Robust trajectory following for underactuated Robot fingers

Underactuated fingers of the Bristol Elumotion Robot Hand (BERUL) have many problems which need to be resolved for the implementation of a trajectory following and position control scheme. The hand has significant friction and stiction and unknown parameters; it is light in weight and fragile. Moreover, the hand has 5 fingers with 16 degrees of freedom and most of the fingers are underactuated. All of these problems create a very nonlinear dynamic system. This paper investigates 4 different trajectory tracking and positioning techniques namely PID, adaptive, Conventional Sliding Mode and Integral Sliding Mode Controllers to alleviate the aforementioned problems. Comparative performance characteristics have shown that the ISMC is the most suitable candidate to provide good experimental trajectory following and positioning control for underactuated BERUL fingers.