Decentralized adaptive control of robot manipulators

Abstract

Abstract A decentralized adaptive control scheme is proposed for the trajectory tracking of a general n ‐degree‐of‐freedom robot manipulator. The robot is considered as a set of decoupled second‐order systems with disturbances. The controller consists of feedforward from the desired trajectory based on the “inverse system” of the model, PID feedback from the actual trajectory, and auxiliary input for the compensation of the neglected terms in modeling in each subsystem. The gain is derived in diagonal matrix form, and is adjusted by the model reference adaptive control theory based on the Lyapunov's direct method. The result is high accuracy in path tracking despite the high speed, load change, and sudden torque disturbances. Numerical simulations on.a planar two‐link robot manipulator are presented to show the performance under various practical considerations.