Two-motor driven variable-stiffness elastic joint of robot

Abstract

The invention discloses a two-motor driven variable-stiffness elastic joint of a robot. The two-motor driven variable-stiffness elastic joint comprises an output shaft, a flexible transmission mechanism and a driving end which are positioned on the same rotating axial line, wherein the driving end comprises two hollow shaft driving motors coaxially connected to two ends of the flexible transmission mechanism in a driving manner; the output shaft is fixedly connected with the middle part of the flexible transmission mechanism, and one end of the output shaft penetrates through and extends out of hollow shafts of the hollow shaft driving motors; under the impact of different loads on the output shaft, the two hollow shaft driving motors change an included rotation angle between the two motors to adjust the length of a force arm of the flexible transmission mechanism for driving the output shaft to rotate, thus adjusting the stiffness and realizing elastic buffering. The two-motor driven variable-stiffness elastic joint of the robot has the characteristics of high real-time response speed and high adjustment precision; the safety and the environment friendliness of the robot are improved; the two-motor driven variable-stiffness elastic joint is simple, portable, high in universality and wide in application range.

Description

technical field [0001] The invention relates to a robot bionic joint, in particular to a dual-motor-driven robot elastic joint with adjustable stiffness. The device is applicable to various joint-type robots and improves the safety and environmental friendliness of the robot. Background technique [0002] For a long time, the traditional robot joint design theory believes that the transmission mechanism with higher stiffness should be given priority to the mechanical connection mode between the power drive device and the joint hinge. Therefore, in the research of joint robots such as industrial robot arms, bionic multi-legged robots, and rehabilitation medical prostheses, the driving scheme of rigid connection between the motor output shaft and the joint mechanism is generally used. Its advantages lie in simple structure, precise positioning, and fast response. Meet the needs of various operations and applications. However, due to the lack of compliance of this driving sche...

AI Technical Summary

Problems solved by technology

After searching the existing technical literature, it is found that most of the existing public series elastic drive joints do not have the function of stiffness adjustment. For example, Yang Qizhi of Jiangsu University proposed a soft elastic joint based on Archimedes spiral elastic body , Patent Publication No. CN105082170A, the elastic body adopts two circular spring pieces, and there are Archimedes spiral grooves on the spring pieces to increase the flexibility of the joint. Although the device is compact in structure, the range of motion is limited and the stiffness cannot be adjusted.

Even if there are very few spring devices with stiffness adjustment at present, there are still problems such as low integration, cumbersomeness, and poor versatility. For example, a robot joint with variable stiffness proposed by Huang Qiang et al. of Beijing Institute of Technology, patent Publication No. CN104440936A, a main friction plate and two secondary friction plates are installed on the joint, and the friction force is generated under the pre-tightening force of the bolts. The friction characteristics of the friction plates are used to adjust the stiffness, but the friction plates are consumables. It will lose its original function after a period of time and needs to be replaced regularly, and it only has two levels of stiffness adjustment, which cannot achieve linearly adjustable stiffness characteristics

More importantly, the currently disclosed stiffness-adjustable flexible joints all use one motor to drive the joint, and another motor to adjust the stiffness instead of driving the joint, which wastes the power of the stiffness-adjusting motor; and if a low Performance stiffness adjustment motor, it is difficult to ensure that the joint stiffness can be adjusted in time in the event of a collision

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