CN114603542A - Driving mechanism and robot - Google Patents

Abstract

A driving mechanism comprises a driving part and a transmission part; the driving part comprises a motor and a planetary reducer, and a motor shaft of the motor is fixedly connected with a sun gear of the planetary reducer; the transmission part comprises an input shaft, an output shaft and steel wire ropes wound on the input shaft and the output shaft, the steel wire ropes are in a tensioning state, and the input shaft is fixedly connected with a planet carrier of the planetary reducer. According to the driving mechanism, the driving part jointly uses the motor and the planetary reducer to form a near direct-drive driving mode, the driving part is fixedly connected with the sun gear of the planetary reducer through the motor shaft of the motor, and the planet carrier of the planetary reducer is fixedly connected with the input shaft, so that the output of the driving force of the motor can be realized. The mode can realize large torque density and high back driving capability of the driving mechanism, and the control precision is higher. The transmission part adopts a steel wire rope for transmission, has no forward and reverse transmission gap errors, is light in weight and low in inertia, can improve the leg swinging frequency and the walking speed, and is higher in control precision.

Description

Driving mechanism and robot

Technical Field

The invention relates to the technical field of robots, in particular to a driving mechanism applicable to leg joints of a robot and a robot comprising the driving mechanism.

Background

Leg joint driving structures of leg-foot robots, particularly quadruped robots, are various, ball screws are adopted for driving shanks of Spotmini of foreign quadruped robots, inertia of the ball screws is large, and frequency of swinging legs is affected; the foreign Anymal quadruped robot adopts an integrated joint, integrates components such as a motor, a gear, a spring, a driver, an encoder and the like, increases the leg inertia and influences the leg swinging frequency; the legs of domestic Laika and shadow-eliminating quadruped robots are driven by adopting a four-bar linkage, gaps are inevitably generated between the connecting bars due to factors such as manufacturing and installation, transmission errors and control errors are caused by the gaps, and inertia of the linkage is larger than that of rope transmission inertia.

Therefore, when the tail end of the legged robot is driven by a ball screw, a connecting rod and other transmission mechanisms, the swing frequency of the swing leg driven by the mechanisms is too low (namely, the walking speed is too slow), and transmission clearance errors exist in forward and reverse transmission, so that the motion control precision is influenced.

Disclosure of Invention

In view of the above, it is desirable to provide a driving mechanism with high control accuracy and a robot using the driving mechanism.

A driving mechanism comprises a driving part and a transmission part;

the driving part comprises a motor and a planetary reducer, and a motor shaft of the motor is fixedly connected with a 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 tensioning state, and the input shaft is fixedly connected with a planet carrier of the planetary reducer.

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

the stator is arranged in the shell and fixedly connected with the shell;

the rotor is fixedly connected with the motor shaft;

the outer plate is arranged at one end of the motor, which is far away from the planetary reducer, and the outer plate is fixedly connected with the shell;

the first bearing is arranged on the inner side of the outer plate;

the motor shaft is fixedly connected with the outer ring of the first bearing.

In one embodiment, the motor further comprises an outer ring gland and an inner ring gland, and two sides of the first bearing are respectively pressed by the outer ring gland and the inner ring gland.

In one embodiment, the driving portion further includes a second bearing, the second bearing is sleeved on the motor shaft, and the planet carrier of the planetary reducer is fixedly connected with an outer ring of the second bearing.

In one embodiment, the steel wire rope comprises a first steel wire section and a second steel wire section, one end of the first steel wire section is connected with one end of the second steel wire section, the other end of the first steel wire section is fixedly connected with the other end of the second steel wire section, the first steel wire section is wound on the input shaft, and the second steel wire section is wound on the output shaft;

two first fixed shafts are fixedly arranged on the first steel wire section, two first slotted holes are formed in the outer side wall of the input shaft, and the two first fixed shafts are respectively embedded in the two first slotted holes;

the second steel wire section is fixedly provided with two second fixed shafts, the outer wall of the output shaft is provided with two second slotted holes, and the two second fixed shafts are respectively embedded in the two second slotted holes.

In one embodiment, the length of the steel wire between the two first fixing shafts of the first steel wire section is larger than the distance between the two first slotted holes;

the length of the steel wire between the two second fixed shafts of the second steel wire section is larger than the distance between the two second slotted holes.

In one embodiment, the wire rope further comprises a first tensioning column and a second tensioning column, one end of the first wire section and one end of the second wire section are connected and tensioned by the first tensioning column, and the other end of the first wire section and the other end of the second wire section are connected and tensioned by the second tensioning column.

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

In one embodiment, the planetary reducer is a one-stage planetary reducer.

A robot comprises a thigh plate, a shank shaft, a third bearing, a shank and the driving mechanism;

the thigh plate is connected with a shell of the motor;

the lower leg shaft sequentially penetrates through the upper leg plate, the third bearing and the output shaft;

the lower leg is connected with the output shaft, and the lower leg can rotate around the lower leg shaft.

According to the driving mechanism, the driving part jointly uses the motor and the planetary reducer to form a near direct-drive driving mode, the driving part is fixedly connected with the sun gear of the planetary reducer through the motor shaft of the motor, and the planet carrier of the planetary reducer is fixedly connected with the input shaft, so that the output of the driving force of the motor can be realized. The mode can realize large torque density and high back driving capability of the driving mechanism, and the control precision is higher. The input shaft is driven by the driving part to rotate, and the output shaft is driven to rotate under the action of the steel wire rope. The transmission part adopts a steel wire rope for transmission, has no forward and reverse transmission gap error, light weight and low inertia, and can improve the leg swinging frequency and the walking speed. Therefore, compared with a driving structure of a four-bar linkage mechanism and a ball screw, the driving mechanism has the advantages of larger transmission motion range, lower inertia and higher control precision.

The robot has the advantages that the driving mechanism is used, the driving part jointly uses the motor and the planetary reducer to form a near direct-drive driving mode, the driving part is fixedly connected with the sun gear of the planetary reducer through the motor shaft of the motor, the planet carrier of the planetary reducer is fixedly connected with the input shaft, the output of the driving force of the motor can be realized, the large torque density and the high reverse driving capability of the driving mechanism are realized, and the control precision is higher. The input shaft is driven by the driving part to rotate, and the output shaft is driven to rotate under the action of the steel wire rope. The transmission part adopts a steel wire rope for transmission, has no forward and reverse transmission gap error, light weight and low inertia, and can improve the leg swinging frequency and the walking speed. Therefore, the robot has the advantages of larger transmission motion range, lower inertia and higher control precision.

Drawings

Fig. 1 is a partial schematic configuration diagram of a robot including a drive mechanism according to an embodiment;

FIG. 2 is a partial cross-sectional view of the robot shown in FIG. 1 including a drive mechanism;

FIG. 3 is a cross-sectional view of a drive portion of the drive mechanism shown in FIG. 1;

FIG. 4 is a schematic structural view of a transmission portion of the driving mechanism shown in FIG. 1;

FIG. 5 is a schematic view of one embodiment of a wireline coupled to an input shaft;

FIG. 6 is a schematic view of an embodiment of a steel cord connected to an output shaft;

fig. 7 is a schematic structural view of bidirectional tensioning of a steel cord according to an embodiment.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. The fixed connection in the present invention includes direct fixed connection and indirect fixed connection.

Referring to fig. 1 to 2, a driving mechanism includes a driving portion 1 and a transmission portion 2. The driving part 1 comprises a motor and a planetary reducer 19, and a motor shaft 15 of the motor is fixedly connected with a sun gear of the planetary reducer 19. The transmission part 2 comprises an input shaft 21, an output shaft 25 and a steel wire rope wound on the input shaft 21 and the output shaft 25, the steel wire rope is in a tensioning state, and the input shaft 21 is fixedly connected with a planet carrier of the planetary reducer 19.

In the driving mechanism, the driving part 1 combines the motor and the planetary reducer 19 to form a near-direct-drive driving mode, the driving part 1 is fixedly connected with the sun gear of the planetary reducer 19 through the motor shaft 15 of the motor, and the planet carrier of the planetary reducer 19 is fixedly connected with the input shaft 21, so that the output of the driving force of the motor can be realized. The mode can realize large torque density and high back driving capability of the driving mechanism, and the control precision is higher. The input shaft 21 is driven by the driving part 1 to rotate, and the output shaft 25 is driven to rotate through the action of the steel wire rope. The transmission part 2 adopts a steel wire rope for transmission, has no forward and reverse transmission gap error, light weight and low inertia, and can improve the leg swinging frequency and the walking speed. Therefore, compared with a driving structure of a four-bar linkage mechanism and a ball screw, the driving mechanism has the advantages of larger transmission motion range, lower inertia and higher control precision.

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.

The planetary gear 19 is a primary planetary gear. Specifically, the planetary reducer 19 is a one-stage planetary reducer with a small reduction ratio (i is less than or equal to 10). The small reduction ratio planetary reducer allows for relatively less intra-articular friction. The combination of the brushless permanent magnet torque motor and the primary planetary reducer is close to direct drive, so that the high torque density and high reverse drive capability of the leg joint can be realized, and the joint torque control is more favorably realized. Compared with the scheme that an expensive torque sensor and an integrated joint are arranged at the joint, the method is a joint driving structure with low cost and high reliability.

As shown in fig. 3, 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 disposed in the housing 11, and the stator 12 is fixedly connected to the housing 11. The rotor 14 is fixedly connected with a motor shaft 15. The outer plate 13 is arranged at one end of the motor far away from the planetary reducer 19, and the outer plate 13 is fixedly connected with the shell 11. The first bearing 16 is provided inside the outer panel 13. The motor shaft 15 is fitted to the outer race of the first bearing 16, and the motor shaft 15 is fitted to the inner race of the first bearing.

In the embodiment shown in fig. 3, the motor further includes an outer ring gland 17 and an inner ring gland 18, and both sides of the first bearing 16 are respectively compressed by the outer ring gland 17 and the inner ring gland 18.

Specifically, the stator 12 and the housing 11 are adhesively connected. The rotor 14 and the motor shaft 15 are adhesively connected. The rotor 14 and the motor shaft 15 are bonded and placed in the outer ring of the first bearing 16 mounted on the outer plate 13, so that the rotating system of the frameless torque motor stator 12 and the rotor 14 is formed.

In the embodiment shown in fig. 3, the driving part 1 further includes a second bearing 111, the second bearing 111 is sleeved on the motor shaft 15, the motor shaft 15 is engaged with the outer ring of the second bearing 11, the motor shaft 15 is engaged with the inner ring of the second bearing 11, and the planet carrier of the planetary reducer 19 is fixedly connected with the outer ring of the second bearing 111.

In the embodiment shown in fig. 3, the drive unit 1 further includes an input shaft adapter flange 110, the input shaft adapter flange 110 is fixedly connected to the outer race of the second bearing 111, the input shaft adapter flange 110 is fixedly connected to the carrier of the planetary gear set 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 gear set 19 to the electric machine, whose torque is transmitted via the planetary gear set 19. The input shaft adapter flange 110 is an external output flange of the driving part 1 and is responsible for connecting with the input shaft 21 of the transmission part 2.

Specifically, as shown in fig. 1, the outer ring of the planetary gear set 19 is connected to the stator housing 11.

In the embodiment shown in fig. 4, the steel wire rope includes a first wire section 22 and a second wire section 24, one end of the first wire section 22 is connected to one end of the second wire section 24, the other end of the first wire section 22 is fixedly connected to the other end of the second wire section 24, the first wire section 22 is wound on the input shaft 21, and the second wire section 24 is wound on the output shaft 25.

Referring to fig. 5, two first fixing shafts 222 are fixedly disposed on the first steel wire section 22, two first slots 212 are disposed on the outer side wall of the input shaft 21, the two first fixing shafts 222 are respectively embedded in the two first slots 212, and the length of the steel wire between the two first fixing shafts 222 of the first steel wire section 22 is greater than the distance between the two first slots 212. Preferably, the length of the wire between the two first fixing shafts 222 of the first wire section 22 is about 1cm greater than the distance between the two first slots 212.

Referring to fig. 6, two second fixing shafts 242 are fixedly disposed on the second steel wire section 24, two second slots 252 are disposed on the outer wall of the output shaft 25, the two second fixing shafts 242 are respectively embedded in the two second slots 252, and the length of the steel wire between the two second fixing shafts 242 of the second steel wire section 24 is greater than the distance between the two second slots 252. Preferably, the length of the wire between the two second fixed shafts 242 of the second wire section 24 is about 1cm greater than the distance between the two second slots 252.

The transmission part 2 is driven by a bidirectional gapless steel wire rope. The first steel wire section 22 and the second steel wire section 24 are wound on the input shaft 21 and the output shaft 25 respectively for a certain number of turns and then tensioned, thereby forming a gapless transmission component of the input shaft 21, the steel wire rope and the output shaft 25. The two first fixed shafts 222 of the first steel wire section 22 and the two first slots 212 of the input shaft 21 are clamped with each other under the action of tension, the two second fixed shafts 242 of the second steel wire section 24 and the two second slots 252 of the output shaft 25 are clamped with each other under the action of tension, and then the input shaft 21 drives the output shaft 25 to move through the two first fixed shafts 222 on the first steel wire section 22, so that two opposite gapless movements are realized.

Due to the existence of machining errors, the length of the wire between the two first fixing shafts 222 of the first wire section 22 and the distance between the two first slots 212 may not be completely equal, if the length of the wire between the two first fixing shafts 222 of the first wire section 22 is less than the distance between the two first slots 212, the outer sides of the two first fixing shafts 222 are not guaranteed to be in contact with the outer sides of the two first slots 212, respectively, and if the outer sides of the two first fixing shafts 222 are not in contact with the outer sides of the two first slots 212, the first fixing shafts 222 will move in the first slots 212, and a transmission gap is generated when the first fixing shafts move in the forward direction and the reverse direction, so that transmission errors are caused.

The length of the wire between the two first fixing shafts 222 of the first wire section 22 is greater than the distance between the two first slots 212, and the length of the wire between the two second fixing shafts 242 of the second wire section 24 is greater than the distance between the two second slots 252, so that, when the two sides are tensioned, the two first fixing shafts 222 of the first steel wire section 22 can be respectively contacted with the outer side surfaces of the two sides of the first slot 212, the two second fixing shafts 242 of the second steel wire section 24 can be respectively contacted with the outer side surfaces of the two sides of the second slot 252, while the wire between the two first fixed shafts 222 and the wire between the two second fixed shafts 242 are in a "relaxed" state, and further, when the tension is ensured, the first steel wire section 22 and the second steel wire section 24 respectively drive the input shaft 21 and the output shaft 25 to be completely tensioned in the positive direction and the negative direction, no gap exists, and a bidirectional gapless rope transmission mechanism is formed.

In the embodiment shown in fig. 7, the steel cord further comprises a first tensioning column 23 and a second tensioning column 27. One end of the first wire section 22 and one end of the second wire section 24 are connected and tensioned by a first tensioning column 23, and the other end of the first wire section 22 and the other end of the second wire section 24 are connected and tensioned by a second tensioning column 27.

Two sides of the steel wire rope are respectively provided with a tensioning column for ensuring that the steel wire rope in the forward direction and the backward direction is in a tensioning state.

The first steel wire section 22 is wound on the input shaft 21 for a certain number of turns, the second steel wire section 24 is wound on the output shaft 25 for a certain number of turns, the first steel wire section 22 and the second steel wire section 24 are connected and tensioned through the first tensioning column 23 and the second tensioning column 27, the steel wire rope is wound for multiple turns, the rigidity of the mechanism can be increased, the larger the number of turns is, the larger the rigidity is, and meanwhile, the larger movement range of the output shaft 25 is provided. Different rotation angles can be obtained by changing the number of turns of winding of the steel wire rope. The steel wire rope is wound for more than 1.5 circles, so that a 360-degree rotating angle can be realized, and the leg movement range is enlarged by a large angle.

Specifically, both ends of the first steel wire section 22 are provided with left-handed screw studs 226, both ends of the second steel wire section 24 are provided with right-handed screw studs 246, both ends of the first tensioning column 23 are provided with left-handed internal threads and right-handed internal threads, and both ends of the second tensioning column 27 are provided with left-handed internal threads and right-handed internal threads. The structure of the first and second tensioning columns 23 and 27 can simultaneously tension the first and second wire lengths 22 and 24 when the first or second tensioning columns 23 or 27 are rotated. The input shaft 21, the steel wire rope and the output shaft 25 are clamped tightly under the action of the tension force, so that the input shaft 21, the steel wire rope and the output shaft 25 are combined together, and the torque of the input shaft 21 is transmitted to the output shaft 25 by means of the steel wire rope. The structure realizes the gapless fixation of double axes, no transmission gap exists, the generation of shaking amount is avoided, and the joint motion performance is improved.

The first and second tensioning columns 23 and 27 are arranged on the outside to facilitate tensioning of the steel cable. The tensioning of the steel wire rope is simpler and more reliable.

In addition, referring to fig. 1 and 2, a robot is provided, which comprises a thigh plate 3, a shank shaft 5, a third bearing 4, a shank 6 and the driving mechanism. The thigh plate 3 is connected to the housing 11 of the motor. The lower leg shaft 5 passes through the upper leg plate 3, the third bearing 4 and the output shaft 25 in this order. The lower leg 6 is connected to the output shaft 25, and the lower leg 6 is rotatable about the lower leg shaft 5. The structure of the driving mechanism is as above, and is not described herein.

In the robot, the driving part 11 drives the transmission part 22 to move in the forward and backward directions, and the output shaft 25 of the transmission part 22 drives the lower legs 6 to move in the forward and backward directions.

The robot adopts the driving mechanism, the driving part 1 combines the motor and the planetary reducer 19 to form a near-direct-drive driving mode, the driving part 1 is fixedly connected with the sun gear of the planetary reducer 19 through the motor shaft 15 of the motor, and the planet carrier of the planetary reducer 19 is fixedly connected with the input shaft 21, so that the output of the driving force of the motor can be realized, the large torque density and the high reverse driving capability of the driving mechanism are realized, and the control precision is higher. The input shaft 21 is driven by the driving part 1 to rotate, and the output shaft 25 is driven to rotate through the action of the steel wire rope. The transmission part 2 adopts a steel wire rope for transmission, has no forward and reverse transmission gap error, light weight and low inertia, and can improve the leg swinging frequency and the walking speed. Therefore, the robot has the advantages of larger transmission motion range, lower inertia and higher control precision

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (10)

1. A driving mechanism is characterized by comprising a driving part and a transmission part;

the driving part comprises a motor and a planetary reducer, and a motor shaft of the motor is fixedly connected with a 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 tensioning state, and the input shaft is fixedly connected with a planet carrier of the planetary reducer.

2. The drive mechanism as recited in claim 1, wherein the motor includes a housing, a stator, a rotor, a motor shaft, a first bearing, and an outer plate;

the stator is arranged in the shell and fixedly connected with the shell;

the rotor is fixedly connected with the motor shaft;

the outer plate is arranged at one end of the motor, which is far away from the planetary reducer, and the outer plate is fixedly connected with the shell;

the first bearing is arranged on the inner side of the outer plate;

the motor shaft is fixedly connected with the outer ring of the first bearing.

3. The drive mechanism of claim 2, wherein the motor further comprises an outer ring gland and an inner ring gland, and both sides of the first bearing are compressed by the outer ring gland and the inner ring gland, respectively.

4. The driving mechanism as recited in claim 1, wherein the driving portion further includes a second bearing, the second bearing is sleeved on the motor shaft, and the planet carrier of the planetary gear reducer is fixedly connected with an outer ring of the second bearing.

5. The drive mechanism of claim 1, wherein the wire rope includes a first wire segment and a second wire segment, one end of the first wire segment is connected to one end of the second wire segment, the other end of the first wire segment is fixedly connected to the other end of the second wire segment, the first wire segment is wound around the input shaft, and the second wire segment is wound around the output shaft;

two first fixed shafts are fixedly arranged on the first steel wire section, two first slotted holes are formed in the outer side wall of the input shaft, and the two first fixed shafts are respectively embedded in the two first slotted holes;

the second steel wire section is fixedly provided with two second fixing shafts, the outer wall of the output shaft is provided with two second slotted holes, and the two second fixing shafts are embedded in the two second slotted holes respectively.

6. The drive mechanism as recited in claim 5, wherein the length of the wire between the two first stationary axles of the first wire segment is greater than the distance between the two first slots;

the length of the steel wire between the two second fixed shafts of the second steel wire section is larger than the distance between the two second slotted holes.

7. The drive mechanism of claim 6, wherein the wire rope further comprises a first tension column and a second tension column, one end of the first length of wire and one end of the second length of wire are connected and tensioned by the first tension column, and the other end of the first length of wire and the other end of the second length of wire are connected and tensioned by the second tension column.

8. The drive mechanism as recited in claim 7, wherein said first wire segment has left-hand studs on both ends thereof, said second wire segment has right-hand studs on both ends thereof, said first tensioning stud has left-hand and right-hand internal threads on both ends thereof, and said second tensioning stud has left-hand and right-hand internal threads on both ends thereof.

9. A drive mechanism as claimed in claim 1, wherein said planetary reduction is a one-stage planetary reduction.

10. A robot comprising a thigh plate, a shank shaft, a third bearing, a shank and a drive mechanism according to any of claims 1-9;

the thigh plate is connected with a shell of the motor;

the lower leg shaft sequentially penetrates through the upper leg plate, the third bearing and the output shaft;

the lower leg is connected with the output shaft, and the lower leg can rotate around the lower leg shaft.

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