A multifunctional biped robot foot structure adaptable to different working states

Abstract

The application relates to a multifunctional biped robot foot structure which can adapt to different working states, and the whole foot structure is designed in a functional modularization mode; when walking is needed, the foot structure can acquire the sole sensor information in real time and realize self-adaptive posture adjustment of the biped robot on uneven and smooth ground through two stages, the two stages include preliminary fine adjustment of anti-skid air cushions and two-side torsional springs and comprehensive adjustment of five toe joints and two side plates made by a pneumatic driving mechanism; when the biped robot is in a state needing fixed foot structure such as grabbing, a plurality of pneumatic driving devices are driven to lift the toes and the side plates, a vacuum generator is driven and the gas in an adaptive suction disc mechanism is extracted, so that the biped robot foot structure is firmly adsorbed on the ground. The application realizes the adaptability of the robot foot to the ground in different working states by utilizing the torsional spring characteristics and the pneumatic control technology and cooperatively controlling the toes, the side plates and other mechanisms.

Description

Technical Field

[0001] This invention relates to the field of robotics, and in particular to a multifunctional bipedal robot foot structure that can adapt to different working conditions. Background Technology

[0002] Over the past half-century, bipedal robots have rapidly evolved from basic automated devices into a global interdisciplinary research field. The continuous development of advanced robots often leads to greater theoretical and methodological challenges, while simultaneously promoting advancements in mechanics, machinery, information, and control science. Bipedal robots can assist humans in performing tasks or activities in hazardous environments, utilizing their two legs to achieve stable and varied gaits on complex outdoor terrain. They hold promise for applications in personal assistance and care, education and entertainment, search and rescue, manufacturing and maintenance, public services, and healthcare.

[0003] In current research on bipedal robots, some domestic research institutions have made significant progress in motion control, gait planning, and autonomous navigation. However, there is a lack of innovative design in the mechanical structure of bipedal robot prototypes, especially in their foot structure. When bipedal robots traverse uneven terrain, even if they can determine their surroundings using depth cameras and radar, their foot placement is often constrained by the foot structure, reducing the stability and controllability of their gait and making them prone to instability. Furthermore, after completing autonomous navigation tasks, bipedal robots often need to perform a series of grasping tasks. The non-fixed bipedal structure introduces errors into these grasping tasks, hindering high-precision positioning and leading to grasping failures. Therefore, the foot structure of bipedal robots directly affects their walking stability and positioning accuracy during grasping operations, requiring further optimization and improvement of their mechanical mechanisms.

[0004] Chinese invention patent CN113443043A discloses a bipedal robot foot structure adaptable to uneven terrain. This invention provides a bipedal robot foot structure adaptable to uneven terrain, connecting four thin plates of the robot's foot with torsion springs. Utilizing the characteristics of the torsion springs, the foot structure achieves passive self-adaptation to the ground. A multi-degree-of-freedom ball bearing spherical hinge is used to connect the thin plates to the integrated connecting block. By controlling the pressure of the gas in the air chamber, active adaptive adjustment of the foot's posture is achieved. However, the design of its multi-degree-of-freedom ball bearing spherical hinge has high requirements. On the one hand, it needs to support the bipedal robot's walking; when impacted by the ground, it can damage the petal-shaped structure, causing it to deviate from the grooved track, ultimately leading to robot instability. On the other hand, uneven ground can generate disturbance forces on the torsion spring structure, causing the robot to vibrate slightly, affecting the positioning accuracy during grasping operations. This design lacks universality when the bipedal robot is in different working states. Summary of the Invention

[0005] To address the issue of existing bipedal robot foot structures being unable to adapt to different working conditions, a multifunctional bipedal robot foot structure adaptable to various working states is proposed. When the bipedal robot is walking, anti-slip air cushions and torsion springs connecting the sole plate and side plates allow for initial, minor adjustments to the foot structure to accommodate disturbances from uneven terrain. An array of FSR pressure sensors detects the foot's condition and drives multiple pneumatic actuators to adjust the toes and side plates, enabling active adjustment to rough surfaces. When the bipedal robot is in a grasping or other position requiring foot fixation, multiple pneumatic actuators lift the toes and side plates, activating a vacuum generator to extract gas from the adaptive suction cup mechanism, firmly attaching the bipedal robot's foot structure to the ground. This multi-adaptive adjustment system enhances the adaptability of bipedal robots, enabling them to adapt to different working conditions.

[0006] To solve the above problems, the present invention provides the following technical approach: a multifunctional bipedal robot foot structure that can adapt to different working states, the foot structure including a foot plate, five toe joints connected to the foot plate, a pneumatic drive mechanism, two foot side plates, a flexible passive connector and an array of FSR pressure sensors;

[0007] The foot array FSR pressure sensors are installed in the bottom circular openings at the four corners of the foot plate via wired connections. The sensor harnesses are connected to the robot's host computer through miniature cylindrical pipes on the bottom circular openings, transmitting the pressure of the robot's feet on the ground to the host computer for analysis and to determine the foot status. Each toe joint is individually controlled by a pneumatic drive mechanism. Based on the information collected by the foot array FSR pressure sensors, the five toe joints are controlled to adjust the foot landing posture to achieve a smooth landing. When the robot loses stability while walking on rough terrain, the pneumatic drive mechanism is adjusted to press the toes into the ground, thus adjusting the robot's center of gravity position.

[0008] The foot side plate and foot sole plate are connected by a flexible passive connector, including two torsion spring shaft fixers, three torsion springs, four torsion spring rod fixers, and a central torsion spring shaft. The central torsion spring shaft passes sequentially through the torsion spring shaft fixers, the three torsion springs, and the torsion spring rod fixers, making the torsion spring shaft fixers, torsion springs, and torsion spring rod fixers coaxial. The central torsion spring shaft is fixedly connected to the torsion spring shaft fixers by a shoulder to prevent relative rotation. The torsion springs are simultaneously fixed to the foot sole plate and the foot side plate by the torsion spring rod fixers. The torsion springs are fixed to the foot side plate by the front torsion spring shaft fixers and to the foot sole plate by the rear torsion spring shaft fixers. When the robot walks on rough terrain, it can achieve adaptive passive adjustment through the flexible rotation of the torsion spring torque.

[0009] Furthermore, the foot plate includes five first pneumatic drive mechanism connectors, two second pneumatic drive mechanism connectors, two third pneumatic drive mechanism connectors, five toe joint connectors, four foot array FSR pressure sensors, and a suction cup assembly mounting circular opening;

[0010] Each toe joint connector is equipped with a toe joint, and the toe joint is connected to the first pneumatic drive mechanism connector via a pneumatic drive mechanism.

[0011] Each third pneumatic drive mechanism connector is connected to the front end of the corresponding foot side plate via the pneumatic drive mechanism; each third pneumatic drive mechanism connector is connected to the rear end of the corresponding foot side plate via the pneumatic drive mechanism.

[0012] Furthermore, the five first pneumatic drive mechanism connectors and the five toe joint connectors are all arranged in an arc shape and have the same center.

[0013] Furthermore, the two second pneumatic drive mechanism connectors are arranged in an arc shape, sharing the same center as the circular opening for mounting the suction cup assembly.

[0014] Furthermore, the anti-slip air cushion is attached to the underside of the foot plate. The lower surface of the anti-slip air cushion that contacts the ground has anti-slip texture to increase the friction between the foot and the ground. At the same time, the anti-slip air cushion has a certain degree of elasticity, which can absorb the impact when the bipedal robot lands and play a cushioning role.

[0015] Furthermore, the two foot side plates and the foot sole plate have two connection methods, and the bipedal robot can achieve stable walking through both active and passive adjustment methods;

[0016] Firstly, it connects to the foot plate through a flexible passive connector to achieve adaptive flexible passive adjustment;

[0017] Secondly, the pneumatic drive mechanism is fixedly connected to the connector on the foot side plate. The pneumatic drive mechanism is fixedly connected to the connector of the second pneumatic drive mechanism and the connector of the third pneumatic drive mechanism. Each foot side plate is jointly controlled by two pneumatic drive mechanisms. By adjusting the pneumatic drive mechanism, the two foot side plates can be actively adjusted, enabling the robot to walk stably on rough roads.

[0018] Furthermore, an adaptive suction cup mechanism is installed on the circumference of the circular opening of the suction cup assembly on the foot plate. A vacuum generator is fixedly installed on the adaptive suction cup mechanism. When the bipedal robot walks, the vacuum generator does not work. When the bipedal robot needs to be fixed on the ground and the robot's robotic arm begins to perform grasping operations, the combined drive pneumatic drive mechanism lifts the two side plates of the feet and the five toe joints. The vacuum generator works and extracts the gas in the adaptive suction cup mechanism, eliminating the shaking and disturbance of the robot's feet caused by uneven ground due to the torsion spring flexible structure. This allows the bipedal robot's foot structure to be firmly attached to the ground, improving its grasping accuracy.

[0019] The beneficial effects of this invention are as follows:

[0020] The optimized design and layout of the pneumatic drive mechanism in this invention enables the bipedal robot to achieve all-round adaptive adjustment when subjected to the reaction force and impact of uneven road surfaces, thereby improving the robot's walking stability and adaptability, and extending the robot's service life.

[0021] The vacuum generator and adaptive suction cup mechanism of the foot plate in this invention firmly fix the foot to the ground. The pneumatic drive mechanism lifts the foot side plate, eliminating the shaking and disturbance of the robot's foot caused by uneven ground due to the torsion spring flexible structure. This improves the positioning accuracy required for the robot to grasp or perform other actions that require fixing the foot structure.

[0022] The bipedal robot foot structure of this invention proposes multiple adaptive adjustment methods based on torsion springs, air pressure, and foot soles according to different task working states. The designed foot structure has a certain degree of versatility and can achieve good adaptability to different task working states. Attached Figure Description

[0023] Figure 1 This is an isometric view of the foot structure of the bipedal robot in an embodiment of the present invention;

[0024] Figure 2 This is an isometric view of the footplate structure of the bipedal robot in an embodiment of the present invention;

[0025] Figure 3 This is a front view of the footplate structure of the bipedal robot in an embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of a flexible passive connector used to connect the foot plate and the side plate in an embodiment of the present invention;

[0027] Figure 5 This is a schematic diagram illustrating the active toe adjustment of the bipedal robot's foot structure during a walking task, as described in an embodiment of the present invention.

[0028] Figure 6 This is a schematic diagram illustrating the fixed adjustment of the bipedal robot's foot structure during a fixed task in an embodiment of the present invention.

[0029] Figure 7 This is a front view of the foot structure of the bipedal robot in an embodiment of the present invention;

[0030] Figure 8 This is a top view of the foot structure of the bipedal robot in an embodiment of the present invention;

[0031] Figure 9 This is a left view of the foot structure of the bipedal robot in an embodiment of the present invention; Detailed Implementation

[0032] To make the technical approach of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. It should be noted that the embodiments described below are merely illustrative of the invention and are not intended to limit the invention.

[0033] This invention provides a multifunctional bipedal robot foot structure adaptable to different working states, comprising a foot plate 1, five toe joints 2 connected to the foot plate and a pneumatic drive mechanism 3, two foot side plates 4 and pneumatic drive mechanisms 3, a non-slip air cushion 5, a flexible passive connector 6, an array of FSR pressure sensors 15, a vacuum generator 7, and an adaptive suction cup mechanism 8, etc. Figure 1As shown, the five toe joints 2, two foot side plates 4, nine pneumatic drive mechanisms 3, array FSR pressure sensors 15, and flexible passive connectors 6 are all symmetrically arranged. They are ultimately connected and assembled with the foot plate 1. The foot plate 1 is fixedly connected to the vacuum generator 7 and the adaptive suction cup mechanism 8, and the connection to the robot's leg is achieved through the threaded structure on the top of the vacuum generator. The flexible passive connector 6 and the pneumatic drive mechanisms 3 consist of multiple components, requiring high assembly precision and special processing techniques.

[0034] like Figure 2 As shown, the foot plate 1 includes five first pneumatic drive mechanism connectors 11, two second pneumatic drive mechanism connectors 12, two third pneumatic drive mechanism connectors 13, five toe joint 2 connectors 14, four foot array FSR pressure sensors 15, and a suction cup assembly mounting circular opening 16, arranged symmetrically. Each connector has a through-hole structure with identical dimensions and threaded holes for connection to the pneumatic drive mechanism. The five first pneumatic drive mechanism connectors 11 and the five toe joint 2 connectors 14 are arranged in an arc shape with the same center. The two third pneumatic drive mechanism connectors 13 are also arranged in an arc shape with the same center as the suction cup assembly mounting circular opening 16. To obtain foot posture information, foot array FSR pressure sensors 15 are mounted on the foot plate 1. The foot array FSR pressure sensors 15 are wired and mounted on the bottom circular opening 152 of the foot plate 1. Figure 3 As shown, its wiring harness connects from the miniature cylindrical pipe 151 to the robot's main control computer, and transmits the pressure between the robot's feet and the ground to the robot's main control computer for analysis and to obtain the foot state, which is the force condition of the foot sole; the anti-slip air cushion 5 is attached to the foot plate 1. The lower surface of the air cushion that contacts the ground has anti-slip texture to increase the friction between the foot and the ground. At the same time, the air cushion has a certain elasticity and can absorb the impact when the bipedal robot lands, playing a buffering role.

[0035] Five toe joints 2 are fixedly connected to five toe joint connectors 14 on the foot plate 1. The upper connectors of these connectors are fixedly connected to five pneumatic drive mechanisms 3, which in turn are fixedly connected to a first pneumatic drive mechanism connector 11. Each toe joint 2 is individually controlled by a pneumatic drive mechanism 3. This connection method allows control of the pneumatic drive mechanism 3's stroke by controlling the valve's state, causing each toe joint 2 to rotate along the toe joint connector 14, generating force on the ground to adjust the robot's posture. This foot structure uses a foot array FSR pressure sensor 15 to acquire foot status information in real time, controlling the five toe joints 2 to adjust the foot's landing posture for a stable landing. When the robot loses stability while walking on rough terrain, the valves can be adjusted to control the pneumatic drive mechanisms 3 to press the toes into the ground, adjusting the robot's center of gravity and enabling adaptive posture adjustment of the bipedal robot on uneven terrain.

[0036] The flexible passive connector 6 includes two torsion spring shaft retainers 61, three torsion springs 62, four torsion spring rod retainers 63, and a central torsion spring shaft 64, as shown below. Figure 4 As shown; the central torsion spring shaft 64 passes sequentially through the torsion spring shaft fixing member 61, three torsion springs 62 and the torsion spring rod fixing member 63, making the torsion spring shaft fixing member 61, torsion springs 62 and torsion spring rod fixing member 63 coaxial; the central torsion spring shaft 64 and the torsion spring shaft fixing member 61 are fixedly connected by a shaft shoulder to prevent relative rotation; the torsion springs 62 are fixed to the foot plate 1 or the foot side plate 4 respectively by the torsion spring rod fixing member 63. When the robot walks on rough roads, it can achieve adaptive passive adjustment through the torque flexible rotation of the torsion springs 62.

[0037] When bipedal robots face complex environments with unknown road conditions, relying solely on anti-slip air cushions 5 and flexible passive devices cannot completely overcome ground disturbances. Therefore, an active road adaptation structure is needed. Consequently, the two foot side plates 4 and foot soles 1 have two connection methods, such as... Figure 1 As shown, one foot plate is connected to the foot plate 1 via a flexible passive connector 6 to achieve adaptive flexible passive adjustment; the other foot plate is fixedly connected to the pneumatic drive mechanism 3 via its upper connector 41. The pneumatic drive mechanism 3 is fixedly connected to the connectors 12 and 13 of the second and third pneumatic drive mechanisms. Each foot plate 4 is jointly controlled by two pneumatic drive mechanisms 3. The two foot plates can be actively adjusted by adjusting the valve to control the pneumatic drive mechanism 3, so that the robot can walk stably on rough roads.

[0038] Based on the spatial arrangement of the foot structure described above, when the bipedal robot is walking, the foot structure acquires real-time information from the FSR sensors on the soles of the feet and achieves adaptive posture adjustment on uneven or smooth surfaces through a two-stage process. When the soles of the feet touch uneven ground, if the foot structure is a non-flexible steel plate, the external forces from the ground will cause the bipedal robot to tilt, leading to instability and a fall. In this invention, a two-stage posture adjustment can be used, such as... Figure 5 As shown: First, the anti-slip air cushion 5 will deform to maintain the horizontal position of the foot structure. At the same time, if the lateral force of the ground on the sole of the foot is large, it will drive the torsion spring connecting the sole plate 1 and the two side foot plates 4 to twist, realizing the initial small adjustment of the foot to ensure the robot walks stably. Second, when the IMU of the bipedal robot detects that the aforementioned small adjustment still cannot stabilize the robot and there is a tendency to tilt in various directions, it will immediately drive multiple pneumatic drive devices 3 to adjust the position of the toe joints 2 and the side foot plates 4. Through the force of the five toe joints 2 and the two side foot plates 4 on the ground, the posture of the bipedal robot is adjusted so that its zero torque point falls within the range of the foot support polygon, thus realizing the robot walks stably.

[0039] The suction cup assembly of the foot plate 1 has a circular opening 16 for fixing a vacuum generator 7 and an adaptive suction cup mechanism 8. When the bipedal robot walks, the vacuum generator 7 is not activated. When the bipedal robot is in a state requiring foot structure fixation, such as when the robotic arm mounted on it begins to perform grasping operations, the pneumatic drive mechanism 3 is activated to lift the two side plates 4 of the feet and the five toe joints 2. The vacuum generator 7 then activates and extracts gas from the adaptive suction cup mechanism. Figure 6 As shown, the flexible structure of the torsion spring 62 eliminates the shaking and disturbance caused by uneven ground on the robot's feet, allowing the bipedal robot's foot structure to firmly adhere to the ground and improving its grasping accuracy.

[0040] Based on the description of the above embodiments, as follows Figure 7 , Figure 8 and Figure 9 These are the front, top, and left views of the robot's foot structure. Based on different task working states, the designed foot structure utilizes a combination of torsion springs, pneumatic drives, and foot soles for adaptive adjustment. This results in a well-adaptive foot structure that can effectively adapt to various task working states. A bipedal robot equipped with this foot structure can walk stably on unknown, uneven terrain. Furthermore, when performing tasks requiring a fixed foot structure, such as grasping, it eliminates the vibrations caused by the torsion springs, significantly improving the stability and accuracy of target positioning during grasping and other tasks. This is of great significance for conducting multi-functional robot task experiments.

[0041] In summary, the above-described process is merely one embodiment of the present invention and should not be used to limit the scope of application of the present invention. The part naming method used herein is for better explanation of the structural body and does not exclude the possibility of using other terms. It can be understood that any modifications, substitutions, or other operations made within the design principles and structural design scope of the present invention are within the protection scope of the present invention.

Claims

1. A multifunctional bipedal robot foot structure adaptable to different working conditions, characterized in that: The foot structure includes a foot plate (1), five toe joints (2) connected to the foot plate (1), a pneumatic drive mechanism (3), two foot side plates (4), a flexible passive connector (6), and a foot array FSR pressure sensor (15). The foot array FSR pressure sensor (15) is installed in the bottom circular opening (152) at the four corners of the foot plate (1). The sensor harness is connected to the robot's host computer from the miniature cylindrical pipe (151) on the bottom circular opening (152), and transmits the pressure of the robot's foot to the ground to the robot's host computer for analysis and to obtain the foot status. Each toe joint (2) is controlled by a pneumatic drive mechanism (3) to adjust the foot landing posture according to the information collected by the foot array FSR pressure sensor (15) to achieve a smooth landing. When the robot loses its balance when walking on a rough road, the toes press the ground by adjusting the pneumatic drive mechanism (3) to adjust the robot's center of gravity position. The foot plate (1) includes five first pneumatic drive mechanism connectors (11), two second pneumatic drive mechanism connectors (12), two third pneumatic drive mechanism connectors (13), five toe joint connectors (14), four foot array FSR pressure sensors (15), and a suction cup assembly mounting circular opening (16). Each toe joint connector (14) is equipped with a toe joint (2), and the toe joint (2) is connected to the first pneumatic drive mechanism connector (11) via a pneumatic drive mechanism (3); Each second pneumatic drive mechanism connector (12) is connected to the front end of the foot side plate (4) on the corresponding side via the pneumatic drive mechanism (3); each third pneumatic drive mechanism connector (13) is connected to the rear end of the foot side plate (4) on the corresponding side via the pneumatic drive mechanism (3); The foot side plate (4) and the foot sole plate (1) are connected by a flexible passive connector (6); including two torsion spring shaft fixing members (61), three torsion springs (62), four torsion spring rod fixing members (63), and a central torsion spring shaft (64); the central torsion spring shaft (64) passes through the torsion spring shaft fixing members (61) and the three torsion springs (62) in sequence, making the torsion spring shaft fixing members (61) and the torsion springs (62) coaxial; the central torsion spring shaft (64) and the torsion spring shaft fixing members (61) The torsion spring (62) is fixed to the foot plate (1) and foot side plate (4) by the torsion spring rod fixing member (63). The torsion spring (62) is fixed to the foot side plate (4) by the torsion spring shaft fixing member (61) at the front end and to the foot plate (1) by the torsion spring shaft fixing member (61) at the rear end. When the robot walks on a rough road, it can achieve adaptive passive adjustment by the flexible rotation of the torque of the torsion spring (62).

2. The multifunctional bipedal robot foot structure adaptable to different working states according to claim 1, characterized in that: The five first pneumatic drive mechanism connectors (11) and the five toe joint connectors (14) are arranged in an arc shape and have the same center.

3. The multifunctional bipedal robot foot structure adaptable to different working states according to claim 1, characterized in that: The two second pneumatic drive mechanism connectors (12) are arranged in an arc shape and have the same center as the circular opening (16) for mounting the suction cup assembly.

4. The multifunctional bipedal robot foot structure adaptable to different working states according to claim 1, characterized in that: The anti-slip air pad (5) is attached to the underside of the foot plate (1). The lower surface of the anti-slip air pad (5) in contact with the road surface has anti-slip texture, which increases the friction between the foot and the ground. At the same time, the anti-slip air pad (5) has a certain elasticity, which can absorb the impact when the bipedal robot lands and play a buffering role.

5. A multifunctional bipedal robot foot structure adaptable to different working states according to claim 1, characterized in that: The two foot side plates (4) and the foot sole plate (1) have two connection methods, and the bipedal robot can walk stably through both active and passive adjustment methods. Firstly, it is connected to the foot plate (1) through a flexible passive connector (6) to achieve adaptive flexible passive adjustment; Secondly, the foot side plate (4) is fixedly connected to the pneumatic drive mechanism (3) through the connector (41) on the foot side plate (4). The pneumatic drive mechanism (3) is fixedly connected to the second pneumatic drive mechanism connector (12) and the third pneumatic drive mechanism connector (13). Each foot side plate (4) is jointly controlled by two pneumatic drive mechanisms (3). By adjusting the pneumatic drive mechanism (3), the two foot side plates can be actively adjusted, so that the robot can walk stably on the rugged road surface.

6. The multifunctional bipedal robot foot structure adaptable to different working states according to claim 1, characterized in that: An adaptive suction cup mechanism (8) is installed on the circumference of the circular opening (16) of the suction cup assembly of the foot plate (1). A vacuum generator (7) is fixedly installed on the adaptive suction cup mechanism (8). When the bipedal robot walks, the vacuum generator (7) does not work. When the bipedal robot needs to be fixed on the ground and the robot's mechanical arm starts to perform grasping operations, the pneumatic drive mechanism (3) is driven to lift the two side plates (4) of the feet and the five toe joints (2). The vacuum generator (7) works and extracts the gas in the adaptive suction cup mechanism (8), eliminating the shaking and disturbance of the flexible structure of the torsion spring (62) caused by the uneven ground on the robot's feet, so that the foot structure of the bipedal robot is firmly attached to the ground, improving its grasping accuracy.

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