Bell shaped impedance control to minimize jerk while capturing delicate moving objects

Abstract

Catching requires the ability to predict the position and intercept a moving object at relatively high speeds. Because catching is a contact task, it requires an understanding of the interaction between the forces applied and position of the object being captured. The application of force to a mass results in a change in acceleration. The rate of change of acceleration is called jerk. Jerk causes wear on the manipulator over time and can also damage the object being captured. This paper uses a curve that asymptotes to zero gradient at +/infinity to develop an impedance controller, to decelerate an object to a halt after it has been coupled with the end effector. It is found that this impedance control method minimizes the jerk that occurs during capture, and eliminates the jerk spikes that are existent when using spring dampers, springs or constant force to decelerate an object.