Active-passive variable stiffness joint and stiffness adjustment method thereof

Abstract

The invention relates to an active-passive variable stiffness joint and a stiffness adjustment method thereof. The active-passive variable stiffness joint comprises a joint output rod, a joint drive rod, a central shaft, a stepping motor, a motor mounting base, a helical rack wheel, a torsion spring, a helical pinion, a first set of steel balls, a first cone disk, a first disc spring, a first slider, a second slider, a second disc spring, a second cone disk, a second set of steel balls, a left end cover, a first compression spring, a right-handed Nut, a left-handed nut, a sleeve, a second compression spring, a first shaft sleeve and a second shaft sleeve. By adjusting the compression of the two disc springs, the joint stiffness is changed to achieve the active variable stiffness function of the joint; when joints are relatively turned, the torsion spring is twisted and the sleeve is squeezed and deformed, so that the first set of steel balls and the first cone disk cooperate with eachother, and the second set of steel balls and the second cone disk cooperate with each other to convert the radial displacement into axial displacement, the first disc spring and the second disc springare compressed to hinder the relative rotation of the joint drive rod and the joint output rod, and therefore flexible output of the joint is achieved.

Description

technical field [0001] The invention relates to the technical field of robot joints, in particular to an active-passive variable stiffness joint and a stiffness adjustment method thereof. Background technique [0002] With the rapid development of technology, traditional rigid robot designs have reached their limits. At present, service medical robots are on the rise. In the field of human-computer interaction, safety constraints are an important aspect of robot-human interaction, while traditional rigid robots move slowly and lack power, making it difficult to apply them in practice; in the fields of industrial production, flexible assembly, and fixed load assembly, flexible It is sensitive to the interaction force and the application of high-precision torque sensor has the disadvantages of high cost and high real-time requirements of the control system. [0003] Application number 201710289744.3 discloses a compact variable-stiffness rotating flexible joint, including a j...

AI Technical Summary

Problems solved by technology

At present, service medical robots are on the rise. In the field of human-computer interaction, safety constraints are an important aspect of robot-human interaction, while traditional rigid robots move slowly and lack power, making it difficult to apply them in practice; in the fields of industrial production, flexible assembly, and fixed load assembly, flexible It is sensitive to the interaction force and the application of high-precision torque sensor has the disadvantages of high cost and high real-time requirements of the control system

[0003] Application number 201710289744.3 discloses a compact variable-stiffness rotating flexible joint, including a joint drive plate, a joint output plate, a joint passive inner plate, a first cam, a first passive variable-stiffness adjustment seat, a first set of compression springs, an optical axis, a second The first variable stiffness adjustment seat, the turbine screw structure, the second variable stiffness adjustment seat, the second set of compression springs, the second passive variable stiffness adjustment seat, the second cam, cylindrical gear, worm, absolute encoder, motor and arc Rack, although this mechanism has the function of active-passive adjustment of joint stiffness, the structure is relatively complex. The overall size of the designed joint is 160mm in diameter, 45mm in height, and the maximum angle of flexible deformation is 45°. The volume is large and the relative rotation angle is relatively small. , the breadth of application to various small and medium-sized robots is limited

The structure of the existing variable stiffness joint is relatively complex, the volume is large, the control is complicated, and the variable stiffness characteristic is poor. Based on the above reasons, it is of great practical significance to design a variable stiffness joint with a simple structure, small size, and good active stiffness adjustment characteristics.

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