A Compliant Rotational Joint with Torque Limiting Function

Abstract

The invention discloses a flexible rotational joint with a torque limitation function. The flexible rotational joint comprises a joint driving device and a torque limitation device, wherein the torque limitation device comprises a bearing base; the bearing base sleeves a rotary table; an input torque end of the rotary table is fixedly connected with an output torque end of a torque input flange; the torque input flange is connected with the joint driving device; the torque input flange rotates relative to the bearing base; a limiting switch is fixed on a side wall in the bearing base; the rotary table is provided with a plurality of stopping blocks; and when the torque input flange drives the rotary table to rotate and the stopping blocks touch the limiting switch, the joint stops running. When a load of the torque limitation device exceeds a pre-set threshold value, the limiting switch is triggered and a motor stops running. The position of a spring guide rod is adjustable and the threshold value of a rotary torque is adjusted through adjusting the spring guide rod; the spring can load a pre-tightening force and the rigidity of a system is adjustable; and the flexible rotational joint with the torque limitation function has the advantages of passive flexibility, adjustable bidirectional rigidity and bidirectional torque limitation function.

Description

technical field [0001] The invention belongs to the technical field of robots and relates to a compliant rotary joint with a torque limiting function. Background technique [0002] With the development of modern industry and robot technology, robots are coming out of the safety fence of the factory, working side by side with workers in an open environment, coexisting harmoniously, and completing tasks together, which puts forward high requirements for the safety of robots . [0003] Traditional industrial robots generally use rigid joints, and use motors and reducers to form drive units to control the joints' precise position or speed. Although this method has high motion precision, it has poor flexibility and is difficult to adapt to the working environment of human-machine cooperation. When the robot collides with humans and the surrounding environment, it is easy to cause harm to humans or itself. [0004] In recent years, attention has been paid to the design of compli...

AI Technical Summary

Problems solved by technology

Chinese patent CN102626930A modular joint of manipulator with power-off braking and multiple sensing functions and Chinese patent CN102218739A modular joint of manipulator with force-position sensing function both use torque sensing and active compliance control methods to improve joint flexibility, they The joint motion is driven by the motor and the reducer, and the torque sensor is used to measure the joint output torque to achieve high-precision force control and stable contact with the environment, but expensive force / torque sensors and complex force / position control algorithms limit this approach. Wide application; Chinese patent CN1275470A robot control equipment, according to the set value of the force and torque in the working coordinate system to limit the torque generated by the servo motor driving the joint, when there is an external force applied to it, it can flexibly follow the external force action, using This device controls robot joints, which can improve joint flexibility, but is not intrinsically safe

This kind of joint achieves two-way compliance through a plane torsion spring, but the spring cannot be loaded with pre-tightening force, and the stiffness of the system cannot be adjusted; the Chinese patent CN102744731A integrated rotary joint and the method of determining the zero position of the integrated rotary joint utilize uniformly distributed circumferential The spring and incremental encoder realize the transmission and measurement of torque. Although the joint has flexibility and force sensing function, its structure is complex and the spring preload cannot be adjusted; The motor adjusts the effective working length of the flat non-contact scroll spring to adjust the stiffness, but it can only achieve one-way compliance of the joint

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