A rigid-flexible coupled pneumatic soft wrist

Abstract

The present application relates to the field of robot technology, in particular to a kind of rigid-flexible coupling pneumatic soft wrist, comprising: support structure, two first air pressure drivers are symmetrically provided on the support structure;First blocking mechanism, be provided on the support structure, and close to the first air pressure driver;First rotating mechanism, be provided on the first air pressure driver and first blocking mechanism, the first air pressure driver and first blocking mechanism rotate around the first rotating mechanism;Second air pressure driver and second blocking mechanism, the second air pressure driver has two, and symmetrically provided on the support structure, located below the first air pressure driver and first blocking mechanism;The soft wrist not only has fixed rotating shaft in each joint, but also has the bidirectional air pressure driver of larger output torque, increase the bending curvature of soft wrist, which greatly improves the flexibility of wrist.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of robots, in particular to a rigid-flexible coupling pneumatic soft wrist. BACKGROUND

[0002] With the progress of science and technology, dexterous hands of robots have been more and more widely used in the industrial field. As the end effector of a robot system, a dexterous hand can realize various operations such as grasping and clamping, and both rigid and flexible dexterous hands have been widely studied. A large number of previous studies on robot hands mainly focus on fingers and palms, and less attention is paid to their wrists. However, recent studies have shown that wrist joints play an important role in the performance of robot hands, and can significantly improve the flexibility and accuracy of operation.

[0003] A rigid mechanism can easily realize three degrees of freedom similar to a human wrist, but in unstructured application scenarios, a rigid structure often lacks sufficient adaptability and can easily harm the operating object. Therefore, there are certain safety problems in the interaction with fragile objects and living beings. In recent years, soft robots have developed rapidly due to their special environmental adaptability brought by inherent flexibility, and soft wrists have also attracted people's attention in solving the adaptability and safety problems in unstructured environments.

[0004] Some people have proposed a soft wrist with modular design for underwater environment, which is driven by hydraulic pressure and can perform fine operations in underwater environment with a depth of more than 2300 meters. A team has developed a soft wrist driven by independent cables, which realizes variable stiffness on the basis of a new type of interference mechanism. A soft wrist driven by four parallel air chambers successfully realizes rotation and bending motion, and its spiral structure provides more possibilities for the driving mode. A team has studied a spring-driven soft wrist, which uses a new learning framework to meet the requirements of human-computer interaction. In the field of rehabilitation of patients with wrist injuries, some people have proposed a flexible wearable wrist equipped with a paper folding mechanism actuator, which adopts a modular design and is equipped with 8 drivers. At the same time, one of the biggest challenges of soft robots is variable stiffness, because their inherent flexibility brings advantages in environmental adaptation, but also means smaller force output. Variable stiffness systems based on jamming interference mechanism have recently received extensive attention from researchers and have been used in the design of many kinds of soft robots. For example, a soft gripper with passive variable stiffness based on jamming principle, a granular jamming pneumatic finger for robust grasping, a new multifunctional soft gripper with adjustable stiffness based on textiles, and a flexible robot with large-range adjustable stiffness based on jamming principle.

[0005] However, the current soft wrist is generally faced with two important problems. First, the existing soft wrist has a small bending curvature, which brings inconvenience to subsequent motion planning; second, the research on soft wrist with adjustable stiffness is limited, which greatly limits its adaptability to various operation tasks. SUMMARY

[0006] Therefore, the technical problem to be solved by the present application is to overcome the problem of the existing soft wrist in the prior art, which has a small bending curvature and brings inconvenience to subsequent motion planning, thereby providing a rigid-flex coupled pneumatic soft wrist.

[0007] In order to solve the above technical problems, the present application provides a rigid-flex coupled pneumatic soft wrist, comprising: a support structure, two first pneumatic actuators are symmetrically arranged on the support structure; a first blocking mechanism is arranged on the support structure and close to the first pneumatic actuator; a first rotating mechanism is arranged on the first pneumatic actuator and the first blocking mechanism, the first pneumatic actuator and the first blocking mechanism rotate around the first rotating mechanism; two second pneumatic actuators are symmetrically arranged on the support structure below the first pneumatic actuator and the first blocking mechanism; a second rotating mechanism is arranged on the second pneumatic actuator and the second blocking mechanism, the second pneumatic actuator and the second blocking mechanism rotate around the second rotating mechanism, the rotating directions of the first rotating mechanism and the second rotating mechanism are opposite; the first pneumatic actuator and the first blocking mechanism, the second pneumatic actuator, and the second blocking mechanism are connected with a gas pump.

[0008] Further, the first pneumatic actuator and the second pneumatic actuator each comprise: a body; a front end adapter block and a rear end adapter block located at both ends of the body, and the front end adapter block and the rear end adapter block are arranged on the support structure, and a gas filling port is arranged on the rear end adapter block.

[0009] Further, the cylinder body comprises an inner silica gel layer and a fiber reinforced layer, an outer silica gel layer, and the inner silica gel layer and the fiber reinforced layer, the outer silica gel layer are sequentially arranged from inside to outside.

[0010] Further, the first blocking mechanism comprises: a first housing, a first flexible film is arranged in the first housing, an end cover is arranged on the first housing, and a first gas adapter port is arranged on the first housing; a first locking rod, one end of the first locking rod is arranged in the first housing, and the other end of the first locking rod is connected with the support structure; blocking particles are filled in the first housing.

[0011] Further, the second blocking mechanism comprises a second shell, a second flexible film is arranged in the second shell, a second gas switching port is arranged on the second shell, and the blocking particles are filled in the second shell; a second locking rod is arranged in one end of the second shell and connected with the support structure in the other end.

[0012] Further, the support structure comprises a first joint framework, a palm connecting seat is arranged on the first joint framework, the first pneumatic driver and the first blocking mechanism are arranged between the first joint framework and the palm connecting seat; a second joint framework is arranged at the bottom of the first joint framework, and the second pneumatic driver and the second blocking mechanism are arranged between the first joint framework and the second joint framework.

[0013] Further, the first locking rod comprises a rod body, a groove is arranged at one end of the rod body, and the groove is matched with the protrusion on the palm connecting seat; a plurality of locking blocks are arranged on the outer wall of the rod body at intervals.

[0014] Further, the second locking rod comprises a fixed plate connected with the first joint framework, a connecting rod arranged at one end away from the first joint framework, a groove arranged at the other end of the connecting rod, a locking ring with a protrusion arranged in the inside, the protrusion is matched with the groove, and a plurality of locking blocks are arranged on the outer wall of the locking ring at intervals.

[0015] Further, the first rotating mechanism comprises a rotating seat arranged on the first joint framework, and a first rotating cylinder arranged on the palm connecting seat, a first rotating shaft penetrating through the rotating seat and the first rotating cylinder, and the first rotating shaft is coaxially arranged with the first locking rod.

[0016] Further, the second rotating mechanism comprises a second rotating cylinder arranged on the second joint framework, and a second rotating shaft arranged in the second rotating cylinder, and the second rotating shaft is connected with the second locking rod.

[0017] The technical scheme of the present application has the following advantages:

[0018] The rigid-flexible coupling pneumatic soft wrist provided by the application comprises a support structure, two first air pressure drivers are symmetrically arranged on the support structure, a first blocking mechanism is arranged on the support structure and close to the first air pressure drivers, a first rotating mechanism is arranged on the first air pressure drivers and the first blocking mechanism, the first air pressure drivers and the first blocking mechanism rotate around the first rotating mechanism, two second air pressure drivers are symmetrically arranged on the support structure below the first air pressure drivers and the first blocking mechanism, a second rotating mechanism is arranged on the second air pressure drivers and the second blocking mechanism, the second air pressure drivers and the second blocking mechanism rotate around the second rotating mechanism, the rotating directions of the first rotating mechanism and the second rotating mechanism are opposite, and the first air pressure drivers and the first blocking mechanism, the second air pressure drivers and the second blocking mechanism are connected with an air pump.

[0019] The first air pressure drivers and the first blocking mechanism are arranged on the support structure, and the first air pressure drivers can rotate around the first rotating mechanism, so as to drive the first blocking mechanism to rotate with the first air pressure drivers, thereby realizing the forward flexion / rear extension of the wrist of the soft body; the second air pressure drivers and the second blocking mechanism are also arranged on the support structure, that is, the support structure supports the second air pressure drivers and the second blocking mechanism; the second air pressure drivers can rotate around the second rotating mechanism, so as to drive the second blocking mechanism to rotate with the second air pressure drivers, thereby realizing the internal rotation / external rotation of the wrist of the soft body.

[0020] The soft wrist not only has a fixed rotating shaft in each joint, but also has a bidirectional air pressure driver with a large output torque, which increases the bending curvature of the soft wrist, greatly improving the flexibility of the wrist. The variable stiffness mechanism can provide a large impedance torque to help the wrist withstand external loads, and the impedance torque of each joint can be individually adjusted by air pressure, which greatly improves the stability and flexibility of the wrist.

[0021] The summary section is provided to introduce a selection of concepts in a simplified form, which will be further described below in the detailed description. The summary section is not intended to identify key or essential features of the disclosure, nor is it intended to limit the scope of the disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the specific embodiments of the application or the technical solutions in the prior art, the drawings required to be used in the specific embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0023] Figure 1 Structure diagram of freedom and movement range of human wrist provided by the present application;

[0024] Figure 2 Perspective view of rigid-flexible coupling pneumatic soft wrist provided by the present application;

[0025] Figure 3 Perspective view of rigid-flexible coupling pneumatic soft wrist provided by the present application;

[0026] Figure 4 Working principle diagram of pre-stretching installation of air pressure driver of rigid-flexible coupling pneumatic soft wrist provided by the present application;

[0027] Figure 5 Working principle diagram of blocking mechanism of rigid-flexible coupling pneumatic soft wrist provided by the present application;

[0028] Figure 6 Manufacturing process diagram of air pressure driver of rigid-flexible coupling pneumatic soft wrist provided by the present application;

[0029] Figure 7 Structure diagram of experimental test platform of rigid-flexible coupling pneumatic soft wrist provided by the present application;

[0030] Figure 8 Structure diagram of experimental data curve of rigid-flexible coupling pneumatic soft wrist provided by the present application;

[0031] Figure 9 Characteristic test diagram of rigid-flexible coupling pneumatic soft wrist provided by the present application;

[0032] Figure 10 Experimental result diagram of rigid-flexible coupling pneumatic soft wrist provided by the present application;

[0033] Figure 11 Movement experiment diagram of rigid-flexible coupling pneumatic soft wrist provided by the present application;

[0034] Figure 12 Structure diagram of palm connecting seat of rigid-flexible coupling pneumatic soft wrist provided by the present application;

[0035] Figure 13 Structure diagram of first blocking mechanism of rigid-flexible coupling pneumatic soft wrist provided by the present application;

[0036] Figure 14 Structure diagram of first joint skeleton of rigid-flexible coupling pneumatic soft wrist provided by the present application;

[0037] Figure 15Structure diagram of the first rotating shaft of the rigid-flexible coupling pneumatic soft wrist provided by the present application;

[0038] Figure 16 Exploded view of the first blocking mechanism of the rigid-flexible coupling pneumatic soft wrist provided by the present application;

[0039] Figure 17 Structure diagram of the second blocking mechanism of the rigid-flexible coupling pneumatic soft wrist provided by the present application;

[0040] Figure 18 Structure diagram of the second joint skeleton of the rigid-flexible coupling pneumatic soft wrist provided by the present application;

[0041] Figure 19 Structure diagram of the second locking rod of the rigid-flexible coupling pneumatic soft wrist provided by the present application;

[0042] Figure 20 Perspective view of the second joint skeleton of the rigid-flexible coupling pneumatic soft wrist provided by the present application;

[0043] Figure 21 Structure diagram of the second rotating shaft of the rigid-flexible coupling pneumatic soft wrist provided by the present application;

[0044] Figure 22 Structure diagram of the first locking rod of the rigid-flexible coupling pneumatic soft wrist provided by the present application;

[0045] Figure 23 Structure diagram of the second gas switching interface of the rigid-flexible coupling pneumatic soft wrist provided by the present application;

[0046] Figure 24 Structure diagram of the rigid-flexible coupling pneumatic soft wrist provided by the present application.

[0047] Explanation of reference signs:

[0048] 1, support structure; 2, first pneumatic driver; 3, first blocking mechanism; 4, first rotating mechanism; 5, second pneumatic driver; 6, second blocking mechanism; 7, second rotating mechanism; 8, body; 9, front adapter block; 10, rear adapter block; 11, gas inlet; 12, inner silica gel layer; 13, fiber reinforced layer; 14, outer silica gel layer; 15, first shell; 16, first flexible film; 17, end cover; 18, first gas adapter; 19, first locking rod; 20, blocking particle; 21, second shell; 22, second flexible film; 23, second gas adapter; 24, second locking rod; 25, first joint framework; 26, palm connecting seat; 27, second joint framework; 28, rod body; 29, groove; 30, protrusion; 31, locking block; 32, fixed plate; 33, connecting rod; 331, groove body; 34, locking ring; 35, protrusion; 36, rotating seat; 37, first rotating cylinder; 38, first rotating shaft; 39, second rotating cylinder; 40, second rotating shaft; 41, bearing. DETAILED DESCRIPTION

[0049] Hereinafter, only certain exemplary embodiments are simply described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present disclosure. Therefore, the drawings and the description are considered to be exemplary in nature rather than limiting.

[0050] In the description of the present disclosure, it is to be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "straight", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, only for the purpose of facilitating the description of the present disclosure and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present disclosure. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present disclosure, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0051] In the description of the present disclosure, it is necessary to explain that, unless otherwise explicitly specified and limited, the terms "mount", "connect", "connection" should be understood in a broad sense, for example, can be fixed connection, can be detachable connection, or integrally connected; can be mechanical connection, or electrical connection or can communicate with each other; can be directly connected, or indirectly connected through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present disclosure can be understood according to the specific circumstances.

[0052] In the present disclosure, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can include that the first and second features are in direct contact, or the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "over" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "under", "below" and "under" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0053] The following disclosure provides many different embodiments or examples for implementing different structures of the present disclosure. In order to simplify the disclosure of the present disclosure, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present disclosure. In addition, the present disclosure can repeatedly refer to numbers and / or letters in different examples, and such repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present disclosure provides various specific examples of processes and materials, but those skilled in the art can realize the application of other processes and / or the use of other materials.

[0054] The preferred embodiments of the present disclosure are described below in conjunction with the accompanying drawings, and it should be understood that the preferred embodiments described herein are only used to illustrate and explain the present disclosure, and are not intended to limit the present disclosure.

[0055] Please refer to Figures 1 to 24As shown, the present application provides a rigid-flexible coupling pneumatic soft wrist, comprising: a support structure 1, two first pneumatic drivers 2 are symmetrically arranged on the support structure 1; a first blocking mechanism 3 is arranged on the support structure 1 and close to the first pneumatic driver 2; a first rotating mechanism 4 is arranged on the first pneumatic driver 2 and the first blocking mechanism 3, and the first pneumatic driver 2 and the first blocking mechanism 3 rotate around the first rotating mechanism 4; two second pneumatic drivers 5 are symmetrically arranged on the support structure 1 below the first pneumatic driver 2 and the first blocking mechanism 3; a second rotating mechanism 7 is arranged on the second pneumatic driver 5 and the second blocking mechanism 6, and the second pneumatic driver 5 and the second blocking mechanism 6 rotate around the second rotating mechanism 7, and the rotating directions of the first rotating mechanism 4 and the second rotating mechanism 7 are opposite; the first pneumatic driver 2 and the first blocking mechanism 3, the second pneumatic driver 5 and the second blocking mechanism 6 are connected with a gas pump.

[0056] By arranging the first pneumatic driver 2 and the first blocking mechanism 3 on the support structure 1, the first pneumatic driver 2 can rotate around the first rotating mechanism 4, thereby driving the first blocking mechanism 3 to rotate with the first pneumatic driver 2, and the forward flexion / rear extension of the soft wrist is realized; the second pneumatic driver 5 and the second blocking mechanism 6 are arranged on the support structure 1, i.e. the support structure 1 supports the second pneumatic driver 5 and the second blocking mechanism 6; wherein the second pneumatic driver 5 can rotate around the second rotating mechanism 7, thereby driving the second blocking mechanism 6 to rotate with the second pneumatic driver 5, and the internal rotation / external rotation of the soft wrist is realized.

[0057] The soft wrist not only has a fixed rotating shaft in each joint, but also has a bidirectional pneumatic driver with a large output torque, which increases the bending curvature of the soft wrist, greatly improving the flexibility of the wrist. The variable stiffness mechanism can provide a large impedance torque to help the wrist withstand external loads, and the impedance torque of each joint can be adjusted individually by pneumatic pressure, which greatly improves the stability and flexibility of the wrist.

[0058] The performance of the first pneumatic driver 2 and the second pneumatic driver 5 determines the movement ability and static force output of the joint, and the state of the driver is completely controlled by pneumatic pressure. Therefore, it is necessary to test the relationship between the pneumatic pressure and the angular displacement of the support structure 1 and the output torque.

[0059] The test platform is as follows Figure 7The test platform consists of an air pump, a 12V DC power supply, a valve, a torque sensor and a camera. The IR2010-02-A of SMC is selected as the valve, and the torque sensor is DYDJ-104, whose range is 5Nm and accuracy is 0.3%. The torque sensor is connected with the first air pressure driver 2 and the second air pressure driver 5, the first blocking structure and the second blocking mechanism 6, and is fixed on a base, so that the torque can be directly read from its display screen when the air pressure changes. The angles of the first air pressure driver 2 and the second air pressure driver 5, the first blocking structure and the second blocking mechanism 6 are measured by machine vision, and after the positions of the first air pressure driver 2 and the second air pressure driver 5, the first blocking structure and the second blocking mechanism 6 are zeroed, the air pressure is introduced into the driver to make the two QR codes rotate relative to each other. Once the camera captures the image information, the program calculates the angle relative to the initial position. Under the same conditions, each test is repeated for 8 groups, and the average value is taken as the final data.

[0060] wherein, Figure 7 is the experimental test platform. (a) Torque test and required torque sensor. (b) Angle test and QR code label for visual angle measurement. (c) Overall structure of the platform

[0061] In some optional embodiments, the first air pressure driver 2 and the second air pressure driver 5 each comprise: a body 8; a front adapter block 9 and a rear adapter block 10 located at both ends of the body 8, and the front adapter block 9 and the rear adapter block 10 are arranged on the support structure 1, and the rear adapter block 10 is provided with an adapter port.

[0062] The adapter port on the rear adapter block can be effectively connected with the air pump, that is, the first air pressure driver 2 and the second air pressure driver 5 are filled with gas, so that the first air pressure driver 2 and the second air pressure driver 5 act.

[0063] In some optional embodiments, the cylinder body comprises an inner silica gel layer 12 and a fiber reinforced layer 13, and an outer silica gel layer 14, and the inner silica gel layer 12 and the fiber reinforced layer 13, and the outer silica gel layer 14 are sequentially arranged from inside to outside.

[0064] The inner silica gel layer 12 is made of relatively hard silica gel material, has strong tensile strength and the ability to withstand large air pressure, and is the basic layer of the air chamber. The fiber reinforced layer 13 is a fiber wound on the inner silica gel layer, which enhances the pressure bearing capacity of the air chamber and limits the radial expansion of the air chamber. The outer silica gel layer 14 plays a role in protecting and fixing the fiber reinforced layer 13, so its material is much softer than the inner silica gel layer 12.

[0065] Since the pneumatic actuators are symmetrically installed in the support structure, if one of the pneumatic actuators is extended under pressure, the other pneumatic actuator will inevitably be compressed and folded. When the pneumatic actuators are in a natural state, they need a large force to press them due to their own hardness. Once folded and deformed, most of the reaction force will be released instantaneously, resulting in sudden changes in angle and torque. In order to reduce the nonlinear influence of this resistance on the output angle and torque, the pneumatic actuators use a pre-stretching installation method. When the pneumatic actuators are compressed, they will naturally fold and deform under the constraint of the blocking mechanism and its elastic force, without the need for external force. Figure 4 The working principle of the pre-stretching actuator is demonstrated, and its working effect is compared with that of the actuator in a natural state.

[0066] The materials of the inner silicone layer 12 and the outer silicone layer 14 in the pneumatic actuator are silicone (Dragon Skin 10) and copolyester (Ecoflex 00-30), respectively. The material of the fiber reinforced layer 13 is a glass fiber rope, the position of which is fixed by the groove 29 on the inner silicone layer 12 and the outer silicone layer 14. Silicone (Dragon Skin 10) is also selected as the material of the flexible film of the blocking mechanism.

[0067] In some alternative embodiments, the first blocking mechanism 3 comprises: a first housing 15, a first flexible film 16 is arranged in the first housing 15, an end cover 17 is arranged on the first housing 15, and a first gas adapter 18 is arranged on the first housing 15; a first locking rod 19, one end of which is arranged in the first housing 15, and the other end is connected with the support structure 1; and blocking particles 20 filled in the first housing 15.

[0068] In some alternative embodiments, the second blocking mechanism 6 comprises: a second housing 21, a second flexible film 22 is arranged in the second housing 21, the first gas adapter 18 is arranged on the first housing 15, and the blocking particles 20 are filled in the second housing 21; and a second locking rod 24, one end of which is arranged in the second housing 21, and the other end is connected with the support structure 1.

[0069] When the air pressure is not increased, the blocking particles 20 are loose, and there is no extrusion force between the blocking particles 20, so the first locking rod 19 can rotate freely relative to the rigid first housing 15. When the air pressure is increased, the flexible film will deform and extrude the blocking particles 20 under the action of air pressure. Due to the mutual extrusion between the blocking particles 20, the resistance of the first locking rod 19 will also increase, which eventually leads to the increase of the rotational resistance of the first blocking mechanism 3. Under the condition of sufficient air pressure, the force required for the wrist joint to rotate at the same angle under the action of external force will increase significantly, thereby achieving the effect of increasing the rigidity. Figure 5The working principle of the blocking mechanism is illustrated.

[0070] The blocking mechanism is made of 3D printed resin, which takes into account the lightweight and strength. The adhesive between the silica gel and the resin is selected as a silicone adhesive (Sil-Poxy). The manufacturing process of the actuator is as shown in Figure 6 .

[0071] In some alternative embodiments, the support structure 1 comprises: a first joint skeleton 25, a palm connecting seat 26 is arranged on the first joint skeleton 25, and the first pneumatic driver 2 and the first blocking mechanism 3 are arranged between the first joint skeleton 25 and the palm connecting seat 26; a second joint skeleton 27 is arranged at the bottom of the first joint skeleton 25, and the second pneumatic driver 5 and the second blocking mechanism 6 are arranged between the first joint skeleton 25 and the second joint skeleton 27.

[0072] Among them, the first joint skeleton 25, the palm connecting seat 26, the first pneumatic driver 2, and the first blocking mechanism 3 are connected into an upper joint, and the second joint skeleton 27, the second pneumatic driver 5, and the second blocking mechanism 6 are connected into a lower joint. The first joint skeleton 25 and the palm connecting seat 26, and the second joint skeleton 27 play a role in supporting and positioning the first pneumatic driver 2, the first blocking mechanism 3, the second pneumatic driver 5, and the second blocking mechanism 6.

[0073] In some alternative embodiments, the first locking rod 19 comprises a rod body 28 and a locking block 31, one end of the rod body 28 is provided with a groove 29, and the groove 29 is matched with a protrusion 30 on the palm connecting seat 26; the locking block 31 has a plurality of locking blocks 31 which are arranged on the outer wall of the rod body 28.

[0074] By arranging the groove 29 at the end of the rod body 28, the rod body 28 and the palm connecting seat 26 are connected into an integrated structure, and the palm connecting seat 26 and the first blocking mechanism 3 are facilitated to rotate relative to the first pneumatic driver 2.

[0075] At the same time, the locking block 31 is arranged inside the shell, and the blocking particles 20 can be extruded to reduce the gap between the blocking particles 20.

[0076] In some alternative embodiments, the second locking rod 24 comprises a fixed plate 32 and a connecting rod 33, and a locking ring 34; wherein the fixed plate 32 is connected with the first joint skeleton 25; the connecting rod 33 is arranged at one end away from the first joint skeleton 25, and a groove 331 is arranged at the other end of the connecting rod 33; the locking ring 34 is internally provided with a protrusion 35 which is matched with the groove 331, and a plurality of locking blocks 31 are arranged on the outer wall of the locking ring 34.

[0077] The second locking rod 24 is fixedly connected with the first joint framework 25 through the fixing plate 32, so as to realize the connection of the upper joint and the lower joint. Meanwhile, a groove 331 is arranged at the bottom of the connecting rod 33, which can be connected with the protrusion 35 on the locking ring 34, so as to realize the connection of the connecting rod 33 and the locking ring 34, and ensure the integrity of the second locking rod 24. The locking block 31 is arranged inside the shell, and the blocking particles 20 can be used to extrude the locking block, so as to reduce the gap between the blocking particles 20.

[0078] The shell, the first locking rod 19, the second locking rod 24 and the end cover 17 are rigid members.

[0079] In some optional embodiments, the first rotating mechanism 4 comprises a rotating seat 36 and a first rotating cylinder 37; the rotating seat 36 is arranged on the first joint framework 25; the first rotating cylinder 37 is arranged on the palm connecting seat 26; a first rotating shaft 38 penetrates through the rotating seat 36 and the first rotating cylinder 37, and the first rotating shaft 38 is coaxially arranged with the first locking rod 19.

[0080] Through the cooperation of the rotating seat 36 and the first rotating cylinder 37, and by penetrating the rotating seat 36 and the first rotating cylinder 37 with the first rotating shaft 38, the two first pneumatic drivers 2 can rotate around the first rotating shaft 38, so as to realize the flexion / extension movement of the soft wrist. Moreover, the first rotating shaft 38 is coaxially arranged with the second locking rod 24, so as to ensure the consistency of the rotation of the first pneumatic driver 2.

[0081] In some optional embodiments, the second rotating mechanism 7 comprises a second rotating cylinder 39 and a second rotating shaft 40; the second rotating cylinder 39 is arranged on the second joint framework 27; the second rotating shaft 40 is arranged in the second rotating cylinder 39, and the second rotating shaft 40 is connected with the second locking rod 24.

[0082] The arrangement of the second rotating cylinder 39 provides a mounting position for the arrangement of the second locking rod 24, and the second rotating shaft is arranged in the second locking rod 24, so that the second pneumatic driver 5 rotates around the second rotating shaft, thereby realizing the pronation / supination of the soft wrist.

[0083] Figure 8 (a, b) show the relationship between the air pressure and the output torque of the upper joint and the lower joint at different positions, which have linear relationship and almost the same slope. The output torque of the joint tends to decrease with the increase of the angle position, and the interval between the curves is basically uniform. The maximum output torque of the upper joint and the lower joint is 1.18 Nm and 1.40 Nm respectively at the initial position and under the air pressure of 110 kPa. Figure 8(c) The angular displacement of the upper and lower joints versus air pressure is shown. The relationship between air pressure and angular displacement is non-linear. In order to avoid interference of the components, the maximum rotation angle of the joints is limited to about 45°. Since this is only the range in one direction, the total rotation range of the joints is ±45°. Figure 8 (d) The natural restoring torque of the upper and lower joints at different positions is shown. The torque is generated entirely by the elastic deformation of the air pressure actuator itself.

[0084] Figure 8 (e) The relationship between the resistive torque at the lower joint and the air pressure input of the second resistive mechanism 6 is shown. The results show that the resistive torque increases linearly with the increase of air pressure. The resistive mechanism starts to have a significant resistive torque at 30 kPa, with a value of about 0.45 Nm; when the air pressure rises to 110 kPa, the resistive torque reaches 1.80 Nm. Compared with the output torque of the actuator shown in (a, b), the second resistive mechanism 6 can generate significantly greater torque when the joint is rotated to any position. Therefore, when the wrist needs to maintain a posture under external load, the second resistive mechanism 6 can provide a larger additional resistance to the wrist. Therefore, the stiffness enhancement function of the second resistive mechanism 6 can greatly improve the stability of the wrist. Figure 8

[0085] Figure 8 The experimental data curves are shown in (a) the relationship between the output torque of the upper joint and the air pressure at different angular positions; (b) the relationship between the output torque of the lower joint and the air pressure at different angular positions; (c) the relationship between the rotation angle of the upper and lower joints and the air pressure; (d) the relationship between the restoring torque of the upper and lower joints and the angular position; (e) the relationship between the maximum resistive torque of the variable stiffness mechanism of the lower joint and the air pressure.

[0086] Actual performance tests were conducted on individual joints to intuitively evaluate the working capacity of the wrist. In the experiment shown in (a) and (b), the weight of the load lifted was 585 grams, and the distance between the suspension point and the rotation axis of the joint was 200 mm. Figure 9 Figure 9 (a) and (b) respectively show the torque changes of the upper and lower joints. As the air pressure of the air pressure actuator increases, the load is significantly lifted. Figure 9 Figure 9 (c) and (d) show the bending stiffness of the upper and lower joints. The air pressures of the first and second air pressure actuators 5 were 80 kPa and 50 kPa, respectively. After the load was installed, the joint rotated a certain angle under the action of its own gravity. After the load was removed, the joint returned to the initial position shown in the control group. If the air pressure of the variable stiffness mechanism is increased and the load is installed again, the rotation angle of the joint will gradually decrease. Figure 9 Figure 10 ​​​​The results of the joint stiffness experiment are shown, which show that the upper joint stiffness is increased by 55.3% at 120 kPa, and the lower joint stiffness is increased by 67.2% at 100 kPa. As shown in Figure 11 The soft wrist is equipped with a rigid-flexible coupled five-fingered dexterous hand, and the initial position of the wrist and the final position of each joint are shown, and it is explained how the soft wrist increases the motion range of the dexterous hand.

[0087] Figure 9 The characteristics of the soft wrist are tested. (a) Torque output test of the upper joint. (b) Torque output test of the lower joint. (c) Stiffness change test of the upper joint. (d) Stiffness change test of the lower joint. AP represents the driver air pressure, and VSP represents the stiffness change air pressure of the blocking mechanism.

[0088] Figure 10 The experimental results of the joint stiffness change are shown. (a) Stiffness change test of the upper joint. (b) Stiffness change test of the lower joint.

[0089] Figure 11 Soft wrist motion experiment. (a) Initial state of the wrist. (b, c) Limit motion position of the lower joint. (d, e) Limit motion position of the upper joint. (f-i) Limit motion position of the upper joint and the lower joint working simultaneously.

[0090] The rigid-flexible coupled pneumatic soft wrist can realize pre-stretching, and the specific structure of the wrist is described in detail, including the manufacturing process of the air pressure driver. Due to the limitation of the rigid part, the rotational motion of the soft wrist has a fixed axis, thereby improving the dexterity and controllability of the soft wrist. The pre-stretching installation method of the air pressure driver eliminates the nonlinear effects of folding on torque and angular position. When the soft wrist needs to withstand external load and avoid pose change, the blocking mechanism can increase additional impedance torque for the stability of the wrist. Due to the linear relationship between impedance torque and air pressure, and the independent control of the joint variable stiffness mechanism, the stiffness of the wrist can be flexibly controlled.

[0091] Figure 4 The working principle of the pre-stretching installed air pressure driver is shown. (a) is the initial state of the air pressure driver. (b) is the working state of the driver installed in the natural state, and there is obvious antagonism on the side of extrusion, and the state changes abruptly when the first rotating mechanism 4 rotates. (c) is the working state of the pre-stretching installed air pressure driver, which naturally bends and folds under the action of its own restoring force, and generates very small impedance force.

[0092] Figure 5The working principle of the blocking mechanism. (a) The initial state of the blocking mechanism, at this time it can rotate freely, almost no resistance. (b) The working state of the blocking mechanism, at this time the blocking particles 20 are extruded by the flexible film, and the locking rod is resisted when it has a tendency to rotate.

[0093] Figure 6 The manufacturing process of the pneumatic actuator. (a) Assemble the mold of the inner silica gel layer 12. (b) Pour the silica gel (Dragin Skin 10) into the mold. (c) Wrap the glass fiber rope on the inner silica gel layer 12. (d) Assemble the outer mold of the outer silica gel layer 14. (e) Install the inner silica gel layer 12 on the inner mold of the outer silica gel layer 14. (f) Pour the silica gel (Ecoflex 00-30) into the outer mold, then insert the inner mold and the inner silica gel layer 12 into the outer mold. (g) Disassemble the mold and take out the air chamber. (h) Stick the air chamber to the mounting seat with glue (Sil-Poxy). (i) The complete structure of the pneumatic driver.

[0094] Specific experimental tests, including the driver and variable stiffness characteristics, and the demonstration of wrist movement. The experimental results show that the range of motion of the two joints of the soft wrist reaches ±45°, the maximum driving torque of the upper joint and the lower joint is 1.18 Nm and 1.40 Nm respectively, and the maximum torque of the first blocking mechanism 3 and the second blocking mechanism 6 is 0.80 Nm and 1.80 Nm. In the experiment of lifting the load, the first blocking mechanism 3 and the second blocking mechanism 6 increase the stiffness of the upper joint and the lower joint by 55.3% and 67.2% respectively. In summary, the soft wrist not only has a fixed rotation axis in each joint, but also has a bidirectional pneumatic driver with a larger output torque, which greatly improves the flexibility of the wrist. The variable stiffness mechanism provided can provide a larger impedance torque to help the wrist withstand external loads, and the impedance torque of each joint can be adjusted individually by air pressure, which greatly improves the stability and flexibility of the wrist.

[0095] Obviously, the above embodiments are only examples for clear illustration, and are not limitations to the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the embodiments do not need to be exhausted, and the obvious changes or variations derived therefrom are still within the protection scope of the present invention.

[0096] Obviously, the above embodiments are only examples for clear illustration, and are not limitations to the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the embodiments do not need to be exhausted, and the obvious changes or variations derived therefrom are still within the protection scope of the present invention.

Claims

1. A rigid-flex coupled pneumatic soft body wrist, characterized in that, The utility model relates to a kind of air pressure driven device, including: Support structure (1), two first air pressure drivers (2) are symmetrically provided on the support structure (1); First blocking mechanism (3), be located on the support structure (1), and close to the first air pressure driver (2); First rotating mechanism (4), be located on the first air pressure driver (2) and first blocking mechanism (3), the first air pressure driver (2) and first blocking mechanism (3) rotate around the first rotating mechanism (4); Second air pressure driver (5) and second blocking mechanism (6), the second air pressure driver (5) has two, and symmetrically provided on the support structure (1), located below the first air pressure driver (2) and first blocking mechanism (3); Second rotating mechanism (7), be located on the second air pressure driver (5) and second blocking mechanism (6), the second air pressure driver (5) and second blocking mechanism (6) rotate around the second rotating mechanism (7), the rotating direction of the first rotating mechanism (4) and second rotating mechanism (7) is opposite; The first air pressure driver (2) and first blocking mechanism (3), second air pressure driver (5), second blocking mechanism (6) are connected with air pump; The first blocking mechanism (3) includes: First shell (15), the first flexible film (16) is provided in the shell, and end cover (17) is provided on the first shell (15), first gas adapter (18) is provided on the first shell (15); First locking rod (19), one end is located in the first shell (15), and the other end is connected with the support structure (1); Blocking particles (20), filled in the first shell (15).

2. The rigid-flexible coupled pneumatic soft body wrist of claim 1, wherein, The first air pressure driver (2) and second air pressure driver (5) include: Body (8); Front end adapter block (9) and rear end adapter block (10) are located at both ends of the body (8), and the front end adapter block (9) and rear end adapter block (10) are provided on the support structure (1), gas inflation port (11) is provided on the rear end adapter block (10).

3. The rigid-flexible coupled pneumatic soft body wrist of claim 2, wherein, The body (8) includes inner silica gel layer (12) and fiber reinforced layer (13), outer silica gel layer (14), the inner silica gel layer (12) and fiber reinforced layer (13), outer silica gel layer (14) are sequentially arranged from inside to outside.

4. The rigid-flexicoupled pneumatic soft wrist of any one of claims 1-3, wherein, The second blocking mechanism (6) includes: Second shell (21), the second flexible film (22) is provided in the second shell (21), the second gas adapter (23) is provided on the second shell (21), and the blocking particles (20) are filled in the second shell (21); Second locking rod (24), one end is located in the second shell (21), and the other end is connected with the support structure (1); 5. The rigid-flexible coupled pneumatic soft body wrist of claim 4, wherein, The support structure (1) includes: First joint framework (25), palm connecting seat (26) is provided on the first joint framework (25), the first air pressure driver (2) and first blocking mechanism (3) are located between the first joint framework (25) and palm connecting seat (26); A second joint skeleton (27) is arranged at the bottom of the first joint skeleton (25), and the second pneumatic driver (5) and the second blocking mechanism (6) are arranged between the first joint skeleton (25) and the second joint skeleton (27).

6. The rigid-flexible coupled pneumatic soft body wrist of claim 5, wherein, The first locking rod (19) comprises: A rod body (28) is provided with a groove (29) at one end, and the groove (29) is matched with a protrusion (30) on the palm connecting seat (26); A plurality of locking blocks (31) are arranged on the outer wall of the rod body (28).

7. The rigid-flexible coupled pneumatic soft body wrist of claim 5, wherein, The second locking rod (24) comprises: A fixed plate (32) is connected with the first joint skeleton (25); A connecting rod (33) is arranged at one end away from the first joint skeleton (25), and a groove (331) is arranged at the other end of the connecting rod (33); A locking ring (34) is internally provided with a protrusion (35), and the protrusion (35) is matched with the groove (331), and a plurality of locking blocks (31) are arranged on the outer wall of the locking ring (34).

8. The rigid-flexible coupled pneumatic soft body wrist of claim 5, wherein, The first rotating mechanism (4) comprises: A rotating seat (36) is arranged on the first joint skeleton (25); A first rotating cylinder (37) is arranged on the palm connecting seat (26), a first rotating shaft (38) penetrates the rotating seat (36) and the first rotating cylinder (37), and the first rotating shaft (38) is coaxially arranged with the first locking rod (19).

9. The rigid-flexible coupled pneumatic soft body wrist of claim 8, wherein, The second rotating mechanism (7) comprises: A second rotating cylinder (39) is arranged on the second joint skeleton (27); A second rotating shaft (40) is arranged in the second rotating cylinder (39), and the second rotating shaft is connected with the second locking rod (24).

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