An experimental oscillation damping impedance control for the Novint Falcon haptic device based on the phase trajectory length function concept

摘要

This paper aims at designing an oscillationless open-loop impedance controller for a well-known low-cost haptic device, namely the Novint Falcon haptic device. In this regard, the oscillation number index standing for the ratio of the traversed path in the corresponding phase portrait systems for a certain state to its radial value is employed to evaluate the oscillatory behavior of the system. Based on the identified parameters of the dynamic equation, a precise model of the intended robot is developed in the SimMechanics simulator. According to the obtained results in the simulation, one can infer that there is a certain impedance value in which the value of the oscillation number index has its minimum value. The obtained experimental results reveal that the oscillation number index based controller possesses lower oscillation in comparison to the Falcon's official software development kit. In fact, by tuning the system's impedance will result in a better performance for the haptic purposes.