A compact modular variable stiffness joint

Abstract

A compact modular variable stiffness joint, which includes a joint housing, a main drive module, an elastic module and a stiffness adjustment module; the elastic module includes a variable stiffness base, a linear spring module and a lever assembly; the variable stiffness base consists of the main drive module The output end of the variable stiffness base is driven to rotate; two axisymmetrically arranged lever assemblies are rotatably arranged on the variable stiffness base, each lever assembly has a chute, and the linear spring module is slidably set on the variable stiffness base; The stiffness adjustment module includes a stiffness adjustment driver, a bevel gear pair, a cam disc seat, a cam disc, a slider and a first cam bearing follower; the stiffness adjustment driver is installed on the joint housing, and the cam disc seat is rotatably arranged in the joint housing , two sliders are slidably arranged in the joint housing, and a first cam bearing follower is mounted on opposite side surfaces of each slider. The invention has a large stiffness adjustment range and a large bearing capacity, and can meet the flexible adjustment of the joint stiffness under different load conditions.

Description

technical field [0001] The invention relates to a variable stiffness joint, in particular to a compact modular variable stiffness joint. The invention belongs to the technical field of robot joints. Background technique [0002] Traditional industrial robots are designed with rigid joints and have high position control accuracy, but their safety is poor, and they generally work in a closed environment. Robot systems such as service robots and field special operation robots generally work in an open environment, not only need to deal with flexible and complex operation tasks, but also have the requirements for human-computer safety interaction and interaction between robots and unstructured environments. Therefore, the traditional Rigid joints cannot well meet the manipulation requirements of collaborative robots. [0003] In the prior art, screw nuts are used to adjust the joint stiffness (such as the publication number CN 111390695A, a general-purpose variable stiffness j...

AI Technical Summary

Problems solved by technology

[0002] Traditional industrial robots adopt rigid joint design, which has high position control accuracy, but poor safety, and generally work in a closed environment

Robot systems such as service robots and field special operation robots generally work in an open environment, not only need to deal with flexible and complex operation tasks, but also have the requirements for human-computer safety interaction and interaction between robots and unstructured environments. Therefore, the traditional Rigid joints cannot well meet the operational needs of collaborative robots

[0003] In the prior art, screw nuts are used to adjust the joint stiffness (such as the publication number CN 111390695A, a general-purpose variable stiffness joint mechanical arm joint), which has the disadvantages of large friction and high energy consumption of the stiffness adjustment system; in addition, this arc-based The variable stiffness structure of the shape surface has a strong nonlinear stiffness curve, and it is impossible to achieve a wide range of stiffness adjustment near the equilibrium position

Its stiffness value will increase rapidly with the increase of joint load, and the decoupling of joint load and stiffness value cannot be realized. Therefore, the stiffness characteristics are easily affected by joint load

There is also the use of torsion springs to adjust the stiffness. This method will have the defects of poor linearity of joint stiffness, high hysteresis and poor stability.

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