An optimal control approach to robust control of robot manipulators

We present a new optimal control approach to robust control of robot manipulators in the framework of Lin (1997). Due to the unknown load placed on a manipulator and the other uncertainties in the manipulator dynamics, it is important to design a robust control law that will guarantee the performance of the manipulator under these uncertainties. To solve this robust control problem, we first translate the robust control problem into an optimal control problem, where the uncertainties are reflected in the performance index. We then use the optimal control approach to solve the robust control problem. We show that the solution to the optimal control problem is indeed a solution to the robust control problem. We illustrate this approach using a two-joint SCARA type robot, whose robust control is obtained by solving an algebraic Riccati equation.