Biped robot and linear actuator applied to biped robot

Abstract

The biped robot comprises a main body connecting part and leg parts arranged on the two sides of the main body connecting part, and each leg part comprises a thigh part, a shank part, a sole assembly and a connecting rod assembly used for connection which are sequentially connected; the thigh part comprises a thigh rotating joint, a thigh lifting linear joint, a shank bending linear joint and a thigh supporting plate, the thigh lifting linear joint and the shank bending linear joint are linear actuators and are oppositely arranged, and the two ends of the thigh lifting linear joint and the two ends of the shank bending linear joint are rotationally installed; the shank part comprises an ankle linear joint and a shank supporting plate, the upper end of the ankle linear joint is rotatably connected with the shank supporting plate, and the lower end of the ankle linear joint is connected with the sole assembly. The method has the beneficial effects that the load capacity of the biped robot is improved, and the requirements of the biped robot for large load, high response speed and high precision can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of robots, and in particular to a biped robot and a linear actuator used in the same. Background Art

[0002] A bipedal robot is a bionic robot that can realize bipedal walking and related movements. Bipedal robots are generally divided into thigh joint rotation movement, calf joint rotation movement, ankle joint pitch movement and ankle joint flip movement. Traditional bipedal robots all use rotary joints to achieve the above movements; for full-size bipedal robots or load-bearing bipedal robots using rotary joints, in order to ensure sufficient torque, the joint motor at the thigh position will be very large, affecting the anthropomorphism and aesthetics of the entire machine. In contrast, the use of linear joints can make good use of the space at the thigh position, hide the linear actuator within the thigh contour, and provide sufficient thrust, so that the bipedal robot has sufficient load capacity.

[0003] However, the use of linear actuators also has the following disadvantages: a linear actuator is a joint that converts rotational motion into linear motion. Most of them are open-loop or semi-closed-loop control, which cannot eliminate the transmission error at the end of the linear motion. Or closed-loop control is used, and a linear displacement sensor needs to be added to measure the displacement of the end of the linear motion, but the cost is high and the size is large. Moreover, for bipedal robots that use linear actuators, the only data that the control end can read for real-time position and posture is the rotation angle data of the encoder at the motor end. Then, it is necessary to convert the push-out distance of the linear actuator, and then convert the push-out distance of the linear actuator into the rotation angle of the end joint through a four-bar structure, and calculate the final rotation angle posture of the joint. The process requires a large amount of calculation and large calculation errors. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a bipedal robot and a linear actuator used therein, which can realize closed-loop control of the speed and position of the dual encoders of the bipedal robot, have the characteristics of large load, high motion precision, long life and small size, and can meet the requirements of large load, high response speed and high precision of the bipedal robot.

[0005] Specifically, the present invention discloses a bipedal robot, comprising: a main body connection part and legs arranged on both sides of the main body connection part, the legs comprising a thigh part, a calf part, a sole assembly and a connecting rod assembly connected in sequence; the thigh part comprises: a thigh rotation joint, a thigh leg-lifting linear joint, a calf bending linear joint and a thigh support plate, the thigh leg-lifting linear joint and the calf bending linear joint are both linear actuators, and are arranged in opposite directions, and both ends of the thigh leg-lifting linear joint and both ends of the calf bending linear joint are rotatably installed; the calf part comprises an ankle linear joint and a calf support plate, the upper end of the ankle linear joint is rotatably connected to the calf support plate, and the lower end is connected to the sole assembly.

[0006] The benefit of adopting the above technical solution is that it improves the load capacity of the bipedal robot and can meet the requirements of the bipedal robot for large load, high response speed and high precision.

[0007] Furthermore, the connecting rod assembly includes connecting rod 1 and connecting rod 2, which are used to connect the thigh rotation joint, the thigh leg lifting linear joint and the thigh support plate, and also includes a connecting shaft for connecting the thigh support plate and the thigh rotation joint, and the connecting shaft is provided with a linear joint encoder 1.

[0008] The benefit of adopting the above technical solution is that the setting of the linear joint encoder can accurately sense the rotation angle and speed data of the thigh support plate, reduce transmission errors, form a closed-loop control with the encoder in the linear actuator, and improve the accuracy of the entire leg operation control.

[0009] Furthermore, the connecting rod assembly also includes connecting rod three and connecting rod four for connecting the thigh and the calf, connecting rod three and connecting rod four are connected by pin shaft one, and the thigh support plate and the calf support plate are also connected by pin shaft two, and pin shaft two is provided with linear joint encoder two.

[0010] Furthermore, the connecting rod three includes a first connecting portion and a symmetrically arranged second connecting portion extending to the side, the second connecting portion is provided with a connecting hole for the pin shaft one to pass through, the connecting rod four is provided with a lug connected to the pin shaft one, and the other end of the connecting rod four is connected to the calf support plate.

[0011] The benefit of adopting the above technical solution is that connecting rod three and connecting rod four are connected to the thigh support plate and the calf support plate, optimizing the force structure and making the transmission between the thigh and the calf more precise.

[0012] Furthermore, the ankle linear joint includes ankle linear joint one and ankle linear joint two arranged side by side, one end of which is rotationally connected to the calf support plate, and the other end of which is rotationally connected to the sole assembly. A cross shaft is provided at the lower end of the calf support plate and connected to the sole assembly, and ankle linear encoder three and ankle linear encoder four are provided on the cross shaft.

[0013] The benefit of adopting the above technical solution is that the ankle linear joints arranged side by side can realize the forward and backward pitching movement of the sole assembly when pushed out or retracted together, and can realize the left and right rolling movement of the sole assembly during differential movement, making the robot movement process smoother.

[0014] Furthermore, the thigh rotation joint includes: a thigh rotation joint 1 and a thigh rotation joint 2, and the rotation axes of the thigh rotation joint 1 and the thigh rotation joint 2 are perpendicular.

[0015] The benefit of adopting the above technical solution is that the provision of two rotating joints enables the legs to have freedom in multiple directions to meet usage requirements.

[0016] Furthermore, the thigh support plates are symmetrically arranged, and the thigh leg lifting linear joint and the calf bending linear joint are located between the thigh support plates.

[0017] The benefit of adopting the above technical solution is that the symmetrically arranged thigh support plates play a supporting and protective role, making the legs more stable.

[0018] Furthermore, the present application also discloses a linear actuator, which is applied to the bipedal robot described in the above technical solution, including: a housing, a motor, a planetary ball screw group, and an encoder. The motor is arranged in the housing, the planetary ball screw group includes an output shaft and a screw nut, the screw nut is connected to the motor, and the encoder is arranged at one end of the screw nut.

[0019] The benefit of adopting the above technical solution is that it has the characteristics of large load, high motion precision, long life, small size, etc., and can meet the requirements of large load, high response speed and high precision of bipedal robots.

[0020] Furthermore, a connecting seat 1 and a connecting seat 2 are provided on both sides of the shell, the connecting seat 1 is connected to the shell through a sensor, and the connecting seat 2 is connected to the protruding end of the output shaft.

[0021] The benefit of adopting the above technical solution is that the two connecting seats are convenient to connect. By setting a force sensor outside the linear actuator, force\torque closed-loop control can be achieved, and the three-loop (speed, position, force) control of the system can be realized as a whole to improve accuracy.

[0022] Furthermore, bearings are provided on both sides of the lead screw nut, sealing covers are provided at both ends of the housing, and the sealing covers are provided with sealing components.

[0023] The benefit of adopting the above technical solution is that the setting of the sealing component makes the linear actuator have excellent dust and water resistance, which can meet the needs of more application scenarios with higher protection requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0025] Figure 1 This is a schematic diagram of the overall structure of the biped robot of the present invention.

[0026] Figure 2 This is an enlarged view of A of the present invention

[0027] Figure 3 1 is a side view of the biped robot of the present invention

[0028] Figure 4 This is a rear view of the biped robot of the present invention.

[0029] Figure 5 This is the exploded view of the leg of the present invention

[0030] Figure 6 Schematic diagram of the connecting rod of the present invention

[0031] Figure 7 Schematic diagram of the connecting rod of the present invention

[0032] Figure 8 This is a schematic diagram of the cross shaft structure of the present invention.

[0033] Fig. 9 sectional view of the linear actuator of the present invention

[0034] The reference numerals in the accompanying drawings are as follows:

[0035] Main body connection part 1; thigh part 2; thigh rotation joint 21; thigh rotation joint 1 211; thigh rotation joint 2 212; thigh leg lifting linear joint 22; calf bending linear joint 23; thigh support plate 24; thigh adapter 25; calf part 3; ankle linear joint 31; ankle linear joint 1 311; ankle linear joint 2 312; calf support plate 32; cross shaft 33; sole assembly 4; connecting rod 1 51; connecting rod 2 52; connecting shaft 53; connecting rod Three 54; pin shaft 1 541; pin shaft 2 542; first connecting part 543; second connecting part 544; connecting rod four 55; lug 551; linear joint encoder 1 61; linear joint encoder 2 62; ankle linear encoder 3 63; ankle linear encoder 4 64; housing 7; motor 71; stator 711; rotor 712; sealing cover 72; encoder 73; output shaft 74; screw nut 75; connecting seat 1 76; connecting seat 2 77; sensor 78. DETAILED DESCRIPTION

[0036] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0037] like Figure 1-5 As shown, the present invention discloses a biped robot, comprising: a main body connection part 1 and legs arranged on both sides of the main body connection part 1, the legs are symmetrically arranged on the left and right sides of the main body connection part 1, the legs include a thigh part 2, a calf part 3, a sole assembly 4 and a connecting rod assembly connected in sequence; the thigh part 2 includes: a thigh rotation joint 21, a thigh leg lifting linear joint 22, a calf bending linear joint 23 and a thigh support plate 24, the thigh leg lifting linear joint 22 and the calf bending linear joint 23 are both linear actuators, and are arranged in reverse, and both ends of the thigh leg lifting linear joint 22 and the two ends of the calf bending linear joint 23 are rotatably installed; the calf part 3 includes an ankle linear joint 31 and a calf support plate 32, the upper end of the ankle linear joint 31 is rotatably connected to the calf support plate 32, and the lower end is connected to the sole assembly 4. The ankle linear joint 31 is also a linear actuator.

[0038] In some embodiments, the connecting rod assembly includes connecting rod 1 51, connecting rod 2 52 and connecting shaft 53, which are used to connect the thigh rotating joint 21, the thigh leg lifting linear joint 22 and the thigh support plate 24. The connecting shaft 53 is provided with a linear joint encoder 1 61. The connecting shaft 53 connects the thigh adapter 25 and the thigh support plates 24 on both sides. The thigh rotating joint 21 is rotatably connected to the connecting rod 1 51 through the thigh adapter 25. The thigh adapter 25 is fixedly connected to the thigh rotating joint 21 and rotates under the drive of the thigh rotating joint 21. The output end of the thigh leg lifting linear joint 22 is rotatably connected to the connecting rod 1 51, and the other end of the connecting rod 1 51 is rotatably connected to the thigh adapter 25. The connecting rod 1 51 and the connecting rod 2 52 are relatively rotatably connected, and one end of the connecting rod 2 52 is rotatably connected to the thigh support plate 24. When the lead screw shaft of the thigh leg lifting linear joint 22 is pushed out, the entire thigh can be lifted.

[0039] In some embodiments, the connecting rod assembly further includes a connecting rod 3 54 and a connecting rod 4 55 ( Figure 6-7 As shown), connecting rod three 54 and connecting rod four 55 are connected by pin shaft one 541, the thigh support plate 24 and the calf support plate 32 are also connected by pin shaft two 542, pin shaft two 542 is provided with linear joint encoder two 62, the upper end of connecting rod one 51 is rotatably connected to the thigh support plate 24, the lower end of connecting rod four 55 is connected to the calf support plate 32, one end of the calf bending linear joint 23 is rotatably connected to the thigh support plate 24, the output end of the calf bending linear joint 23 is rotatably connected to the pin shaft one 541, when the screw shaft of the calf bending linear joint 23 is pushed out, the whole calf can be bent backward; the thigh leg lifting linear joint 22 and the calf bending linear joint 23 coordinate with each other to realize the bending action of the thigh and calf, and realize anthropomorphic walking through control.

[0040] The setting of the connecting rod assembly optimizes the motion trajectory of the thigh lifting and calf bending movements, reduces singular points, and at the same time increases the force arm of the push-out force of the linear joints of the thigh lifting and calf bending movements, making the output of the linear joints in the entire process smoother and reducing impact. Simplifying the bipedal robot of this application, the thigh lifting linear joint 22 pushes the thigh support plate 24 to rotate around the thigh adapter 25 to achieve the thigh lifting movement, and the calf bending linear joint 23 pushes the calf support plate 32 to rotate around the thigh support plate 24 to achieve the calf bending movement.

[0041] Furthermore, connecting rod three 54 includes a first connecting portion 543 and a symmetrically arranged second connecting portion 544 extending to the side, the second connecting portion 544 is provided with a connecting hole for the pin shaft 1 541 to pass through, connecting rod four 55 is provided with an ear 551 connected to the pin shaft 1 541, and the other end of connecting rod four 55 is connected to the calf support plate 32.

[0042] In some embodiments, the ankle linear joint 31 includes an ankle linear joint 1 311 and an ankle linear joint 2 312 arranged side by side, one end of which is rotatably connected to the calf support plate 32, and the other end is rotatably connected to the sole assembly 4, and a cross shaft 33 is arranged at the lower end of the calf support plate 32 ( Figure 8 The calf support plate 32 is connected to the sole assembly 4, and the cross shaft 33 is provided with an ankle linear encoder 3 63 and an ankle linear encoder 4 64. The calf support plate 32 is connected to the sole assembly 4 through the cross shaft 33, so that the sole assembly 4 can realize relative rotation in two directions around the calf support plate 32. When the ankle linear joint 1 311 and the ankle linear joint 2 312 are pushed out or retracted together, the pitch motion (Pitch motion) of the sole assembly 4 can be realized; when the ankle linear joint 1 311 and the ankle linear joint 2 312 perform differential motion, the roll motion (Roll motion) of the sole assembly 4 can be realized.

[0043] Furthermore, the thigh rotation joint 21 includes: a thigh rotation joint 211 and a thigh rotation joint 212, the rotation axes of the thigh rotation joint 211 and the thigh rotation joint 212 are perpendicular, the thigh rotation joint 211 and the thigh rotation joint 212 are both installed on the main connecting part 1, the thigh rotation joint 212 is connected to the thigh connection joint 1, and the thigh connection joint 2 is driven by the thigh connection joint 1 to rotate, the thigh rotation joint 212 is connected to the thigh adapter 25, the application of rotation joints in robots is existing technology, and there are many choices, and its specific structure will not be described here.

[0044] Furthermore, the thigh support plates 24 are symmetrically arranged, and the thigh leg lifting linear joint 22 and the calf bending linear joint 23 are located between the thigh support plates 24 .

[0045] In the present application, there is also an encoder inside the thigh leg lifting linear joint 22, and the two encoders cooperate to achieve closed-loop control, avoiding errors in the transmission process, reducing the amount of calculation for solving the rotation angle of the thigh support plate 24, and avoiding calculation errors. Similarly, linear joint encoder 1 61 and linear joint encoder 2 62 are installed between the thigh support plate 24 and between the thigh support plate 24 and the calf support plate 32, and can directly and accurately read the rotation angle and speed data of the calf support plate 32, and cooperate with the calf bending linear joint 23 to achieve closed-loop control of the dual encoders; similarly, linear joint encoder 3 and linear joint encoder 4 installed at the ankle position can directly read the data of the Pitch and Roll motion of the sole assembly 4, and form a closed-loop control with the ankle linear joint 31.

[0046] In some embodiments, the present application also discloses a linear actuator (such as Fig. 9As shown), the biped robot applied to the above technical solution includes: a shell 7, a motor 71, a planetary ball screw group, and an encoder 73. The motor 71 is arranged in the shell 7. The motor 71 has a stator 711 and a rotor 712. The planetary ball screw group includes an output shaft 74 and a screw nut 75. The rotor 712 is sleeved on the outer surface of the screw nut 75 to reduce the space occupied by the motor. A bearing seat is arranged at one end of the screw nut 75, and a bearing is arranged in the bearing seat. The encoder 73 is arranged at one end of the screw nut 75 and is installed on the bearing seat. The rotation of the motor 71 drives the screw nut 75 to rotate, and the output shaft 74 is pushed out or retracted. At the same time, the encoder 73 senses the rotation speed and angle of the screw nut 75, and can directly obtain the angle, speed and other data of the rotor 712 of the motor 71, so as to realize the control of the motor 71. At the same time, no separate reducer is required, which greatly shortens the total length of the actuator.

[0047] Furthermore, a connection seat 1 76 and a connection seat 2 77 are provided on both sides of the housing 7, which can be used to install and fix the linear actuator. The connection seat 1 76 is connected to the housing 7 via a sensor 78, and the connection seat 2 77 is connected to the extended end of the output shaft 74. The sensor 78 can be a force sensor, which can directly read the tension or pressure data of the linear actuator during the action process, and compare it with the torque data of the motor 71 to achieve closed-loop control of force / torque;

[0048] Furthermore, bearings are provided on both sides of the lead screw nut 75, sealing covers 72 are provided at both ends of the housing 7, and the sealing covers 72 are provided with sealing assemblies. The sealing assemblies include sealing rings arranged on the outside of the bearings and oil seals arranged at the output shaft 74, which can ensure the waterproof effect of the linear actuator and make the application scenarios of the linear actuator more extensive.

[0049] This application has the following advantages:

[0050] 1. The biped robot of the present application adopts a linear actuator as the actuator, which can provide a large load capacity, and can optimize the system force through a four-link design;

[0051] 2. By setting encoders at the joint rotation, the speed and position closed-loop control of the biped robot dual encoders can be achieved. Compared with the solution of a single encoder or directly adding a displacement sensor at the position 74 of the linear actuator output shaft, the errors in the transmission process and the calculation conversion process are eliminated, the control accuracy is improved, and the control difficulty is reduced; by setting a force sensor at the end of the actuator, the closed-loop control of the actuator force / torque is achieved;

[0052] 3. The linear actuator adopts the transmission scheme of planetary ball screw, which has the characteristics of large load, high motion precision, long life and small size, and can meet the requirements of large load, high response speed and high precision of bipedal robots;

[0053] 4. The linear actuator is a waterproof actuator that can meet the needs of more application scenarios with higher protection requirements.

[0054] For those skilled in the art, several modifications and improvements can be made without departing from the inventive concept of the present invention, all of which fall within the protection scope of the present invention.

Claims

1. A bipedal robot, characterized in that: include: A main body connection part (1) and legs arranged on both sides of the main body connection part (1), the legs comprising a thigh part (2), a calf part (3), a sole assembly (4) and a connecting rod assembly connected in sequence; the thigh part (2) comprising: a thigh rotation joint (21), a thigh leg lifting linear joint (22), a calf bending linear joint (23) and a thigh support plate (24), the thigh leg lifting linear joint (22) and the calf bending linear joint (23) are both linear actuators and are arranged in opposite directions, and both ends of the thigh leg lifting linear joint (22) and the two ends of the calf bending linear joint (23) are both rotatably mounted; the calf part (3) comprises an ankle linear joint (31) and a calf support plate (32), the upper end of the ankle linear joint (31) is rotatably connected to the calf support plate (32), and the lower end is connected to the sole assembly (4).

2. The biped robot according to claim 1, characterized in that: The connecting rod assembly includes connecting rod one (51) and connecting rod two (52), which are used to connect the thigh rotating joint (21), the thigh leg lifting linear joint (22) and the thigh support plate (24), and also includes a connecting shaft (53) for connecting the thigh support plate (24) and the thigh rotating joint (21), and the connecting shaft (53) is provided with a linear joint encoder one (61).

3. The biped robot according to claim 1, characterized in that: The connecting rod assembly also includes connecting rod three (54) and connecting rod four (55) for connecting the thigh part (2) and the calf part (3), and the connecting rod three (54) and connecting rod four (55) are connected by pin one (541), and the thigh support plate (24) and the calf support plate (32) are also connected by pin two (542), and the pin two (542) is provided with linear joint encoder two (62).

4. The biped robot according to claim 3, characterized in that: The connecting rod three (54) includes a first connecting portion (543) and a symmetrically arranged second connecting portion (544) extending to the side, the second connecting portion (544) is provided with a connecting hole for the pin shaft one (541) to pass through, the connecting rod four (55) is provided with an ear (551) connected to the pin shaft one (541), and the other end of the connecting rod four (55) is connected to the calf support plate (32).

5. The biped robot according to claim 1, characterized in that: The ankle linear joint (31) comprises an ankle linear joint 1 (311) and an ankle linear joint 2 (312) arranged side by side, one end of which is rotationally connected to a calf support plate (32) and the other end of which is rotationally connected to a sole assembly (4); a cross shaft (33) is arranged at the lower end of the calf support plate (32) and is connected to the sole assembly (4); an ankle linear encoder 3 (63) and an ankle linear encoder 4 (64) are arranged on the cross shaft (33).

6. The biped robot according to claim 1, characterized in that: The thigh rotation joint (21) comprises: a thigh rotation joint 1 (211) and a thigh rotation joint 2 (212), and the rotation axes of the thigh rotation joint 1 (211) and the thigh rotation joint 2 (212) are perpendicular.

7. The biped robot according to claim 1, characterized in that: The thigh support plates (24) are symmetrically arranged, and the thigh leg lifting linear joint (22) and the calf bending linear joint (23) are located between the thigh support plates (24).

8. A linear actuator, characterized in that: The bipedal robot applied to the above claims 1-7 comprises: a housing (7), a motor (71), a planetary ball screw assembly, and an encoder (73), wherein the motor (71) is arranged in the housing (7), the planetary ball screw assembly comprises an output shaft (74) and a screw nut (75), the screw nut (75) is connected to the motor (71), and the encoder (73) is arranged at one end of the screw nut (75).

9. The linear actuator according to claim 6, characterized in that: A connecting seat 1 (76) and a connecting seat 2 (77) are provided on both sides of the shell (7); the connecting seat 1 (76) is connected to the shell (7) via a sensor (78), and the connecting seat 2 (77) is connected to the protruding end of the output shaft (74).

10. The linear actuator according to claim 1, characterized in that: Bearings are arranged on both sides of the lead screw nut (75), sealing covers (72) are arranged at both ends of the housing (7), and the sealing covers (72) are provided with sealing components.

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