A variable stiffness soft gripper based on dielectric fluid drive

Abstract

The present invention discloses a variable stiffness soft gripper based on dielectric fluid drive. It comprises a plurality of finger bodies, finger drivers and a connection platform. The plurality of finger bodies are fixedly connected to the corresponding finger drivers to form a plurality of variable stiffness fingers. The finger drivers of the plurality of variable stiffness fingers are connected via the connection platform to form a variable stiffness soft gripper. In the variable stiffness finger, the dielectric fluid in the inner and outer layers of the flow channel is driven from the inside to the outside by the electrode assembly, and the volume of the inner and outer chambers changes, thereby causing the finger to bend and deform, which can be used for gripping objects. The present invention can control the pumping effect of the dielectric fluid driver by adjusting the voltage applied to the positive line of the deformation layer and the positive line of the variable stiffness layer. On a macro level, the bending angle and stiffness change ratio of the flexible finger can be arbitrarily controlled, and the adaptive gripping requirements of the gripper for soft, hard and brittle objects can be achieved by relying solely on the adjustment of the voltage.

Description

Technical Field

[0001] The present invention relates to a soft gripper with variable stiffness, and in particular to a soft gripper driven by dielectric fluid and having a certain stiffness adjustment capability. Background Art

[0002] Traditional rigid grippers are difficult to adapt to the grasping of soft and fragile objects, while the existing typical soft grippers based on fluid drive such as gas and liquid have poor load-bearing capacity. At the same time, the necessary external pump source and piping components also limit the portability of the gripper.

[0003] In view of the above situation, it is necessary to study a new type of portable soft gripper with adjustable stiffness to solve these problems. Summary of the Invention

[0004] To address the problems presented in the prior art, the present invention provides a portable, adjustable-rigidity soft gripper. This invention utilizes a dielectric fluid as a drive and incorporates a blocking plate to allow for controllable gripper stiffness. This expands the functionality of the soft gripper, enabling it to meet the demands of grasping soft, hard, and brittle objects.

[0005] The technical solution adopted in the present invention is:

[0006] The present invention includes multiple finger bodies, finger drivers and a connecting platform. The multiple finger bodies are fixedly connected to the corresponding finger drivers to form multiple variable-rigidity fingers. The finger drivers of the multiple variable-rigidity fingers are connected through the connecting platform to form a variable-rigidity soft gripper. The variable-rigidity fingers are driven to control the variable-rigidity soft gripper to grasp objects.

[0007] The finger actuator includes a first separator, an inner shell, an outer shell and an electrode assembly;

[0008] The top of the outer shell is fixedly connected to the connecting platform, the outer shell is hollow, the inner shell is arranged inside the outer shell, the inner shell and the outer shell are spaced apart, and the electrode assembly is fixedly installed in the chamber between the inner shell and the outer shell; the shell is also hollow, the first separator is arranged inside the inner shell, the first separator and the inner shell are spaced apart, and the electrode assembly is fixedly installed in the chamber between the first separator and the inner shell;

[0009] From the outside to the inside, the interior of the finger body is sequentially provided with an outer deformation cavity, an outer variable stiffness cavity, an inner variable stiffness cavity and an inner deformation cavity; the outer deformation cavity, the outer variable stiffness cavity, the inner variable stiffness cavity and the inner deformation cavity are not interconnected; the bottom of the outer shell and the inner shell are provided with openings, the top of the cavity wall between the outer variable stiffness cavity and the inner variable stiffness cavity is fixedly connected to the bottom of the first separator, the top of the cavity wall between the outer deformation cavity and the outer variable stiffness cavity, and the top of the cavity wall between the inner variable stiffness cavity and the inner deformation cavity are fixedly connected to the bottom of the inner shell, so that the cavity between the inner shell and the first separator is connected with the outer variable stiffness cavity and the inner variable stiffness cavity to form a variable stiffness layer, and the variable stiffness layer is filled with dielectric fluid; the top of the finger body outside the outer deformation cavity and the top of the finger body outside are fixedly connected to the bottom of the outer shell, so that the cavity between the inner shell and the outer shell is connected with the outer deformation cavity and the inner deformation cavity to form a deformation layer, and the deformation layer is filled with dielectric fluid.

[0010] The electrode assembly is composed of multiple groups of electrode pairs fixedly installed in the chamber of the finger actuator at intervals. Each group of electrode pairs includes multiple triangular electrodes and multiple slit electrodes. In each group of electrode pairs, multiple triangular electrodes are connected to form a triangular electrode group, and multiple slit electrodes are connected to form a slit electrode group. The triangular electrode groups and the slit electrode groups are arranged at intervals and are all fixedly installed in the chamber of the finger actuator. One of the tips of each triangular electrode is opposite to the slit of the corresponding slit electrode to form an electrode pair. When the electrode pair is energized, the dielectric liquid in the chamber flows from the triangular electrode to the slit electrode to form a jet.

[0011] In the inner shell and the outer shell, the triangular electrode of the electrode assembly close to the inner side is arranged below the corresponding slit electrode, and the tip of the triangular electrode points to the top of the shell; the triangular electrode of the electrode assembly close to the outer side is arranged above the corresponding slit electrode, and the tip of the triangular electrode points to the bottom of the shell.

[0012] A blocking piece is also provided in the inner variable stiffness cavity of the finger body.

[0013] The inner side surface of the finger body is provided with a plurality of protrusions or grooves, and the plurality of protrusions or grooves are arranged at intervals, so that the outer surface of the finger body is concave-convex.

[0014] The volume of the variable stiffness cavity is smaller than the volume of the deformation cavity.

[0015] The beneficial effects of the present invention are:

[0016] The soft gripper provided by the present invention can realize controllable adjustment of stiffness, achieve adaptive grasping for different targets such as soft, hard and brittle, and is highly portable.

[0017] The present invention has greatly improved the grasping ability and system portability compared with the traditional soft gripper and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0019] Figure 2 is the overall schematic diagram of the dielectric fluid driver on the left;

[0020] Figure 3 It is a structural diagram of the dielectric fluid driver on the left;

[0021] Figure 4 is a schematic diagram of a triangle-slit electrode pair;

[0022] Figure 5 is a cross-sectional view of the dielectric fluid driver on the left;

[0023] Figure 6 is a schematic diagram of the deformation of the flexible finger on the left;

[0024] Figure 7 is a schematic diagram of the cross-sectional structure of the flexible finger on the left;

[0025] Figure 8 It is a schematic diagram of the driving principle of the triangle-slit electrode pair;

[0026] Figure 9 This is a schematic diagram of the deformation principle of the flexible finger on the left;

[0027] Figure 10 It is a schematic diagram of the layer blocking variable stiffness principle;

[0028] Figure 11 This is a schematic diagram of the principle of variable stiffness of the flexible finger on the left;

[0029] Figure 12 This is a schematic diagram of the soft gripper grasping operation.

[0030] In the figure: 1. Left flexible finger, 2. Right flexible finger, 3. Rear flexible finger, 4. Left dielectric fluid driver, 5. Right dielectric fluid driver, 6. Rear dielectric fluid driver, 7. Connecting platform, 8. Deformation layer positive line, 9. Variable stiffness layer positive line, 10. Common negative line, 11. Outer cover, 12. Inner cover, 13. First separator, 14. Inner shell, 15. Outer shell, 16. Second separator, 17. Electrode pair, 18. Negative electrode group, 19. Positive electrode group, 20. Outer flow channel, 21. Inner flow channel, 22. Outer deformation cavity, 23. Inner deformation cavity, 24. Outer variable stiffness cavity, 25. Inner variable stiffness cavity, 26. Blocking plate. DETAILED DESCRIPTION

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] like Figure 1 As shown, the present invention includes multiple finger bodies, finger drivers and a connecting platform 7. The multiple finger bodies are fixedly connected to the corresponding finger drivers to form multiple variable-rigidity fingers. The finger drivers of the multiple variable-rigidity fingers are connected through the connecting platform 7 to form a variable-rigidity soft gripper. The variable-rigidity fingers are driven to control the variable-rigidity soft gripper to grasp objects.

[0033] In the specific implementation, the soft gripper with variable stiffness is changed to a three-finger gripper, such as Figure 1 As shown, the left variable-stiffness finger, right variable-stiffness finger, and rear variable-stiffness finger are respectively designated as the left variable-stiffness finger. The left variable-stiffness finger is composed of the left flexible finger 1 and the left dielectric fluid actuator 4, the right flexible finger 2 and the right dielectric fluid actuator 5 are composed of the right variable-stiffness finger, and the rear variable-stiffness finger is composed of the rear flexible finger 3 and the rear dielectric fluid actuator 6. The three fingers of the soft gripper have the same structure and are evenly distributed along the circumference, forming an equilateral triangle when viewed from above. The positive electrode wire 8 of the deformable layer, the positive electrode wire 9 of the variable-stiffness layer, and the common negative electrode wire 10 each pass through a small hole on the top side of the dielectric fluid actuator and are connected to an external circuit. This gripper uses dielectric fluid as the driving medium. Applying a voltage to the electrode pair can drive the liquid flow, eliminating the need for a traditional pump source to achieve gripper deformation. A blocking plate is embedded in the soft gripper, and voltage is used to control the flow of liquid within the blocking layer to achieve adjustable gripper stiffness, thereby improving the gripper's load capacity.

[0034] like Figure 2 、 Figure 3 and Figure 5 As shown, the finger actuator includes a first separator 13, an inner shell 14, an outer shell 15, a second separator 16 and an electrode assembly;

[0035] The top of the outer shell 15 is fixedly connected to the connecting platform 7. The interior of the outer shell 15 is hollow. The inner shell 14 is arranged inside the outer shell 15. The inner shell 14 and the outer shell 15 are spaced apart. An electrode assembly is fixedly installed in the chamber between the inner shell 14 and the outer shell 15. Each electrode assembly is fixedly connected to the cavity walls of the inner shell 14 and the outer shell 15 respectively. In a specific implementation, the electrode assembly is fixedly installed in the inner chamber and the outer chamber between the inner shell 14 and the outer shell 15, where the inner and outer sides are relative to the object in the variable stiffness soft gripper; the interior of the inner shell 14 is also hollow. The first separator 13 is arranged inside the inner shell 14. The first separator 13 and the inner shell 14 are spaced apart. An electrode assembly is fixedly installed in the chamber between the first separator 13 and the inner shell 14; each electrode assembly is fixedly connected to the cavity wall of the first separator 13 and the inner shell 14 respectively. In a specific implementation, the electrode assembly is fixedly installed in the inner chamber and the outer chamber between the first separator 13 and the inner shell 14. The bottoms of the outer shell 15 and inner shell 14 are provided with openings. Specifically, one side panel of the outer shell 15 is provided as a removable outer cover 11, and the side panel of the inner shell 14 on the same side as the outer shell 15 is provided as a removable inner cover 12. The inner cover 12 and the first separator 13 are spaced apart. An electrode assembly is fixedly installed in the chamber between the inner cover 12 and the first separator 13. The electrode assembly is fixedly connected to the cavity walls of the inner cover 12 and the first separator 13, respectively. Specifically, the electrode assembly is fixedly installed in the chamber between the inner cover 12 and the first separator 13. A second separator 16 is provided at the bottom of the outer shell 15 and the inner shell 14. The top of the second separator 16 is fixedly connected to the inner cover 12, the first separator 13, and the bottom of the inner shell 14. A through slot is provided in the second separator 16, leaving the bottom of the finger actuator chamber open. The outer cover 11 and inner cover 12 are spaced apart, and an electrode assembly is fixedly installed in the cavity between the outer cover 11 and the inner cover 12. Each electrode assembly is fixedly connected to the cavity wall of the outer cover 11 and the inner cover 12. From the inside to the outside of the finger, the first electrode assembly, inner shell 14, second electrode assembly, first separator 13, third electrode assembly, inner cover 12, fourth electrode assembly and outer cover 11 are arranged in sequence.

[0036] like Figure 6 and Figure 7As shown, from the outside to the inside, the interior of the finger body is sequentially provided with an outer deformation cavity 22, an outer variable stiffness cavity 24, an inner variable stiffness cavity 25 and an inner deformation cavity 23; the outer deformation cavity 22, the outer variable stiffness cavity 24, the inner variable stiffness cavity 25 and the inner deformation cavity 23 are not interconnected; in a specific implementation, the cavity openings of the outer variable stiffness cavity 24 and the upper part of the inner variable stiffness cavity 25 are successively reduced downward, that is, the cross-section of the cavity of the outer variable stiffness cavity 24 and the upper part of the inner variable stiffness cavity 25 is an inverted cone. Except for the wires of the electrode assembly passing upward through the top of the outer shell 15 and the inner shell 14, the top and sides of the outer shell 15 and the inner shell 14 are all closed structures. The top of the cavity wall between the outer variable stiffness cavity 24 and the inner variable stiffness cavity 25 is fixedly connected to the bottom of the second separator 16, and the top of the cavity wall between the outer deformation cavity 22 and the outer variable stiffness cavity 24, the top of the cavity wall between the inner variable stiffness cavity 25 and the inner deformation cavity 23, and the top of the finger body between the outer variable stiffness cavity 24 and the inner variable stiffness cavity 25 are all fixedly connected to the bottom of the inner shell 14, so that the cavity between the inner shell 14 and the first separator 13 is connected with the outer variable stiffness cavity 24 and the inner variable stiffness cavity 25 to form a variable stiffness layer, that is, an inner flow channel; the variable stiffness layer is filled with dielectric fluid, which flows upward from the inside of the variable stiffness layer and then flows downward from the top to the outside of the variable stiffness layer until it flows to the bottom of the outside of the variable stiffness layer. The outer deformation chamber 22 and the inner deformation chamber 23 are two independent chambers with larger volumes, while the outer variable stiffness chamber 24 and the inner variable stiffness chamber 25 are smaller. The top of the left flexible finger 1 is connected to the bottom of the left dielectric fluid driver 4 and sealed; the top of the finger body outside the outer deformation chamber 22 and the top of the finger body inside the inner deformation chamber 23 are fixedly connected to the bottom of the outer shell 15, so that the chamber between the inner shell 14 and the outer shell 15 is connected to the outer deformation chamber 22 and the inner deformation chamber 23 to form a deformation layer, i.e., the outer flow channel; the deformation layer is filled with dielectric fluid, which flows upward from the inner side of the deformation layer and then downward from the top to the outer side of the deformation layer until it reaches the outer bottom of the deformation layer.

[0037] A blocking plate is also located within the internal variable stiffness cavity 25 of the finger body. When an object is in contact and squeezed between the gripper and the gripper, a voltage is applied to the positive electrode line 9 of the variable stiffness layer, causing fluid to flow through the internal flow channel. This creates a negative pressure and high friction environment in the area where the blocking plate is located, hardening the finger and increasing its stiffness.

[0038] like Figure 4As shown, the electrode assembly consists of multiple groups of electrode pairs fixedly installed in the chamber of the finger actuator at intervals, each group of electrode pairs includes multiple triangular electrodes and multiple slit electrodes; in each group of electrode pairs, multiple triangular electrodes are connected to form a triangular electrode group, and multiple slit electrodes are connected to form a slit electrode group. The triangular electrode group and the slit electrode group are arranged at intervals and are all fixedly installed in the chamber of the finger actuator. One of the tips of each triangular electrode is opposite to the slit of the corresponding slit electrode to form a microelectrode pair unit, namely, electrode pair 17. After the electrode pair 17 is energized, since the chamber is filled with dielectric liquid, a non-uniform electric field is formed between the triangular electrode and the slit electrode, so that the dielectric liquid in the chamber flows from the triangular electrode to the slit electrode to form a jet, that is, a jet is formed flowing from the positive electrode to the negative electrode. In a specific implementation, the triangular electrode group serves as the positive electrode group 19. The triangular electrode groups of multiple electrode pairs are connected via a first U-shaped connecting frame. The slit electrode group serves as the negative electrode group 18. The slit electrode groups are connected via a second U-shaped connecting frame. The first and second U-shaped connecting frames are fixedly mounted on the inner wall of the chamber. The three branches of the first U-shaped connecting frame are staggered with the three branches of the second U-shaped connecting frame, so that each triangular electrode is arranged relative to the corresponding slit electrode with upper and lower spacing. The wire connected to the triangular electrode group in the variable stiffness layer is denoted as the variable stiffness layer positive line 9, the wire connected to the triangular electrode group in the deformable layer is denoted as the deformable layer positive line 8, and the wire connected to the slit electrode group is denoted as the common negative line 10. The common negative line 10 is connected to the negative electrode groups 18 of all four electrode pairs 17 in the left dielectric fluid driver 4, and passes through a small hole on one side of the top of the outer shell 15; similarly, the deformable layer positive line 8 is connected to the positive electrode groups 19 of the two electrode pairs 17 in the outer flow channel 20, and passes through the small hole on the other side of the top of the outer shell 15; the variable stiffness layer positive line 9 is connected to the positive electrode groups 19 of the other two electrode pairs 17 in the inner flow channel 21, and also passes through the small hole on the other side of the top of the outer shell 15. In a specific implementation, four sets of electrode pairs 17 are connected to wires. The electrode pairs can be inserted into the slots of each driver component in a specific direction, and the wires are passed through the small holes in the top of the outer shell 15. The assembly is carried out in the order of outer shell 15, inner shell 14, separator 13, inner cover 12, and outer cover 11 from the inside to the outside, and the electrode pairs 17 are inserted between two adjacent components during the process. Finally, the second separator 16 is bonded to the bottom surface of the dielectric fluid driver. Adhesive is used to apply to the gaps on each side of the left dielectric fluid driver 4 and the small holes for the wires to ensure the sealing of the dielectric fluid driver.

[0039] The top surface of the dielectric fluid driver 4 on the left is rectangular, and the small pins on the four corners are interference fit with the small holes on the connecting platform 7 and glued together; the circular hole in the center is the injection hole, and the working liquid is injected through this hole after the overall assembly is completed. To ensure the fluid chamber is closed during operation, an adhesive is used to seal it.

[0040] In the inner shell 14 and the outer shell 15, the triangular electrode of the electrode assembly close to the inner side is arranged below the corresponding slit electrode, and the tip of the triangular electrode points to the top of the shell; the triangular electrode of the electrode assembly close to the outer side is arranged above the corresponding slit electrode, and the tip of the triangular electrode points to the bottom of the shell.

[0041] The inner side surface of the finger body is provided with a plurality of protrusions or grooves, and the plurality of protrusions or grooves are arranged at intervals, so that the outer surface of the finger body is concave and convex, thereby increasing the gripping friction.

[0042] The working principle of the present invention is as follows:

[0043] Working principle of dielectric fluid driver 4 on the left:

[0044] Dielectric fluids, a type of polarizable insulating liquid, can be directly pumped by the electric field when placed in a sufficiently strong external electric field, generating flow and thus forming dielectric fluid actuators. The microscopic principle behind this is based on dielectric fluid dynamics. Generally speaking, in an electrostatic field, a small number of molecules within the dielectric fluid generate charged particles on a microscopic level through electron injection or molecular dissociation into positive or negative ions. These particles move rapidly along the direction of the electric field lines, dragging a large number of liquid molecules with them, resulting in directional pumping of the liquid on a macroscopic level.

[0045] like Figure 8 As shown, in the electrode pair 17, multiple groups of non-uniform strong electric fields exist between the top lines of each unit of the positive electrode group 19 and the slits corresponding to the negative electrode group 18, forming pumping channels. On a macro scale, the dielectric fluid flows along the direction of the triangular prism of the positive electrode group 19. Furthermore, connecting multiple pairs of units in series along the flow direction can improve the output capacity.

[0046] Working principle of the left flexible finger 1:

[0047] Using the dielectric fluid driver 4 to drive the flexible finger 1 essentially still belongs to the category of fluid drive, and the design of the finger structure follows the general design principles of flexible fingers.

[0048] The deformation principle of the left flexible finger 1 of the present invention is as follows Figure 9 As shown, the outer deformation cavity 22 and inner deformation cavity 23 of the left flexible finger 1, along with the outer flow channel 20 of the left dielectric fluid driver 4, form a large U-shaped space. The dielectric fluid within this space generates pressure due to the electric field, flowing from the inner deformation cavity 23 to the outer deformation cavity 22. Due to the incompressibility of liquids, the inner deformation cavity 23 of the left flexible finger 1 contracts, while the outer deformation cavity 22 expands, causing the volume of the flexible cavity to change, thereby causing the finger to bend.

[0049] Principle of lamellar blocking and variable stiffness:

[0050] like Figure 10As shown in Figure 1, if multiple layers of sheet material are stacked within a closed space made of flexible material, the entire structure will bend and deform under external forces, with low stiffness. However, when the closed space becomes negatively pressurized, friction between the sheet-like layers increases, making the model more resistant to external interference, which manifests as increased stiffness.

[0051] like Figure 11 As shown, blocking piece 26 is encapsulated within the inner variable stiffness chamber 25 of the left flexible finger 1. When the deformable layer positive line 8 is energized, the electrode pairs in the outer flow channel 20 of the left dielectric fluid driver 4 activate, causing the left flexible finger 1 to bend to a certain angle. At this point, the variable stiffness layer positive line 9 is connected, and the electrode pairs 17 in the inner flow channel 21 of the left dielectric fluid driver 4 activate, causing the liquid in the inner variable stiffness chamber 25 of the flexible finger 1 to flow into the outer variable stiffness chamber 24. Blocking piece 26 is in a negative pressure hardened state, and the finger as a whole enters a high stiffness state.

[0052] Working principle of soft gripper invention:

[0053] As described above, a DC high voltage of 3000-8000V is applied to the lead-out ends of the positive electrode line 8 of the deformation layer, the positive electrode line 9 of the variable stiffness layer, and the common negative electrode line 10 to drive the soft gripper to work.

[0054] After dielectric fluid, such as linalyl acetate, is filled into the left dielectric fluid driver 4, the right dielectric fluid driver 5, and the rear dielectric fluid driver 6 through the liquid filling holes on the connection platform 7, a single-component silicone adhesive is used to apply to each joint to ensure the sealing of the soft gripper.

[0055] like Figure 12 When voltage is applied to the deformable layer's positive electrode wire 8, the left dielectric fluid driver 4, right dielectric fluid driver 5, and rear dielectric fluid driver 6 all begin to operate, pumping liquid. Furthermore, the left flexible finger 1, right flexible finger 2, and rear flexible finger 3 bend and deform due to the hydraulic pressure differential, enabling them to grasp objects. When the target object is in contact and compression with the gripper, voltage is applied to the variable stiffness layer's positive electrode wire 9, placing the blocking plate 26 in a negative pressure, high friction state. This hardens the fingers and increases gripper stiffness.

[0056] By adjusting the voltage applied to the deformable layer positive wire 8 and the variable stiffness layer positive wire 9, the pumping capacity of the left dielectric fluid driver 4, the right dielectric fluid driver 5, and the rear dielectric fluid driver 6 can be controlled. On a macro level, the bending angle and stiffness change ratio of the left flexible finger 1, the right flexible finger 2, and the rear flexible finger 3 can be arbitrarily controlled, meeting the needs of adaptive grasping of soft, hard, and brittle objects by relying solely on voltage adjustment.

[0057] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure.

[0058] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0059] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A variable stiffness soft gripper based on dielectric fluid drive, characterized in that: The invention comprises a plurality of finger bodies, finger drivers and a connection platform (7), wherein the plurality of finger bodies are fixedly connected to the corresponding finger drivers to form a plurality of variable stiffness fingers, and the finger drivers of the plurality of variable stiffness fingers are connected via the connection platform (7) to form a variable stiffness soft gripper, and the variable stiffness fingers are driven to control the variable stiffness soft gripper to grasp an object; The finger actuator comprises a first separator (13), an inner shell (14), an outer shell (15) and an electrode assembly; The top of the outer shell (15) is fixedly connected to the connecting platform (7), the outer shell (15) is hollow inside, the inner shell (14) is arranged inside the outer shell (15), the inner shell (14) and the outer shell (15) are spaced apart, and an electrode assembly is fixedly installed in the chamber between the inner shell (14) and the outer shell (15); the shell (14) is also hollow inside, the first separator (13) is arranged inside the inner shell (14), the first separator (13) and the inner shell (14) are spaced apart, and the electrode assembly is fixedly installed in the chamber between the first separator (13) and the inner shell (14); From the outside to the inside, the interior of the finger body is provided with an outer deformation cavity (22), an outer variable stiffness cavity (24), an inner variable stiffness cavity (25) and an inner deformation cavity (23) in sequence; the outer deformation cavity (22), the outer variable stiffness cavity (24), the inner variable stiffness cavity (25) and the inner deformation cavity (23) are not interconnected; the bottoms of the outer shell (15) and the inner shell (14) are provided with openings, the top of the cavity wall between the outer variable stiffness cavity (24) and the inner variable stiffness cavity (25) is fixedly connected to the bottom of the first separator (13), and the top of the cavity wall between the outer deformation cavity (22) and the outer variable stiffness cavity (24), the top of the cavity wall between the inner variable stiffness cavity (25) and the outer variable stiffness cavity (23) are fixedly connected to the bottom of the first separator (13). The tops of the cavity walls between the inner deformation cavities (23) are fixedly connected to the bottom of the inner shell (14), so that the cavity between the inner shell (14) and the first separator (13) is connected to the outer variable stiffness cavity (24) and the inner variable stiffness cavity (25) to form a variable stiffness layer, and the variable stiffness layer is filled with a dielectric fluid; the top of the finger body outside the outer deformation cavity (22) and the top of the outer finger body are fixedly connected to the bottom of the outer shell (15), so that the cavity between the inner shell (14) and the outer shell (15) is connected to the outer deformation cavity (22) and the inner deformation cavity (23) to form a deformation layer, and the deformation layer is filled with a dielectric fluid; A blocking piece (26) is also provided in the internal variable stiffness cavity (25) of the finger body.

2. The variable stiffness soft gripper based on dielectric fluid drive according to claim 1, characterized in that: The electrode assembly is fixedly installed in the chamber of the finger driver with multiple groups of electrode pairs spaced apart from each other, each group of electrode pairs including multiple triangular electrodes and multiple slit electrodes; in each group of electrode pairs, multiple triangular electrodes are connected to form a triangular electrode group, and multiple slit electrodes are connected to form a slit electrode group, the triangular electrode group and the slit electrode group are arranged at intervals and are all fixedly installed in the chamber of the finger driver, one of the tips of each triangular electrode is opposite to the slit of the corresponding slit electrode to form an electrode pair (17), and when the electrode pair (17) is energized, the dielectric liquid in the chamber flows from the triangular electrode to the slit electrode to form a jet.

3. The variable stiffness soft gripper based on dielectric fluid drive according to claim 2, characterized in that: In the inner shell (14) and the outer shell (15), the triangular electrode of the electrode assembly close to the inner side is arranged below the corresponding slit electrode, and the tip of the triangular electrode points to the top of the shell; the triangular electrode of the electrode assembly close to the outer side is arranged above the corresponding slit electrode, and the tip of the triangular electrode points to the bottom of the shell.

4. The variable stiffness soft gripper based on dielectric fluid drive according to claim 1, characterized in that: The inner side surface of the finger body is provided with a plurality of protrusions or grooves, and the plurality of protrusions or grooves are arranged at intervals, so that the outer surface of the finger body is concave-convex.

5. The variable stiffness soft gripper based on dielectric fluid drive according to claim 1, characterized in that: The chamber volume of the outer variable stiffness chamber (24) is smaller than the chamber volume of the outer deformation chamber (22), and the chamber volume of the inner variable stiffness chamber (25) is smaller than the chamber volume of the inner deformation chamber (23).

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