Robot leg structure and biped robot

Abstract

The invention belongs to the related technical field of robots, and discloses a robot leg structure and a biped robot, a hip joint module in the leg structure comprises a side extension driving module, a turnover driving module and a pitching driving module, one ends of the three modules are installed on a hip joint installation frame in a series connection mode, and the other ends of the three modules are connected with thighs; the knee joint module is located in the containing cavity of the thigh part, the knee joint module comprises a linear driving module, the fixed end of the linear driving module is rotationally connected with the upper portion of the thigh part, the movable end of the linear driving module is in transmission connection with the top of the shank part, and the linear driving module drives the shank part to do pitching motion through linear telescopic movement; the bottom of the shank part is hinged to the foot bottom part through a cross shaft structure, and the ankle joint module is arranged on the shank part and is in transmission connection with the foot bottom part so as to complete pitching and side stretching movement. The design of hybrid driving of the linear and rotary joint modules gives consideration to the requirements of high robustness and low energy consumption of the foot-type robot in a real scene.

Description

Technical Field

[0001] The present invention belongs to the technical field related to robots, and more specifically, relates to a robot leg structure and a biped robot. Background Art

[0002] With the rapid development of the reinforcement learning motion control algorithm for legged robots, biped robots have received a great deal of attention and achieved remarkable development due to their high terrain passability and natural high adaptability to the human living environment.

[0003] Currently, there are mainly two configurations for twelve-degree-of-freedom biped robots. One is to use rotary motors to drive all twelve degrees of freedom. The advantage of this configuration is that it maximally utilizes the high dynamic force-position response advantage of the rotary joint module, improving the robustness of the robot when walking in an unstructured ground environment. The disadvantage is that in the actual application scenarios of biped robots, the proportion of low-dynamic working conditions is very large. Due to the electrical characteristics limitations of the rotary joint module, when the robot is in a low-dynamic or quasi-static state, the energy consumption of the rotary joint module is relatively high.

[0004] The other solution is to use linear joint modules to drive all twelve degrees of freedom. The linear joint module usually uses a brushless DC motor to drive a planetary roller screw to output linear motion and then drive the joint motion. The planetary roller screw gives the joint module the characteristic of high rigidity, with the advantages of large load and low energy consumption, but it sacrifices part of the dynamic response ability of the robot and reduces the robustness. Summary of the Invention

[0005] Aiming at the above defects or improvement requirements of the prior art, the present invention provides a robot leg structure and a biped robot, which are used to solve the contradiction of high energy consumption in the configuration scheme of using all rotary joints and poor robustness in all linear joints in the existing biped robot configuration.

[0006] To achieve the above object, according to one aspect of the present invention, a robot leg structure is provided, which is composed of a hip joint module, a thigh part, a knee joint module, a calf part, an ankle joint module, and a foot bottom, wherein:

[0007] The hip joint module includes a lateral abduction drive module, a circumduction drive module, and a pitch drive module. The three modules are installed at one end on the hip joint mounting frame in series, and the other end is connected to the top of the thigh part. Each of the three modules contains a rotary motor, and they are combined to form a three-degree-of-freedom hip joint;

[0008] The bottom of the thigh part is rotatably connected to the top of the calf part. The thigh part has a receiving cavity, and the knee joint module is located in the receiving cavity of the thigh part. The knee joint module includes a linear drive module. The fixed end of the linear drive module is rotatably connected to the upper part of the thigh part, and the moving end of the linear drive module is drivingly connected to the top of the calf part. The linear drive module drives the calf part to perform pitching motion through linear telescopic movement;

[0009] The bottom of the calf part is hinged to the sole part through a cross-axis structure. The ankle joint module is arranged on the calf part, and the ankle joint module is drivingly connected to the sole part to drive the sole part to complete pitching and abduction motions.

[0010] According to the robot leg structure provided by the present invention, the hip joint mounting frame includes a front bracket, a rear bracket and a connecting plate. The front bracket and the rear bracket are respectively connected to the connecting plate to form a receiving cavity; the abduction drive module includes an abduction drive motor, and the output end of the abduction drive motor is connected to the rear bracket. The slewing drive module is located in the receiving cavity between the front bracket and the rear bracket. The slewing drive module includes a slewing drive motor and a slewing drive motor base. The output end of the slewing drive motor is connected to the slewing drive motor base. One end of the slewing drive motor base is connected to the output shaft of the abduction drive motor, and the other end is hinged to the front bracket;

[0011] The pitching drive module includes a pitching drive motor and a bracket assembly. The pitching drive motor is connected to the output shaft of the slewing drive motor through the bracket assembly, and the output shaft of the pitching drive motor is connected to the top of the thigh part.

[0012] According to the robot leg structure provided by the present invention, the slewing drive module further includes a slewing crossed roller bearing, an inner ring pressing flange of the bearing and an outer ring pressing flange of the bearing; the slewing crossed roller bearing is arranged in the opening of the slewing drive motor base. The output shaft of the slewing drive motor is connected to the inner ring pressing flange of the bearing. The inner ring pressing flange of the bearing is in abutting fit with the inner ring of the slewing crossed roller bearing. The outer ring pressing flange of the bearing is connected to the slewing drive motor base. The outer ring pressing flange of the bearing and the slewing drive motor base jointly press the outer ring of the slewing crossed roller bearing; the bracket assembly is connected to the inner ring pressing flange of the bearing.

[0013] According to the robot leg structure provided by the present invention, the bracket assembly includes a pitch motor bracket and an auxiliary bracket arranged on both sides of the pitch drive motor, the tops of the pitch motor bracket and the auxiliary bracket are simultaneously connected to the bearing inner ring clamping flange, and the top of the pitch motor bracket is simultaneously abutted against the inner ring of the epicyclic cross roller bearing; the tail end of the pitch drive motor is connected to the pitch motor bracket, the auxiliary bracket is connected to the output end of the pitch drive motor, the pitch motor bracket is connected to one end of the pitch bearing seat, the other end of the pitch bearing seat is connected to the pitch cross roller bearing, one side of the top of the thigh is connected to the output shaft of the pitch drive motor, and the other side is connected to the pitch cross roller bearing.

[0014] According to the robot leg structure provided by the present invention, the thigh part includes a thigh outer plate and a thigh inner plate that are relatively arranged, the thigh outer plate and the thigh inner plate are connected to each other by a plug bolt to form a accommodating cavity, the thigh outer plate and the thigh inner plate are connected to each other at the upper part by a first plug bolt, and the fixed end of the linear drive module can be rotatably connected to the first plug bolt.

[0015] According to the robot leg structure provided by the present invention, the outer thigh plate and the inner thigh plate are also connected at the lower part by the second driving bolt and the third driving bolt; the linear drive module is transmission-connected to the calf through the upper knee link and the lower knee link, the moving end of the linear drive module is rotationally connected to the first end of the upper knee link and the first end of the lower knee link at the same time, the second end of the upper knee link is rotatably connected to the second driving bolt, the second end of the lower knee link is rotationally connected to the top of the calf, and the top of the calf is also rotationally connected to the thigh through the third driving bolt.

[0016] According to the robot leg structure provided by the present invention, the upper knee link and the lower knee link are both Y-shaped, and the first end of the upper knee link and the first end of the lower knee link are respectively forked ends.

[0017] According to the robot leg structure provided by the present invention, the movable end of the linear drive module, the first end of the upper knee link and the first end of the lower knee link are respectively sleeved on the upper and lower link shafts, knee joint bearings are respectively provided between the first end of the upper knee link and the upper and lower link shafts and between the first end of the lower knee link and the upper and lower link shafts, and upper and lower link shaft sleeves are provided on the upper and lower link shafts at a position located on one side of the knee joint bearings.

[0018] According to the robot leg structure provided by the present invention, the ankle joint module includes two ankle joint drive motors installed upper and lower on the calf, and rockers are installed on the output shafts of the two ankle joint drive motors. The upper rocker is hinged to one end of a long connecting rod, and the lower rocker is hinged to one end of a short connecting rod. The other ends of the long connecting rod and the short connecting rod are respectively hinged to the sole of the foot and distributed on both sides of the sole of the foot.

[0019] According to another aspect of the present invention, there is provided a bipedal robot comprising any one of the robot leg structures described above.

[0020] In general, compared with the prior art, the robot leg structure and bipedal robot provided by the present invention are:

[0021] 1. The use of rotary joint modules to drive the three degrees of freedom of the hip joint and the two degrees of freedom of the ankle can ensure that the robot has basic high dynamic characteristics. The use of linear joint modules to drive one degree of freedom of the knee joint can greatly reduce the energy consumption of the robot under low dynamic conditions and increase the robot load. This hybrid drive design of linear and rotary joint modules takes into account the high robustness and low energy consumption requirements of the legged robot in real scenarios.

[0022] 2. The specific connection structure space design of the three modules in the hip joint module is reasonable and compact, with a simple structure and easy assembly; the linear drive module in the knee joint module is specifically connected to the calf through the upper knee connecting rod and the lower knee connecting rod, which is conducive to improving the stability of the transmission;

[0023] 3. The Y-shaped structure design of the upper knee link and the lower knee link can blunt the quick return characteristics of the link mechanism, that is, the torque and speed output at the end are more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the structure of a biped robot according to an embodiment of the present invention;

[0025] Figure 2 An exploded view of a hip joint module according to an embodiment of the present invention;

[0026] Figure 3 This is an exploded view of a turnover drive module according to an embodiment of the present invention;

[0027] Figure 4 This is an exploded view of a pitch drive module according to an embodiment of the present invention;

[0028] Figure 5 A diagram showing a thigh portion of an embodiment of the present invention;

[0029] Figure 6It is the exploded view of the knee joint module shown in the embodiment of the present invention;

[0030] Figure 7 It is the exploded view of the ankle joint module shown in the embodiment of the present invention;

[0031] In all the drawings, the same reference numerals are used to represent the same elements or structures, where:

[0032] 1. Hip joint module; 11. Hip joint mounting frame; 12. Abduction drive module; 13. Revolution drive module; 14. Pitch drive module; 111. Front bracket; 112. Rear bracket; 113. Connecting plate; 131. Revolution drive motor; 132. Inner ring pressing flange of bearing; 133. Base of revolution drive motor; 134. Revolution bearing; 135. Revolution crossed roller bearing; 136. Outer ring pressing flange of bearing; 141. Auxiliary bracket; 142. Pitch drive motor; 143. Pitch motor bracket; 144. Pitch bearing seat; 145. Pitch crossed roller bearing; 2. Leg main body; 21. Thigh part; 22. Calf part; 211. Outer thigh plate; 212. Inner thigh plate; 213. First set screw; 214. Second set screw; 215. Third set screw; 3. Knee joint module; 31. Linear cylinder; 32. Upper knee connecting rod; 33. Lower knee connecting rod; 34. Upper and lower connecting rod shaft; 35. Inner side upper and lower connecting rod bushing; 36. Outer side upper and lower connecting rod bushing; 37. Lower connecting rod calf shaft; 38. Lower connecting rod bushing; 39. Knee joint bearing; 4. Ankle joint module; 41. Ankle joint drive motor; 42. Rocker; 43. Long connecting rod; 44. Short connecting rod; 45. Connecting rod shaft; 46. Eyeball bearing; 47. Ankle joint bushing; 48. Connecting rod cover plate; 49. Cross shaft structure; 50. Ankle joint bearing; 51. Axial end nut; 52. Foot sole. Detailed implementation manners

[0033] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0034] Please refer to Figure 1 , this embodiment provides a robot leg structure, which is composed of a hip joint module 1, a thigh part 21, a knee joint module 3, a calf part 22, an ankle joint module 4 and a foot bottom part. The thigh part 21 and the calf part 22 form a leg main body 2, where:

[0035] The hip joint module 1 includes an abduction drive module 12, a circumduction drive module 13, and a pitch drive module 14. The three modules are installed at one end on the hip joint mounting frame 11 in series, and the other end is connected to the top of the thigh part 21. Each of the three modules includes a rotary motor, which are combined to form a three-degree-of-freedom hip joint and can independently drive the thigh part 21 to move in three directions: abduction, circumduction, and pitch.

[0036] The bottom of the thigh part 21 is rotatably connected to the top of the calf part 22. The thigh part 21 has a receiving cavity, and the knee joint module 3 is located in the receiving cavity of the thigh part 21. The knee joint module 3 includes a linear drive module. The fixed end of the linear drive module is rotatably connected to the upper part of the thigh part 21, and the moving end of the linear drive module is drivingly connected to the top of the calf part 22. The linear drive module drives the calf part 22 to perform a pitch movement through linear telescopic movement.

[0037] The bottom of the calf part 22 is hinged to the bottom of the foot through a cross-axis structure 49. The ankle joint module 4 is provided on the calf part 22, and the ankle joint module 4 is drivingly connected to the bottom of the foot to drive the bottom of the foot to complete pitch and abduction movements.

[0038] In some specific embodiments, referring to Figure 2 and Figure 3 , the hip joint mounting frame 11 includes a front bracket 111, a rear bracket 112, and a connecting plate 113. The front bracket 111 and the rear bracket 112 are respectively connected to the connecting plate 113 through bolts or the like to form a receiving cavity. The abduction drive module 12 includes an abduction drive motor, which is a rotary motor. The output end of the abduction drive motor is connected to the rear bracket 112 through bolts or the like.

[0039] The circumduction drive module 13 is located in the receiving cavity between the front bracket 111 and the rear bracket 112. The circumduction drive module 13 includes a circumduction drive motor 131 and a circumduction drive motor base 133. The output end of the circumduction drive motor 131 is connected to the circumduction drive motor base 133 through screws or the like. One end of the circumduction drive motor base 133 is connected to the output shaft of the abduction drive motor, and the other end is hinged to the front bracket 111. The output end of the motor is the end provided with the output shaft, and the connection of the output end refers to the connection of the motor housing components.

[0040] One end of the circumduction drive motor base 133 is provided with a mounting boss, and the mounting boss is connected to the output shaft of the abduction drive motor through screws. The other end of the circumduction drive motor base 133 is provided with a connecting shaft, and the front bracket 111 is provided with a mounting hole. The connecting shaft is inserted into the mounting hole and is rotatably connected to the front bracket 111 through a circumduction bearing 134.

[0041] During assembly, the side expansion drive module 12 should be first installed on the rear bracket 112, and then the turnover drive motor base 133 is connected to the output shaft of the side expansion drive module 12 with screws and the rear bracket 112 is installed on the connecting plate 113, ensuring that the other end of the turnover drive motor base 133 is located within the bearing hole of the front bracket 111. Then, the turnover bearing 134 is installed into the bearing hole of the front bracket 111, so that the outer ring of the turnover bearing 134 fits with the bearing hole and the inner ring fits with the other end of the turnover drive motor base 133. Finally, a retaining ring is installed to prevent the turnover bearing 134 from falling off. Thus, the turnover drive module 13 is hinged to the hip joint mounting frame 11, and the side expansion drive module 12 can drive the turnover drive module 13 to perform a side expansion movement.

[0042] Reference Figure 3 and Figure 4 The pitching drive module 14 includes a pitching drive motor 142 and a bracket assembly. The pitching drive motor 142 is connected to the output shaft of the turnover drive motor 131 through the bracket assembly, and the output shaft of the pitching drive motor 142 is connected to the top of the thigh part 21.

[0043] The turnover drive module 13 further includes a turnover crossed roller bearing 135, an inner ring pressing flange 132 of the bearing, and an outer ring pressing flange 136 of the bearing. The turnover crossed roller bearing 135 is arranged in the opening of the turnover drive motor base 133. The output shaft of the turnover drive motor 131 is connected to the inner ring pressing flange 132 of the bearing with screws or the like. The inner ring pressing flange 132 abuts and cooperates with the inner ring of the turnover crossed roller bearing 135. The outer ring pressing flange 136 is connected to the turnover drive motor base 133, and the outer ring pressing flange 136 and the turnover drive motor base 133 jointly press the outer ring of the turnover crossed roller bearing 135. The bracket assembly is connected to the inner ring pressing flange 132 of the bearing.

[0044] Reference Figure 3 There is a circular opening in the middle of the turnover drive motor base 133, and the circular opening is provided with a stepped opening on the downward side. The turnover crossed roller bearing 135 is placed on the stepped surface of the stepped opening, specifically, the outer ring is placed on the stepped surface and the inner ring is located inside the circular opening. The bottom of the inner ring pressing flange 132 of the bearing is provided with a convex platform, and the convex platform is inserted into the inner ring of the turnover crossed roller bearing 135 and is in contact with the inner wall surface of the inner ring. At the same time, the inner ring pressing flange 132 of the bearing is pressed on the upper end surface of the inner ring. So that the inner ring pressing flange 132 cooperates with the inner ring of the turnover crossed roller bearing 135 and abuts against the end face of the inner ring of the turnover crossed roller bearing 135.

[0045] The outer ring pressing flange 136 of the bearing is also provided with an opening, and the upper end surface is provided with a circle of annular bosses at the outer edge of the opening. When the outer ring pressing flange 136 of the bearing is connected to the epicyclic drive motor base 133 by screws, the annular bosses are pressed against the lower end surface of the outer ring of the epicyclic cross roller bearing 135. The outer ring pressing flange 136 of the bearing and the epicyclic drive motor base 133 are pressed against the outer ring of the epicyclic cross roller bearing 135 together. Specifically, the circular opening on the epicyclic drive motor base 133 is set as a secondary step surface on the downward side, the outer ring of the epicyclic cross roller bearing 135 is placed on the upper step surface, and the outer ring ground is flush with the lower step surface, so that the annular bosses on the outer ring pressing flange 136 of the bearing are pressed against the outer ring and the lower step surface at the same time; then the edge of the outer ring pressing flange 136 of the bearing is connected to the epicyclic drive motor base 133.

[0046] When assembling the epicyclic drive module 13, the epicyclic drive motor 131 should be installed first, then the bearing inner ring clamping flange 132 should be installed, and then the epicyclic cross roller bearing 135 should be installed. After confirming that the inner ring, outer ring and inner ring end face of the epicyclic cross roller bearing 135 are in place, the bearing outer ring clamping flange 136 should be installed. The pitch drive module 14 is connected to the epicyclic drive module 13 through the bearing inner ring clamping flange 132, so that the epicyclic drive module 13 can drive the pitch drive module 14 to perform epicyclic motion.

[0047] refer to Figure 4 The bracket assembly includes a pitch motor bracket 143 and an auxiliary bracket 141 disposed on both sides of the pitch drive motor 142. The tops of the pitch motor bracket 143 and the auxiliary bracket 141 are simultaneously connected to the bearing inner ring pressing flange 132. The flange plate on the top of the auxiliary bracket 141 can be simultaneously connected to the bearing inner ring pressing flange 132 below the flange plate on the top of the pitch motor bracket 143. The bolts for installing the auxiliary bracket 141 will pass through the through holes at the corresponding positions of the pitch motor bracket 143 and be connected to the bearing inner ring pressing flange 132.

[0048] The upper end of the flange at the top of the pitch motor bracket 143 may be provided with a boss, which may be inserted into the inner ring of the epicyclic cross roller bearing 135, and at the same time, the flange at the top of the pitch motor bracket 143 presses the lower end surface of the inner ring. The top of the pitch motor bracket 143 is simultaneously abutted against the inner ring of the epicyclic cross roller bearing 135, and together with the bearing inner ring pressing flange 132, presses the inner ring of the epicyclic cross roller bearing 135.

[0049] The tail end of the pitching drive motor 142 is connected to the pitching motor bracket 143. The auxiliary bracket 141 is connected to the output end of the pitching drive motor 142. The pitching motor bracket 143 and one end of the pitching bearing block 144 are connected by screws or the like. The other end of the pitching bearing block 144 is connected with a pitching crossed roller bearing 145, for example, connected to the outer ring of the pitching crossed roller bearing 145 by screws. One side of the top of the thigh part 21 is connected to the output shaft of the pitching drive motor 142, and the other side is connected to the pitching crossed roller bearing 145, for example, connected to the inner ring of the pitching crossed roller bearing 145 by screws.

[0050] Reference Figure 5 , the thigh part 21 includes a relatively arranged thigh outer plate 211 and a thigh inner plate 212. The thigh outer plate 211 and the thigh inner plate 212 are connected by dowel bolts to form a receiving cavity. The thigh outer plate 211 and the thigh inner plate 212 are connected by a first dowel bolt 213 at the upper part. The fixed end of the linear drive module is rotatably connected to the first dowel bolt 213.

[0051] The thigh inner plate 212 and the thigh outer plate 211 are provided with a hollow structure. Mounting posts are respectively arranged on the inner sides of the thigh inner plate 212 and the thigh outer plate 211. The mounting posts are provided with through holes for passing through the dowel bolts and also for limiting the components sleeved on the dowel bolts.

[0052] Reference Figure 5 , the thigh outer plate 211 and the thigh inner plate 212 are also connected by a second dowel bolt 214 and a third dowel bolt 215 at the lower part; the thigh outer plate 211 and the thigh inner plate 212 are connected by the first dowel bolt 213, the second dowel bolt 214 and the third dowel bolt 215 to form a receiving cavity. At the same time, the thigh outer plate 211 is connected to the inner ring of the pitching crossed roller bearing 145. Therefore, the pitching drive module 14 can drive the thigh part 21 to complete the pitching movement. The thigh inner plate 212 is connected to the output shaft of the pitching drive motor 142. The thigh part 21 and the calf part 22 are hinged together by the third dowel bolt 215 and a nut.

[0053] Reference Figure 5, the knee joint module 3 further includes an upper knee link 32 and a lower knee link 33; the linear drive module can be a linear electric cylinder 31. The linear drive module is drivingly connected to the lower leg part 22 through the upper knee link 32 and the lower knee link 33. The moving end of the linear drive module is rotatably connected to the first ends of both the upper knee link 32 and the lower knee link 33 at the same time. The second end of the upper knee link 32 is rotatably connected to a second set screw 214, and the second end of the lower knee link 33 is rotatably connected to the top of the lower leg part 22. The top of the lower leg part 22 is also rotatably connected to the thigh part 21 through a third set screw 215.

[0054] Specifically, both the upper knee link 32 and the lower knee link 33 are in a Y shape, including a large end and a small end. The end with a fork is the large end, and the end without a fork is the small end. The first ends of the upper knee link 32 and the lower knee link 33 are respectively the forked ends.

[0055] Reference Figure 6 , the moving end of the linear drive module, the first end of the upper knee link 32 and the first end of the lower knee link 33 are respectively sleeved on an upper and lower link shaft 34. Knee joint bearings 39 are respectively provided between the first end of the upper knee link 32 and the upper and lower link shaft 34 and between the first end of the lower knee link 33 and the upper and lower link shaft 34. And on the part of the upper and lower link shaft 34 on one side of the knee joint bearing 39, an upper and lower link shaft sleeve is provided.

[0056] Specifically, knee joint bearings 39 are installed at the large end and the small end of the upper knee link 32 and the lower knee link 33. The knee joint bearings 39 have flange edges, and the end with the flange edge faces the outside of the link during installation. The fixed end of the linear electric cylinder 31 is hinged to the outer thigh plate 211 and the inner thigh plate 212 through a first set screw 213, and the output end is rotatably connected coaxially with the large end of the upper knee link 32 and the large end of the lower knee link 33 through the upper and lower link shaft 34.

[0057] Circlips are installed at both ends of the upper and lower link shaft 34 to prevent the knee joint bearing 39 at the large end of the upper knee link 32 from falling off. The outer upper and lower link shaft sleeve 36 is installed between the knee joint bearings 39 of the upper knee link 32 and the lower knee link 33 for axial positioning; the inner upper and lower link shaft sleeve 35 is installed between the knee joint bearing 39 of the lower knee link 33 and the output end of the linear electric cylinder 31 for axial positioning. Knee joint bearings 39 are respectively installed on both sides of the hole at the small end of the upper knee link 32 to cooperate with the second set screw 214 to realize the hinge connection between the upper knee link 32 and the thigh part 21.

[0058] One end of the calf part 22 close to the thigh part 21 has four bearing mounting holes, two on the upper side and two on the lower side, for mounting the knee joint bearings 39. The end of the knee joint bearing 39 with a flange faces the outside of the calf part 22. The two upper knee joint bearings 39 are used to cooperate with the third plug bolt 215 to realize the hinge connection between the calf part 22 and the thigh part 21. The two lower knee joint bearings 39 and the knee joint bearings 39 on the small end of the lower connecting rod of the knee joint 33 are hinged through the lower connecting rod calf shaft 37. Axial positioning between the two bearings is carried out through the lower connecting rod bushing 38. Retaining rings are installed at both ends of the lower connecting rod calf shaft 37 to prevent the bearings from falling off. Thus, the movement of the output end of the linear electric cylinder will be transmitted to the calf part 22 through the upper connecting rod of the knee 32 and the lower connecting rod of the knee 33, driving the knee joint to bend. This knee joint mechanism can blunt the quick-return characteristic of the link mechanism, that is, the torque and speed of the end output are more stable.

[0059] Reference Figure 7 , the ankle joint module 4 includes two ankle joint driving motors 41 mounted up and down on the calf part 22. Rocking rods 42 are installed on the output shafts of the two ankle joint driving motors 41. The rocking rod 42 located above is hinged to one end of the long connecting rod 43, and the rocking rod 42 located below is hinged to one end of the short connecting rod 44. The other ends of the long connecting rod 43 and the short connecting rod 44 are respectively hinged to the bottom of the foot and are distributed on both sides of the bottom of the foot.

[0060] The calf part 22 includes a calf frame, and two annular mounting frames are provided on the calf frame for mounting the two ankle joint driving motors 41. The bottom of the foot includes a foot sole plate 52.

[0061] Specifically, the two ankle joint driving motors 41 are connected to the calf part 22 at the tail end, one inside and one outside, one above and one below. Among them, the ankle joint driving motor 41 with the output shaft facing the inside of the body is installed above the calf part 22, and the ankle joint driving motor 41 with the output shaft facing the outside of the body is installed below the calf part 22. Rocking rods 42 are installed on the output shafts of the two ankle joint driving motors 41. The rocking rod 42 located inside the body is hinged to one end of the long connecting rod 43, and the rocking rod 42 located outside the body is hinged to one end of the short connecting rod 44. The other end of the long connecting rod 43 is hinged to the inside of the foot sole plate 52, and the other end of the short connecting rod 44 is hinged to the outside of the foot sole plate 52. The long connecting rod 43 and the short connecting rod 44 are the same in structure except for the length, and the structures at both ends of the connecting rod are also the same. The structural details are introduced below taking the long connecting rod 43 as an example.

[0062] During assembly, first place the spherical eye bearing 46 into the bearing holes reserved at both ends of the long connecting rod 43, and fix the spherical eye bearing 46 through the connecting rod cover plate 48. Then, pass the connecting rod shaft 45 through the shaft hole of the rocker 42 and the inner ring of the spherical eye bearing 46 to achieve the hinged connection between the long connecting rod 43 and the rocker 42. There are retaining rings at both ends of the connecting rod shaft 45 to prevent it from slipping out of the hinged parts. The axial positioning of the inner ring of the spherical eye bearing 46 is achieved through the ankle joint bushing 47, and the ankle joint bushing 47 is sleeved on the connecting rod shaft 45. The two ends of the long connecting rod 43 and the short connecting rod 44 are both hinged to the rocker 42 and the foot plate 52 through the above method. The rotation of the ankle joint drive motor 41 is transmitted to the foot plate 52 through the rocker 42, the long connecting rod 43, and the short connecting rod 44, driving the foot plate 52 to complete the pitching and lateral expansion movements.

[0063] Furthermore, the cross-axis structure 49 includes two first shaft holes arranged along the same axial direction, and two second shaft holes arranged along another same axial direction. The axial directions of the first shaft holes and the second shaft holes can be perpendicular. The upper end of the calf part 22 is hinged to the thigh part 21, and the lower end is hinged to two coaxial shaft holes of the cross-axis structure 49, such as the first shaft holes. The other two coaxial shaft holes of the cross-axis structure 49, such as the second shaft holes, are hinged to the foot plate 52.

[0064] The hinged manner can be, for example, that the end face of the shaft hole of the cross-axis abuts and cooperates with the inner side end face of the inner ring of the ankle joint bearing 50, and the outer ring of the ankle joint bearing 50 cooperates with the stepped counterbore of the lower end of the calf part 22. The stepped counterbore can achieve the axial positioning of the calf part 22. The four shaft holes of the cross-axis are all threaded holes. By screwing the shaft end nut 51 into the threaded hole, the head of the shaft end nut 51 abuts and cooperates with the outer side end face of the inner ring of the ankle joint bearing 50, and the axial fixation of the ankle joint bearing 50 can be achieved. The foot plate 52 can be connected to the other two shaft holes of the cross-axis in the same hinged manner. Thus, the foot plate 52 can be connected to the calf part 22 through the cross-axis structure 49 to perform movements in two directions of pitching and lateral expansion. The hinged manner between the cross-axis structure 49 and the calf part 22 and between the cross-axis structure 49 and the foot plate 52 can also be other ways, aiming to enable the foot plate 52 to rotate in two degrees of freedom relative to the calf part 22, and the details will not be elaborated here.

[0065] Furthermore, this embodiment also provides a biped robot, which includes the robot leg structure described in any one of the above, specifically including two legs, and the two legs are chiral symmetric to each other.

[0066] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A robot leg structure, characterized in that, It is composed of a hip joint module, a thigh part, a knee joint module, a calf part, an ankle joint module and a sole part, where: The hip joint module includes a abduction drive module, a circumduction drive module and a pitch drive module. One end of the three modules is installed on the hip joint mounting frame in series, and the other end is connected to the top of the thigh part. Each of the three modules contains a rotary motor, and they are combined to form a three-degree-of-freedom hip joint; The bottom of the thigh part is rotatably connected to the top of the calf part. The thigh part has a receiving cavity. The knee joint module is located in the receiving cavity of the thigh part. The knee joint module includes a linear drive module. The fixed end of the linear drive module is rotatably connected to the upper part of the thigh part, and the moving end of the linear drive module is drivingly connected to the top of the calf part. The linear drive module drives the calf part to perform pitch motion through linear telescopic movement; The bottom of the calf part is hinged to the sole part through a cross-axis structure. The ankle joint module is arranged on the calf part, and the ankle joint module is drivingly connected to the sole part to drive the sole part to complete pitch and abduction motions.

2. The robot leg structure according to claim 1, characterized in that, The hip joint mounting frame includes a front bracket, a rear bracket and a connecting plate. The front bracket and the rear bracket are respectively connected to the connecting plate to form a receiving cavity; the abduction drive module includes an abduction drive motor, and the output end of the abduction drive motor is connected to the rear bracket. The circumduction drive module is located in the receiving cavity between the front bracket and the rear bracket. The circumduction drive module includes a circumduction drive motor and a circumduction drive motor base. The output end of the circumduction drive motor is connected to the circumduction drive motor base. One end of the circumduction drive motor base is connected to the output shaft of the abduction drive motor, and the other end is hinged to the front bracket; The pitch drive module includes a pitch drive motor and a bracket assembly. The pitch drive motor is connected to the output shaft of the circumduction drive motor through the bracket assembly, and the output shaft of the pitch drive motor is connected to the top of the thigh part.

3. The robot leg structure according to claim 2, characterized in that, The circumduction drive module further includes a circumduction crossed roller bearing, an inner ring pressing flange of the bearing and an outer ring pressing flange of the bearing; the circumduction crossed roller bearing is arranged in the opening of the circumduction drive motor base. The output shaft of the circumduction drive motor is connected to the inner ring pressing flange of the bearing. The inner ring pressing flange of the bearing is in abutting cooperation with the inner ring of the circumduction crossed roller bearing. The outer ring pressing flange of the bearing is connected to the circumduction drive motor base. The outer ring pressing flange of the bearing and the circumduction drive motor base jointly press the outer ring of the circumduction crossed roller bearing; the bracket assembly is connected to the inner ring pressing flange of the bearing.

4. The robot leg structure according to claim 3, characterized in that, The bracket assembly includes a pitch motor bracket and an auxiliary bracket arranged on both sides of the pitch drive motor, the tops of the pitch motor bracket and the auxiliary bracket are simultaneously connected to the bearing inner ring clamping flange, and the top of the pitch motor bracket is simultaneously abutted against the inner ring of the epicyclic cross roller bearing; the tail end of the pitch drive motor is connected to the pitch motor bracket, the auxiliary bracket is connected to the output end of the pitch drive motor, the pitch motor bracket is connected to one end of the pitch bearing seat, the other end of the pitch bearing seat is connected to the pitch cross roller bearing, one side of the top of the thigh is connected to the output shaft of the pitch drive motor, and the other side is connected to the pitch cross roller bearing.

5. The robot leg structure according to any one of claims 1-4, characterized in that, The thigh portion includes an outer thigh plate and an inner thigh plate that are relatively arranged. The outer thigh plate and the inner thigh plate are connected to each other by a plug bolt to form a accommodating cavity. The outer thigh plate and the inner thigh plate are connected to each other at the upper part by a first plug bolt. The fixed end of the linear drive module can be rotatably connected to the first plug bolt.

6. The robot leg structure according to claim 5, characterized in that, The outer thigh plate and the inner thigh plate are also connected at the lower part by the second driving bolt and the third driving bolt; the linear drive module is transmission-connected to the calf through the upper knee connecting rod and the lower knee connecting rod, the movable end of the linear drive module is rotationally connected to the first end of the upper knee connecting rod and the first end of the lower knee connecting rod at the same time, the second end of the upper knee connecting rod is rotatably connected to the second driving bolt, the second end of the lower knee connecting rod is rotationally connected to the top of the calf, and the top of the calf is also rotationally connected to the thigh through the third driving bolt.

7. The robot leg structure according to claim 6, characterized in that, The upper knee connecting rod and the lower knee connecting rod are both Y-shaped, and the first end of the upper knee connecting rod and the first end of the lower knee connecting rod are respectively forked ends.

8. The robot leg structure according to claim 6, characterized in that, The movable end of the linear drive module, the first end of the upper knee link and the first end of the lower knee link are respectively sleeved on the upper and lower link shafts, and knee joint bearings are respectively provided between the first end of the upper knee link and the upper and lower link shafts and between the first end of the lower knee link and the upper and lower link shafts, and upper and lower link shaft sleeves are provided on the upper and lower link shafts at a position located on one side of the knee joint bearings.

9. The robot leg structure according to any one of claims 1-4, characterized in that, The ankle joint module includes two ankle joint drive motors installed upper and lower on the calf, and rockers are installed on the output shafts of the two ankle joint drive motors. The upper rocker is hinged to one end of a long connecting rod, and the lower rocker is hinged to one end of a short connecting rod. The other ends of the long connecting rod and the short connecting rod are respectively hinged to the sole of the foot and distributed on both sides of the sole of the foot.

10. A bipedal robot, characterized in that, A robot leg structure comprising any one of claims 1 to 9.

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