Leg joint structure of foot type robot and quadruped and hexapod robot

Abstract

The invention discloses a leg joint structure of a foot type robot. The leg joint structure comprises a motor assembly, a thigh shell, a connecting rod transmission assembly, a shank and a foot end. The motor assembly drives the shank to rotate relative to the thigh through the connecting rod transmission assembly. In the connecting rod transmission assembly, a speed reduction connecting rod is introduced between a driving crank and a thigh connecting rod, so that the transmission angle of the driving crank and a next-stage connecting rod is larger, and a motor can drive a shank to move with smaller torque; by designing equal-length speed reduction connecting rods at the two ends of the thigh connecting rod, the transmission angles of a driving crank and a next-stage connecting rod as well as a driven crank and an upper-stage connecting rod in the movement process are improved; and meanwhile, two pairs of parallel pin roller structures are mounted on a thigh shell to limit a thigh connecting rod to only do translational motion, so that the leg joint structure provided by the invention has a larger space movement range before a driving crank and a driven crank reach a dead point position compared with a leg joint without introducing a speed reducing connecting rod and pin roller limiting.

Description

Technical Field

[0001] The 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- or six-legged robot that is energy-saving and can increase the range of leg space activities. Background Art

[0002] The hexapod robot is a carefully designed bionic robot that can walk like an animal, walk in complex environments, and perform stable operations. In recent years, the field of hexapod robots has developed rapidly. Compared with wheeled, multi-rotor robots and other legged robots, hexapod robots have greater advantages in stability and operability, and are more capable of replacing humans in dangerous and complex tasks such as pipeline inspection and maintenance.

[0003] In the existing leg joint configurations of four-legged and six-legged robots, the connecting rod transmission mostly adopts a four-bar mechanism, which has a small spatial activity range 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 particularly prominent when designing large four-legged and six-legged 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 of 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 lower leg to swing forward and backward. Wherein, the connecting rod transmission assembly is located inside the thigh shell, and the position between the thigh shell and the motor assembly is relatively fixed.

[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 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 form a whole through a support; 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 revolving 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 revolving 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 revolving pair.

[0010] The overall shape of the driven crank is the same as that of the active crank, and a detachable inner plate is provided 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 the driven crank shaft is connected to form a revolving pair. The front end of the driven crank is coaxially connected to the front end of the thigh shell through the knee joint shaft to form 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, and fits 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 lower leg 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 lower leg 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 connecting rod, the thigh connecting rod and the second reduction connecting rod 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 connecting rods of equal length and installing them on both sides of the thigh connecting rod, before the active crank and the driven crank reach the dead point position, there is a larger spatial range of movement compared to a leg joint structure without a reduction connecting rod and a roller limiter.

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

[0017] 3. The present invention provides a leg joint structure of 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 translational motion only in the direction of the center line connecting the two pairs of rollers, and cannot make other movements. While ensuring the freedom of movement of the mechanism, 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 is solved. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0020] Figure 3 It is 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 It is a schematic diagram of the connection mode of the active crank, the first reduction connecting rod and the thigh connecting rod in the leg joint of the foot-type robot of the present invention;

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

[0023] Figure 6 It is a schematic diagram of the connection method of the driven crank, the thigh shell and the second reduction connecting rod in the leg joint of the foot-type robot of the present invention;

[0024] Figure 7 It is a schematic diagram of the limiting method of the thigh connecting rod 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] Fig. 9 A schematic diagram of a hexapod robot using the leg joint structure of the foot-type robot of the present invention;

[0027] Fig.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 figure:

[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-washer 310-adjusting shaft 311-adjusting sleeve

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

[0039] 315-outer knee shaft 316-knee bearing 501-sole rubber

[0040] 601-Leg connection surface DETAILED DESCRIPTION

[0041] The present invention is 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 body; the rotor of the hip joint drive motor 101 is coaxially fixedly installed on the connection flange designed in the middle of the outer wall surface of the arc-shaped hip joint motor connector 102. The inner arc surface of the arc-shaped hip joint motor connector 102 is fixed to the outer wall surface of the thigh drive motor 103; and 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 the connecting rod transmission assembly 3 .

[0046] The inner side of the hip joint cover 105 fits with the front end of the calf drive motor 104, so that the output end of the calf drive motor 104 is located inside the hip joint cover 105; the hip joint cover 105 is further fixed to the front end of the calf drive motor 104 by screws in the circumferential direction. A circular hole is coaxially opened on the outer side of the hip joint cover 105, and a dust cover 106 is installed at the circular hole by a snap-fitting manner to seal the inside of the hip joint cover 105. The side of the hip joint cover 105 has a protruding part 107 for connecting to the thigh shell 2.

[0047] The thigh shell 2 is composed of an inner shell and an outer shell, which are buckled to form an integral rod-shaped structure shell, and the front end of the integral shell structure has a downward bend, the bend angle is 60°, and the bend position is smoothly transitioned. At the same time, the bend part only has left and right wall surfaces to avoid interfering with the movement of the knee joint. The ends of the inner shell and the outer shell are respectively fixed to the inner and outer sides of the protruding part 107 on the side 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 the two parts are connected by a support to form an integral active crank 301. The end of the integral active crank 301 is a large diameter end, and the front end is a small diameter end, which is a teardrop-shaped structure and is located inside the hip joint cover 105. The end of the inner crank 301a is coaxially fixed to the rotor of the calf drive motor 103 through circumferentially arranged screws. A first reduction connecting rod 303 is arranged between the front ends of the inner crank and the outer crank; the input end of the first reduction connecting rod 303 is fixed on the active crank shaft 307 and placed 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 through flange bearings 308 to form a revolving pair. The axial limit of the first reduction connecting rod 301 on the active crank shaft 307 is achieved by the annular shoulder designed on the active crank shaft 307 and the gasket 309 sleeved on the active crank shaft 307.

[0050] The connection position of the active crank 301, the first reduction connecting rod 303 and the thigh connecting rod 305 is located at the circular hole on the outer side of the hip joint cover 105, and the active crank 301, the first reduction connecting rod 303 and the thigh connecting rod 305 inside the hip joint cover 105 can be easily installed and removed by removing the dust cover 6 without having to disassemble 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 through an adjustment shaft 310 to form a revolving pair; the adjustment shaft 310 is sleeved with an adjustment sleeve 311 to reduce the friction of the adjustment shaft rotation, and the axial position of the thigh link 305 is limited by the annular shoulders at both ends of the adjustment sleeve 311; further, the two ends of the adjustment shaft 310 are fixedly sleeved with an adjustment shaft retaining ring 312 to limit the axial position of the adjustment shaft 310. The front end of the thigh link 305 is connected to the input end of the second reduction link 304 of the same length as the first reduction link 303 through an adjustment shaft, an adjustment sleeve and an adjustment shaft retaining ring in the same way as above to form a revolving 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 a detachable inner plate 302a is provided 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 they are connected through the driven crank shaft 313 to form a rotating pair; 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 through the knee joint axis to form a revolute pair. The knee joint axis includes an inner knee axis 314 and an outer knee axis 315; wherein the inner knee axis 314 is inserted from the inner side of the thigh shell 2 into the corresponding axis hole opened 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 through the knee bearing 316; the outer knee axis 315 is threadedly fixed by the outer side of the thigh shell 2 and the coaxially designed threaded hole at 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 respectively located at the front and rear positions of the thigh shell 2; each pair of two rollers 306 are respectively located at the upper and lower sides of the thigh connecting rod 305, fit with the thigh connecting rod 305, and are connected to the thigh shell 2 through the bearing to form a revolute pair. Thus, the two pairs of rollers 306 ensure that the thigh connecting rod 305 can only move along its own axis in the thigh shell 2, and cannot move in other directions. The lower leg 4 is a rod-shaped structure, the end of which is plugged into the rear part of the driven crank 302 and fixed by screws in the circumferential direction. The annular foot end 5 is fixedly installed at the front end of the lower leg 4. The foot end 5 is fixedly connected and fixed by the inner hole thread designed on the threaded joint designed on the circumferential side wall and the inner hole thread designed at the front end of the lower leg 4; the sole position of the foot end 5 on the circumferential side wall opposite to the threaded joint is fixedly installed with a sole rubber 501, which is used to increase the friction when the foot end 5 contacts the ground and ensure the movement of the four-legged robot. The above-mentioned lower leg 4 can be designed as a hollow structure, which can realize the internal routing of the sole sensor while achieving weight reduction.

[0055] The leg joint structure of the legged robot of the above structure can be designed as multiple groups of 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 motor 101 in the two symmetrical leg joint structures 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 6, the axis of the hip joint drive motor 101 is along the front and rear direction of the body 6, thereby forming a quadruped robot, such as Figure 8 By installing the body end of the hip joint drive motor 101 in the three sets of leg joint structures with symmetrical structure 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 motor 101 is along the front and rear direction of the body 6, thereby forming a six-legged robot, as shown in FIG. Fig. 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; and can drive the active crank 301 to rotate clockwise / clockwise around the axis of the output end of the calf drive motor by controlling the calf drive motor 103 to rotate clockwise / counterclockwise, 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 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. Fig.10 The calf 4 gradually closes in a clockwise rotation, and the minimum closing angle is 9 degrees. At this time, the front foot end 5 of the calf 4 fits with the hip joint cover 105, as shown Figure 3 During the above movement, the thigh connecting rod 305 is restricted to translational movement by 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 (the first reduction connecting rod 303) and the driven crank and its previous-level connecting rod (the 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 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 in that: 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 shell, and the position between the thigh shell 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 form a whole through a support; the end of the active crank is coaxially fixedly connected 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 overall shape of the driven crank is the same as that of the driving crank, and a detachable inner plate is provided 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 the driven crank shaft is connected 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 shaft to form a rotating pair; The roller is installed inside the thigh shell, and is installed on the upper and lower sides of the thigh connecting rod through bearings, and fits with the two 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; The calf is a rod-shaped structure, the end of which is sleeved with the rear part of the driven crank and fixed by screws; the foot end is fixedly mounted at the front end of the calf, and a sole rubber is mounted at the bottom of the foot end; 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 driven crank is driven through the first reduction connecting rod, the thigh connecting rod and the second reduction connecting rod, and the driven crank drives the calf to rotate counterclockwise / clockwise; the calf gradually expands under the counterclockwise rotation and gradually closes under the clockwise rotation.

2. A leg joint structure of a foot-type robot as claimed in 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. A leg joint structure of a foot-type robot as claimed in 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 outer side of the hip joint cover, and a dust cover is installed at the opening; the installation and disassembly of the active crank, the first reduction connecting rod and the thigh connecting rod can be achieved by removing the dust cover.

4. A leg joint structure of a foot-type robot as claimed in claim 1, characterized in that: The thigh shell is fixed in relative position to the motor assembly, and 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 provided at corresponding positions on the inner and outer wall surfaces of the thigh shell.

5. The leg joint structure of a foot-type robot as claimed in claim 1, characterized in that: The input end of the first reduction connecting rod is fixed on the driving crank shaft, and the two ends of the driving crank shaft 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 crank shaft is achieved by the annular shoulder designed on the driving crank shaft and the gasket sleeved on the driving crank shaft; the connection method between the driven crank shaft and the second reduction connecting rod and the driven crank is the same as that of the driving crank shaft.

6. A leg joint structure of a foot-type robot as claimed in 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, adjusting shaft retaining rings are fixedly sleeved at both ends of the adjusting shaft to limit the axial position of the adjusting shaft.

7. A leg joint structure of a foot-type robot as claimed in claim 1, characterized in that: The knee joint axis includes an inner knee axis and an outer knee axis; the inner knee axis passes through the corresponding axis holes opened in 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 a knee bearing; the outer knee axis is fixed by threading through a threaded hole coaxially designed with the end of the inner knee axis on the other side of the thigh shell.

8. The leg joint structure of a foot-type robot as claimed in 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 as claimed in 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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