A leg joint structure of a foot-type robot and a quadruped or hexapod robot

Abstract

The present invention discloses a leg joint structure of a foot-type robot, comprising a motor assembly, a thigh housing, a connecting rod transmission assembly, a calf and a foot end. The motor assembly drives the calf to rotate relative to the thigh through the connecting rod transmission assembly. In the connecting rod transmission assembly, by introducing a reduction link between the active crank and the thigh connecting rod, the transmission angle between the active crank and the next-stage connecting rod is increased, and the motor can drive the calf to move with a smaller torque; and by designing reduction links of equal length at both ends of the thigh connecting rod, the transmission angles of the active crank and its next-stage connecting rod, and the driven crank and its previous-stage connecting rod during movement are improved; at the same time, two pairs of mutually parallel roller structures are installed on the thigh housing to limit the thigh connecting rod to only linear motion, so that before the active crank and the driven crank reach the dead point position, the leg joint structure provided by the present invention has a larger spatial range of motion compared to leg joints without the introduction of reduction links and roller limits.

Description

Technical Field

[0001] The present invention belongs to the field of robotics and mechanical technology, and designs a leg joint structure for a foot-type robot, specifically a leg joint configuration of a four-legged robot that is energy-saving and can increase the range of leg space activities. Background Art

[0002] Hexapod robots are carefully designed bionic robots that can achieve an animal-like gait, capable of navigating complex environments and performing stable operations. The field of hexapod robots has seen rapid development in recent years. Compared to wheeled, multi-rotor, and other legged robots, hexapod robots offer significant advantages in stability and maneuverability, making them well-suited to replacing humans in dangerous and complex tasks such as pipeline inspection and maintenance.

[0003] In the existing leg joint configurations of hexapod robots, the connecting rod transmission mostly adopts a four-bar mechanism, which has a small spatial range of activity and a small starting working angle between the active crank and the thigh connecting rod, so the energy efficiency is relatively high. This problem is especially prominent when designing large-scale hexapod robots.

[0004] Based on the above reasons, it is necessary to design a leg joint configuration of a footed robot that is more energy-efficient and has a larger spatial range of activity. Summary of the Invention

[0005] In order to address the deficiencies of the prior art, the present invention proposes a leg joint configuration for a hexapod robot that is energy-efficient and can increase the range of leg activity space, so as to support the hexapod robot to work for a longer time and in a larger range of activity space.

[0006] The leg joint structure of the foot-type robot of the present invention comprises a motor component, a thigh shell, a connecting rod transmission component, a shank and a foot end.

[0007] The motor assembly is used to drive the connecting rod transmission assembly to move, thereby driving the calf to swing back and forth. Wherein, the connecting rod transmission assembly is located inside the thigh shell, and the thigh shell and the motor assembly are relatively fixed in position.

[0008] The connecting rod transmission assembly includes an active crank, a driven crank, a first reduction connecting rod, a second reduction connecting rod, a thigh connecting rod and a roller.

[0009] The active crank has a large diameter end at the end and a small diameter end at the front end, forming a teardrop-shaped structure. The active crank consists of an inner crank and an outer crank, which are symmetrically arranged and connected to each other by a support to form a whole; the end of the active crank is coaxially fixed to the rotor of the motor assembly. The input end of the first reduction link is placed between the inner crank and the front end of the outer crank, and is connected to the inner crank and the outer crank through the active crank shaft to form a rotating pair; the output end of the first reduction link is connected to the end of the thigh link through an adjusting shaft to form a rotating pair. The front end of the thigh link is connected to the input end of the second reduction link of the same length as the first reduction link through an adjusting shaft to form a rotating pair.

[0010] The driven crank has the same overall shape as the driving crank, with a removable inner plate on the inner front end. A U-shaped groove is formed between the inner plate and the front end of the crank. The output end of the second reduction connecting rod is located within the groove, and the two are connected via the driven crank shaft to form a revolving pair. The front end of the driven crank is coaxially connected to the front end of the thigh shell via the knee joint axis, forming a revolving pair.

[0011] The roller is installed inside the thigh shell and is installed on the upper and lower sides of the thigh connecting rod through bearings, fitting with both sides of the thigh connecting rod; the roller ensures that the thigh connecting rod can only move along its own axis in the thigh shell.

[0012] The shank is a rod-shaped structure, the end of which is sleeved with the driven crank end and fixed by screws. The front end of the shank is fixed with the foot end, and the bottom of the foot end is equipped with a sole rubber.

[0013] Through the above scheme, the motor assembly is controlled to drive the active crank to rotate clockwise / clockwise around the axis of the output end of the calf drive motor, and then the first reduction link, the thigh link and the second reduction link drive the driven crank, and the driven crank further drives the calf to rotate counterclockwise / clockwise; the calf gradually expands under counterclockwise rotation and gradually closes under clockwise rotation.

[0014] The advantages of the present invention are:

[0015] 1. The present invention provides a leg joint structure of a foot-type robot. By designing two reduction links of equal length and installing them on both sides of the thigh link, the active crank and the driven crank have a larger spatial range of movement before reaching the dead point position, compared with a leg joint structure without a reduction link and a roller limiter.

[0016] 2. The present invention provides a leg joint structure of a foot-type robot, in which a first reduction link is designed, one end of which is connected to the active crank and the other end is connected to the thigh link. Compared with the method of directly connecting the thigh link to the active crank, this configuration has a larger transmission angle between the active crank and its next-level link in the initial working stage, thereby being more energy-efficient throughout the entire working stage.

[0017] 3. The present invention provides a leg joint structure for a foot-type robot. By designing two pairs of parallel roller structures on the inner and outer thigh shells, the thigh connecting rod is restricted to linear motion only in the direction of the center line connecting the two pairs of rollers, and cannot perform other movements. While ensuring the freedom of movement of the mechanism, it solves the problem of reduced range of motion of the leg joint due to interference between the thigh connecting rod and the inner and outer thigh shells. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the overall leg joint structure of the foot-type robot of the present invention.

[0019] Figure 2 Schematic diagram of the hip joint structure of the leg joint structure of the foot-type robot of the present invention;

[0020] Figure 3 A schematic diagram of the installation method of the thigh shell in the leg joint structure of the foot-type robot of the present invention;

[0021] Figure 4 Schematic diagram of the connection between the active crank, the first reduction link, and the thigh link in the leg joint of the foot-type robot of the present invention;

[0022] Figure 5 Schematic diagram of the driven crank structure in the leg joint of the foot-type robot of the present invention;

[0023] Figure 6 Schematic diagram of the connection between the driven crank, thigh housing and second reduction connecting rod in the leg joint of the foot-type robot of the present invention;

[0024] Figure 7 Schematic diagram of the thigh connecting rod limiting method in the leg joint structure of the foot-type robot of the present invention.

[0025] Figure 8 A schematic diagram of a quadruped robot using the leg joint structure of the foot-type robot of the present invention;

[0026] Figure 9 A schematic diagram of a hexapod robot using the leg joint structure of the foot-type robot of the present invention;

[0027] Figure 10 This is a schematic diagram of the leg joint structure of the foot-type robot of the present invention in an extended state;

[0028] In the picture:

[0029] 1-Motor assembly 2-Thigh housing 3-Connecting rod transmission assembly

[0030] 4- Lower leg 5- Foot end 6- Robot body

[0031] 101- Hip joint drive motor 102- Hip joint motor connector 103- Thigh drive motor

[0032] 104- Calf drive motor 105- Hip joint cover 106- Dust cover

[0033] 107-protruding part 301-active crank 301a-inner crank

[0034] 301b - outer crank 302 - driven crank 302a - inner plate

[0035] 303-first deceleration link 304-second deceleration link 305-thigh link

[0036] 306- roller 307- driving crankshaft 308- flange bearing

[0037] 309-gasket 310-adjusting shaft 311-adjusting sleeve

[0038] 312-adjusting shaft retaining ring 313-driven crankshaft 314-inner knee shaft

[0039] 315-External knee shaft 316-Knee bearing 501-Foot rubber

[0040] 601-Leg connection surface DETAILED DESCRIPTION

[0041] The present invention will be further described in detail below with reference to the accompanying drawings.

[0042] The leg joint structure of the foot-type robot of the present invention comprises a motor assembly 1, a thigh housing 2, a connecting rod transmission assembly 3, a shank 4 and a foot end 5. Figure 1 shown.

[0043] like Figure 2 As shown, the motor assembly 1 includes a hip joint drive motor 101 , a hip joint motor connector 102 , a thigh drive motor 103 , a calf drive motor 104 , a hip joint cover 105 and a dust cover 106 .

[0044] The body end of the hip joint drive motor 101 is connected to the robot's body. The rotor of the hip joint drive motor 101 is coaxially fixed to a connecting flange designed in the middle of the outer wall of the arc-shaped hip joint motor connector 102. The inner curved surface of the arc-shaped hip joint motor connector 102 is fixed to the outer wall of the thigh drive motor 103. The rotor axis of the hip joint drive motor 101 is perpendicular to the rotor axis of the thigh drive motor 103.

[0045] The body of the calf drive motor 104 is coaxially fixedly connected to the rotor of the thigh drive motor 103 , and the rotor of the thigh drive motor 103 is coaxially fixed to the end of the body of the calf drive motor 104 . The rotor of the calf drive motor 104 is used to connect to the connecting rod transmission assembly 3 .

[0046] The inner side of the hip joint cover 105 fits snugly against the front end of the calf drive motor 104, positioning the output of the calf drive motor 104 within the hip joint cover 105. The hip joint cover 105 is further secured to the front end of the calf drive motor 104 via circumferential screws. A coaxial circular hole is formed on the outer side of the hip joint cover 105, into which a dust cover 106 is snap-fitted, sealing the interior of the hip joint cover 105. The side of the hip joint cover 105 has a protrusion 107 for connection to the thigh housing 2.

[0047] The thigh shell 2 consists of an inner shell and an outer shell, which interlock to form a single, rod-shaped structure. The front end of the structure features a downward bend at a 60° angle, creating a smooth transition. The bend only has left and right walls to prevent interference with knee joint movement. The ends of the inner and outer shells are respectively secured to the inner and outer sides of the protruding portions 107 on the sides of the hip joint cover 105.

[0048] like Figure 3 As shown, the connecting rod transmission assembly 3 is arranged inside the thigh shell 2 and the hip joint cover 105, including an active crank 301, a driven crank 302, a first reduction connecting rod 303, a second reduction connecting rod 304, a thigh connecting rod 305 and a roller 306.

[0049] The active crank 301 is composed of an inner crank 301a and an outer crank 301b. Figure 4 As shown, the two parts are symmetrically arranged and connected by a support to form an integral active crank 301. The integral active crank 301 has a large diameter end and a small diameter end, forming a teardrop-shaped structure. It is located inside the hip joint cover 105. The end of the inner crank 301a is coaxially connected to the rotor of the calf drive motor 103 via circumferentially arranged screws. A first reduction connecting rod 303 is positioned between the inner crank and the front end of the outer crank. The input end of the first reduction connecting rod 303 is fixed to the active crank shaft 307, positioned between the front ends of the inner crank 301a and the outer crank 301b. The two ends of the active crank shaft 307 are connected to the inner crank 301a and the outer crank 301b via flange bearings 308 to form a revolute pair. The axial position of the first reduction connecting rod 301 on the active crank shaft 307 is achieved by an annular shoulder designed on the active crank shaft 307 and a gasket 309 sleeved on the active crank shaft 307.

[0050] The connection positions of the above-mentioned active crank 301, the first reduction link 303 and the thigh link 305 are located at the circular hole on the outside of the hip joint cover 105. By removing the dust cover 6, the active crank 301, the first reduction link 303 and the thigh link 305 inside the hip joint cover 105 can be easily installed and removed without having to dismantle other shells as a whole.

[0051] The output end of the first reduction link 303 is connected to the end of the thigh link 305 via an adjustment shaft 310, forming a revolute pair. This adjustment shaft 310 is sheathed with an adjustment sleeve 311, which reduces friction during rotation. Annular shoulders at both ends of the adjustment sleeve 311 limit the axial position of the thigh link 305. Furthermore, adjustment shaft retaining rings 312 are fixedly sleeved at both ends of the adjustment shaft 310, limiting the axial position of the adjustment shaft 310. The front end of the thigh link 305 is connected to the input end of a second reduction link 304, the same length as the first reduction link 303, via an adjustment shaft, adjustment sleeve, and adjustment shaft retaining ring in the same manner as previously described, forming a revolute pair.

[0052] like Figure 5 、 Figure 6 As shown, the front part of the driven crank 302 has the same shape as the driving crank, and has a detachable inner plate 302a on the inner side of the front end. A U-shaped groove is formed between the inner plate 302a and the front end of the crank, and the output end of the second reduction connecting rod 304 is arranged in the groove, and is connected to form a rotating pair through the driven crank shaft 313; the installation method of the driven crank shaft 313 is the same as that of the driving crank shaft 307.

[0053] The front end of the driven crank 301 is coaxially connected to the front end of the thigh shell 2 via a knee joint axis, forming a revolute pair. This knee joint axis comprises an inner knee axis 314 and an outer knee axis 315. The inner knee axis 314 extends from the inner side of the thigh shell 2 into corresponding axial holes defined at the front end of the thigh shell 2 and the rear end of the driven crank 302, and is connected to the driven crank 302 via a knee bearing 316. The outer knee axis 315 is secured by threading through a coaxial threaded hole on the outer side of the thigh shell 2, which is coaxial with the end of the inner knee axis 314.

[0054] There are two pairs of rollers 306 installed inside the thigh shell 2. Figure 7 As shown, two pairs of rollers 306 are located at the front and rear of the thigh housing 2. Each pair of rollers 306 is located on either side of the thigh connecting rod 305, affixing it to the thigh connecting rod 305 and forming a revolute pair with the thigh housing 2 via bearings. Thus, the two pairs of rollers 306 ensure that the thigh connecting rod 305 can only move axially within the thigh housing 2, preventing any other movement. The lower leg 4 is a rod-shaped structure, its end plugging into the rear portion of the driven crank 302 and secured to it via circumferential screws. A circular foot end 5 is fixed to the front end of the lower leg 4. The foot end 5 is secured to the inner hole of the front end of the lower leg 4 via a threaded joint designed on the circumferential sidewall. A foot rubber 501 is fixed to the sole of the foot end 5, opposite the threaded joint, on the circumferential sidewall. This increases friction when the foot end 5 contacts the ground, ensuring the movement of the hexapod robot. The lower leg 4 can be designed as a hollow structure, reducing weight while facilitating internal routing of the foot sensor.

[0055] The leg joint structure of the leg-type robot of the above structure can be designed as multiple groups of bilaterally symmetrical structures, which are installed on the left and right sides of the robot body 6 to form a quadruped or hexapod robot. Among them, by installing the body ends of the hip joint drive motors 101 in the two symmetrical leg joint structures on the left and right sides of the front face and the left and right sides of the rear face of the robot body 6, the axis of the hip joint drive motors 101 is along the front-back direction of the body 6, thereby forming a quadruped robot, such as Figure 8 By installing the body ends of the hip joint drive motors 101 in the three symmetrical leg joint structures on the front face of the robot body 6, the leg mounting surfaces 601 on both sides of the middle part, and the left and right sides of the rear face, the axis of the hip joint drive motors 101 is along the front-to-back direction of the body 6, thereby forming a hexapod robot, as shown in FIG. Figure 9 shown.

[0056] A foot-type robot equipped with the leg joint structure of the present invention can drive the entire leg joint structure to swing inward or outward by controlling the hip joint drive motor 101; can drive the entire leg joint structure to swing forward or backward by controlling the thigh drive motor 101; can drive the calf drive motor 103 to rotate clockwise / counterclockwise, and can drive the active crank 301 to rotate clockwise / clockwise around the axis of the calf drive motor output end, and then drive the driven crank 302 through the first reduction link 303, the thigh link 305 and the second reduction link 304, and the driven crank 302 drives the calf 4 to rotate counterclockwise / clockwise. The calf 4 gradually unfolds under the counterclockwise rotation, and the maximum unfolding angle (the angle between the axis of the calf 4 and the axis of the thigh link 305) is 126.5 degrees. Figure 10 calf 4 is gradually closed under clockwise rotation, the minimum closing angle is 9 degrees, at this time the front end of the calf 4 5 and the hip joint cover 105 fit, as Figure 3 During the above movement, the thigh connecting rod 305 is restricted to translation by the two pairs of rollers 306, thereby solving the problem of reduced range of motion of the knee joint due to interference between the thigh connecting rod 305 and the thigh shell 2.

[0057] In summary, the leg joint structure of the present invention improves the transmission angle of the active crank 301 and its next-level connecting rod (first reduction connecting rod 303), the driven crank and its previous-level connecting rod (second reduction connecting rod 304) during movement by introducing the first reduction connecting rod 303 between the active crank 301 and the thigh connecting rod 305, and introducing the second reduction connecting rod 304 between the thigh connecting rod 305 and the driven crank 302, so that the active crank 301 and the driven crank 302 have a larger spatial range of movement before reaching the dead point position compared with the leg joint configuration without the introduction of the reduction connecting rod; and by introducing the first reduction connecting rod 303 between the active crank 301 and the thigh connecting rod 305, the transmission angle between the active crank 301 and its next-level connecting rod is also made larger, and the motor can drive the calf to move with a smaller torque, thereby having an energy-saving effect.

Claims

1. A leg joint structure of a foot-type robot, characterized by: It includes a motor assembly, a thigh housing, a connecting rod transmission assembly, a calf and a foot end; The motor assembly is used to drive the connecting rod transmission assembly to move, thereby driving the calf to swing forward and backward; wherein the connecting rod transmission assembly is located inside the thigh housing, and the position between the thigh housing and the motor assembly is relatively fixed; The connecting rod transmission assembly includes an active crank, a driven crank, a first reduction connecting rod, a second reduction connecting rod, a thigh connecting rod and a roller; The end of the active crank is a large-diameter end, and the front end is a small-diameter end, presenting a teardrop-shaped structure; the active crank is composed of an inner crank and an outer crank, which are symmetrically arranged and connected to each other by a support to form a whole; the end of the active crank is coaxially fixed to the rotor of the motor assembly; the input end of the first reduction connecting rod is placed between the inner crank and the front end of the outer crank, and is connected to the inner crank and the outer crank through the active crank shaft to form a rotating pair; the output end of the first reduction connecting rod is connected to the end of the thigh connecting rod through an adjusting shaft to form a rotating pair; the front end of the thigh connecting rod is connected to the input end of the second reduction connecting rod of the same length as the first reduction connecting rod through an adjusting shaft to form a rotating pair; The driven crank has the same overall shape as the active crank, with a detachable inner plate on the inner side of the front end. A U-shaped groove is formed between the inner plate and the front end of the crank. The output end of the second reduction connecting rod is arranged in the groove and is connected to the driven crank shaft to form a rotating pair. The front end of the driven crank is coaxially connected to the front end of the thigh shell through the knee joint axis to form a rotating pair. The rollers are installed inside the thigh shell and are installed on the upper and lower sides of the thigh connecting rod through bearings, fitting closely with both sides of the thigh connecting rod; the rollers ensure that the thigh connecting rod can only move in translation along its own axis inside the thigh shell; The shank is a rod-shaped structure, the end of which is sleeved with the rear part of the driven crank and fixed by screws; the front end of the shank is fixed with the foot end, and the bottom of the foot end is installed with a sole rubber; By controlling the motor assembly, the active crank is driven to rotate clockwise / clockwise around the axis of the output end of the calf drive motor, and then the driven crank is driven through the first reduction link, the thigh link and the second reduction link, and the driven crank drives the calf to rotate counterclockwise / clockwise; the calf gradually expands under counterclockwise rotation and gradually contracts under clockwise rotation.

2. The leg joint structure of a foot-type robot according to claim 1, characterized in that: The motor assembly includes a hip joint drive motor, a hip joint motor connector, a thigh drive motor, and a calf drive motor; wherein, the body end of the hip joint drive motor is connected to the robot body; the rotor of the hip joint drive motor is coaxially fixedly installed on a connecting flange designed in the middle of the outer wall surface of the arc-shaped hip joint motor connector; the inner arc surface of the arc-shaped hip joint motor connector is fixed to the outer wall surface of the thigh drive motor; and the rotor axis of the hip joint drive motor is perpendicular to the rotor axis of the thigh drive motor; the calf drive motor body is coaxially fixedly connected to the rotor of the thigh drive motor, and the rotor of the calf drive motor is connected to the connecting rod transmission assembly.

3. The leg joint structure of a foot-type robot according to claim 1, characterized in that: A hip joint cover is coaxially installed on the motor assembly so that the rotor of the calf drive motor is located inside the hip joint cover; a coaxial opening is provided on the outside of the hip joint cover, and a dust cover is installed at the opening; the active crank, the first reduction link and the thigh link can be installed and disassembled by removing the dust cover.

4. The leg joint structure of a foot-type robot according to claim 1, characterized in that: The relative position between the thigh shell and the motor assembly is fixed, and it is composed of an inner shell and an outer shell, which are buckled to form an integral rod-shaped structural shell; weight-reducing holes are opened at corresponding positions on the inner and outer walls of the thigh shell.

5. The leg joint structure of a foot-type robot according to claim 1, characterized in that: The input end of the first reduction connecting rod is fixed on the driving crankshaft, and the two ends of the driving crankshaft are connected to the inner crank and the outer crank through flange bearings to form a rotating pair; the axial limitation of the first reduction connecting rod on the driving crankshaft is achieved by the annular shoulder designed on the driving crankshaft and the gasket sleeved on the driving crankshaft; the connection method between the driven crankshaft and the second reduction connecting rod and the driven crank is the same as that of the driving crankshaft.

6. The leg joint structure of a foot-type robot according to claim 1, characterized in that: An adjusting shaft sleeve is sleeved on the outside of the adjusting shaft to reduce the friction of the adjusting shaft during rotation; at the same time, the annular shoulders at both ends of the adjusting shaft sleeve limit the axial position of the thigh connecting rod; further, an adjusting shaft retaining ring is fixedly sleeved at both ends of the adjusting shaft to limit the axial position of the adjusting shaft.

7. The leg joint structure of a foot-type robot according to claim 1, characterized in that: The knee joint axis includes an inner knee axis and an outer knee axis; among them, the inner knee axis passes through the corresponding axis holes opened on the thigh shell and the rear end of the driven crank from one side of the thigh shell, and is connected to the driven crank through the knee bearing; the outer knee axis is fixed by threading the threaded hole coaxially designed on the other side of the thigh shell and the end of the inner knee axis.

8. The leg joint structure of a foot-type robot according to claim 1, characterized in that: A quadruped robot is formed by installing motor components on the left and right sides of the front end surface and the left and right sides of the rear end surface of the robot body.

9. The leg joint structure of a foot-type robot according to claim 1, characterized in that: A hexapod robot is formed by installing motor components on the left and right sides of the front end surface, the left and right sides of the rear end surface, and the left and right sides of the middle part of the robot body.

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