Robust Pole Assignment for Computed Torque Robotic Manipulators Control

Robotic manipulator control designers often assume accurate knowledge of the system parameters. In practice, such as assumption will often lead to unacceptable deterioration in controller performance and robust approaches for the design of manipulator controllers are required. In this paper, the computed torque method is used to reduce the manipulator controller design to a linear problem. A robust pole assignment approach is used to select a suitable linear state feedback for the nominal computed torque model. The effect of modeling errors is accounted for by a state-dependent acceleration disturbance vector. Stability bounds for this acceleration vector are obtained using the Lyapunov approach and robustness measures to assess its effect are suggested. A 2-D.O.F. manipulator design example is given to demonstrate the design approach. Simulation results suggest that state feedback that recouples the state variables decoupled in the computed torque approach may offer some advantages over decoupled designs.