Variable-rigidity bionic water snake robot based on rope drive

Abstract

The invention discloses a variable-rigidity bionic water snake robot based on rope drive. The variable-rigidity bionic water snake robot comprises a head cabin, a plurality of connecting cabins and a tail cabin which are arranged in sequence. The head cabin and the connecting cabins, the adjacent connecting cabins and the connecting cabins and the tail cabin are connected through variable-rigidity rotating joints; the variable-rigidity rotating joint comprises two rotating unit bases, a variable-rigidity spine, a rope driving mechanism and a waterproof corrugated pipe. The rigidity-variable spine is made of rigidity-variable materials and is connected between the two rotating unit bases. By the adoption of the variable stiffness technology, the snake-shaped robot can show better environmental adaptability in environments with different stiffness requirements. By adjusting the joint rigidity of the snakelike robot, the snakelike robot can obtain corresponding flexibility, maneuverability, load capacity and the like according to environment requirements, and the snakelike robot can better complete underwater operation.

Description

Technical Field

[0001] The present invention relates to the field of robots, and particularly to a cable-driven variable stiffness bionic water snake robot. Background Art

[0002] In recent years, snake robots have shown excellent performance in the fields of detection, rescue, medical treatment, etc. due to their flexibility and environmental adaptability. However, it is difficult to ensure the motion accuracy of flexible snake robots in complex underwater environments, and their load-bearing capacity is poor. Pure rigid snake robots lack flexibility, and there are safety problems when considering human-robot interaction. For example, when a snake robot moves in narrow areas such as pipelines and coral reefs, the robot needs to reduce its stiffness (flexible state) to flexibly deform and pass through obstacles. When facing complex terrains such as rocks and sunken ships, it is necessary to increase the stiffness (rigid state) to enhance the impact resistance and avoid structural damage. The flexible state can imitate the undulating swimming of water snakes, reduce fluid resistance, and improve the motion efficiency. When performing tasks such as grasping and detection, it is necessary to maintain rigidity to resist water flow interference and stably output force.

[0003] Most existing snake robots are designed to be rigid or flexible. Rigid structures have good load-bearing capacity, while flexible structures have high degrees of freedom and strong environmental adaptability. However, neither of them can adjust their own stiffness according to the usage requirements to achieve functional compatibility. Currently, the existing variable stiffness snake robots basically simply connect flexible modules and rigid modules in series, and it is still difficult to improve the operation ability while ensuring the motion control accuracy.

[0004] The application of variable stiffness technology can enable snake robots to show better environmental adaptability in environments with different stiffness requirements. By adjusting the joint stiffness of the snake robot, it can obtain corresponding flexibility, mobility, and load-bearing capacity according to environmental requirements, so that the snake robot can better complete underwater operations. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to develop a cable-driven variable stiffness bionic water snake robot, so that the water snake robot can achieve stiffness conversion under the condition of precise motion control.

[0006] The cable-driven variable stiffness bionic water snake robot of the present invention includes a head cabin, a plurality of connecting cabins, and a tail cabin arranged in sequence; the head cabin and the connecting cabins, adjacent connecting cabins, and the connecting cabin and the tail cabin are all connected by variable stiffness rotating joints;

[0007] The variable stiffness rotating joint includes two rotating unit bases, a variable stiffness spine, a cable drive mechanism, and a waterproof bellows; the variable stiffness spine is made of a material with variable stiffness and is connected between the two rotating unit bases; the cable drive mechanism includes a wire winding shaft, a cable drive motor, and a pulley assembly arranged on the rotating unit base; one end of the wire rope is fixed and wound around the wire winding shaft, and the other end of the wire rope passes around the pulley assembly on the opposite rotating unit base and then is connected to the rotating unit base where it is located; both ends of the waterproof bellows are fixedly connected to the outer circular surface of the rotating unit base.

[0008] Preferably, a plurality of spiral link rods surrounding the variable stiffness spine are arranged between the two rotating unit bases; both ends of the spiral link rods are correspondingly hinged to the two rotating unit bases.

[0009] Preferably, a camera mounting part is provided at the front end of the head cabin for mounting a binocular camera and is encapsulated for waterproofing through an optical glass sheet; a waterproof control panel power button is provided at the top of the head cabin; a control panel and a control panel power supply are installed inside the head cabin.

[0010] Preferably, two of the pulley assemblies are symmetrically installed on each rotating unit base; the pulley assembly includes a pulley fixing frame, a pulley, and a rope restraint frame; the pulley fixing frame is fixed to the opposite end face of the rotating unit base; the pulley is rotatably installed in the pulley fixing frame, the rope restraint frame is fixedly connected to the side of the pulley fixing frame, and two wire rope through holes are provided on the rope restraint frame.

[0011] Preferably, the wire winding shaft and the cable drive motor are installed on the opposite end faces of the rotating unit base; the rotating unit base is provided with a through hole for the wire rope to pass through; the cable drive motor drives the wire winding shaft to rotate through a gear pair.

[0012] Preferably, the phase difference between the two rotating unit bases of the variable stiffness rotating joint is 90°.

[0013] Preferably, the variable stiffness spine includes a support skeleton formed by connecting multiple spherical socket joints in series, a skin wrapped outside the support skeleton, and an organic phase change material filled between the support skeleton and the skin; a heating core is embedded in the organic phase change material.

[0014] Preferably, a drive power supply is installed in the tail cabin, and a waterproof button for controlling the on / off of the drive power supply is provided at the top of the tail cabin; two round holes are provided on each rotating joint base, and waterproof sealed connectors are installed thereon. One of the round holes serves as a control communication bus channel, and the other round hole serves as a power bus channel.

[0015] Preferably, the tail cabin is detachably connected to a mechanical claw connection cabin; the mechanical claw is installed outside the mechanical claw connection cabin through a servo connection frame, and the mechanical claw is driven by a grasping drive servo to realize the clamping movement.

[0016] Advantages of the present invention: A variable stiffness bionic water snake robot based on cable drive proposed by the present invention. Its driving principle is that the motor drives two oppositely installed cables fixedly connected, the cables drive the variable stiffness rotating joint to rotate, and the variable stiffness process is realized by adjusting the temperature of the variable stiffness spine embedded inside the rotating joint. The variable stiffness spine is filled with organic phase change material, and the normal temperature rigidity becomes flexible through heating, and the stiffness decreases as the temperature rises. The design of the variable stiffness rotating joint enables the stiffness of the bionic water snake robot to be adjustable, so that while it can move flexibly in a flexible state during movement, the cable drive method outside the spine ensures the accuracy of the rotating joint control while changing the stiffness, making the control of the bionic water snake robot more precise. And the installation of the mechanical claw increases the operation function of the robot, and the joint can be adjusted to maintain rigidity during the operation process to improve the operation ability. Brief Description of the Drawings

[0017] The present invention will be further described below in conjunction with the drawings and embodiments:

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

[0019] Figure 2 It is a schematic diagram of the internal structure of the middle section of the variable stiffness rotating joint of the present invention;

[0020] Figure 3 It is a schematic diagram of the base structure of the variable stiffness rotating joint of the present invention;

[0021] Figure 4 It is a schematic diagram of the pulley assembly structure of the present invention;

[0022] Figure 5 It is a schematic diagram of the structure of the mechanical claw of the present invention;

[0023] Figure 6 It is a schematic diagram of the variable stiffness spine structure of the present invention;

[0024] Figure 7 It is a schematic diagram of the internal structure of the variable stiffness spine of the present invention;

[0025] Figure 8 is Figure 7 the A-A cross-sectional view in

[0026] Reference numerals: 1 - head cabin, 2 - waterproof bellows, 3 - bellows retaining ring, 4 - connection cabin, 5 - tail cabin, 6 - rotating joint base, 7 - pulley fixing bracket, 8 - pulley, 9 - spiral connecting rod, 10 - variable stiffness spine, 11 - connecting block, 12 - rope restraint bracket, 13 - wire winding rotating shaft, 14 - driven gear, 15 - driving gear, 16 - rope driving motor, 17 - mechanical claw connection cabin, 18 - servo connection bracket, 19 - connecting rod support, 20 - grasping driving servo, 21 - driving connecting rod frame, 22 - driven connecting rod frame I, 23 - driven connecting rod frame II, 24 - spine support, 25 - cable tie, 26 - skin, 27 - sealing ring, 28 - heating core, 29 - ball-and-socket joint imitation. Detailed implementation mode

[0027] As Figure 1 shown, a cable-driven variable stiffness bionic water snake robot according to this embodiment includes a head cabin 1, six connection cabins 4, and a tail cabin 5 arranged in sequence; the head cabin 1 and the connection cabin 4, adjacent connection cabins 4, and the connection cabin 4 and the tail cabin 5 are all connected by variable stiffness rotating joints.

[0028] As Figure 2 shown, the variable stiffness rotating joint includes two rotating unit bases, a variable stiffness spine 10, a cable drive mechanism, and a waterproof bellows 2; the variable stiffness spine 10 is made of a material with variable stiffness and is connected between the two rotating unit bases and located at the central axis position. As Figures 6 - 8 shown, the variable stiffness spine 10 includes a support skeleton formed by connecting multiple ball-and-socket joint imitations 29 in series, a skin 26 wrapped around the support skeleton, and an organic phase change material filled between the support skeleton and the skin 26; both ends of the variable stiffness spine 10 are fixed to the variable stiffness rotating joint base 6 through two spine supports 24, and the stiffness change is realized by controlling the solid-liquid state of the organic phase change material by changing the temperature; the temperature control method is to install a small relay in a single variable stiffness rotating joint, and realize it by converting the heating signal into heat energy and burying the heating core 28 into the filler, and the skin 26 seals the organic phase change filling material through cable ties 25 and sealing rings 27.

[0029] As Figures 2 - 4As shown in the figure, the cable drive mechanism includes a wire winding rotating shaft 13, a cable drive motor 16 and a pulley assembly arranged on the base of the rotating unit; one end of the wire rope is fixed and wound around the wire winding rotating shaft 13, and the other end of the wire rope passes around the pulley assembly on the base of the opposite rotating unit and then is connected to the base of the rotating unit where it is located; two of the pulley assemblies are symmetrically installed on each rotating unit base; the pulley assembly includes a pulley fixing frame 7, a pulley 8 and a rope constraint frame 12; the pulley fixing frame 7 is fixed to the opposite end face of the rotating unit base; the pulley 8 is rotatably installed in the pulley fixing frame 7, the rope constraint frame 12 is fixedly connected to the side of the pulley fixing frame 7, and two wire rope through holes are provided on the rope constraint frame 12. The wire winding rotating shaft 13 and the cable drive motor 16 are installed on the opposite end faces of the rotating unit base; the rotating unit base is provided with a through hole for the wire rope to pass through; the cable drive motor 16 drives the wire winding rotating shaft 13 to rotate through a gear pair. The phase difference between the two rotating unit bases of the variable stiffness rotating joint is 90°, that is, the positions of the two rotating unit bases are orthogonal, and two pulley fixing frames 7 are symmetrically installed on a single rotating unit base; the wire winding rotating shaft 13 is key-connected to the driven gear 14, the output shaft of the cable drive motor 16 is key-connected to the driving gear 15, and the cable drive motor 16 drives the wire winding rotating shaft 13 to rotate through the driving gear 15 and the driven gear 14; two small holes processed on the wire winding rotating shaft 13 are respectively fixedly connected with two ropes, as Figure 3 , the rope fixedly connected to the upper small hole on the wire winding rotating shaft 13 extends into the variable stiffness rotating joint through the through hole on the left side outside the rotating unit base, passes through the small hole on the corresponding rope constraint frame 12 of the opposite rotating unit base, then bypasses the pulley, returns to the other through hole on the left side outside the rotating unit base through another small hole on the rope constraint frame 12, and is fixed on the rotating unit base. The small hole on the lower side of the wire winding rotating shaft 13 completes the same rope connection with the corresponding small hole on the right side of the base. The cable drive motor rotates the rotating shaft through a gear, and the ropes distributed in an antagonistic manner fixedly connected to the rotating shaft contract on one side and relax on the other side, causing the joint to rotate. Since the two rotating unit bases are orthogonal to each other, the joint can be respectively driven to perform yaw rotation and pitch rotation.

[0030] As Figure 2 , three spiral connecting rods 9 surrounding the variable stiffness spine 10 are arranged between the two rotating unit bases; both ends of the spiral connecting rods 9 are correspondingly hinged to the two rotating unit bases, and three connecting blocks 11 are hinged to the opposite end faces of the rotating unit bases. The three connecting blocks 11 are respectively hinged to the three spiral connecting rods 9, so that the variable stiffness rotating joint has two-way degrees of freedom in yaw and pitch and can rotate within a certain range.

[0031] Both ends of the waterproof corrugated pipe 2 are fixedly connected to the outer circular surface of the rotating unit base. The four grooves on the outer circular surface are the mounting grooves for the sealing ring 27, and threaded holes are provided as mounting holes so that it can be fixedly connected to the head cabin 1, the waterproof corrugated pipe 2, the corrugated pipe retaining ring 3, the connection cabin 4, and the tail cabin 5; the waterproof rubber corrugated pipe 2 is fixed to the rotating unit base through the corrugated pipe retaining ring 3. The waterproof corrugated pipe 2 is designed according to the motion limit of the rotating joint and is made by casting and film covering with a rubber material having a Shore hardness of 30.

[0032] As Figure 1 , the front end of the head cabin 1 is provided with a camera mounting part for mounting a binocular camera, and is encapsulated and waterproofed by an optical glass sheet; a waterproof button for the control board power supply is provided on the top of the head cabin 1; a control board and a control board power supply are installed inside the head cabin 1. A driving power supply is installed inside the tail cabin 5, and a waterproof button for controlling the on / off of the driving power supply is provided at the top end of the tail cabin 5; two round holes are provided on each rotating joint base 6, and waterproof sealed joints are installed thereon. One of them serves as a control communication bus channel starting from the head cabin 1 and running through the entire snake-shaped robot internally, and the other starts from the tail power supply and serves as a power bus channel running through the snake-shaped robot internally.

[0033] The tail cabin 5 is detachably connected to a mechanical claw connection cabin 174; the mechanical claw is installed on the outside of the mechanical claw connection cabin 174 through a servo connecting frame 18, and the mechanical claw is driven by a grasping driving servo 20 to realize the clamping movement; the mechanical claw is driven by two grasping driving servos 20, and the servos respectively control the rotation of the active link frame 21 and drive the driven link frame I 22 and the driven link frame II 23 installed on the link support 19 to perform the opening and closing clamping movement.

[0034] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications; any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A rope-driven variable stiffness bionic water snake robot, characterized by: It includes a head cabin, several connecting cabins and a tail cabin arranged in sequence; the head cabin and the connecting cabin, the adjacent connecting cabins, and the connecting cabin and the tail cabin are all connected by variable stiffness rotating joints; The variable stiffness rotation joint includes two rotation unit bases, a variable stiffness spine, a rope drive mechanism and a waterproof bellows; the variable stiffness spine is made of variable stiffness material and is connected between the two rotation unit bases; the rope drive mechanism includes a winding shaft, a rope drive motor and a pulley assembly arranged on the rotation unit base; one end of the rope is fixed and wound around the winding shaft, and the other end of the rope is connected to the rotation unit base where it is located after passing through the pulley assembly on the opposite rotation unit base; both ends of the waterproof bellows are fixedly connected to the outer cylindrical surface of the rotation unit base.

2. The variable stiffness bionic water snake robot based on rope drive according to claim 1, characterized in that: A plurality of spiral connecting rods surrounding the variable-rigidity spine are arranged between the two rotating unit bases; two ends of the spiral connecting rods are correspondingly hinged to the two rotating unit bases.

3. The variable stiffness bionic water snake robot based on rope drive according to claim 2 is characterized in that: The front end of the head cabin is provided with a camera installation position for installing a binocular camera, and is encapsulated and waterproofed by an optical glass sheet; a control panel power waterproof button is provided on the top of the head cabin; and a control panel and a control panel power supply are installed inside the head cabin.

4. The variable stiffness bionic water snake robot based on rope drive according to claim 3 is characterized in that: Two pulley assemblies are symmetrically installed on each rotating unit base; the pulley assembly includes a pulley fixing frame, a pulley and a rope restraining frame; the pulley fixing frame is fixed to the opposite end surface of the rotating unit base; the pulley is rotatably installed in the pulley fixing frame, the rope restraining frame is fixedly connected to the side of the pulley fixing frame, and two rope passing holes are provided on the rope restraining frame.

5. The variable stiffness bionic water snake robot based on rope drive according to claim 4 is characterized in that: The winding shaft and the rope driving motor are installed on the opposite end faces of the rotating unit base; the rotating unit base is provided with a through hole for the rope to pass through; the rope driving motor drives the winding shaft to rotate through a gear pair.

6. The variable stiffness bionic water snake robot based on rope drive according to claim 5, characterized in that: The phase difference between the two rotating unit bases of the variable stiffness rotating joint is 90°.

7. The variable stiffness bionic water snake robot based on rope drive according to claim 6 is characterized in that: The variable stiffness spine comprises a supporting frame formed by a plurality of simulated ball-and-socket joints connected in series, a skin wrapped around the supporting frame, and an organic phase change material filled between the supporting frame and the skin; a heating core is embedded in the organic phase change material.

8. The variable stiffness bionic water snake robot based on rope drive according to claim 7 is characterized in that: A driving power supply is installed in the tail cabin, and a waterproof button for controlling the on and off of the driving power supply is provided at the top of the tail cabin; two circular holes are provided on each rotating joint base, on which a waterproof sealing joint is installed, one of the circular holes is used as a control communication bus channel, and the other circular hole is used as a power bus channel.

9. The variable stiffness bionic water snake robot based on rope drive according to claim 8, characterized in that: The tail cabin is detachably connected to a mechanical claw connection cabin; the mechanical claw is installed on the outside of the mechanical claw connection cabin through a steering gear connection frame, and the mechanical claw is driven by a grasping driving steering gear to realize the clamping movement.

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