Global Stability of a Saturated Nonlinear PID Controller for Robotic Manipulators

This paper presents a simple and globally stable nonlinear proportional-integral-derivative (N-PID) controller incorporated with a saturated function design. The proposed controller is formulated by using a new class of saturated function derived from quasi-natural potential function to shape the position and velocity errors. The global asymptotic stability of the controlled system for the setpoint position control is proven. Experiments are performed on an industrial robot manipulator to demonstrate the improved performance of the proposed approach over conventional linear PID controller