Adaptive control scheme for a robot manipulator: direct decoupler and PID controller

Abstract

A two level adaptive controller for the control of a high speed robot is proposed. Dynamic interaction effects of the robot system are eliminated by applying a centralized adaptive multivariable decoupler. Decentralized adaptive PID controllers stabilize and eliminate the static positioning errors of the robot system. No prior knowledge of robot dynamics is required for this scheme. Output transients caused by sensitivity to the system parameter variations is reducible by adjusting the gain constants of the decoupler. Computation load for the implementation of the decoupler is minimal due to its direct nature. The effectiveness of the scheme is demonstrated by simulation results in high speed repetitive motion trackings and load change conditions.

Novel Fuzzy Logic Controllers with Self-Tuning Capability

“…When the robot moves from low to high speed, many parameter values in the linearized discrete time model can go up to 10 times for each link [12]. Moreover, strong interactions between the two links can cause severe additional problems to the motion of each individual joint controller.…”

“…They are compared on their tracking performance in controlling a two-links revolute robot with different speed settings. It is well known that the two-links revolute robot is a highly coupled nonlinear system [12] because the inertia loading, the coupling between joints and the gravity effects are highly sensitive to position and velocity conditions. During high speed motions, the inertia loading terms can change drastically.…”