Smoothly Connected Preemptive Impact Reduction and Contact Impedance Control

TL;DR

This paper introduces a novel serial combined impedance control framework enabling seamless transition from preemptive impact reduction to contact impedance control in robots, minimizing impact forces and contact force fluctuations during contact.

Contribution

It presents a new control method that allows smooth switching between impact reduction and contact impedance control, enhancing robotic force control performance.

Findings

Effective impact force reduction demonstrated in experiments

Seamless transition without undesirable contact forces achieved

Virtual viscous force minimizes reflectance effects

Abstract

This study proposes novel control methods that lower impact force by preemptive movement and smoothly transition to conventional contact impedance control. These suggested techniques are for force control-based robots and position/velocity control-based robots, respectively. Strong impact forces have a negative influence on multiple robotic tasks. Recently, preemptive impact reduction techniques that expand conventional contact impedance control by using proximity sensors have been examined. However, a seamless transition from impact reduction to contact impedance control has not yet been accomplished. The proposed methods utilize a serial combined impedance control framework to solve this problem. The preemptive impact reduction feature can be added to the already implemented impedance controller because the parameter design is divided into impact reduction and contact impedance control. There is no undesirable contact force during the transition. Furthermore, even though the preemptive impact reduction employs a crude optical proximity sensor, the influence of reflectance is minimized using a virtual viscous force. Analyses and real-world experiments confirm these benefits.