An electrofluid-driven variable-stiffness flexible robotic arm

Abstract

The present invention discloses a variable stiffness flexible robotic arm driven by an electric fluid. A central cavity is provided in the middle of the flexible robotic arm body, and a plurality of side cavities arranged at intervals along the circumference are provided in the flexible robotic arm body outside the central cavity. Each of the central cavity and all the side cavities is filled with dielectric liquid. An electrode drive assembly is fixedly installed on the top of each chamber to drive the flow of liquid. The sub-cavity where each electrode drive assembly is located is recorded as an electrode chamber, and a gap is provided between each electrode drive assembly and the top of the corresponding chamber to form a liquid storage chamber. The chamber below each electrode chamber is recorded as a deformation chamber, and fibers are provided in the deformation chambers of the four side chambers to locally change the stiffness of the flexible robotic arm. The robotic arm of the present invention is free from the constraints of external air pumps, solenoid valves, etc., and integrates the fluid drive components into the interior of the robotic arm, thereby increasing the portability of the robotic arm; at the same time, by adopting direct current drive, the robotic arm can achieve a higher variable stiffness frequency and drive frequency.

Description

Technical Field

[0001] The present invention relates to a variable-rigidity flexible robotic arm, in particular to a variable-rigidity flexible robotic arm driven by an electric fluid. Background Art

[0002] Traditional pneumatic manipulators require external air pumps, which are bulky and heavy, limiting the manipulator's portability and flexibility. Multi-degree-of-freedom pneumatic manipulators require multiple solenoid valves to control pressure in different areas to achieve various deformation modes. Silicone tubing is used to transfer gas between the solenoid valves and the manipulator. Too long silicone tubing results in slow manipulator response and pressure loss along the way; too short silicone tubing limits the manipulator's operating range. To address these issues, a variable-stiffness, fully flexible manipulator based on a novel drive method is needed. Summary of the Invention

[0003] In order to solve the problems existing in the background technology, the purpose of the present invention is to provide an electrofluid-driven variable-stiffness flexible robotic arm for use in scenarios such as human-computer interaction and industrial operations.

[0004] The technical solution adopted in the present invention is:

[0005] The present invention includes a flexible robotic arm body, a dielectric liquid and an electrode drive assembly; a central cavity is opened in the middle of the flexible robotic arm body, and a plurality of side cavities arranged at intervals along the circumference are opened in the flexible robotic arm body outside the central cavity. Each of the central cavity and all the side cavities is filled with dielectric liquid, and an electrode drive assembly is fixedly installed on the top of each cavity. The sub-cavity where each electrode drive assembly is located is recorded as an electrode chamber, and a gap is set between each electrode drive assembly and the top of the corresponding cavity to form a liquid storage chamber. The cavity below each electrode chamber is recorded as a deformation chamber.

[0006] The electrode drive assembly is composed of multiple groups of electrode pairs arranged at intervals along the axial direction. Each group of electrode pairs is fixedly installed in the electrode chamber. Each group of electrode pairs includes multiple triangular electrodes and multiple slit electrodes. The multiple triangular electrodes are connected to each other as positive electrodes, and the multiple slit electrodes are connected to each other as negative electrodes. One of the tips of all triangular electrodes is facing the slit of the corresponding slit electrode. When the electrode pair is energized, a non-uniform electric field is formed between the triangular electrodes and the slit electrodes, so that the dielectric liquid in the electrode chamber flows from the triangular electrodes to the slit electrodes to form a jet.

[0007] In the side cavity, the electrode pair of the electrode driving assembly is centered, the triangular electrode is arranged below the slit electrode, and the tip of the triangular electrode points to the liquid storage chamber. When the electrode pair is energized, the dielectric liquid in the side cavity is driven to flow from the deformation cavity to the liquid storage chamber, thereby changing the stiffness of the side cavity.

[0008] In the central cavity, the electrode pair of the electrode driving assembly is centered, and the triangular electrode is arranged above the slit electrode. The tip of the triangular electrode points to the deformation cavity. When the electrode pair is energized, the dielectric liquid in the central cavity is driven to flow from the liquid storage chamber to the deformation cavity, causing the entire flexible robotic arm to bend and deform. The bending direction depends on the stiffness distribution of the side cavity.

[0009] Fibers are also arranged in the deformation cavity of the side cavity.

[0010] The dielectric liquid is linalyl acetate.

[0011] The electrode pair is made of a rigid metal material or a flexible conductive material.

[0012] The beneficial effects of the present invention are:

[0013] The present invention is based on electrofluidic technology. The electrode pair used is small in size and can be directly integrated into the interior of the robotic arm, making the robotic arm easy to move and carry; the electrode pair is driven by direct current, and the working range and performance of the robotic arm are no longer limited by the length of the silicone tube; by changing the local stiffness of the robotic arm through electric drive, the robotic arm can be bent in different directions with high flexibility; the variable stiffness technology based on electrofluid has a high response frequency and a small size, and has obvious advantages over traditional pneumatic or electric heating variable stiffness technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0015] Figure 2 is the cross section of the flexible robotic arm;

[0016] Figure 3 is a cross-sectional view of the electrode chamber;

[0017] Figure 4 is a cross-sectional view of the flexible robotic arm;

[0018] Figure 5 It is a schematic diagram of the working principle of the electrode pair;

[0019] Figure 6 is a schematic diagram of the distribution of electrode pairs in the electrode chamber;

[0020] Figure 7 It is a schematic diagram of the variable stiffness principle;

[0021] Figure 8 It is a deformation diagram of the variable stiffness flexible robotic arm.

[0022] In the figure: 1, liquid storage chamber, 2, electrode chamber, 3, deformation chamber, 4, first side chamber, 5, second side chamber, 6, third side chamber, 7, fourth side chamber, 8, central chamber, 9, electrode pair, 10, fiber, 11, triangular electrode, 12, slit electrode. DETAILED DESCRIPTION

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] like Figure 1 、 Figure 2 、 Figure 3 and Figure 4 As shown, the present invention includes a flexible robotic arm body, a dielectric liquid, an electrode drive assembly, and a fiber 10;

[0025] A central cavity 8 is provided in the middle of the flexible manipulator body. A plurality of side cavities are provided in the flexible manipulator body outside the central cavity 8, which are arranged at equal intervals along the circumference. Adjacent side cavities and the side cavities and the central cavity are not connected to each other. In a specific implementation, the cross section of the central cavity 8 is circular, and the side cavities are arranged in four sectors with the same cross section and are arranged at equal intervals along the circumference, respectively designated as the first side cavity 4, the second side cavity 5, the third side cavity 6, and the fourth side cavity 7. In the central cavity 8 and all the side cavities, each cavity is filled with a dielectric liquid, which is linalyl acetate. An electrode drive assembly is fixedly installed on the top of each cavity for driving the liquid flow. The subcavity where each electrode drive assembly is located is designated as the electrode chamber 2. Each electrode drive assembly is provided with a gap at the top of the corresponding cavity and forms a liquid storage chamber 1. The cavity below the electrode chamber 2 corresponding to the four side cavities and the central cavity is designated as the deformation cavity 3. Fiber 10 is provided in the deformation cavity 3 for locally changing the stiffness of the flexible manipulator. There is no fiber in the deformation cavity 3 below the electrode chamber 2 of the central cavity 8. The electrode drive assembly and fiber 10 are both encapsulated in a dielectric fluid. A step is provided at the junction between the deformation chamber 3 and the electrode chamber 2 to limit the position of the fiber 10. This robotic arm eliminates the need for external air pumps, solenoid valves, and other components, integrating fluid drive components within the arm for increased portability. Furthermore, the use of DC drive allows for a high frequency of variable stiffness and drive.

[0026] The working principle of the electrode pair 9 is as follows Figure 5 and Figure 6As shown, the arrow indicates the direction of jet flow. The electrode drive assembly consists of multiple groups of electrode pairs 9 arranged in an axially spaced manner. Each group of electrode pairs 9 is fixedly installed in the electrode chamber 2, that is, fixedly installed on the inner wall of the electrode chamber 2. Each group of electrode pairs 9 includes multiple triangular electrodes 11 and multiple slit electrodes 12. The multiple triangular electrodes 11 are connected by a connecting frame to serve as positive electrodes, and the multiple slit electrodes 12 are connected by a connecting frame to serve as negative electrodes. One of the tips of all triangular electrodes 11 is facing the slit of the corresponding slit electrode 12. Because the chamber is filled with dielectric liquid, when the electrode pair 9 is energized, a non-uniform electric field is formed between the triangular electrode 11 and the slit electrode 12, causing the dielectric liquid in the electrode chamber 2 to flow from the triangular electrode 11 to the slit electrode 12 to form a jet, that is, a jet flowing from the positive electrode to the negative electrode.

[0027] In the side cavity, in the electrode pair 9 of the electrode drive assembly, the triangular electrode 11 is arranged below the slit electrode 12, and the tip of the triangular electrode 11 points to the liquid storage chamber 1. When the electrode pair 9 is energized, the dielectric liquid in the side cavity is driven to flow from the deformation cavity 3 to the liquid storage chamber 1, thereby changing the stiffness of the side cavity. In a specific embodiment, the electrode drive assembly in the side cavity is composed of three groups of electrode pairs 9 arranged in an axially spaced manner. The connecting frame of each group of electrode pairs 9 is provided with a plurality of triangular electrodes 11 and corresponding slit electrodes 12 arranged in a circumferential manner. The triangular electrodes 11 and the corresponding slit electrodes 12 are arranged in an axially spaced manner.

[0028] In the central cavity, in the electrode pair 9 of the electrode drive assembly, the triangular electrode 11 is arranged above the slit electrode 12, and the tip of the triangular electrode 11 points to the deformation cavity 3. After the electrode pair 9 is energized, the dielectric liquid in the central cavity is driven to flow from the liquid storage chamber 1 to the deformation cavity 3, causing the entire flexible robotic arm to bend and deform. The bending direction depends on the stiffness distribution of the side cavity. In a specific implementation, the electrode drive assembly in the center is also composed of three groups of electrode pairs 9 arranged at intervals in the upper and lower directions along the axial direction. Since the chamber cross-section of the central cavity is large, more electrode pairs 9 are required to drive the dielectric liquid. Therefore, a plurality of electrode pair rings with gradually decreasing radial radius are provided in the connecting frame of each group of electrode pairs 9. Each electrode pair ring is composed of a plurality of triangular electrodes 11 and corresponding slit electrodes 12 arranged at intervals along the circumference. The triangular electrodes 11 and the corresponding slit electrodes 12 are arranged at intervals in the axial direction.

[0029] Variable stiffness principle Figure 7As shown, arrows indicate the direction of applied load. The triangular electrodes 11 in the first, second, third, and fourth side cavities 4, 5, 6, and 7 point toward the liquid reservoir 1, while the triangular electrode 11 in the central cavity 8 points toward the deformation cavity 3. When the electrode pair 9 is in the unactivated state, the fibers 10 in the deformation cavity 3 are loose, resulting in low stiffness. When the electrode pair 9 is activated, the liquid in the deformation cavity 3 is drawn away by the jet generated by the electrode pair, causing the internal pressure to become negative. This squeezes the fibers 10 together, and the friction between the fibers 10 increases the stiffness of the deformation cavity 3.

[0030] The electrode pair 9 is made of a rigid metal material, such as aluminum, copper, etc., or a flexible conductive material, such as conductive rubber, etc. If the electrode pair 9 is made of a flexible conductive material, the robotic arm is a fully flexible robotic arm.

[0031] The working principle of the variable stiffness robotic arm is as follows Figure 8 As shown, Figure 8 a- Figure 8 d are the top views of the robotic arm bending forward, left, backward, and right respectively. Figure 8 e- Figure 8 The h are front views of the manipulator bending forward, left, back, and right, respectively. By controlling the stiffness of the deformation chamber 3 of the first side chamber 4, the second side chamber 5, the third side chamber 6, and the fourth side chamber 7, respectively, the flexible manipulator can bend in different directions.

[0032] The electrode pair 9 in the electrode chamber 2 of the first side chamber 4 is driven, and the electrode pairs 9 in the second side chamber 5, the third side chamber 6, and the fourth side chamber 7 remain in an undriven state. The dielectric liquid in the deformation chamber 3 of the first side chamber 4 is pumped to the first side chamber 4 of the liquid storage chamber 1, thereby increasing the stiffness of the first side chamber 4 of the deformation chamber 3; then the electrode pair 9 in the electrode chamber 2 of the central chamber 8 is driven, and the dielectric liquid in the central chamber 8 of the liquid storage chamber 1 is pumped to the central chamber 8 of the deformation chamber 3. Due to the greater stiffness of the first side chamber 4, the deformation chamber 3 as a whole bends forward in the opposite direction of the first side chamber 4.

[0033] The electrode pair 9 in the electrode chamber 2 of the second side chamber 5 is driven, and the electrode pairs 9 in the first side chamber 4, the third side chamber 6, and the fourth side chamber 7 remain in an undriven state. The dielectric liquid in the second side chamber 5 of the side chamber 3 is pumped to the second side chamber 5 of the liquid storage chamber 1, thereby increasing the rigidity of the second side chamber 5 of the side chamber 3; then the electrode pair 9 in the electrode chamber 2 of the central chamber 8 is driven, and the dielectric liquid in the central chamber 8 of the liquid storage chamber 1 is pumped to the central chamber 8 of the side chamber 3. Due to the greater rigidity of the second side chamber 5, the side chamber 3 as a whole bends to the left in the opposite direction of the second side chamber 5.

[0034] The electrode pair 9 in the electrode chamber 2 of the third side chamber 6 is driven, and the electrode pairs 9 in the first side chamber 4, the second side chamber 5, and the fourth side chamber 7 remain in an undriven state. The dielectric liquid in the third side chamber 6 of the side chamber 3 is pumped to the third side chamber 6 of the liquid storage chamber 1, thereby increasing the stiffness of the third side chamber 6 of the side chamber 3; then the electrode pair 9 in the electrode chamber 2 of the central chamber 8 is driven, and the dielectric liquid in the central chamber 8 of the liquid storage chamber 1 is pumped to the central chamber 8 of the side chamber 3. Due to the greater stiffness of the third side chamber 6, the side chamber 3 as a whole bends backward in the opposite direction of the third side chamber 6.

[0035] The electrode pair 9 in the electrode chamber 2 of the fourth side chamber 7 is driven, and the electrode pairs 9 in the first side chamber 4, the second side chamber 5, and the third side chamber 6 remain in an undriven state. The dielectric liquid in the fourth side chamber 7 of the side chamber 3 is pumped to the fourth side chamber 7 of the liquid storage chamber 1, thereby increasing the rigidity of the fourth side chamber 7 of the side chamber 3; then the electrode pair 9 in the electrode chamber 2 of the central chamber 8 is driven, and the dielectric liquid in the central chamber 8 of the liquid storage chamber 1 is pumped to the central chamber 8 of the side chamber 3. Due to the greater rigidity of the fourth side chamber 7, the side chamber 3 as a whole bends to the right in the opposite direction of the fourth side chamber 7.

[0036] 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.

[0037] 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.

[0038] 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. An electrofluid-driven variable-stiffness flexible robotic arm, characterized in that: It includes a flexible robotic arm body, a dielectric liquid and an electrode drive component; A central cavity (8) is provided in the middle of the flexible manipulator body, and a plurality of side cavities arranged at intervals along a circumference are provided in the flexible manipulator body outside the central cavity (8). Each cavity in the central cavity (8) and all the side cavities is filled with a dielectric liquid, and an electrode drive assembly is fixedly installed on the top of each cavity. The subcavity where each electrode drive assembly is located is recorded as an electrode chamber (2), and a gap is provided between each electrode drive assembly and the top of the corresponding cavity to form a liquid storage chamber (1). The cavity below each electrode chamber (2) is recorded as a deformation chamber (3); The electrode drive assembly is composed of a plurality of electrode pairs (9) arranged at intervals along the axial direction, each electrode pair (9) includes a plurality of triangular electrodes (11) and a plurality of slit electrodes (12). In the side cavity, in the electrode pair (9) of the electrode drive assembly, the triangular electrode (11) is arranged below the slit electrode (12), and the tip of the triangular electrode (11) points to the liquid storage chamber (1). When the electrode pair (9) is energized, the dielectric liquid in the side cavity is driven to flow from the deformation cavity (3) to the liquid storage chamber (1), thereby changing the stiffness of the side cavity; in the central cavity, in the electrode pair (9) of the electrode drive assembly, the triangular electrode (11) is arranged above the slit electrode (12), and the tip of the triangular electrode (11) points to the deformation cavity (3). When the electrode pair (9) is energized, the dielectric liquid in the central cavity is driven to flow from the liquid storage chamber (1) to the deformation cavity (3), causing the entire flexible robotic arm to bend and deform; and a fiber (10) is also arranged in the deformation cavity (3) of the side cavity.

2. The variable stiffness flexible robotic arm driven by electrofluid according to claim 1, characterized in that: Each electrode pair (9) is fixedly installed in the electrode chamber (2), and a plurality of triangular electrodes (11) are connected to serve as positive electrodes, and a plurality of slit electrodes (12) are connected to serve as negative electrodes, and one of the tips of all triangular electrodes (11) faces the slit of the corresponding slit electrode (12); after the electrode pair (9) is energized, a non-uniform electric field is formed between the triangular electrode (11) and the slit electrode (12), so that the dielectric liquid in the electrode chamber (2) flows from the triangular electrode (11) to the slit electrode (12) to form a jet.

3. The variable stiffness flexible robotic arm driven by electrofluid according to claim 1, characterized in that: The dielectric liquid is linalyl acetate.

4. The variable stiffness flexible robotic arm driven by electrofluid according to claim 1, characterized in that: The material of the electrode pair (9) is a rigid metal material or a flexible conductive material.

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