipulator.

[0015] Furthermore, by controlling the first servo and the second servo to rotate at different angles, the springs at the proximal joint and distal joint of the finger have different stretching amounts, and then the drive motor is rotated to drive the drive cable to contract, so that the variable stiffness soft finger is bent to achieve the corresponding grasping action, so that the two finger joints have different bending angles, and grasping operations are performed on objects with different grasping requirements, thereby realizing the grasping mode adjustment of the variable stiffness soft manipulator.

[0016] Compared with the prior art, the present invention has the following obvious outstanding substantive features and significant advantages:

[0017] 1. The present invention overcomes the shortcomings of the prior art. Before the variable stiffness soft finger is bent, it is stretched by a spring driving mechanism, so that a pre-tightening force is applied to the joint to form a constraint restriction; then the soft finger is driven by a driving motor, and the finger joint is bent to a certain angle under the influence of the pre-tightening force and stops moving. Then, the pre-tightening force on the finger joint is further increased by further adjusting the pre-stretching length of the spring, so that the variable stiffness soft finger can obtain different stiffness at any bending angle, realize its variable stiffness function, and improve the load-bearing performance of the soft manipulator;

[0018] 2. The present invention stretches the springs of the proximal joint and distal joint of the finger to different lengths through a spring driving mechanism, thereby applying different preload forces at the proximal joint and distal joint, forming different constraints on the joints; subsequently, when the driving motor is used to drive the soft finger to bend, the proximal joint and distal joint of the finger will present different bending angles after being restricted by the preload force, thereby realizing the function of adjusting the grasping mode of the soft manipulator, and finally stably grasping objects of different shapes and sizes;

[0019] 3. The present invention adopts three soft fingers with the same size and variable stiffness, which are arranged alternately on the front and rear sides of the base. The proximal joint spring drive cables of the three fingers are connected to the drive shaft of the servo 1 on the left side of the base, and the distal joint spring drive cables are connected to the drive shaft of the servo 2 on the right side of the base. The finger body drive cable is connected to the drive shaft of the drive motor;

[0020] 4. The spring drive mechanism and the finger body drive mechanism of the present invention both adopt an under-drive mode to ensure the consistency of the movement of each joint of the finger. It has a simple structure, is easy to operate, and has a low cost, and is suitable for popularization and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the three-dimensional structure of a variable-rigidity soft manipulator with multiple grasping modes according to a preferred embodiment of the present invention.

[0022] Figure 2 It is a schematic diagram of the three-dimensional structure of a variable-rigidity soft finger in a variable-rigidity soft manipulator with multiple grasping modes in a preferred embodiment of the present invention.

[0023] Figure 3 It is a schematic diagram of the cable connection between the spring drive mechanism and the finger body drive mechanism of the variable stiffness soft finger in the variable stiffness soft manipulator with multiple grasping modes in the preferred embodiment of the present invention.

[0024] Figure 4 It is a schematic diagram of the envelope grasping mode of a variable stiffness soft manipulator with multiple grasping modes according to a preferred embodiment of the present invention.

[0025] Figure 5 It is a schematic diagram of a single-joint grasping mode of a variable-rigidity soft manipulator with multiple grasping modes in a preferred embodiment of the present invention.

[0026] Figure 6 It is a schematic diagram of the double-knuckle grasping mode of the variable-rigidity soft manipulator with multiple grasping modes in the preferred embodiment of the present invention.

[0027] Figure 7 It is a schematic diagram of the pinching mode of the variable stiffness soft mechanical finger joints with multiple grasping modes in the preferred embodiment of the present invention. DETAILED DESCRIPTION

[0028] The above scheme is further described below in conjunction with specific implementation examples. The preferred embodiments of the present invention are described in detail as follows:

[0029] Embodiment 1:

[0030] In this embodiment, see Figure 1-3 , a variable stiffness soft manipulator with multiple grasping modes, comprising a variable stiffness soft finger 1 and a base 2; three variable stiffness soft fingers 1 are alternately arranged on the front and rear sides of the base 2, the proximal root of each variable stiffness soft finger 1 is directly connected to the base 2, each variable stiffness soft finger 1 comprises three flexible knuckles 6 and two joints, the working surface of the variable stiffness soft finger 1 faces the left and right inward bending direction of the finger, and the back of the variable stiffness soft finger 1 faces the opposite direction of the left and right inward bending of the finger;

[0031] In each variable stiffness soft finger 1, a proximal joint spring driving mechanism 17 and a distal joint spring driving mechanism 16 are also arranged near the back of the variable stiffness soft finger 1 to form a variable stiffness control system; the proximal joint spring driving mechanism 17 is arranged on the left side of the base 2, and the distal joint spring driving mechanism 16 and the finger body driving mechanism 18 are arranged on the right side of the base 2; the proximal joint spring driving mechanism 17 includes a finger proximal joint spring 10, a first driving cable 15, and a first servo 3, one end of the first driving cable 15 is connected to the end of the proximal joint spring 10, and the other end is connected to the first driving shaft 20 at the output end of the first servo 3; the distal joint spring driving mechanism 16 includes a finger distal joint spring 9, a second driving cable 14, and a second servo 4, one end of the second driving cable 14 is connected to the end of the finger distal joint spring 9, and the other end is connected to the second driving shaft 19 at the output end of the second servo 4; the body stiffness of the variable stiffness soft finger 1 is controlled by each servo;

[0032] In each variable stiffness soft finger 1, a finger body driving mechanism 18 is also arranged near the working surface of the variable stiffness soft finger 1. The finger body driving mechanism 18 includes a third driving cable 13. The third driving cable 13 is arranged in a U-shaped manner. After passing through each section of the flexible finger joint 6 of the finger body, the end is connected to the third driving shaft 21 of the driving motor 5. The driving motor 5 is used to realize the bending angle control of the proximal joint 12 and the distal joint 11 of the finger.

[0033] The variable stiffness soft finger 1 is used to grasp or release the object; and the target object is operated in multiple grasping modes through the coordinated work of the variable stiffness control system and the finger body driving mechanism 18 .

[0034] When in use, the servo of the spring drive mechanism and the finger body drive motor are connected to an external power supply, and the length of the spring at the finger joint is adjusted by controlling the rotation of the first servo and the second servo, and then the drive cable is driven to contract by controlling the rotation of the drive motor, so that the variable stiffness soft finger is bent to achieve the corresponding grasping action. When the finger joint bends and gradually approaches the target angle, the spring stretch length and the drive cable contraction length are further adjusted to make the variable stiffness soft finger reach the predetermined bending angle and stiffness, realizing the variable stiffness function of the soft manipulator.

[0035] By controlling the first servo and the second servo to rotate at different angles, the springs at the proximal joint and the distal joint of the finger have different stretching amounts, and then the driving cable is driven to contract by the rotation of the driving motor, so that the variable stiffness soft finger is bent to achieve the corresponding grasping action, so that the two finger joints have different bending angles, and grasping operations are performed on objects with different grasping requirements, thereby realizing the grasping mode adjustment of the variable stiffness soft manipulator. This embodiment has a variable stiffness soft manipulator with multiple grasping modes, which has the advantages of rich grasping modes, easy manufacturing and compact structure.

[0036] Embodiment 2:

[0037] This embodiment is basically the same as the first embodiment, except that: Specific implementation method one:

[0039] Combination Figures 1 to 3 The present embodiment is described as a variable stiffness soft manipulator with multiple grasping modes, comprising a variable stiffness soft finger 1 , a base 2 , a proximal joint spring drive mechanism 17 , a distal joint spring drive mechanism 16 and a finger body drive mechanism 18 .

[0040] Three variable-rigidity soft fingers 1 are alternately arranged on the front and rear sides of the base 2, a proximal joint spring drive mechanism 17 is arranged on the left side of the base 2, and a distal joint spring drive mechanism 16 and a finger body drive mechanism 18 are arranged on the right side; one end of the first drive cable 15 is connected to the end of the proximal joint spring 10, and the other end is connected to the first drive shaft 20 at the output end of the first servo 3 in the proximal joint spring drive mechanism 17; one end of the second drive cable 14 is connected to the end of the distal joint spring 9, and the other end is connected to the second drive shaft 19 at the output end of the second servo 4 in the distal joint spring drive mechanism 16; the third drive cables 13 of the three fingers are arranged in a U-shaped manner and pass through the finger body, and the ends are connected to the third drive shaft 21 of the drive motor 5.

[0041] In this specific embodiment, when in use, the spring at the finger joint is stretched by the spring driving mechanism, so that a preload is applied to the proximal joint 12 and the distal joint 11 to form a constraint. Then, the variable stiffness soft finger 1 is driven by the driving motor 5, and the two joints of the finger stop moving after bending to a certain angle under the influence of the preload. Then, the preload on the two joints of the finger is further increased by further adjusting the preload length of the spring at the joint, so that the variable stiffness soft finger 1 can obtain different stiffness at any bending angle, realize its variable stiffness function, and improve the load-bearing performance of the soft manipulator. Specific implementation method 2:

[0043] This embodiment further limits the adjustment of the gripping mode of the variable stiffness soft manipulator with multiple gripping modes described in Specific Embodiment 1. The adjustment of the gripping mode is achieved by stretching the springs at the variable stiffness soft finger joints to different lengths, that is, applying different preload forces, so as to obtain different joint stiffnesses, and then obtain different joint bending angles after the drive motor is operated.

[0044] In this specific embodiment, when in use, the spring drive mechanism of the two joints stretches the proximal joint spring 10 and the distal joint spring 9 to different lengths, thereby applying different preload forces at the proximal joint 12 and the distal joint 11, forming different constraints on the joints. When the variable stiffness soft finger 1 is subsequently driven by the drive motor 5 to bend, the proximal joint 12 and the distal joint 11 of the finger will present different bending angles after being restricted by the preload force, thereby realizing the function of adjusting the grasping mode of the soft manipulator, and finally stably grasping objects of different shapes and sizes. Specific implementation method three:

[0046] Combination Figure 2-Figure 4 This embodiment further limits the implementation of the envelope grasping mode of the variable stiffness soft manipulator with multiple grasping modes described in the second embodiment. The springs at the joints are stretched to the same length by two spring drive mechanisms, so that the preload forces at the joints are the same, so that the same bending angle is obtained when the variable stiffness soft fingers are bent to perform envelope grasping of objects.

[0047] In this specific embodiment, when in use, the proximal joint spring 10 is first stretched by the proximal joint spring driving mechanism 17, and then the distal joint spring 9 is stretched by the distal joint spring driving mechanism 16. When the two joint springs are stretched to the same length, the drive motor 5 is used to drive the variable stiffness soft finger 1, so that the proximal joint 12 and the distal joint 11 of the finger are bent at the same angle, thereby realizing the grasping operation of the object in an envelope grasping manner. Specific implementation method four:

[0049] Combination Figure 2 and Figure 5 This embodiment further limits the single-knuckle grasping mode of the variable-rigidity soft manipulator with multiple grasping modes described in the second embodiment. The proximal joint spring is stretched by the proximal joint spring driving mechanism to change it to a high-rigidity state, and the distal joint spring maintains the initial state, so that when the variable-rigidity soft finger is bent, the distal joint is bent to drive the distal knuckle to grasp the object.

[0050] In this specific embodiment, when in use, the proximal joint spring 10 is first stretched by the proximal joint spring driving mechanism 17, so that the proximal joint 12 becomes a high-rigidity state, and the distal joint spring 9 is not stretched, so that the distal joint 11 maintains a low-rigidity state. When the spring length is fully adjusted, the drive motor 5 drives the drive cable to contract, so that when the variable-rigidity soft finger moves, the proximal joint does not bend, and the distal joint bends to drive the distal knuckle to grasp the object. Specific implementation method five:

[0052] Combination Figure 2 and Figure 6 This embodiment further limits the realization of the double-knuckle grasping mode of the variable-rigidity soft manipulator with multiple grasping modes described in the second embodiment. The distal joint spring is stretched by the distal joint spring driving mechanism to change it into a high-rigidity state, and the proximal joint spring maintains the initial state, so that when the variable-rigidity soft finger is bent, the proximal joint is bent to drive the distal knuckle and the middle knuckle to grasp the object.

[0053] In this specific embodiment, when in use, the distal joint spring 9 is first stretched by the distal joint spring driving mechanism 16 to change the distal joint 11 into a high stiffness state, and the proximal joint spring 10 is not stretched to keep the proximal joint 12 in a low stiffness state. When the spring length is fully adjusted, the driving motor 5 drives the driving cable to contract, so that when the variable stiffness soft finger moves, the distal joint 9 does not bend, and the proximal joint 10 bends to drive the distal knuckle and the middle knuckle to grasp the object. Specific implementation method six:

[0055] Combination Figure 2 and Figure 7 This embodiment further limits the pinching mode of the variable stiffness soft manipulator with multiple grasping modes described in the second embodiment. On the basis of the fifth embodiment, the drive cable is further contracted to increase the bending degree of the proximal joint, thereby realizing the pinching operation of the object.

[0056] In this specific embodiment, when in use, the distal joint spring 9 is first stretched by the distal joint spring driving mechanism 16, so that the distal joint 11 becomes a high-rigidity state, and the proximal joint spring 10 is not stretched, so that the proximal joint 12 remains in a low-rigidity state. When the spring length is fully adjusted, the driving motor 5 drives the driving cable to contract, so that when the variable-rigidity soft finger 1 moves, the distal joint 11 does not bend, and the proximal joint 12 bends, driving the distal knuckle and the middle knuckle to move. The contraction amount of the finger driving cable is further increased by adjusting the number of rotations of the driving motor, thereby realizing the pinching operation of the distal knuckle on the object.

[0057] How it works

[0058] When in use, the proximal joint spring 10 is stretched by the proximal joint spring driving mechanism 17, and the distal joint spring 9 is stretched by the distal joint spring driving mechanism 16. The movement of the two joints of the finger is restricted by applying a preload force to them, thereby achieving stiffness adjustment. The driving cable is then driven by the driving motor 5 to drive the finger, so that the variable stiffness soft finger 1 is bent and deformed to achieve the corresponding grasping action. When the grasping mode needs to be changed, different preload forces can be applied to the finger joints by adjusting the length of the proximal joint spring and the distal joint spring respectively, so that the finger joints have different stiffnesses. When driven by the driving motor, the proximal joint 12 and the distal joint 11 of the finger can move at different bending angles, thereby achieving adjustment of the grasping mode.

[0059] In summary, the above embodiment has a variable stiffness soft manipulator with multiple grasping modes, and designs the field of soft robot technology. In order to solve the shortcomings of the existing variable stiffness soft manipulator, such as complex structure, cumbersome preparation process, interference in stiffness adjustment and deformation, and single grasping mode. Three variable stiffness soft fingers of the same size are alternately arranged on the front and back sides of the base. The left side of the base is arranged with a spring driving mechanism for adjusting the stiffness of the proximal joints of the variable stiffness soft fingers, and the right side is arranged with a spring driving mechanism for adjusting the stiffness of the distal joints of the variable stiffness soft fingers and a driving mechanism for driving the finger body. The output end of the servo in the spring driving mechanism and the output end of the driving motor are both equipped with a driving shaft, and one end of the driving cable of the spring driving mechanism is connected to the driving shaft, and the other end is connected to the spring. The driving cable of the finger body passes through the reserved cavity in the finger in a U-shaped arrangement, and is finally fixed on the driving shaft of the driving motor to drive the finger body.

[0060] The above describes the embodiments of the present invention in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Various changes can be made according to the purpose of the invention. Any changes, modifications, substitutions, combinations or simplifications made according to the spirit and principle of the technical solution of the present invention should be equivalent replacement methods. As long as they meet the purpose of the invention and do not deviate from the technical principles and inventive concepts of the present invention, they belong to the protection scope of the present invention.

Claims

1. A variable stiffness soft manipulator with multiple grasping modes, comprising a variable stiffness soft finger (1) and a base (2); characterized in that: Three variable stiffness soft fingers (1) are alternately arranged on the front and rear sides of the base (2); the proximal root of each variable stiffness soft finger (1) is directly connected to the base (2); each variable stiffness soft finger (1) comprises three flexible knuckles (6) and two joints; the working surface of the variable stiffness soft finger (1) faces the left and right inward bending direction of the finger, and the back surface of the variable stiffness soft finger (1) faces the opposite direction of the left and right inward bending of the finger; In each variable stiffness soft finger (1), a proximal joint spring drive mechanism (17) and a distal joint spring drive mechanism (16) are also arranged near the back of the variable stiffness soft finger (1), forming a variable stiffness control system; the proximal joint spring drive mechanism (17) is arranged on the left side of the base (2), and the distal joint spring drive mechanism (16) and the finger body drive mechanism (18) are arranged on the right side of the base (2); the proximal joint spring drive mechanism (17) includes a finger proximal joint spring (10), a first drive cable (15), a first servo (3 ), one end of the first drive cable (15) is connected to the end of the finger proximal joint spring (10), and the other end is connected to the first drive shaft (20) at the output end of the first servo (3); the distal joint spring drive mechanism (16) comprises a finger distal joint spring (9), a second drive cable (14), and a second servo (4), one end of the second drive cable (14) is connected to the end of the finger distal joint spring (9), and the other end is connected to the second drive shaft (19) at the output end of the second servo (4); the body stiffness of the variable stiffness soft finger (1) is controlled by each servo; In each variable-rigidity soft finger (1), a finger body driving mechanism (18) is also provided near the working surface of the variable-rigidity soft finger (1). The finger body driving mechanism (18) comprises a third driving cable (13). The third driving cable (13) is arranged in a U-shaped manner, passes through each section of the flexible finger joints (6) of the finger body, and the end thereof is connected to a third driving shaft (21) of a driving motor (5). The driving motor (5) is used to control the bending angles of the proximal joint (12) and the distal joint (11) of the finger. A variable stiffness soft finger (1) is used to grasp or release the object; a variable stiffness control system and a finger body drive mechanism (18) are used to coordinate the operation to perform multiple grasping mode operations on the target object; The variable-rigidity soft finger (1) comprises three sections of flexible finger joints (6), a rigid skeleton (7), a finger proximal joint spring (10), a finger distal joint spring (9) and a drive cable; a spring slide groove (8) is provided in the rigid skeleton (7) to facilitate length adjustment of the spring; The finger body drive mechanism (18) comprises a third drive cable (13), a drive motor (5) and a third drive shaft (21); the third drive cable (13) is arranged in a U-shape and passes through the finger joints, and its end is wound around the third drive shaft (21); the third drive shaft (21) is mounted on the output end of the drive motor (5), and the fixed part of the drive motor (5) is mounted on the base (2).

2. The variable stiffness soft manipulator with multiple grasping modes according to claim 1, characterized in that: The material of the three sections of flexible knuckles (6) is the rubber-like material Agilus30, and the material of the rigid skeleton (7) is Vero Pure White.

3. The variable stiffness soft manipulator with multiple grasping modes according to claim 2, characterized in that: The Polyjet 3D printing method is used to deposit and print two materials simultaneously.

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