CN111232088A

CN111232088A - Leg mechanism of legged robot and legged robot

Info

Publication number: CN111232088A
Application number: CN202010181605.0A
Authority: CN
Inventors: 赵逸栋; 张学垠; 陈申红; 李超; 朱秋国
Original assignee: Hangzhou Deeprobotics Co ltd
Current assignee: Hangzhou Deeprobotics Co ltd
Priority date: 2020-03-16
Filing date: 2020-03-16
Publication date: 2020-06-05
Also published as: WO2021185032A1

Abstract

The invention discloses a leg mechanism of a leg-foot type robot and the leg-foot type robot, wherein the leg mechanism comprises a thigh and a shank which are hinged with each other, the upper end of the thigh is provided with a motor shell and a planetary speed reducing mechanism, the inner side of the motor shell is provided with a motor stator and a motor rotor which is coaxially arranged with the motor stator, the motor rotor is fixedly connected with a sun wheel shaft of the planetary speed reducing mechanism, and a planet wheel output frame of the planetary speed reducing mechanism is connected with the shank through a pull rod. The leg mechanism of the legged robot has the advantages of simple structure, convenience in disassembly and assembly and low cost.

Description

Leg mechanism of legged robot and legged robot

Technical Field

The invention relates to the field of legged robots, in particular to a leg mechanism of a legged robot and the legged robot.

Background

With the economic growth and the disappearance of the population dividends, the social security cost rises year by year. The legged robot is used for replacing people to carry out tasks such as security patrol, disaster area rescue and the like in some dangerous areas, so that casualties of people can be effectively reduced. These harsh environments often accompany rough terrain, placing high demands on the off-road capabilities of legged robots. The leg-foot type robot has the characteristics of strong adaptability to terrain and discrete movement track, and is particularly suitable for moving on jungle mountains, steps and other terrains.

Disclosure of Invention

The invention aims to provide a leg mechanism of a legged robot and the legged robot, which are used for solving the problems that in the related technology, the heat dissipation capacity of a motor is limited and the motor is easy to collide in the movement of the quadruped robot, and further, electronic parts such as the motor are damaged, and the problem that the body capacity is limited due to the fact that the body space of the quadruped robot is narrow.

In order to achieve the above object, in a first aspect, an embodiment of the present invention provides a leg mechanism of a legged robot, including a thigh and a shank that are hinged to each other, a motor housing and a planetary reduction mechanism are installed at an upper end of the thigh, a motor stator and a motor rotor coaxially installed with the motor stator are installed inside the motor housing, the motor rotor is fixedly connected to a sun gear shaft of the planetary reduction mechanism, and a planet wheel output carrier of the planetary reduction mechanism is connected to the shank through a pull rod.

Further, the motor cooling fin is designed on the outer side of the motor shell, and the motor stator is installed on the inner side of the motor shell where the motor cooling fin is arranged.

Furthermore, the planetary reduction mechanism comprises a sun wheel, a sun wheel shaft, a planetary wheel, an inner gear ring, a planetary wheel shaft and a planetary wheel output frame, the reducer shell is fixed at the upper end of the thigh, the sun wheel is installed on the sun wheel shaft, the sun wheel, the planetary wheel and the inner gear ring are meshed in sequence, the inner gear ring is fixed in the reducer shell, and the planetary wheel is hinged to the planetary wheel output frame through the planetary wheel shaft.

Furthermore, one end of the sun wheel shaft is hinged with the motor shell through a bearing, the other end of the sun wheel shaft is hinged with the speed reducer shell through a bearing, and the motor rotor is fixedly connected with the sun wheel shaft.

Furthermore, a swing arm radially extends out of the planet wheel output frame, and the upper end of the pull rod is hinged to the swing arm of the planet wheel output frame.

Furthermore, an encoder used for monitoring the rotating speed of the motor rotor is mounted on the speed reducer shell.

Further, cushion pads are installed on the outer sides of the encoder and the reducer shell.

Furthermore, the axis of the sun wheel shaft of the planetary reduction mechanism, the hinged axis of the upper end of the pull rod, the hinged axis of the lower end of the pull rod and the hinged axes of the thigh and the shank are sequentially connected to form a parallelogram.

Furthermore, a limiting part for limiting the movement range of the lower leg is arranged on the thigh.

In a second aspect, an embodiment of the present invention further provides a legged robot including a leg mechanism, where the leg mechanism is the leg mechanism according to the first aspect.

According to the embodiment of the invention, the motor stator and the motor rotor are arranged on the inner side of the motor shell, so that the impact on the motor when the legged robot falls down can be relieved; as the leg parts are arranged at the outer sides of the motor and the planetary reduction mechanism, the space as wide as possible is reserved for the body of the legged robot, and under the condition that the whole width of the legged robot is constant, the space as large as possible is emptied for the body of the legged robot to accommodate more related elements.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a perspective view of a leg mechanism of a legged robot according to an embodiment of the present invention;

FIG. 2 is an axial cross-sectional view of a leg mechanism of a legged robot according to an embodiment of the present invention;

FIG. 3 is a radial cross-sectional view of a leg mechanism of a legged robot according to an embodiment of the present invention;

FIG. 4 is a schematic view of the extreme knee joint contraction of a leg mechanism of a legged robot according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of the ultimate extension of the knee joint of the leg mechanism of a legged robot according to an embodiment of the present invention;

FIG. 6 is a schematic top view of a four legged robot incorporating the leg mechanism of a four legged robot in accordance with an embodiment of the present invention;

in the figure: the motor comprises a motor shell 1, a motor cooling fin 101, a motor stator 2, a motor rotor 3, a reducer sun gear shaft 4, a planet gear 5, an inner gear ring 6, a planet gear shaft 7, a reducer shell 8, a planet gear output frame 9, a pull rod upper shaft 10, a pull rod 11, an encoder 12, a cushion pad 13, a knee joint limiting shaft 14, a thigh 15, a pull rod lower shaft 16, a knee joint rotating shaft 17, a shank 18, a knee contraction limiting zone 1801 and a knee extension limiting zone 1802.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. In the following description and in the drawings, the same numbers in different drawings identify the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatus consistent with certain aspects of the invention, as detailed in the claims below. Various embodiments of the present description are described in an incremental manner.

It should be noted that all the directional indicators (such as up, down, left, right, front, and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the movement situation, etc. in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indicator is changed accordingly.

As shown in fig. 1-2, an embodiment of the present invention provides a leg mechanism of a legged robot, configured to implement a motor-controlled bionic rotary knee joint movement function, including a thigh 15 and a shank 18 that are hinged to each other, a motor housing 1 and a planetary reduction mechanism are installed at an upper end of the thigh 15, a motor stator 2 and a motor rotor 3 coaxially installed with the motor stator 2 are installed inside the motor housing 1, the motor rotor 3 is fixedly connected to a sun gear shaft 4 of the planetary reduction mechanism, and a planet wheel output carrier 9 of the planetary reduction mechanism is connected to the shank 18 through a pull rod 11.

According to the embodiment of the invention, the leg mechanism of the legged robot is simple in structure, convenient to disassemble and assemble and low in cost, and the motor stator and the motor rotor are arranged on the inner side of the motor shell, so that the impact on the motor when the legged robot falls down can be relieved; as the leg parts are arranged at the outer sides of the motor and the planetary reduction mechanism, the space as wide as possible is reserved for the body of the legged robot, and under the condition that the whole width of the legged robot is constant, the space as large as possible is emptied for the body of the legged robot to accommodate more related elements.

In the present embodiment, the motor housing 1 is designed with a motor heat sink 101 on the outside, and the motor stator 2 is mounted on the inside of the motor housing 1 where the motor heat sink 101 is located. The motor radiating fins 101 are not required to be shielded by the cushion pads, so that the radiating capacity of the motor is improved, and the performance of the legged robot is indirectly improved.

In this embodiment, as shown in fig. 3, the planetary reduction mechanism includes a sun gear, a sun gear shaft 4, planet gears 5, an inner gear ring 6, a planet gear shaft 7, and a planet gear output carrier 9, the reducer housing 8 is fixed at the upper end of the thigh 15, the motor housing 1 is fixedly connected with the reducer housing 8, the sun gear is mounted on the sun gear shaft 4, the sun gear, the planet gears 5, and the inner gear ring 6 are sequentially engaged, the inner gear ring 6 is fixed in the reducer housing 8, generally, there are three planet gears 5, the three planet gears 5 are hinged on the planet gear output carrier 9 through the three planet gear shafts 7, and the planet gear output carrier 9 is concentric with the sun gear shaft 4. The planetary gear reducer has the characteristics of compact structure, small volume, light weight, large transmission ratio, good coaxiality, high transmission efficiency and the like, can generally achieve a reduction ratio of 4-10, has good reaction to moment impact, can bear large load, and is suitable for being arranged in a leg-foot type robot joint with tight space.

Furthermore, one end of the sun gear shaft 4 is hinged with the motor shell 1 through a bearing, the other end of the sun gear shaft 4 is hinged with the speed reducer shell 8 through a bearing, and the motor rotor 3 is fixedly connected with the sun gear shaft 4. The sun gear in this embodiment may be directly processed on the sun gear shaft 4, and the rotating shaft of the sun gear shaft 4 and the motor rotor 3 may be one shaft. The sun gear is machined on the sun gear shaft, so that the number of parts of the robot is reduced, the problem that a gap exists in transmission due to machining or installation errors is solved, and the precision of leg and foot movement of the robot is reduced.

Furthermore, a swing arm radially extends out of the planet wheel output frame 9, the upper end of a pull rod 11 is hinged to the swing arm of the planet wheel output frame 9 through a pull rod upper shaft 10, and the lower end of the pull rod 11 is hinged to one end of a lower leg 18 through a pull rod lower shaft 16. The movement of the knee joint of the robot is controlled by the pull rod 11, so that equipment with large mass, such as a knee joint motor and a speed reducer which are arranged coaxially with the knee joint rotating shaft 17 originally, can be transferred to the top end of the thigh 15, the rotary inertia of the lower leg 18 and the thigh 15 of the robot is reduced by the arrangement, and the damage of the motor shell 2 caused by collision of the knee joint rotating shaft 17 during violent movement is avoided; because the pull rod 11 has certain ductility and toughness, when the lower leg 18 is impacted violently, a part of energy can be absorbed, and the safety of the speed reducer and the motor is protected.

One end of the thigh 15 is fixedly connected on the shell 8 of the speed reducer, and the other end of the thigh 15 is hinged with the shank 18 through a knee joint rotating shaft 17; wherein, the connecting line among the axle center of the sun gear shaft 4 of the speed reducer, the axle center of the pull rod upper shaft 10, the axle center of the knee joint rotating shaft 17 and the axle center of the pull rod lower shaft 16 forms a parallelogram. The parallelogram mechanism ensures that the rotating angle of the lower leg 18 relative to the upper leg 15 is always the same as the rotating angle of the planet wheel output frame 9, and theoretically ensures the accuracy of the motion of the leg of the robot.

In the present embodiment, an encoder 12 for monitoring the rotational speed of the motor rotor 3 is mounted on the reducer housing 8. Because the reduction ratio of the planetary reducer is a fixed value, the rotating speed of the motor rotor 3 is monitored through the encoder 12, and the reduction ratio is divided to calculate the angle of the planetary wheel output frame 9 relative to the reducer shell 8; and then the angle of the shank 18 relative to the thigh 15 can be equivalently formed through the equal proportion transmission of the connecting rod 11, so that the balance performance and the accurate feedback in the motion process of the robot are controlled.

In this embodiment, a cushion pad 13 is mounted on the outer sides of the encoder 12 and the decelerator housing 8, and the cushion pad 13 is made of a flexible material such as rubber and is used for protecting the leg mechanism of the legged robot from being damaged by impact.

In this embodiment, the thigh 15 is provided with a limiting part for limiting the moving range of the lower leg 18, and further, the limiting part may be a knee joint limiting shaft 14 or a specially-made protruding part designed on the thigh 15 for limiting the moving range of the lower leg 18. Specifically, the knee joint limiting shaft 14 is installed near the knee joint rotating shaft 17 on the thigh 15, and is used for limiting the moving range of the lower leg 18 rotating around the knee joint rotating shaft 17.

When the knee joint needs to be contracted, as shown in fig. 4, the motor rotor 3 drives the pull rod 11 to move towards the direction close to the knee joint rotating shaft 17 through the revolution of the planet wheel 5, so that the lower leg 18 rotates clockwise in the view angle of fig. 4 under the driving of the pull rod 11. When the knee restraint shaft 14 contacts the knee retraction restraint region 1801, the knee restraint shaft 14 prevents further retraction of the lower leg 18.

When the knee joint needs to be stretched, the motor rotor 3 drives the pull rod 11 to move away from the knee joint rotating shaft 17 through the revolution of the planet wheel 5, so that the lower leg 18 rotates counterclockwise in the view angle of fig. 5 under the driving of the pull rod 11, as shown in fig. 5. When the knee restraint shaft 14 contacts the knee extension restraint region 1802, the knee restraint shaft 14 prevents further extension of the lower leg 18.

The leg mechanism of the legged robot is simple in structure, convenient to disassemble and assemble and low in cost, the motor is arranged on the inner side of the leg mechanism, impact on the motor when the legged robot falls down can be relieved, and the radiating fins of the motor are not required to be shielded by the buffer cushion, so that the radiating capacity of the motor is improved, and the performance of the legged robot is indirectly improved; meanwhile, as shown in fig. 6, since the leg portions are installed at the outer sides of the motor and the reducer, a space as wide as possible is left for the body of the legged robot, and under the condition that the whole width of the legged robot is constant, the space as large as possible is lifted for the body of the legged robot to accommodate more related elements.

The embodiment of the invention also provides a legged robot, which comprises a leg mechanism. The leg mechanism has the advantages of light weight, easy assembly and precise transmission, and can play a special role in protecting a motor driving the leg to move due to the self-provided radiating fins and rubber pads; the knee joint is driven to move by the pull rod, so that the rotational inertia of the leg part can be reduced, and the load of the motor end is further reduced; since the thighs are arranged at the outermost ends of the leg joints, the width of the body can be maximally lifted to accommodate more equipment.

In the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A leg mechanism of a legged robot comprises a thigh and a shank which are hinged with each other, and is characterized in that a motor shell and a planetary reduction mechanism are mounted at the upper end of the thigh, a motor stator and a motor rotor which is coaxially mounted with the motor stator are mounted on the inner side of the motor shell, the motor rotor is fixedly connected with a sun wheel shaft of the planetary reduction mechanism, and a planet wheel output frame of the planetary reduction mechanism is connected with the shank through a pull rod.

2. The leg mechanism of claim 1, wherein the motor housing is designed with motor cooling fins on the outer side, and the motor stator is mounted on the inner side of the motor housing where the motor cooling fins are arranged.

3. The leg mechanism of a leg-foot robot according to claim 1, wherein the planetary reduction mechanism comprises a sun gear, a sun gear shaft, a planet gear, an inner gear ring, a planet gear shaft, and a planet gear output carrier, the reducer housing is fixed to the upper end of the thigh, the sun gear is mounted on the sun gear shaft, the sun gear, the planet gear and the inner gear ring are sequentially engaged, the inner gear ring is fixed in the reducer housing, and the planet gear is hinged to the planet gear output carrier through the planet gear shaft.

4. The leg mechanism of claim 3, wherein one end of the sun gear shaft is hinged to the motor housing through a bearing, the other end of the sun gear shaft is hinged to the reducer housing through a bearing, and the motor rotor is fixedly connected to the sun gear shaft.

5. The leg mechanism of a legged robot according to claim 3, wherein the planetary output carrier has a radially extending swing arm, and the upper end of the pull rod is hinged to the swing arm of the planetary output carrier.

6. The leg mechanism of a legged robot according to claim 3, characterized in that an encoder for monitoring the rotational speed of the motor rotor is mounted on the reducer housing.

7. The leg mechanism of a legged robot according to claim 6, characterized in that cushion pads are mounted on the outside of said encoder and reducer housings.

8. The leg mechanism of a legged robot according to claim 1, wherein the axis of the sun gear shaft of the planetary reduction mechanism, the hinge axis of the upper end of the pull rod, the hinge axis of the lower end of the pull rod, and the hinge axes of the upper leg and the lower leg are connected in sequence to form a parallelogram.

9. The leg mechanism of a legged robot according to claim 1, characterized in that a stopper for limiting the range of motion of the lower leg is attached to the upper leg.

10. A legged robot comprising a leg mechanism, characterized in that the leg mechanism is according to any of claims 1-9.