ROBUST PID REGULATOR FOR ROBOTS YIELDING CONSTANT TORQUE DISTURBANCE REJECTION

This paper proposes a robust PID regulator for robots that is globally asymptotically stable and assumes only that the unknown parameters of the gravity vector belong to a compact set. The design uses a Lure-ty pe Lyapunov function, which is a quadratic form of the velocity vector plus a line integral, which is path independent owing to the fact tha t the gravity vector is the gradient of the potential energy.