A disturbance observer based tracking control algorithm is presented in this paper. The key idea of the proposed method is that the plant nonlinearities and parameter variations can be lumped into a disturbance term. The lumped disturbance signal is estimated based on a plant dynamic observer. A state observer then corrects the disturbance estimation in a two-step design. First, a Lyapunov-based feedback estimation law is used. The estimation is then improved by using a feedforward correction term. The control of a telescopic robot arm is used as an example system for the proposed algorithm. Simulation results comparing the proposed algorithm against a standard adaptive control scheme and a sliding mode control algorithm show that the proposed scheme achieves superior performance, especially when large external disturbances are present. [S0022-0434(00)00802-9]

Issue Section:
Technical Papers
Keywords:
tracking, observers, stability, control nonlinearities, Lyapunov methods, feedback, feedforward, manipulators
Topics:
Tracking control, Sliding mode control, Adaptive control, Manipulators
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