A Variable Stiffness Joint Driven by Giant Electro-Rheological Fluid and Its Application

Abstract

The present invention relates to a variable stiffness joint driven by giant electro-rheological fluid and its application. It includes a front joint, a joint rotation mechanism fixedly connected to the front joint, a hydraulic actuation mechanism for driving the movement of the joint rotation mechanism, a fluid delivery system for supplying fluid to the hydraulic actuation mechanism, a giant electro-rheological fluid control valve arranged between the hydraulic actuation mechanism and the fluid delivery system, a rear joint arranged at the bottom of the giant electro-rheological fluid control valve, and the giant electro-rheological fluid introduced into the hydraulic actuation mechanism through the fluid delivery system via the giant electro-rheological fluid control valve. The technical solution provided by the present invention enables each variable stiffness joint to rotate independently, realizes the artificial control of the joint stiffness, has a small volume, is convenient for maintenance and operation, and has high degrees of freedom of movement and reliability.

Description

Technical Field

[0001] The present invention belongs to the technical field of surgical robots, and particularly relates to a variable stiffness joint driven by giant electro-rheological fluid and its application. Background Art

[0002] Minimally invasive surgery, also known as laparoscopic surgery or endoscopic surgery, is a method of performing surgery by entering the body through small incisions or natural orifices. Compared with the traditional surgical method that requires large-area incisions, the advantages of minimally invasive surgery are that it reduces trauma, recovery time, and complications, and improves the quality of life of patients after surgery. Therefore, minimally invasive surgery has also become a widely accepted and applied surgical method.

[0003] Robot-assisted minimally invasive surgery is an emerging technology that combines robotics and the principles of minimally invasive surgery. Surgeons can operate the robot using a remote control device to achieve highly precise operations. This technology can provide greater stability and precision in some complex surgeries.

[0004] Since the surgery relies on long robotic arms for operation, there are high requirements for the degrees of freedom of the joints of the surgical robotic arms. At the same time, different stiffnesses are required from the joints in different surgical situations to complete the surgery. However, the currently used surgical robots still have certain problems in these aspects. 1. Motion coupling, which will cause different joints to affect each other during movement and ultimately affect the accuracy of the instruments. 2. Control hysteresis, which will cause the instruments to not reach the position in time during control, prolong the surgery time, and reduce the control efficiency. 3. Large wear, which makes the performance of the instruments extremely easy to degrade and cannot be used for a long time. 4. Complex control. Due to the existence of the above problems and the application of some multi-physical field coupling control in the instrument joints, ultimately more calculations are required during the control of the instruments to make up for the errors and the joint action of multiple control methods. In addition, some instruments also have problems such as high energy consumption, complex parts, and the need for heat dissipation, which will also make the surgical instruments more complex and difficult to operate.

[0005] Giant electrorheological fluid (GRF) is a type of colloid in which dielectric particles are uniformly suspended in a non-conductive continuous phase. When an electric field of a certain intensity is applied to the GRF, its rheological properties will immediately change, changing from a liquid to a solid-like state, and when the electric field is removed, it will immediately return to its original liquid state. The giant electrorheological fluid has the following characteristics in an electric field: (1) It can quickly switch between a liquid and a solid-like state, that is, the apparent viscosity can change greatly under static or low shear rate conditions, and it has the shear resistance of a solid property; (2) The conversion between the liquid and the solid is reversible; (3) The conversion between the liquid and the solid is controllable, and only the electric field signal needs to be controlled; (4) The change in apparent viscosity changes continuously with the change in electric field intensity; (5) The conversion between the liquid and the solid and the change in apparent viscosity can be completed within milliseconds, with an extremely high response speed; (6) The energy required to control the phase change is extremely low.

[0006] In the prior art, there are also attempts to use the characteristic that the stiffness of the giant electrorheological fluid changes with the electric field to achieve joint rotation. For example, Chinese Patent CN202010774693.5 discloses a soft body that uses giant electrorheological fluid to achieve segmented bending. It uses giant electrorheological fluid to adjust the segmented variable stiffness of the soft body. Specifically, it realizes the adjustment of the finger stiffness by adjusting the stiffness of multiple variable stiffness layers arranged in parallel with the corrugated pipe. However, the simultaneous adjustment of multiple variable stiffnesses is very complicated, and accurate curvature control cannot be performed either. Summary of the Invention

[0007] The present invention provides a variable stiffness joint and application driven by giant electrorheological fluid to solve the problems of complex control, low accuracy, and large volume of current instrument joints.

[0008] To solve the above technical problems, the technical solution of the present invention is: The variable stiffness joint driven by giant electrorheological fluid includes a front joint, a joint rotation mechanism fixedly connected to the front joint, a hydraulic actuating mechanism for driving the movement of the joint rotation mechanism, a fluid delivery system for supplying liquid to the hydraulic actuating mechanism, a giant electrorheological fluid control valve arranged between the hydraulic actuating mechanism and the fluid delivery system, a rear joint arranged at the bottom of the giant electrorheological fluid control valve, and giant electrorheological fluid introduced into the hydraulic actuating mechanism through the fluid delivery system via the giant electrorheological fluid control valve;

[0009] The giant electrorheological fluid control valve includes a sandwich-type valve body, a diaphragm arranged in the valve body, positive and negative electrode plates located at corresponding positions on both outer sides of the diaphragm, and a fluid passage opened on the diaphragm. One end of the fluid passage communicates with the fluid delivery system, and the other end communicates with the hydraulic actuating mechanism. At least part of the fluid passage is located between the positive and negative electrode plates.

[0010] This application is based on a variable-stiffness surgical instrument joint driven by giant electrorheological fluid, which has the function of variable stiffness. Physicians can adjust the electric field strength between the fluid chamber electrodes according to different surgical situations to control the viscosity of the electrorheological fluid, control the blockage and flow of the fluid chamber, thereby realizing a micro electrorheological fluid control valve that can be used in minimally invasive surgical instruments, and further controlling the stiffness of the surgical instrument joint. In addition, the giant electrorheological fluid is introduced into the hydraulic actuation mechanism as the hydraulic driving power, and then further drives the rotating mechanism, so as to meet the angle requirements of the end effector of the surgical instrument during the operation. The overall control method is simple and the structure is compact.

[0011] The giant electrorheological fluid control valve is designed and manufactured by using a sandwich design method. Since the giant electrorheological fluid control valve has extremely high requirements for the parallel arrangement of the electrode plates, once a part of one electrode is offset, the electrorheological fluid control valve will be electrically broken down. In order to ensure the parallel condition of the two electrode plates, a diaphragm is implanted inside the sandwich as a spacer to maintain the precise gap between the two electrode plates by using the diaphragm.

[0012] Optionally, the material of the valve body is polytetrafluoroethylene, and the diaphragm is a VHB double-sided adhesive film.

[0013] Optionally, the VHB double-sided adhesive film is selected from VHB4905 and / or VHB4910.

[0014] Polytetrafluoroethylene has self-cleaning property and safety. And the two electrodes (copper strips) are respectively pasted on the inner wall of the sandwich of the polytetrafluoroethylene valve body, which can ensure the requirement of the parallelism of the electrode plates. The VHB double-sided adhesive film of 3M Company has strong insulation and incompressibility. At the same time, its adhesiveness to polytetrafluoroethylene is relatively strong, and it can be used as a good spacer for the fluid gap in the chamber, ensuring a good sealing effect between the two electrode plates.

[0015] Optionally, the sandwich-type valve body includes a first valve body, a second valve body, a valve body sandwich between the first valve body and the second valve body, a liquid inlet channel provided on the first valve body or the second valve body, a sealing block connected to the hydraulic actuation mechanism, a liquid outlet channel provided in the sealing block, and a plurality of bolts passing through the first valve body and the second valve body to fixedly connect the two. After the first valve body and the second valve body are joined together, the valve body sandwich is formed. The positive electrode plate, the negative electrode plate, the diaphragm and the fluid channel are located inside the valve body sandwich. The liquid inlet channel is used to conduct the fluid channel and the fluid delivery system, and the liquid outlet channel is used to conduct the fluid channel and the hydraulic actuation mechanism.

[0016] Optionally, the first valve body includes a first half and a protrusion protruding from the surface of the first half toward the second valve body; the second valve body includes a second half spliced with the first half, and a groove matching the protrusion is arranged on the second half, and the protrusion is embedded in the groove to form a valve body sandwich, the positive electrode plate and the negative electrode plate are respectively attached to the surface of the protrusion and the groove, and the diaphragm is attached to the surface of the protrusion on one side and the surface of the groove on the other side.

[0017] Optionally, the joint rotation mechanism includes a joint cavity, a rotating shaft fixed on the joint cavity, a gear rotatably connected to the rotating shaft, and a rack meshing with the gear and extending along the movement direction of the hydraulic actuating mechanism. As the rack moves linearly, the gear meshing with the rack rotates, and the front joint is fixed on the gear and rotates relative to the rotating shaft as the gear rotates.

[0018] Optionally, the sealing block is connected to the hydraulic actuating mechanism via threads.

[0019] Optionally, the hydraulic actuation mechanism includes a hydraulic cylinder, a piston arranged in the hydraulic cylinder to divide it into two areas, a fluid chamber located in the lower area of the piston, an air chamber located in the upper area of the piston, and an antagonistic spring located in the air chamber and clamped between the piston and the top of the hydraulic cylinder. The fluid chamber is connected to the fluid channel of the giant electrorheological fluid control valve. As the liquid flows into the fluid chamber, the piston is pushed to move along the inner wall of the hydraulic cylinder toward the air chamber, thereby providing power for the joint rotation mechanism.

[0020] Optionally, a spring seat for fixing an antagonistic spring is provided on the piston.

[0021] Optionally, at least one sealing ring is provided between the piston and the inner wall of the hydraulic cylinder.

[0022] Optionally, a sealing structure is provided at the interface between the sandwich valve body and the hydraulic cylinder.

[0023] Optionally, the fluid delivery system includes a liquid storage tank, an infusion tube for connecting the liquid in the liquid storage tank to the fluid channel, and a liquid pump for introducing or extracting the liquid in the liquid storage tank into the fluid channel.

[0024] The present invention also provides a laparoscopic surgical robotic arm, which includes a base, an arm extending from the base, a wrist arranged at the farthest end of the arm, a guide rod assembled on the wrist, and an actuator arranged at the farthest end of the guide rod through a joint group, wherein the joint group includes at least one of the above-mentioned variable stiffness joints driven by giant electrorheological fluid. When more than two variable stiffness joints driven by giant electrorheological fluid are included, the front joint of a variable stiffness joint driven by giant electrorheological fluid is clamped with the rear joint of another variable stiffness joint driven by giant electrorheological fluid.

[0025] Optionally, the front joint includes a disc-shaped tray and a plurality of buckles arranged on the tray, and the rear joint includes a chassis arranged at the bottom of the sandwich-type valve body and a clamping groove formed on the chassis. The two giant electro-rheological fluid-driven variable stiffness joints are fixedly connected by inserting the buckles into the clamping grooves.

[0026] The variable stiffness joints in this application are connected in series. Each variable stiffness joint provides rotational power through an independent fluid delivery system. By controlling the giant electro-rheological fluid control valves in one or more target variable stiffness joints, the overall integration of the system can be improved, and multi-degree-of-freedom adjustment of the variable stiffness surgical instrument joints can be achieved.

[0027] The technical solution provided by the present invention has the following advantages compared with the prior art:

[0028] Artificial control of the joint stiffness can be realized. At the same time, there are multiple slave drive units, with a high degree of freedom and more flexible operation;

[0029] Compared with the traditional mechanical valve, the structure is simpler and the maintenance cost is lower;

[0030] Each variable stiffness joint can rotate independently, and the coupling between joints is good, reducing the interference and conflict between joints, thereby improving the performance and reliability of the entire mechanical system. Description of the Drawings

[0031] Figure 1 is a schematic structural diagram of a specific embodiment of the laparoscopic surgical robot arm of the present invention;

[0032] Figure 2 is a schematic structural diagram of a specific embodiment of the giant electro-rheological fluid-driven variable stiffness joint of the present invention;

[0033] Figure 3 is a schematic structural diagram of a specific embodiment of two giant electro-rheological fluid-driven variable stiffness joints connected in series of the present invention;

[0034] Figure 4 is a schematic external view of a partial section of a specific embodiment of the giant electro-rheological fluid-driven variable stiffness joint of the present invention;

[0035] Figure 5 is a sectional view of a specific embodiment of the giant electro-rheological fluid-driven variable stiffness joint of the present invention;

[0036] Figure 6 is a sectional view of a specific embodiment of the valve body of the present invention.

[0037] As shown in the figure:

[0038] 1 - Base, 2 - Arm, 3 - Wrist, 4 - Guide rod, 5 - Joint group, 6 - Actuator;

[0039] 10 - Front joint, 11 - Tray, 12 - Buckle;

[0040] 20 - Joint rotation mechanism, 21 - Joint cavity, 22 - Rotating shaft, 23 - Gear, 24 - Rack;

[0041] 30 - Hydraulic actuating mechanism, 31 - Hydraulic cylinder, 32 - Piston, 33 - Fluid cavity, 34 - Air cavity, 35 - Antagonistic spring, 36 - Spring seat, 37 - Sealing ring;

[0042] 41 - Liquid storage tank, 42 - Infusion tube, 43 - Liquid pump;

[0043] 50 - Giant electro - rheological fluid control valve, 51 - Sandwich - type valve body, 511 - First valve body, 5111 - First half, 5112 - Protrusion, 512 - Second valve body, 5121 - Second half, 5122 - Groove, 513 - Liquid inlet channel, 514 - Thread, 515 - Sealing block, 516 - Liquid outlet channel, 52 - Diaphragm, 53 - Positive electrode plate, 54 - Negative electrode plate, 55 - Fluid channel;

[0044] 60 - Rear joint, 61 - Chassis, 62 - Card slot; 70 - Sealing structure. Detailed implementation mode

[0045] For the convenience of understanding, the variable - stiffness joint and application based on giant electro - rheological fluid drive are described below in conjunction with embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention.

[0046] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation and positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0047] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0048] As Figure 1 shown, the laparoscopic surgical robotic arm includes a base 1, an arm 2 extending from the base 1, a wrist 3 provided at the distal end of the arm 2, a guiding rod 4 assembled on the wrist 3, and an actuator 6 provided at the distal end of the guiding rod 4 through a joint group 5. The joint group 5 includes at least one variable stiffness joint driven by giant electro-rheological fluid as described above, and in this embodiment, it includes a plurality of variable stiffness joints driven by giant electro-rheological fluid.

[0049] Wherein the arm 2 includes a plurality of joints, and the actuator 6 can be an instrument for performing surgical operations such as an electrocautery device, a clamp, a stapler, a harmonic scalpel, etc., or an image device (such as an endoscope) for obtaining images or other surgical tools.

[0050] As Figure 2 shown, the variable stiffness joint driven by giant electro-rheological fluid includes a front joint 10, a joint rotation mechanism 20 fixedly connected to the front joint 10, a hydraulic actuating mechanism 30 for driving the movement of the joint rotation mechanism 20, a fluid delivery system for supplying fluid to the hydraulic actuating mechanism 30, a giant electro-rheological fluid control valve 50 provided between the hydraulic actuating mechanism 30 and the fluid delivery system, a rear joint 60 provided at the bottom of the giant electro-rheological fluid control valve 50, and giant electro-rheological fluid (not shown in the figure) introduced into the hydraulic actuating mechanism 30 through the fluid delivery system via the giant electro-rheological fluid control valve 50; wherein the solid content of the giant electro-rheological fluid is about 15%.

[0051] As Figure 3 shown, the front joint 10 includes a disc-shaped tray 11 and a plurality of buckles 12 provided on the tray 11, and the rear joint 60 includes a chassis 61 and a card slot 62 opened on the chassis 61. Two variable stiffness joints driven by giant electro-rheological fluid are fixedly connected by embedding the buckles 12 into the card slot 62. Continuing to refer to Figure 2 , in this embodiment, the 4 buckles 12 are evenly distributed on the circumference of the tray 11. The card slot 62 can be a plurality of card slots 62 corresponding to the buckles 12 one by one, or a circumferential card slot 62 opened at the corresponding position of the circumference where the buckles 12 are located. Continuing to refer to Figure 3 , the front joint 10 of one variable stiffness joint driven by giant electro-rheological fluid is snap-connected to the rear joint 60 of another variable stiffness joint driven by giant electro-rheological fluid to achieve the series connection of the two variable stiffness joints.

[0052] As Figure 4 and 5As shown, the joint rotation mechanism 20 includes a joint cavity 21, a rotating shaft 22 fixed on the joint cavity 21, a gear 23 rotatably connected to the rotating shaft 22, and a rack 24 meshing with the gear 23. As the rack 24 moves linearly up and down, the gear 23 meshing with the rack 24 rotates accordingly. In this embodiment, the front joint 10 is integrally formed with the gear 23, so rotation occurs. In this embodiment, the joint cavity 21 is provided with an avoidance opening at the movement trajectory of the front joint 10. By adjusting the fitting stroke between the rack 24 and the gear 23, the rotation angle of the front joint 10 can be achieved from -90° to +90°, generally controlled within -30° to +90°.

[0053] Continue to refer to Figure 4 and Figure 5 , the hydraulic actuating mechanism 30 includes a hydraulic cylinder 31, a piston 32 disposed within the hydraulic cylinder 31 that partitions it into two regions, a fluid chamber 33 located in the lower region of the piston 32, an air chamber 34 located in the upper region of the piston 32, and an antagonistic spring 35 disposed within the air chamber 34 and clamped between the piston 32 and the top of the hydraulic cylinder 31. A spring seat 36 for fixing the antagonistic spring 35 is provided on the piston 32. Two sealing rings 37 are provided between the piston 32 and the inner wall of the hydraulic cylinder 31.

[0054] Continue to refer to Figure 4 , the fluid delivery system includes a liquid storage tank 41, an infusion tube 42 for connecting the liquid in the liquid storage tank 41 to a fluid passage, and a liquid pump 43 for introducing or extracting the liquid in the liquid storage tank 41 into or from the fluid passage.

[0055] As Figure 3 and 6 shown, the giant electro-rheological fluid control valve 50 includes a sandwich-type valve body 51, a diaphragm 52 disposed within the valve body 51, positive and negative electrode plates 53 and 54 located at corresponding positions on the two outer sides of the diaphragm 52, and a fluid passage 55 opened on the diaphragm 52.

[0056] Continue to refer to Figure 3 , 4, 5, and 6, the sandwich - type valve body 51 includes a first valve body 511, a second valve body 512, a valve body sandwich between the first valve body 511 and the second valve body 512, a liquid inlet channel 513 provided on the first valve body 511, a sealing block 515 fixedly connected to the hydraulic cylinder 31 through a thread 514, a liquid outlet channel 516 provided in the sealing block 515, and a number of bolts (not shown in the figure) passing through the first valve body 511 and the second valve body 512 to fixedly connect the two. In this embodiment, since the chassis 61 of the rear joint is integrally formed with the first valve body 511, the liquid inlet channel 513 is opened on the side wall of the first valve body 511. That is to say, for the convenience of design, as long as the liquid inlet channel 513 can lead to the fluid channel 55, it is acceptable. In this embodiment, the sealing block 515 is integrally formed with the second valve body 512. To ensure that the fluid does not leak, the sealing block 515 extends into the hydraulic cylinder 31 and is fixed by a thread. In addition, a sealing structure 70 is provided on the contact surface between the two - half valve body and the hydraulic cylinder 31. Specifically, in this embodiment, grooves are opened on the valve body surface, and corresponding grooves are also opened on the hydraulic cylinder surface, and the two are sealed by filling the grooves with an elastic ring.

[0057] The material of the valve body 51 is polytetrafluoroethylene, and the diaphragm is a VHB double - sided adhesive film. According to different heights, the VHB double - sided adhesive film is selected from VHB4905 and / or VHB4910.

[0058] Continue to refer to Figure 3 and Figure 6 , in this embodiment, the specific structure of the valve body 51 is that the first valve body 511 includes a first half 5111 and a convex block 5112 protruding from the surface of the first half 5111 towards the second valve body 512; the second valve body 512 includes a second half 5121 that fits with the first half 5111, and a groove 5122 provided on the second half 5121 to cooperate with the convex block. The convex block 5112 is embedded in the groove 5122 to form a valve body sandwich. The positive electrode plate 53 and the negative electrode plate 54 are respectively attached to the surfaces of the convex block 5112 and the groove 5122, and one side of the diaphragm 52 is attached to the surface of the convex block 5112, and the other side is attached to the surface of the groove 5122.

[0059] There is a threaded hole at each of the fluid inlet and outlet in the valve body to be compatible with a push - in type pipe joint assembly for connecting a pipe (outer diameter 2mm, inner diameter 1mm) to introduce fluid into the internal fluid cavity 33. There are 12 through - holes with a diameter of 3mm on the valve body in the figure to accommodate Delrin bolts. When tightening the nuts, the same torque is applied to ensure that equal stress is applied to each bolt, which helps to form a uniform fluid gap in the fluid channel 55 of the giant electro - rheological fluid control valve 50. The shell uses a steel material and is processed by CNC to improve the overall accuracy. The steel material has good biocompatibility, and at the same time, due to its simple structure, it is also convenient for sterilization and disinfection.

[0060] The parameter indexes of the variable stiffness joint driven by giant electro-rheological fluid in this embodiment are shown in Table 1 as follows:

[0061] Table 1

[0062] Driving stroke of hydraulic actuator 2 - 5 mm Joint rotation angle 0-120° Range of joint stiffness change 42.8 - 193.2 mN·m Weight (giant electro-rheological fluid in the channel) Approximately 38 g 。

[0063] The working process of the robotic arm is briefly described as follows:

[0064] After being introduced into the body, each variable stiffness joint is controlled to rotate independently. Specifically, the liquid pump 43 is controlled, and the fluid can be introduced from the liquid storage tank 41 into the fluid chamber 33 or pumped back from the fluid chamber 33 to the liquid storage tank 41. As the volume of the fluid in the fluid chamber 33 changes, the piston 32 moves up or down accordingly, driving the rack 24 to move. The gear 23 meshing with it will rotate, enabling continuous transmission of the whole. Finally, the angle requirements of the end effector during the operation are achieved.

[0065] Once the angle of the surgical instrument joint reaches the angle required by the surgeon, the giant electro-rheological fluid control valve 50 is activated, and the two electrodes provide a controllable electric field, changing the viscosity of the electro-rheological fluid flowing through the cavity per unit time. However, in order to maintain the shape of the relevant joint, the input force of the driven system caused by the load of the end effector 6 should not exceed the resistance provided by the giant electro-rheological fluid control valve 50, otherwise it will fail. Thus, the change range of the joint stiffness, that is, the load range of the actuator, can be calculated.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A variable stiffness joint driven by giant electro-rheological fluid, characterized in that It includes a front joint, a joint rotation mechanism fixedly connected to the front joint, a hydraulic actuating mechanism for driving the movement of the joint rotation mechanism, a fluid delivery system for supplying liquid to the hydraulic actuating mechanism, a giant electro-rheological fluid control valve provided between the hydraulic actuating mechanism and the fluid delivery system, a rear joint provided at the bottom of the giant electro-rheological fluid control valve, and the giant electro-rheological fluid introduced into the hydraulic actuating mechanism through the fluid delivery system via the giant electro-rheological fluid control valve; The giant electro-rheological fluid control valve includes a sandwich-type valve body, a diaphragm provided in the valve body, positive and negative electrode plates located at corresponding positions on both outer sides of the diaphragm, and a fluid passage opened on the diaphragm. One end of the fluid passage communicates with the fluid delivery system, and the other end communicates with the hydraulic actuating mechanism. At least part of the fluid passage is located between the positive and negative electrode plates; The sandwich-type valve body includes a first valve body, a second valve body, a valve body sandwich between the first valve body and the second valve body, a liquid inlet passage provided on the first valve body or the second valve body, a sealing block connected to the hydraulic actuating mechanism, a liquid outlet passage provided in the sealing block, and a plurality of bolts passing through the first valve body and the second valve body to fixedly connect the two. The first valve body and the second valve body are joined together to form the valve body sandwich. The positive electrode plate, the negative electrode plate, the diaphragm, and the fluid passage are located in the valve body sandwich. The liquid inlet passage is used to conduct the fluid passage and the fluid delivery system, and the liquid outlet passage is used to conduct the fluid passage and the hydraulic actuating mechanism; The first valve body includes a first half and a convex block protruding from the surface of the first half towards the second valve body; the second valve body includes a second half joined to the first half and a groove provided on the second half for cooperating with the convex block. The convex block is embedded in the groove to form the valve body sandwich. The positive electrode plate and the negative electrode plate are respectively attached to the surfaces of the convex block and the groove, and one side of the diaphragm is attached to the surface of the convex block and the other side is attached to the surface of the groove.

2. The variable stiffness joint based on giant electro-rheological fluid drive according to claim 1, characterized in that The material of the valve body is polytetrafluoroethylene, and the diaphragm is a VHB double-sided adhesive film.

3. The variable stiffness joint based on giant electro-rheological fluid drive according to claim 1, characterized in that, The joint rotation mechanism includes a joint cavity, a rotating shaft fixed on the joint cavity, a gear rotatably connected to the rotating shaft, and a rack meshing with the gear and extending along the movement direction of the hydraulic actuating mechanism. As the rack moves linearly, the gear meshing with the rack rotates, and the front joint is fixed on the gear and rotates relative to the rotating shaft as the gear rotates.

4. The variable stiffness joint based on giant electro-rheological fluid drive according to claim 3, wherein The sealing block is threadedly connected to the hydraulic actuating mechanism.

5. The variable stiffness joint based on giant electro-rheological fluid drive according to claim 1, wherein The hydraulic actuating mechanism includes a hydraulic cylinder, a piston provided in the hydraulic cylinder to divide it into two regions, a fluid cavity located in the lower region of the piston, an air cavity located in the upper region of the piston, and an antagonistic spring located in the air cavity and clamped between the piston and the top of the hydraulic cylinder. The fluid cavity communicates with the fluid passage of the giant electro-rheological fluid control valve. As the liquid flows into the fluid cavity, the piston is pushed to move along the inner wall of the hydraulic cylinder towards the air cavity, providing power for the joint rotation mechanism.

6. The variable stiffness joint based on giant electro-rheological fluid drive according to claim 1, characterized in that The fluid delivery system includes a liquid storage tank, an infusion tube for connecting the liquid in the liquid storage tank to the fluid passage, and a liquid pump for introducing or pumping out the liquid in the liquid storage tank to the fluid passage.

7. A laparoscopic surgical robotic arm, characterized in that, It includes a base, an arm extending from the base, a wrist provided at the outermost end of the arm, a guide rod assembled on the wrist, and an actuator provided at the outermost end of the guide rod through a joint group. The joint group includes the variable stiffness joint based on giant electro-rheological fluid drive according to any one of claims 1-6. When there are two or more variable stiffness joints based on giant electro-rheological fluid drive, the front joint of one variable stiffness joint based on giant electro-rheological fluid drive is clamped with the rear joint of another variable stiffness joint based on giant electro-rheological fluid drive.

8. The laparoscopic surgical robotic arm according to claim 7, wherein The front joint includes a disc-shaped tray and a plurality of buckles provided on the tray. The rear joint includes a chassis provided at the bottom of the sandwich-type valve body and a card slot opened on the chassis. The two variable stiffness joints based on giant electro-rheological fluid drive are fixedly connected by inserting the buckles into the card slot.

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