Tactile feedback with adaptive controller for a force-reflecting haptic display. 2. Improvements and evaluation

For pt. 1 see ibid., p.526-9 (1996). This paper describes the initial performance evaluation of a tactile feedback actuator introduced in pt. 1. An adaptive PI algorithm using continuously variable gain scheduling helps to compensate for nonlinearities in the solenoid actuator. The closed-loop behavior meets performance specifications, but the mass added to the force-reflecting haptic interface degrades its performance. Improvements in future prototypes may reduce the mass added by the tactile feedback hardware by over 30%. The work concludes with recommendations for psychophysical research that will increase understanding of human performance in tasks using haptic feedback devices.