Robot joint based on harmonic wave speed reducer

Abstract

The invention relates to a robot joint based on harmonic reducers, which comprises a motor, an encoder connected with the motor, a harmonic reducer connected with a rotor of the motor, and a transmission mechanism connected with the harmonic reducer; wherein, the harmonic reducer comprises a wave generator, a flexible wheel outside the wave generator, a fixed steel wheel outside the flexible wheel and a rotary steel wheel; the transmission mechanism comprises a housing fixedly connected with the fixed steel wheel of the harmonic reducer and an end cover fixedly connected with the rotary steel wheel of the harmonic reducer; a bearing is arranged between the housing and the end cover. The robot joint has the advantages of high drive ratio, high reliability, compact structure, ability to substitute the robot joint in the prior art, gradual decrease with the size of the harmonic reducer, higher applicability to joint transmission of miniature robots, and wide application prospect.

Description

(1) Technical field [0001] The invention relates to a robot joint. (2) Background technology [0002] At present, the transmission modes of robot joints mainly include: rope pulley drive transmission, linkage mechanism transmission, belt transmission, chain transmission, gear transmission and so on. There are also many reports related to this aspect. There are also some relevant reports in the Chinese patent literature, which include about rope pulley drive transmission, linkage mechanism transmission, belt transmission, chain transmission transmission modes, etc., but no technical solution for the robot joint structure using a harmonic reducer has been found. [0003] The rope pulley drive transmission mode is commonly used in bionic robot joints. This transmission mode can conveniently realize the long-distance transmission of motion and power, and can better meet the structural requirements of the joints of the bionic robot. The mechanism of the rope wheel transmission...

AI Technical Summary

Problems solved by technology

There are also some relevant reports in the Chinese patent literature, which include the transmission of rope pulley drive, linkage mechanism transmission, belt transmission, chain transmission, etc., but no technical solution for the joint structure of the robot using harmonic reducers has been found.

[0009] Disadvantages of the rope transmission method: 1. There is tension, easy to deform, and will cause hysteresis in the transmission. Once the use time is too long, the rope will become slack, and it will bring a large motion transmission error

2. The rope can only be pulled but not compressed. Therefore, it is difficult to realize the return stroke. Once the control force is overshooted, it is difficult to eliminate it, but the overshoot phenomenon is inevitable in practice.

[0010] Disadvantages of the connecting rod transmission method: it will make the structure of the bionic robot complicated, making the design and processing of the mechanical body structure more difficult and difficult to realize

[0011] Disadvantages of belt drive transmission mode: This transmission mode has great limitations in the application of micro-robots. The specific performance is that elastic sliding is an inherent characteristic of belt drive. Belt drive cannot maintain an accurate transmission ratio, and the transmission efficiency is low; When the same large circular force is transmitted, the contour size and the pressure on the shaft are relatively large; the belt is subject to alternating stress, which is prone to fatigue damage, and the life of the belt is short; a tensioning device is required; the transmission external dimension is large

[0012] The micro-robot prototype with bevel gear transmission has the following disadvantages in structure: the gap is relatively large, the connection between the motor shaft and the gear and the sleeve shaft is not tight enough, and there may even be relative circular motion when subjected to a large torque. The movement performance of the walking foot is greatly reduced; the bevel gear transmission method is adopted, and there is no self-locking function. As long as the robot maintains a certain posture, the motors at all joints need to be powered, so the energy consumption is relatively large.

[0013] Although the worm and worm drive has self-locking function, it needs to fix the worm and the motor shaft. This feature causes the motor bearing to bear a considerable axial force. This force has a great impact on the life of the motor and the Normal use is destructive

In addition, the micro robot joints using worm gear and worm drive can only use non-standard design, which increases the difficulty of design, the difficulty of processing and the cost of production, and the relatively large reduction ratio, which requires external Appropriate reducer and its matching transmission

[0014] To sum up, the above delivery methods cannot meet the needs of micro-multi-legged robots and micro-manipulation robots.

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