Mooring-free soft body rolling mechanism based on air tendon coupling driving

Abstract

The invention discloses a mooring-free soft body rolling mechanism based on air tendon coupling driving. Comprising a polyhedral shell, and each face of the polyhedral shell is provided with a soft leg mechanism and a servo motor mechanism for driving the soft leg mechanism to do telescopic motion; each soft leg mechanism comprises a corrugated pipe, an upper sealing element and a lower sealing element; an upper opening part and a lower opening part of the corrugated pipe are respectively sealed by an upper sealing piece and a lower sealing piece, so that an air sealing cavity is formed in the corrugated pipe; the gas sealing cavity is filled with gas, so that the corrugated pipe is in an extension state without external force; the tendons are evenly distributed around the corrugated pipe, one end of each tendon is fixed to the lower sealing piece, the other end of each tendon penetrates through a plurality of branching holes or trunkings correspondingly formed in the periphery of the upper sealing piece, then is gathered to a bus outlet to form a strand and is connected to the servo motor mechanism, and the servo motor mechanism pulls the tendons to tighten or loosen the tendons. And the corrugated pipe is stretched or compressed, so that the leg stretching or retracting action is realized.

Description

Technical Field

[0001] The invention relates to components of a robot, and in particular to an untethered soft body tumbling mechanism based on gas-tendon coupling drive. Background Art

[0002] Mobile robots can assist or replace humans in performing a variety of tasks, such as surveying, search and rescue, logistics, etc. These robots can be divided into multiple categories according to their different modes of movement, such as wheeled robots, legged robots, and tumbling robots. How to pass through unstructured natural environments has always been one of the challenges in the field of mobile robots. Tumbling robots rely on methods such as center of gravity shift or changes in overall shape to achieve movement. When moving in complex terrain in the wild, they have the following advantages over other types of mobile robots: 1. The structure of the tumbling robot is highly symmetrical and there is no overturning state; 2. The tumbling robot has a large contact area with the ground, which is suitable for passing through irregular surfaces such as sand or grass; 3. The tumbling robot can roll in any direction, reducing the difficulty of control.

[0003] In recent years, soft robotics technology has developed rapidly. Compared with rigid robotics technology, soft robots have better flexibility and impact resistance.

[0004] Using soft robot technology in the development of tumbling robots can enable tumbling robots to better interact with unstructured environments when working outdoors, reduce damage to the ecological environment, and resist sudden changes and shocks in the external environment.

[0005] Currently, most soft tumbling robots need to be connected to a fixed energy system (such as an air pump or power supply), which limits their range of motion and application scenarios.

[0006] The existing untethered soft tumbling robot technology is limited by the driving method and has various problems. For example, the untethered soft tumbling robot driven by thermally active smart materials (such as SMA) is limited by the long cooling time of the material, resulting in a slow movement speed; the untethered soft tumbling robot based on electroactive smart materials needs to be integrated with a high-voltage power supply, which is dangerous and has a limited carrying capacity; the untethered soft tumbling robot driven by a magnetic field relies on an external magnetic field driving device, while the tumbling robot based on the temperature field and humidity field relies on the environment, which limits its use scenarios and makes it difficult to achieve flexible deployment. The pneumatic untethered soft tumbling robot has a variety of deformation modes and a large output force, but is limited by the small flow rate of the micro pump, resulting in a slow driving speed and difficulty in achieving continuous and precise control. The motor drive has better controllability and flexibility, but it is difficult to balance the flexibility and structural rigidity of the robot.

[0007] In summary, although the existing untethered soft tumbling robots have overcome the limitations of fixed energy systems to a certain extent, they still have problems such as slow speed, complex control, and strong environmental dependence. It can be seen that their application range and motion capabilities still need to be improved. The present invention aims to solve the deficiencies in the prior art and further expand the motion range and application scenarios of soft tumbling robots. Summary of the invention

[0008] The present invention aims to solve many problems existing in the existing untethered soft tumbling robot technology, especially the deficiencies in movement speed and controllability. The present invention cleverly combines the driving method of motor-tendon drive and pneumatic drive coupling, that is, the gas-tendon coupling driving method, to provide an untethered soft tumbling mechanism based on gas-tendon coupling drive.

[0009] The present invention is achieved through the following technical solutions: An untethered soft body tumbling mechanism based on gas-tendon coupling drive comprises a polyhedron shell, on each face of which a soft body leg mechanism and a servo motor mechanism for driving the soft body leg mechanism to perform telescopic motion are respectively installed; Each soft leg mechanism includes a bellows 7, an upper seal 3 and a lower seal 31; The upper and lower openings of the bellows 7 are sealed by the upper seal 3 and the lower seal 31 respectively, so that the interior of the bellows 7 forms an air-sealed cavity; The air-sealed cavity is filled with gas, so that the bellows 7 is in an extended state without being acted upon by external forces; The bellows 7 serve as legs mounted on each face of the polyhedral housing; The air-enclosed cavities of each leg are interconnected through the air tube 1, achieving gas circulation and mutual pumping; The bellows 7 serves as the main support structure of the legs; Multiple tendons 8 are evenly distributed around the bellows 7, one end of each tendon 8 is fixed to the lower seal 31, and the other end passes through a plurality of branching holes or wire grooves correspondingly opened on the periphery of the upper seal 3, and then converges to the bus outlet 81 to form a strand and is connected to the servo motor mechanism. The servo motor mechanism pulls the tendon 8 to tighten or relax the tendon 8, thereby extending or compressing the bellows 7, thereby realizing the movement of extending or contracting the leg.

[0010] The length direction of the tendon 8 is parallel to the axis of the bellows 7 .

[0011] Each servo motor mechanism includes a motor 9, a turntable 10 and a protective cover 11; The motor 9 is fixed on a plane 12 of the polyhedral housing through a base; The bus outlet 81 of the tendon 8 is opened on one side of the turntable 10; The protective cover 11 is sleeved on the outer circumference of the turntable 10 and maintains a gap between the protective cover 11 and the turntable 10; A threading hole 13 is provided on one side of the protective cover 11 located at the bus outlet 81, and a plurality of tendons 8 are gathered into one and connected to the turntable 10 through the threading hole 13; when the motor 9 drives the turntable 10 to rotate forward and reverse, the tendons 8 are tightened and relaxed, so that the bellows 7 is extended or shortened, thereby realizing the leg extension / contraction movement.

[0012] The outer part of the bellows 7 is covered with a flexible sleeve 5 ; there is a gap between the flexible sleeve 5 and the bellows 7 , and the tendon 8 is located in the gap.

[0013] A rubber pad serving as the foot 4 is installed at the bottom of the lower seal 31 .

[0014] The air pipe 1 is fixed on the inner surface of the polyhedral shell through the interface 2; the air pipes 1 of each leg are gathered into a main pipe and then connected to the air pump.

[0015] The actuation system and the sensor system are built into the polyhedral shell; The execution system includes a microcontroller, a servo motor mechanism, and a pneumatic mechanism; The sensing system includes an inertial measurement unit and a barometric pressure sensor; The inertial measurement unit is responsible for sensing the attitude and motion state of the rolling mechanism, and providing acceleration, angular velocity and magnetic field information to the execution system; the air pressure sensor monitors the air pressure changes in the legs in real time. When the air pressure exceeds or falls below the set threshold, the air pressure sensor feeds the data back to the microcontroller, which sends instructions to the air pump to inflate or deflate based on the feedback information to maintain the air pressure within a stable range; The microcontroller instructs the servo motor 9 to rotate at an angle, so that the turntable 10 of the servo motor 9 drives the tendons evenly distributed around the legs to contract or relax; by controlling the length of the tendons of each leg, the center of gravity position and posture of the rolling mechanism are changed to achieve rolling; The pneumatic mechanism inflates the air-sealed cavity inside each bellows 7 through an air pump so that the air pressure inside the air-sealed cavity is within a required range to ensure the rigidity of the leg.

[0016] During the tumbling process of the tumbling mechanism, at least three adjacent legs in contact with the ground are extended or shortened alternately; the pneumatic mechanism extends the bellows 7 to the required length or stiffness through gas pressure.

[0017] The polyhedron shell is made up of twelve planes, which ensure the symmetry and stability of the structure. The twelve legs are connected together by air pipes to form a closed pneumatic circuit. At the same time, the air pressure sensor in the air circuit provides real-time feedback of the current air pressure value to facilitate adjustment of the stiffness of the legs and ensure the adaptability of the rolling mechanism under different terrains.

[0018] Each of the twelve planes is a pentagon.

[0019] The corrugated tube 7 is made of PVC; the flexible sleeve 5 is made of TPU.

[0020] Compared with the prior art, the present invention has the following advantages and effects: The invention is air pressure driven, has flexibility and safety, and can interact safely with the environment or people The tendon drive of the present invention has flexibility and controllability and can achieve precise motion control.

[0021] The present invention improves system integration: by carrying a micro air pump internally or by pre-filling the air, efficient system integration is achieved, dependence on external equipment is reduced, and the robot can achieve untethered motion.

[0022] The present invention expands environmental adaptability: combining the advantages of both air pressure and tendon driving modes, the stiffness of the driver can be adjusted by adjusting the internal air pressure of the coupling driver and the position of the tendon, so that the tumbling mechanism (robot) can better adapt to various unstructured environments (gravel roads, grass, slopes, steps, shallow water and roads with obstacles of different shapes).

[0023] The present invention improves movement efficiency: multiple drivers are interconnected to achieve free flow of compressed gas, and based on this gas flow phenomenon, a mutual pumping effect between drivers is achieved, thereby reducing the size of the tendon-driven pulling force and improving efficiency.

[0024] In summary, the advantages of pneumatic drive, which is flexible and safe, and tendon drive, which is flexible and controllable and can achieve precise motion control, have been combined and have been used to develop a variety of untethered soft robots, such as untethered soft grippers and untethered soft quadruped robots, all of which have demonstrated good controllability, environmental adaptability and system integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the appearance of the untethered soft-body tumbling mechanism based on gas-tendon coupling drive of the present invention.

[0026] Figure 2 This is a schematic diagram of the soft leg mechanism of the present invention, that is, the leg structure.

[0027] Figure 3 It is a schematic diagram of the layout structure of the soft leg mechanism and the servo motor mechanism of the present invention.

[0028] Figure 4 The figure is a gait diagram of the untethered soft rolling mechanism of the present invention moving forward.

[0029] Figure 5 This is a tumbling gait diagram of the untethered software tumbling mechanism of the present invention. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below in conjunction with specific embodiments.

[0031] like Figure 1-4 The present invention discloses an untethered soft body tumbling mechanism based on gas-tendon coupling drive, comprising a polyhedron shell, on each face of which a soft body leg mechanism and a servo motor mechanism for driving the soft body leg mechanism to perform telescopic movement are respectively installed; Each soft leg mechanism includes a bellows 7, an upper seal 3 and a lower seal 31; The upper and lower openings of the bellows 7 are sealed by the upper seal 3 and the lower seal 31 respectively, so that the interior of the bellows 7 forms an air-sealed cavity; The air-sealed cavity is filled with gas, so that the bellows 7 is in an extended state without being acted upon by external forces; The bellows 7 serve as legs mounted on each face of the polyhedral housing; The air-enclosed cavities of each leg are interconnected through the air tube 1, achieving gas circulation and mutual pumping; The bellows 7 serves as the main support structure of the legs; Multiple tendons 8 are evenly distributed around the bellows 7, one end of each tendon 8 is fixed to the lower seal 31, and the other end passes through a plurality of branching holes or wire grooves correspondingly opened on the periphery of the upper seal 3, and then converges to the bus outlet 81 to form a strand and is connected to the servo motor mechanism. The servo motor mechanism pulls the tendon 8 to tighten or relax the tendon 8, thereby extending or compressing the bellows 7, thereby realizing the movement of extending or contracting the leg.

[0032] The length direction of the tendon 8 is parallel to the axis of the bellows 7 .

[0033] Each servo motor mechanism (servo engine) includes a motor 9, a turntable 10 and a protective cover 11; the protective cover 11 is used to prevent the tendon 8 wound on the turntable 10 from loosening and to prevent the tendon from being wound on other structures when relaxed, thereby ensuring the stability of the contraction performance. The tendon 8 can be made of a fishing line with good tensile strength.

[0034] The motor 9 is fixed on a plane 12 of the polyhedral housing through a base; The bus outlet 81 of the tendon 8 is opened on one side of the turntable 10; The protective cover 11 is sleeved on the outer circumference of the turntable 10 and maintains a gap between the protective cover 11 and the turntable 10; A threading hole 13 is provided on one side of the protective cover 11 located at the bus outlet 81, and a plurality of tendons 8 are gathered into one and connected to the turntable 10 through the threading hole 13; when the motor 9 drives the turntable 10 to rotate forward and reverse, the tendons 8 are tightened and relaxed, so that the bellows 7 is extended or shortened, thereby realizing the leg extension / contraction movement.

[0035] The bellows 7 is covered with a flexible sleeve 5, and there is a gap between the flexible sleeve 5 and the bellows 7, in which the tendon 8 is located. The addition of the flexible sleeve 5 can not only increase the initial stiffness of the leg, but also effectively limit the buckling deformation of the leg structure during the extension and contraction process.

[0036] A rubber pad serving as the foot 4 is installed at the bottom of the lower seal 31 .

[0037] The air pipe 1 is fixed on the inner surface of the polyhedral shell through the interface 2; the air pipes 1 of each leg are gathered into a main pipe and then connected to the air pump.

[0038] The actuation system and the sensor system are built into the polyhedral shell; The execution system includes a microcontroller, a servo motor mechanism, and a pneumatic mechanism; The sensing system includes an inertial measurement unit (IMU) and a barometric pressure sensor; The inertial measurement unit is responsible for sensing the posture and motion state of the rolling mechanism, and providing acceleration, angular velocity and magnetic field information to the execution system; the air pressure sensor monitors the air pressure changes in the leg in real time. When the air pressure exceeds or falls below the set threshold, the air pressure sensor feeds back the data to the microcontroller, and the microcontroller sends instructions to the air pump to inflate or deflate according to the feedback information to maintain the air pressure within a stable range. If there is no special requirement, the present invention can also omit the pneumatic mechanism, and only needs to fill the air-sealed cavity with gas in advance.

[0039] The microcontroller (STM32) receives the signal collected by the inertial measurement unit and instructs the rotation angle of the servo motor 9, so that the turntable 10 of the servo motor 9 drives the tendons evenly distributed around the legs to contract or relax; by controlling the length of the tendons of each leg, the center of gravity position and posture of the rolling mechanism are changed to achieve rolling; The pneumatic mechanism inflates the air-sealed cavity inside each bellows 7 through an air pump so that the air pressure inside the air-sealed cavity is within a required range to ensure the rigidity of the leg.

[0040] During the tumbling process of the tumbling mechanism, at least three adjacent legs in contact with the ground are extended or shortened alternately; the pneumatic mechanism extends the bellows 7 to the required length or stiffness through gas pressure.

[0041] The polyhedron shell is made up of twelve planes. The bellows 7 is made of PVC; the flexible sleeve 5 and the foot 4 are made of TPU; the turntable 10, the protective cover 11, the plane (mounting plate) 12, the upper seal 3 and the lower seal 31 are all made of PLA.

[0042] Principle of the invention: As described above, the soft leg structure of the present invention is mainly composed of a pneumatic closed cavity structure and peripheral driving tendons.

[0043] The extension and release of the legs are controlled by tendons, while the stiffness of the legs' interaction with the environment is determined by the internal air pressure.

[0044] The present invention is different from the previous gas-tendon coupling drive. It adopts a design method that interconnects the gas paths between multiple gas-tendon coupling drivers. When one leg is pulled and contracted by the tendon, the internal gas can enter the other leg through the gas path. The gas circulation mechanism can achieve the effect of flow mutual pumping between different legs of the robot during the tumbling process, thereby reducing the tendon tension required when a single leg is compressed. The gas-tendon coupling-driven soft tumbling robot has the advantages of multi-terrain adaptability, no tethering, strong controllability, and strong impact resistance.

[0045] The present invention can put the tumbling robot in an unstable state by lengthening and shortening the leg structure, thereby causing the center of gravity of the overall structure to shift, and regular leg movements can achieve continuous rolling of the tumbling mechanism.

[0046] like Figure 4-5 As shown in the figure, the twelve legs are numbered 1-12. In the initial state, all leg structures have the same length. At this time, the three legs numbered ①, ② and ③ are in contact with the ground, and their contact points form an equilateral triangle on the ground. Subsequently, the leg numbered ① gradually lengthens, while the legs numbered ② and ③ gradually shorten. At this time, the tumbling robot is in an unstable state until the center of gravity changes and it rolls to the next stable state.

[0047] Through the control of motors (servos) and tendons, the extension and retraction speed and length of the twelve legs can be precisely controlled, allowing the robot to achieve different movement modes such as forward, backward, left turn, right turn, fast rolling and slow rolling. Figure 4-5 Only the tumbling strategy for the tumbling mechanism to move forward is shown.

[0048] As described above, the present invention can be better implemented.

[0049] The implementation methods of the present invention are not limited to the above-mentioned embodiments, and any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention shall be equivalent replacement methods and shall be included in the protection scope of the present invention.

Claims

1. An untethered soft body tumbling mechanism based on gas-tendon coupling drive, characterized in that: It comprises a polyhedral shell, on each face of which a soft leg mechanism and a servo motor mechanism for driving the soft leg mechanism to perform telescopic movement are respectively installed; Each soft leg mechanism comprises a bellows (7), an upper sealing member (3) and a lower sealing member (31); The upper and lower openings of the bellows (7) are sealed by an upper sealing member (3) and a lower sealing member (31) respectively, so that an air-sealed cavity is formed inside the bellows (7); The air-sealed cavity is filled with gas, so that the bellows (7) is in an extended state without being acted upon by external forces; The bellows (7) are used as legs mounted on each face of the polyhedral shell; The air-sealed cavities of each leg are interconnected through the air tube (1) to achieve gas circulation and mutual pumping; The bellows (7) serves as the main supporting structure of the leg; A plurality of tendons (8) are evenly distributed around the bellows (7), one end of each tendon (8) is fixed to the lower sealing member (31), and the other end passes through a plurality of branching holes or wire grooves correspondingly provided on the periphery of the upper sealing member (3), and then converges to a bus outlet (81) to form a strand, and is connected to a servo motor mechanism. The servo motor mechanism pulls the tendons (8) to tighten or relax the tendons (8), thereby extending or compressing the bellows (7), thereby achieving the movement of extending or contracting the leg.

2. According to claim 1, the untethered soft body tumbling mechanism based on gas-tendon coupling drive is characterized in that: The length direction of the tendon (8) is parallel to the axis of the bellows (7).

3. The untethered soft body tumbling mechanism based on gas-tendon coupling drive according to claim 2 is characterized in that: Each servo motor mechanism comprises a motor (9), a rotating disk (10) and a protective cover (11); The motor (9) is fixed on a plane (12) of the polyhedral housing via a base; The bus outlet (81) of the tendon (8) is opened on one side of the rotating disk (10); The protective outer cover (11) is sleeved on the outer circumference of the rotating disk (10) and maintains a gap between the protective outer cover and the rotating disk (10); A threading hole (13) is provided on one side of the protective cover (11) located at the bus outlet (81), and a plurality of tendons (8) are gathered into one strand and connected to the turntable (10) through the threading hole (13); when the motor (9) drives the turntable (10) to rotate forward and reverse, the tendons (8) are pulled tight and relaxed, causing the bellows (7) to lengthen or shorten, thereby achieving the leg extension / contraction movement.

4. The untethered soft body tumbling mechanism based on gas-tendon coupling drive according to claim 3 is characterized in that: A flexible sleeve (5) is sleeved on the outside of the bellows (7); a gap is provided between the flexible sleeve (5) and the bellows (7), and the tendon (8) is located in the gap.

5. The untethered soft body tumbling mechanism based on gas-tendon coupling drive according to claim 1 is characterized in that: A rubber pad is installed at the bottom of the lower seal (31) as a foot (4).

6. The untethered soft body tumbling mechanism based on gas-tendon coupling drive according to claim 1 is characterized in that: The air pipe (1) is fixed on the inner surface of the polyhedral shell through an interface (2); the air pipes (1) of each leg are gathered into a main pipe and then connected to an air pump.

7. The untethered soft body tumbling mechanism based on gas-tendon coupling drive according to claim 1 is characterized in that: The actuation system and the sensor system are built into the polyhedral shell; The execution system includes a microcontroller, a servo motor mechanism, and a pneumatic mechanism; The sensing system includes an inertial measurement unit and a barometric pressure sensor; The inertial measurement unit is responsible for sensing the attitude and motion state of the tumbling mechanism and providing acceleration, angular velocity and magnetic field information to the execution system; The air pressure sensor monitors the air pressure changes in the legs in real time. When the air pressure exceeds or falls below the set threshold, the air pressure sensor feeds the data back to the microcontroller, which then sends instructions to the air pump to inflate or deflate based on the feedback information to maintain the air pressure within a stable range. The microcontroller instructs the servo motor (9) to rotate at an angle, so that the turntable (10) of the servo motor (9) drives the tendons evenly distributed around the legs to contract or relax; by controlling the length of the tendons of each leg, the center of gravity position and posture of the rolling mechanism are changed, thereby achieving rolling; The pneumatic mechanism inflates the air-sealed cavities inside the bellows (7) through an air pump, so that the air pressure inside the air-sealed cavities is within a required range, thereby ensuring the rigidity of the legs.

8. The untethered soft body tumbling mechanism based on gas-tendon coupling drive according to claim 7 is characterized in that: During the tumbling process of the tumbling mechanism, at least three adjacent legs in contact with the ground perform an alternating lengthening or shortening action; the pneumatic mechanism extends the bellows (7) to a desired length or stiffness through gas pressure.

9. The untethered soft body tumbling mechanism based on gas-tendon coupling drive according to claim 1 is characterized in that: The polyhedral shell is made up of twelve planes.

10. The untethered soft body tumbling mechanism based on gas-tendon coupling drive according to claim 4 is characterized in that: The corrugated tube (7) is made of PVC material; the flexible sleeve (5) is made of TPU material.

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