A tetherless soft-body tumbling mechanism based on pneumatic coupling drive

Abstract

This invention discloses an untethered soft rolling mechanism based on gas tendon coupling drive; it includes 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 movements are respectively installed; each soft leg mechanism includes a bellows, an upper seal and a lower seal; the upper and lower openings of the bellows are sealed by the upper and lower seals respectively, forming a gas-sealed cavity inside the bellows; the gas-sealed cavity is filled with gas, so that the bellows is in an elongated state when no external force is applied; multiple tendons are evenly distributed around the bellows, one end of each tendon is fixed to the lower seal, and the other end passes through multiple branch holes or grooves corresponding to those opened around the periphery of the upper seal, and then converges to the main outlet to form a single strand, which is connected to the servo motor mechanism. The servo motor mechanism pulls the tendon to tighten or relax the tendon, causing the bellows to extend or compress, thereby realizing the extension or retraction of the leg.

Description

Technical Field

[0001] This invention relates to components of robots, and more particularly to an untethered soft rolling mechanism based on pneumatic coupling drive. Background Technology

[0002] Mobile robots can assist or replace humans in performing various tasks, such as surveying, search and rescue, and logistics. These robots can be categorized into several types based on their locomotion, including wheeled robots, legged robots, and tumbling robots. Navigating unstructured natural environments has always been a challenge in the field of mobile robots. Tumbling robots achieve locomotion by shifting their center of gravity or changing their overall shape. Compared to other types of mobile robots, they have the following advantages when moving through complex terrain in the wild: 1. Tumbling robots have a highly symmetrical structure and do not tip over; 2. Tumbling robots have a large contact area with the ground, making them suitable for traversing irregular surfaces such as sand or grass; 3. Tumbling robots can roll in any direction, reducing the difficulty of control.

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

[0004] Applying soft robotics technology to the development of tumbling robots can enable them to interact better with unstructured environments when working outdoors, reducing damage to the ecological environment and resisting 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] Existing untethered soft tumbling robot technologies are limited by their actuation methods, resulting in various problems. For example, untethered soft tumbling robots driven by thermally active smart materials (such as SMA) are limited by the material's long cooling time, leading to slow movement speeds. Robots based on electrically active smart materials require integrated high-voltage power supplies, posing certain risks, and their load-bearing capacity is also relatively limited. Untethered soft tumbling robots driven by magnetic fields rely on external magnetic field actuation devices, while tumbling robots based on temperature and humidity fields depend on the environment, limiting their application scenarios and hindering flexible deployment. Pneumatic untethered soft tumbling robots offer diverse deformation modes and significant output force, but their limited flow rate from micro-pumps results in slow actuation speeds and makes continuous, precise control difficult. Motor-driven robots offer better controllability and flexibility, but they struggle to balance robot compliance and structural rigidity.

[0007] In summary, while existing untethered soft tumbling robots have overcome the limitations of fixed power systems to some extent, they still suffer from slow speed, complex control, and strong environmental dependence. Therefore, their application range and mobility still need improvement. This invention aims to address the shortcomings of existing technologies and further expand the mobility and application scenarios of soft tumbling robots. Summary of the Invention

[0008] This invention aims to solve several problems existing in the current untethered soft tumbling robot technology, especially the shortcomings in motion speed and controllability. This invention ingeniously combines the driving method of motor-tendon drive and pneumatic drive coupling, namely the gas-tendon coupling drive mode, to provide an untethered soft tumbling mechanism based on pneumatic tendon coupling drive.

[0009] This invention is achieved through the following technical solution:

[0010] A tetherless soft roll mechanism based on air-tendon coupling drive includes a polyhedral shell, on each face of the polyhedral shell are a soft leg mechanism and a servo motor mechanism for driving the soft leg mechanism to perform telescopic motion.

[0011] Each flexible leg mechanism includes a bellows 7, an upper seal 3, and a lower seal 31;

[0012] 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 airtight cavity.

[0013] The airtight cavity is filled with gas, so that the bellows 7 is in an elongated state when no external force is applied.

[0014] The bellows 7 serve as legs mounted on each face of the polyhedral housing;

[0015] The airtight chambers of each leg are interconnected through air tube 1 to achieve gas circulation and mutual pumping;

[0016] The corrugated pipe 7 serves as the main support structure for the legs;

[0017] 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 multiple branch holes or grooves corresponding to those opened around the upper seal 3, and then converges to the bus outlet 81 to form a single strand, which is connected to the servo motor mechanism. The servo motor mechanism pulls the tendon 8 to tighten or relax the tendon 8, causing the bellows 7 to extend or compress, thereby realizing the leg extension or retraction action.

[0018] The length of tendon 8 is parallel to the axis of bellows 7.

[0019] Each servo motor mechanism includes a motor 9, a turntable 10, and a protective cover 11;

[0020] Motor 9 is fixed to a plane 12 of the polyhedral shell via a base;

[0021] The bus outlet 81 of the tendon 8 is located on one side of the turntable 10;

[0022] The protective cover 11 is fitted onto the outer circumference of the turntable 10 and maintains a gap with the turntable 10;

[0023] The protective cover 11 has a wire hole 13 on one side of the bus outlet 81. Multiple tendons 8 converge into one and are connected to the turntable 10 through the wire hole 13. When the motor 9 drives the turntable 10 to rotate forward and backward, it pulls the tendons 8 to tighten and relax, causing the bellows 7 to lengthen or shorten, thereby realizing the leg extension / retraction action.

[0024] A flexible sleeve 5 is fitted over the corrugated pipe 7; there is a gap between the flexible sleeve 5 and the corrugated pipe 7, and the tendon 8 is located in the gap.

[0025] The bottom of the lower seal 31 is fitted with a rubber pad that serves as the foot 4.

[0026] The air tube 1 is fixed to the inner surface of the polyhedral shell through the interface 2; the air tubes 1 of each leg are gathered into a main pipe and then connected to the air pump.

[0027] The actuation system and sensing system are built into the polyhedral housing;

[0028] The execution system includes a microcontroller, a servo motor mechanism, and a pneumatic mechanism;

[0029] The sensing system includes an inertial measurement unit and a barometric pressure sensor;

[0030] 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. The microcontroller sends a command to the air pump to inflate or deflate the air according to the feedback information to maintain the air pressure within a stable range.

[0031] The microcontroller commands the rotation angle of the servo motor 9, causing the turntable 10 of the servo motor 9 to drive the tendons evenly distributed around the legs to contract or relax; by controlling the length of the tendons in each leg, the center of gravity position and posture of the tumbling mechanism are changed, thereby achieving tumbling;

[0032] The pneumatic mechanism uses an air pump to inflate the air-sealed cavities inside each bellows 7, ensuring that the air pressure inside the air-sealed cavities is within the required range to guarantee the rigidity of the legs.

[0033] During the tumbling process of the tumbling mechanism, at least three adjacent legs in contact with the ground alternately extend or shorten; the pneumatic mechanism uses gas pressure to extend the bellows 7 to the required length or stiffness.

[0034] The polyhedral shell is composed of twelve planes, ensuring the symmetry and stability of the structure. The twelve legs are connected by air tubes 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, so as to adjust the stiffness of the legs and ensure the adaptability of the rolling mechanism in different terrains.

[0035] Each of the twelve planes has a pentagonal face.

[0036] The corrugated pipe 7 is made of PVC; the flexible sleeve 5 is made of TPU.

[0037] Compared with the prior art, the present invention has the following advantages and effects:

[0038] This invention is pneumatically driven, exhibiting compliance and safety, and can safely interact with the environment or people.

[0039] This invention relates to a tendon-driven system that offers flexibility and controllability, enabling precise motion control.

[0040] This invention improves system integration: by carrying a micro air pump or pre-inflating the system internally, it achieves efficient system integration, reduces dependence on external equipment, and enables the robot to move tethered.

[0041] This invention expands environmental adaptability: By combining the advantages of both pneumatic and tendon-driven methods, the stiffness of the actuator can be adjusted by regulating the internal pneumatic pressure and tendon position of the coupled actuator, enabling the tumbling mechanism (robot) to better adapt to various unstructured environments (pebble roads, grass, slopes, steps, shallow water, and roads with obstacles of different shapes).

[0042] This invention improves motion efficiency: multiple actuators are interconnected to enable free flow of compressed gas. Based on this gas flow phenomenon, a mutual pumping effect is achieved between the actuators, reducing the magnitude of tendon driving tension and improving efficiency.

[0043] In summary, combining the advantages of pneumatic actuation (compliance and safety) and tendon actuation (flexibility, controllability, and precise motion control), this technology has been used to develop various 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. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the external shape of the untethered soft rolling mechanism based on air tendon coupling driven by the present invention.

[0045] Figure 2 This is a schematic diagram of the soft leg mechanism described in this invention, i.e., the leg structure.

[0046] Figure 3 This is a schematic diagram of the layout structure of the soft leg mechanism and servo motor mechanism of the present invention.

[0047] Figure 4 This is a gait diagram of the untethered soft rolling mechanism of the present invention.

[0048] Figure 5 This is a diagram showing the gait of the untethered soft tumbling mechanism of the present invention. Detailed Implementation

[0049] The present invention will now be described in further detail with reference to specific embodiments.

[0050] like Figure 1-4 As shown. This invention discloses an untethered soft body tumbling mechanism based on pneumatic coupling drive, comprising a polyhedral shell, on each face of the polyhedral shell respectively mounted a soft body leg mechanism and a servo motor mechanism for driving the soft body leg mechanism to perform telescopic motion;

[0051] Each flexible leg mechanism includes a bellows 7, an upper seal 3, and a lower seal 31;

[0052] 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 airtight cavity.

[0053] The airtight cavity is filled with gas, so that the bellows 7 is in an elongated state when no external force is applied.

[0054] The bellows 7 serve as legs mounted on each face of the polyhedral housing;

[0055] The airtight chambers of each leg are interconnected through air tube 1 to achieve gas circulation and mutual pumping;

[0056] The corrugated pipe 7 serves as the main support structure for the legs;

[0057] 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 multiple branch holes or grooves corresponding to those opened around the upper seal 3, and then converges to the bus outlet 81 to form a single strand, which is connected to the servo motor mechanism. The servo motor mechanism pulls the tendon 8 to tighten or relax the tendon 8, causing the bellows 7 to extend or compress, thereby realizing the leg extension or retraction action.

[0058] The length of tendon 8 is parallel to the axis of bellows 7.

[0059] Each servo motor mechanism (servo motor) includes a motor 9, a turntable 10, and a protective cover 11; the protective cover 11 is used to prevent the tendon 8 wrapped around the turntable 10 from loosening and to prevent the tendon from wrapping around other structures when it relaxes, thus ensuring the stability of the contraction performance. The tendon 8 can be made of fishing line with good tensile strength.

[0060] Motor 9 is fixed to a plane 12 of the polyhedral shell via a base;

[0061] The bus outlet 81 of the tendon 8 is located on one side of the turntable 10;

[0062] The protective cover 11 is fitted onto the outer circumference of the turntable 10 and maintains a gap with the turntable 10;

[0063] The protective cover 11 has a wire hole 13 on one side of the bus outlet 81. Multiple tendons 8 converge into one and are connected to the turntable 10 through the wire hole 13. When the motor 9 drives the turntable 10 to rotate forward and backward, it pulls the tendons 8 to tighten and relax, causing the bellows 7 to lengthen or shorten, thereby realizing the leg extension / retraction action.

[0064] A flexible sleeve 5 is fitted over the corrugated pipe 7; there is a gap between the flexible sleeve 5 and the corrugated pipe 7, and the tendon 8 is located within this gap. The addition of the flexible sleeve 5 not only increases the initial stiffness of the leg, but also effectively limits the buckling deformation of the leg structure during extension and retraction.

[0065] The bottom of the lower seal 31 is fitted with a rubber pad that serves as the foot 4.

[0066] The air tube 1 is fixed to the inner surface of the polyhedral shell through the interface 2; the air tubes 1 of each leg are gathered into a main pipe and then connected to the air pump.

[0067] The actuation system and sensing system are built into the polyhedral housing;

[0068] The execution system includes a microcontroller, a servo motor mechanism, and a pneumatic mechanism;

[0069] The sensing system includes an inertial measurement unit (IMU) and a barometric pressure sensor;

[0070] The inertial measurement unit (IMU) 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. A pressure sensor monitors the air pressure changes within the legs in real time. When the air pressure exceeds or falls below a set threshold, the pressure sensor feeds the data back to the microcontroller. The microcontroller then sends a command to the air pump to inflate or deflate the air to maintain the air pressure within a stable range. Unless otherwise specified, the pneumatic mechanism can be omitted in this invention; simply pre-filling the airtight cavity with gas is sufficient.

[0071] The microcontroller (STM32) receives signals collected by the inertial measurement unit and instructs the rotation angle of the servo motor 9, causing the turntable 10 of the servo motor 9 to drive 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 tumbling mechanism are changed, thereby realizing the tumbling.

[0072] The pneumatic mechanism uses an air pump to inflate the air-sealed cavities inside each bellows 7, ensuring that the air pressure inside the air-sealed cavities is within the required range to guarantee the rigidity of the legs.

[0073] During the tumbling process of the tumbling mechanism, at least three adjacent legs in contact with the ground alternately extend or shorten; the pneumatic mechanism uses gas pressure to extend the bellows 7 to the required length or stiffness.

[0074] The polyhedral shell is composed of twelve planes joined together.

[0075] 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 flat surface (mounting plate) 12, the upper seal 3 and the lower seal 31 are all made of PLA.

[0076] Principle of this invention:

[0077] As described above, the soft leg structure of the present invention mainly consists of a pneumatic closed cavity structure and peripheral driving tendons.

[0078] The extension and retraction of the legs are controlled by tendons, while the stiffness of the legs in their interaction with the environment is determined by internal air pressure.

[0079] Unlike previous pneumatic tendon coupling drives, this invention employs a design method that interconnects the air paths between multiple pneumatic tendon coupling actuators. When one leg is pulled and contracted by the tendon, internal gas can enter the other leg through the air path. This gas circulation mechanism enables a mutual pumping effect between different legs during the robot's tumbling process, thereby reducing the tendon tension required when a single leg is compressed. This gives the pneumatic tendon coupling driven soft tumbling robot advantages such as multi-terrain adaptability, tetherless operation, high controllability, and strong impact resistance.

[0080] This invention can make the tumbling robot unstable by extending and shortening the leg structure, thereby causing the center of gravity of the overall structure to shift. Regular leg movements can achieve continuous rolling of the tumbling mechanism.

[0081] like Figure 4-5As shown, the twelve legs are numbered 1-12. Initially, all legs are of the same length. At this point, legs numbered ①, ②, and ③ are in contact with the ground, forming an equilateral triangle at their contact points. Subsequently, leg number ① gradually lengthens, while legs numbered ② and ③ gradually shorten. At this point, the tumbling robot is in an unstable state until its center of gravity changes, allowing it to tumble to the next stable state.

[0082] By controlling motors (servo motors) and tendons, the extension and retraction speed and length of the twelve legs can be precisely controlled, enabling the robot to achieve different movement modes such as forward, backward, left turn, right turn, fast rolling, and slow rolling. Figure 4-5 The image only shows the tumbling strategy of the tumbling mechanism moving forward.

[0083] As described above, the present invention can be implemented well.

[0084] The implementation of the present invention is not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A tetherless soft-body tumbling mechanism based on pneumatic coupling drive, characterized in that, It includes 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 movements are respectively installed; Each flexible 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 airtight cavity; Gas is filled in the airtight cavity, so that the bellows (7) is in an elongated state when no external force is applied. The bellows (7) serves as legs mounted on each face of the polyhedral shell; The air-sealed cavities of each leg are interconnected through air tubes (1) to achieve gas circulation and mutual pumping; Corrugated pipe (7) serves as the main support structure for 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 multiple branch holes or grooves corresponding to the upper seal (3) around the periphery, and then converges to the bus outlet (81) to form a single strand, which is connected to the servo motor mechanism. The servo motor mechanism pulls the tendon (8) to tighten or relax the tendon (8), causing the bellows (7) to lengthen or compress, thereby realizing the leg extension or retraction action. Each servo motor mechanism includes a motor (9), a turntable (10), and a protective cover (11). The motor (9) is fixed to a plane (12) of the polyhedral shell via a base; The bus outlet (81) of the tendon (8) is located on one side of the turntable (10); The protective cover (11) is fitted onto the outer circumference of the turntable (10) and maintains a gap with the turntable (10); The protective cover (11) has a wire hole (13) on one side of the bus outlet (81). Multiple tendons (8) are connected to the turntable (10) through the wire hole (13). When the motor (9) drives the turntable (10) to rotate forward and backward, it pulls the tendons (8) to tighten and relax, causing the bellows (7) to lengthen or shorten, thereby realizing the leg extension / retraction action. The actuation system and sensing system are built into the polyhedral housing; 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 leg 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. The microcontroller sends a command to the air pump to inflate or deflate the air based on the feedback information in order to maintain the air pressure within a stable range. The microcontroller commands the rotation angle of the servo motor (9), causing the turntable (10) of the servo motor (9) to drive 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 tumbling mechanism are changed, thereby realizing tumbling; The pneumatic mechanism inflates the air-sealed cavities inside each bellows (7) with air pumps to ensure that the air pressure inside the air-sealed cavities is within the required range, so as to ensure the rigidity of the legs. During the tumbling process of the tumbling mechanism, at least three adjacent legs in contact with the ground alternately extend or shorten; the pneumatic mechanism uses gas pressure to extend the bellows (7) to the required length or stiffness; The polyhedral shell is a spherical shell composed of twelve planes. Each soft leg mechanism is installed on one of the twelve planes of the spherical shell. In the initial state of the tumbling mechanism, each leg is of the same length. At this time, legs ①, ②, and ③ are in contact with the ground, and the contact points of the three legs form an equilateral triangle on the ground. Subsequently, during the tumbling state, leg ① gradually extends, while legs ② and ③ gradually shorten. At this time, the tumbling robot is in an unstable state until the center of gravity and posture change and it rolls to the next stable action, and so on. The execution system controls the extension and retraction speed and length of the twelve legs, enabling the tumbling mechanism to achieve forward, backward, left turn, right turn, fast rolling, and slow rolling motion modes.

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

3. The untethered soft rolling mechanism based on gas tendon coupling drive according to claim 1, characterized in that, A flexible sleeve (5) is fitted over the outside of the bellows (7); there is a gap between the flexible sleeve (5) and the bellows (7), and the tendon (8) is located in the gap.

4. The untethered soft rolling mechanism based on gas tendon coupling drive according to claim 1, characterized in that, The bottom of the lower seal (31) is fitted with a rubber pad that serves as a foot (4).

5. The untethered soft rolling mechanism based on gas tendon coupling drive according to claim 1, characterized in that, The air tube (1) is fixed to the inner surface of the polyhedral shell through the interface (2); the air tubes (1) of each leg converge into a main tube and are connected to the air pump.

6. The untethered soft rolling mechanism based on gas tendon coupling drive according to claim 1, characterized in that, The corrugated pipe (7) is made of PVC; the flexible sleeve (5) is made of TPU.

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