Equivalent resonance ratio control in two-spring system for stable contact motion in industrial robots

Abstract

It is important to consider the environment for realizing stable contact motion, such as direct teaching for polishing motion including contact with environment. To realize stable contact motion without bouncing, the velocity and acceleration should be brought to zero after contact with the environment. This study focuses on the torque-velocity duality and a two-spring system is constructed using motor-side velocity control for a two-inertia system with environmental considerations. An equivalent resonance ratio control (ERRC) is proposed to suppress the vibrations in a two-spring system. This method achieves the same scheme as the resonance ratio control applied in position control. A force impulse control is applied based on the ERRC for stable contact motion without bouncing. Stable contact motion is realized in all numerical simulations and experiments.