Drive mechanism and robot

Abstract

A driving mechanism includes a driving part and a transmission part; the driving part includes a motor and a planetary reducer, and the motor shaft of the motor is fixedly connected to the sun gear of the planetary reducer; the transmission part includes an input shaft, an output shaft and a steel wire rope wound on the input shaft and the output shaft, the steel wire rope is in a tensioned state, and the input shaft is fixedly connected to the planetary carrier of the planetary reducer. In the above-mentioned driving mechanism, the driving part uses the motor and the planetary reducer together to form a near direct drive mode, and the driving part is fixedly connected to the sun gear of the planetary reducer through the motor shaft of the motor, and the planetary carrier of the planetary reducer is fixedly connected to the input shaft, so as to realize the output of the motor driving force. This method can realize the high torque density and high reverse driving ability of the driving mechanism, and the control accuracy is higher. The transmission part adopts steel wire rope for transmission, has no forward and reverse transmission gap error, is light in weight and low inertia, can increase the leg swing frequency, increase the walking speed, and have higher control accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of robots, and in particular to a driving mechanism suitable for a robot leg joint and a robot comprising the driving mechanism. Background Art

[0002] Some legged robots, especially quadruped robots, have various leg joint drive structures. The foreign quadruped robot Spotmini uses ball screw drive at the calf, and the ball screw has a large inertia, which affects the leg swinging frequency; the foreign Anymal quadruped robot uses integrated joints, integrating motors, gears, springs, drivers, encoders and other components, which increases the leg inertia and affects the leg swinging frequency; the domestic Laika and Jueying quadruped robots use a four-bar linkage for the legs. Due to manufacturing and installation factors, gaps will inevitably occur between the connecting rods, which will cause transmission errors and control errors, and the inertia of the connecting rod mechanism is also larger than the inertia of the rope transmission.

[0003] Therefore, when the leg-type robot uses a ball screw, connecting rod or other transmission mechanism for transmission, the swing frequency of the swinging legs driven by the above mechanism is too low (that is, the walking speed is too slow), and there is a transmission gap error in the forward and reverse transmission, which affects the motion control accuracy. Summary of the invention

[0004] In view of this, it is necessary to provide a driving mechanism with higher control accuracy and a robot using the driving mechanism.

[0005] A driving mechanism comprises a driving part and a transmission part;

[0006] The driving unit includes a motor and a planetary reducer, and the motor shaft of the motor is fixedly connected to the sun gear of the planetary reducer;

[0007] The transmission part comprises an input shaft, an output shaft and steel wire ropes wound around the input shaft and the output shaft, the steel wire ropes are in a tensioned state, and the input shaft is fixedly connected to the planet carrier of the planetary reducer.

[0008] In one embodiment, the motor includes a housing, a stator, a rotor, a motor shaft, a first bearing, and an outer plate;

[0009] The stator is arranged in the shell, and the stator and the shell are fixedly connected;

[0010] The rotor is fixedly connected to the motor shaft;

[0011] The outer plate is arranged at one end of the motor away from the planetary reducer, and the outer plate is fixedly connected to the housing;

[0012] The first bearing is arranged on the inner side of the outer plate;

[0013] The motor shaft and the outer ring of the first bearing are fixedly connected.

[0014] In one embodiment, the motor further includes an outer ring pressure cover and an inner ring pressure cover, and two sides of the first bearing are respectively pressed by the outer ring pressure cover and the inner ring pressure cover.

[0015] In one embodiment, the driving unit further includes a second bearing, which is sleeved on the motor shaft, and the planetary carrier of the planetary reducer and the outer ring of the second bearing are fixedly connected.

[0016] In one embodiment, the steel wire rope includes a first steel wire segment and a second steel wire segment, one end of the first steel wire segment is connected to one end of the second steel wire segment, the other end of the first steel wire segment is fixedly connected to the other end of the second steel wire segment, the first steel wire segment is wound around the input shaft, and the second steel wire segment is wound around the output shaft;

[0017] Two first fixed shafts are fixed on the first steel wire segment, two first slots are provided on the outer wall of the input shaft, and the two first fixed shafts are respectively embedded in the two first slots;

[0018] Two second fixed shafts are fixedly provided on the second steel wire segment, two second slots are provided on the outer wall of the output shaft, and the two second fixed shafts are respectively embedded in the two second slots.

[0019] In one embodiment, the length of the steel wire between the two first fixing shafts of the first steel wire segment is greater than the distance between the two first slots;

[0020] The length of the steel wire between the two second fixing axes of the second steel wire segment is greater than the distance between the two second slot holes.

[0021] In one embodiment, the steel wire rope further includes a first tensioning column and a second tensioning column, one end of the first steel wire segment and one end of the second steel wire segment are connected and tensioned via the first tensioning column, and the other end of the first steel wire segment and the other end of the second steel wire segment are connected and tensioned via the second tensioning column.

[0022] In one embodiment, both ends of the first steel wire segment are provided with left-handed studs, both ends of the second steel wire segment are provided with right-handed studs, both ends of the first tensioning column are left-handed internal threads and right-handed internal threads respectively, and both ends of the second tensioning column are left-handed internal threads and right-handed internal threads respectively.

[0023] In one embodiment, the planetary reducer is a single-stage planetary reducer.

[0024] A robot comprising a thigh plate, a shank shaft, a third bearing, a shank and the driving mechanism as described above;

[0025] The thigh plate is connected to the housing of the motor;

[0026] The calf shaft passes through the thigh plate, the third bearing and the output shaft in sequence;

[0027] The shank is connected to the output shaft, and the shank is rotatable around the shank axis.

[0028] In the above-mentioned driving mechanism, the driving part combines the motor and the planetary reducer to form a near-direct drive mode. The driving part is fixedly connected to the sun gear of the planetary reducer through the motor shaft of the motor, and the planetary carrier of the planetary reducer is fixedly connected to the input shaft, so as to realize the output of the motor driving force. This method can realize the high torque density and high reverse driving ability of the driving mechanism, and the control accuracy is higher. The input shaft rotates under the drive of the driving part, and the output shaft is driven to rotate by the wire rope. The transmission part adopts wire rope for transmission, and there is no forward and reverse transmission gap error. It is light in weight and low inertia, which can increase the leg swing frequency and the walking speed. Therefore, compared with the driving structure of the four-bar linkage and ball screw, the above-mentioned driving mechanism has a larger transmission motion range, lower inertia and higher control accuracy.

[0029] The above-mentioned robot uses the above-mentioned driving mechanism. The driving part uses the motor and the planetary reducer together to form a near-direct drive mode. The driving part is fixedly connected to the sun gear of the planetary reducer through the motor shaft of the motor, and the planetary carrier of the planetary reducer is fixedly connected to the input shaft, so as to realize the output of the motor driving force, realize the high torque density and high reverse driving ability of the driving mechanism, and achieve higher control accuracy. The input shaft rotates under the drive of the driving part, and the output shaft is driven to rotate by the wire rope. The transmission part adopts wire rope for transmission, and there is no forward and reverse transmission gap error. It is light in weight and low inertia, which can increase the leg swing frequency and the walking speed. Therefore, the transmission motion range of the above-mentioned robot is larger, the inertia is lower, and the control accuracy is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic diagram of a partial structure of a robot including a driving mechanism according to an embodiment;

[0031] Figure 2 for Figure 1 A partial cross-sectional view of a robot including a drive mechanism is shown;

[0032] Figure 3 for Figure 1 A cross-sectional view of a driving portion of the driving mechanism shown;

[0033] Figure 4 for Figure 1A schematic structural diagram of a transmission part of a driving mechanism shown in FIG.

[0034] Figure 5 A schematic diagram of the connection between a steel wire rope and an input shaft according to an embodiment;

[0035] Figure 6 A schematic diagram of the connection between a steel wire rope and an output shaft according to an embodiment;

[0036] Figure 7 It is a schematic structural diagram of a bidirectional tensioning of a steel wire rope according to an embodiment. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying 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. The fixed connection mentioned in the present invention includes direct fixed connection and indirect fixation.

[0038] Please refer to Figure 1 to Figure 2 A driving mechanism includes a driving part 1 and a transmission part 2. The driving part 1 includes a motor and a planetary reducer 19, and the motor shaft 15 of the motor is fixedly connected to the sun gear of the planetary reducer 19. The transmission part 2 includes an input shaft 21, an output shaft 25, and a steel wire rope wound around the input shaft 21 and the output shaft 25, the steel wire rope is in a tensioned state, and the input shaft 21 is fixedly connected to the planet carrier of the planetary reducer 19.

[0039] In the above-mentioned driving mechanism, the driving part 1 combines the motor and the planetary reducer 19 to form a near direct drive mode. The driving part 1 is fixedly connected to the sun gear of the planetary reducer 19 through the motor shaft 15 of the motor, and the planetary carrier of the planetary reducer 19 is fixedly connected to the input shaft 21, so as to realize the output of the motor driving force. This method can realize the high torque density and high reverse driving ability of the driving mechanism, and the control accuracy is higher. The input shaft 21 rotates under the drive of the driving part 1, and drives the rotation of the output shaft 25 through the action of the wire rope. The transmission part 2 adopts a wire rope for transmission, and there is no forward and reverse transmission clearance error. It is light in weight and low inertia, which can increase the leg swing frequency and the walking speed. Therefore, compared with the driving structure of the four-bar linkage and the ball screw, the above-mentioned driving mechanism has a larger transmission motion range, lower inertia and higher control accuracy.

[0040] In one embodiment, the motor is a torque motor. Specifically, the motor is a brushless permanent magnet torque motor. The brushless permanent magnet torque motor can provide large torque.

[0041] The planetary reducer 19 is a first-stage planetary reducer. Specifically, the planetary reducer 19 is a first-stage planetary reducer with a small reduction ratio (i≤10). The small reduction ratio planetary reducer makes the friction in the joint relatively smaller. The combination of the brushless permanent magnet torque motor and the first-stage planetary reducer is close to direct drive, which can achieve high torque density and high reverse drive capability of the leg joints, and is more conducive to joint torque control. Compared with expensive torque sensors and integrated integrated joint solutions arranged at the joints, this method is a low-cost and high-reliability joint drive structure.

[0042] like Figure 3 As shown, the motor includes a housing 11, a stator 12, a rotor 14, a motor shaft 15, a first bearing 16 and an outer plate 13. The stator 12 is arranged in the housing 11, and the stator 12 and the housing 11 are fixedly connected. The rotor 14 and the motor shaft 15 are fixedly connected. The outer plate 13 is arranged at one end of the motor away from the planetary reducer 19, and the outer plate 13 and the housing 11 are fixedly connected. The first bearing 16 is arranged on the inner side of the outer plate 13. The motor shaft 15 and the outer ring of the first bearing 16 are matched, and the motor shaft 15 and the inner ring of the first bearing are matched.

[0043] In such Figure 3 In the illustrated embodiment, the motor further comprises an outer ring pressure cover 17 and an inner ring pressure cover 18 , and both sides of the first bearing 16 are pressed by the outer ring pressure cover 17 and the inner ring pressure cover 18 respectively.

[0044] Specifically, the stator 12 is bonded to the housing 11. The rotor 14 is bonded to the motor shaft 15. The rotor 14 and the motor shaft 15 are bonded and placed in the outer ring of the first bearing 16 installed on the outer plate 13, forming a rotating system of the stator 12 and the rotor 14 of the frameless torque motor.

[0045] In such Figure 3 In the illustrated embodiment, the driving unit 1 further includes a second bearing 111, which is sleeved on the motor shaft 15, the motor shaft 15 and the outer ring of the second bearing 11 cooperate with each other, the motor shaft 15 and the inner ring of the second bearing 11 cooperate with each other, and the planetary carrier of the planetary reducer 19 is fixedly connected to the outer ring of the second bearing 111.

[0046] In such Figure 3 In the illustrated embodiment, the drive unit 1 further includes an input shaft adapter flange 110, which is fixedly connected to the outer ring of the second bearing 111, the input shaft adapter flange 110 is fixedly connected to the planet carrier of the planetary reducer 19, and the input shaft adapter flange 110 is fixedly connected to the input shaft 21. The input shaft adapter flange 110 connects the planetary reducer 19 to the motor, and the torque of the motor is transmitted through the planetary reducer 19. The input shaft adapter flange 110 is the external output flange of the drive unit 1, which is responsible for connecting to the input shaft 21 of the transmission unit 2.

[0047] Specifically, Figure 1 As shown, the outer ring of the planetary reducer 19 is connected to the stator housing 11 .

[0048] In such Figure 4 In the illustrated embodiment, the steel wire rope includes a first steel wire segment 22 and a second steel wire segment 24, one end of the first steel wire segment 22 is connected to one end of the second steel wire segment 24, the other end of the first steel wire segment 22 is fixedly connected to the other end of the second steel wire segment 24, the first steel wire segment 22 is wound around the input shaft 21, and the second steel wire segment 24 is wound around the output shaft 25.

[0049] Please refer to Figure 5 , two first fixed shafts 222 are fixed on the first steel wire segment 22, two first slots 212 are provided on the outer wall of the input shaft 21, the two first fixed shafts 222 are respectively embedded in the two first slots 212, and the length of the steel wire between the two first fixed shafts 222 of the first steel wire segment 22 is greater than the distance between the two first slots 212. Preferably, the length of the steel wire between the two first fixed shafts 222 of the first steel wire segment 22 is about 1 cm greater than the distance between the two first slots 212.

[0050] Please refer to Figure 6 , two second fixed shafts 242 are fixedly provided on the second steel wire segment 24, two second slots 252 are provided on the outer wall of the output shaft 25, the two second fixed shafts 242 are respectively embedded in the two second slots 252, and the length of the steel wire between the two second fixed shafts 242 of the second steel wire segment 24 is greater than the distance between the two second slots 252. Preferably, the length of the steel wire between the two second fixed shafts 242 of the second steel wire segment 24 is about 1 cm greater than the distance between the two second slots 252.

[0051] The transmission part 2 is a bidirectional gapless wire rope transmission. The first wire segment 22 and the second wire segment 24 are respectively wound around the input shaft 21 and the output shaft 25 for a certain number of turns and then tensioned, thereby forming a gapless transmission component of the input shaft 21-wire rope-output shaft 25. The two first fixed shafts 222 of the first wire segment 22 and the two first slots 212 of the input shaft 21 are clamped together under the action of the tensioning force, and the two second fixed shafts 242 of the second wire segment 24 and the two second slots 252 of the output shaft 25 are clamped together under the action of the tensioning force, and then the input shaft 21 drives the output shaft 25 to move through the two first fixed shafts 222 on the first wire segment 22, realizing gapless movement in both forward and reverse directions.

[0052] Due to the existence of processing errors, the length of the steel wire between the two first fixed shafts 222 of the first steel wire segment 22 and the distance between the two first slots 212 cannot be completely equal. If the length of the steel wire between the two first fixed shafts 222 of the first steel wire segment 22 is less than the distance between the two first slots 212, it cannot be guaranteed that the outer sides of the two first fixed shafts 222 are in contact with the outer sides of the two first slots 212 respectively. If there is no contact, the first fixed shaft 222 will move in the first slot 212, and a transmission gap will be generated during forward and reverse motion, causing a transmission error.

[0053] The length of the steel wire between the two first fixed shafts 222 of the first steel wire segment 22 is greater than the distance between the two first slot holes 212, and the length of the steel wire between the two second fixed shafts 242 of the second steel wire segment 24 is greater than the distance between the two second slot holes 252. In this way, it can be ensured that when both sides are tensioned, the two first fixed shafts 222 of the first steel wire segment 22 can respectively contact the outer side surfaces on both sides of the first slot hole 212, and the two second fixed shafts 242 of the second steel wire segment 24 can respectively contact the outer side surfaces on both sides of the second slot hole 252, while the steel wire between the two first fixed shafts 222 and the steel wire between the two second fixed shafts 242 are in a "relaxed" state, thereby ensuring that when tensioned, the first steel wire segment 22 and the second steel wire segment 24 are fully tensioned in the positive and reverse directions of the input shaft 21 and the output shaft 25 respectively, without any gap, thereby forming a bidirectional gapless rope transmission mechanism.

[0054] In such Figure 7 In the illustrated embodiment, the steel wire rope further comprises a first tensioning column 23 and a second tensioning column 27. One end of the first steel wire segment 22 and one end of the second steel wire segment 24 are connected and tensioned via the first tensioning column 23, and the other end of the first steel wire segment 22 and the other end of the second steel wire segment 24 are connected and tensioned via the second tensioning column 27.

[0055] A tensioning column is provided on each side of the wire rope to ensure that the wire rope in both the positive and negative directions is in a tensioned state.

[0056] The first steel wire segment 22 is wound around the input shaft 21 for a certain number of turns, and the second steel wire segment 24 is wound around the output shaft 25 for a certain number of turns. The first steel wire segment 22 and the second steel wire segment 24 are connected and tensioned through the first tensioning column 23 and the second tensioning column 27. This multiple turns of steel wire rope can increase the rigidity of the mechanism. The larger the number of turns, the greater the rigidity. At the same time, it also provides a larger range of motion for the output shaft 25. By changing the number of turns of steel wire rope winding, different rotation angles can be obtained. When the steel wire rope is wound for more than 1.5 turns, a rotation angle of 360° can be achieved, and a large angle increases the range of motion of the legs.

[0057] Specifically, both ends of the first steel wire segment 22 are provided with a left-handed stud 226, both ends of the second steel wire segment 24 are provided with a right-handed stud 246, both ends of the first tensioning column 23 are respectively provided with a left-handed internal thread and a right-handed internal thread, and both ends of the second tensioning column 27 are respectively provided with a left-handed internal thread and a right-handed internal thread. With this structure of the first tensioning column 23 and the second tensioning column 27, when the first tensioning column 23 or the second tensioning column 27 rotates, the first steel wire segment 22 and the second steel wire segment 24 can be tensioned simultaneously. Under the action of the tensioning force, the input shaft 21, the steel wire rope and the output shaft 25 are clamped to each other, and then the input shaft 21, the steel wire rope and the output shaft 25 are combined together, and then the torque of the input shaft 21 is transmitted to the output shaft 25 by means of the steel wire rope. This structure realizes biaxial gapless fixation, no longer has transmission gap, avoids the generation of shaking, and improves the joint movement performance.

[0058] The first tensioning column 23 and the second tensioning column 27 are arranged on the outside to facilitate tensioning of the steel wire rope, making the tensioning of the steel wire rope simpler and more reliable.

[0059] In addition, please refer to Figure 1 and Figure 2 , a robot is also provided, including a thigh plate 3, a shank shaft 5, a third bearing 4, a shank 6 and the driving mechanism as described above. The thigh plate 3 is connected to the housing 11 of the motor. The shank shaft 5 passes through the thigh plate 3, the third bearing 4 and the output shaft 25 in sequence. The shank 6 is connected to the output shaft 25, and the shank 6 is rotatable around the shank shaft 5. The structure of the driving mechanism is as described above, and will not be repeated here.

[0060] In the above robot, the driving part 11 drives the transmission part 22 to move in the forward and reverse directions, and the output shaft 25 of the transmission part 22 drives the shank 6 to move in the forward and reverse directions.

[0061] The above-mentioned robot uses the above-mentioned driving mechanism. The driving part 1 combines the motor and the planetary reducer 19 to form a near direct drive mode. The driving part 1 is fixedly connected to the sun gear of the planetary reducer 19 through the motor shaft 15 of the motor, and the planetary carrier of the planetary reducer 19 is fixedly connected to the input shaft 21, which can realize the output of the motor driving force, and realize the high torque density and high reverse driving ability of the driving mechanism, and the control accuracy is higher. The input shaft 21 rotates under the drive of the driving part 1, and drives the rotation of the output shaft 25 through the action of the wire rope. The transmission part 2 uses wire rope for transmission, without forward and reverse transmission gap errors, light weight and low inertia, which can increase the leg swinging frequency and the walking speed. Therefore, the above-mentioned robot has a larger transmission motion range, lower inertia, and higher control accuracy.

[0062] The above are only preferred embodiments of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A driving mechanism, characterized in that: It includes a driving part and a transmission part; The driving unit includes a motor and a planetary reducer, and the motor shaft of the motor is fixedly connected to the sun gear of the planetary reducer; The transmission part comprises an input shaft, an output shaft and a steel wire rope wound on the input shaft and the output shaft, the steel wire rope is in a tensioned state, and the input shaft is fixedly connected to the planet carrier of the planetary reducer; The steel wire rope comprises a first steel wire segment and a second steel wire segment, one end of the first steel wire segment is connected to one end of the second steel wire segment, the other end of the first steel wire segment is fixedly connected to the other end of the second steel wire segment, the first steel wire segment is wound around the input shaft, and the second steel wire segment is wound around the output shaft; Two first fixed shafts are fixed on the first steel wire segment, two first slots are provided on the outer wall of the input shaft, and the two first fixed shafts are respectively embedded in the two first slots; Two second fixed shafts are fixed on the second steel wire segment, two second slots are provided on the outer wall of the output shaft, and the two second fixed shafts are respectively embedded in the two second slots; The length of the steel wire between the two first fixing shafts of the first steel wire segment is greater than the distance between the two first slots; The length of the steel wire between the two second fixing axes of the second steel wire segment is greater than the distance between the two second slot holes.

2. The driving mechanism according to claim 1, characterized in that: The motor comprises a housing, a stator, a rotor, a motor shaft, a first bearing and an outer plate; The stator is arranged in the shell, and the stator and the shell are fixedly connected; The rotor is fixedly connected to the motor shaft; The outer plate is arranged at one end of the motor away from the planetary reducer, and the outer plate is fixedly connected to the housing; The first bearing is arranged on the inner side of the outer plate; The motor shaft and the outer ring of the first bearing are fixedly connected.

3. The driving mechanism according to claim 2, characterized in that: The motor further comprises an outer ring pressure cover and an inner ring pressure cover, and two sides of the first bearing are respectively pressed by the outer ring pressure cover and the inner ring pressure cover.

4. The driving mechanism according to claim 1, characterized in that: The driving part also includes a second bearing, which is sleeved on the motor shaft, and the planetary carrier of the planetary reducer and the outer ring of the second bearing are fixedly connected.

5. The driving mechanism according to claim 1, characterized in that: The steel wire rope also includes a first tensioning column and a second tensioning column, one end of the first steel wire segment and one end of the second steel wire segment are connected and tensioned through the first tensioning column, and the other end of the first steel wire segment and the other end of the second steel wire segment are connected and tensioned through the second tensioning column.

6. The driving mechanism according to claim 5, characterized in that: Both ends of the first steel wire segment are provided with left-handed studs, both ends of the second steel wire segment are provided with right-handed studs, both ends of the first tensioning column are respectively left-handed internal threads and right-handed internal threads, and both ends of the second tensioning column are respectively left-handed internal threads and right-handed internal threads.

7. The driving mechanism according to claim 1, characterized in that: The planetary reducer is a one-stage planetary reducer.

8. A robot, characterized in that: It comprises a thigh plate, a calf shaft, a third bearing, a calf and a driving mechanism as described in any one of claims 1 to 7; The thigh plate is connected to the housing of the motor; The calf shaft passes through the thigh plate, the third bearing and the output shaft in sequence; The shank is connected to the output shaft, and the shank is rotatable around the shank axis.

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