Linear multivariable control of robot manipulators

The paper presents a simple scheme for linear multivariable control of multi-link robot manipulators. The control scheme consists of multivariable feedforward and feedback controllers. The feedforward controller is the minimal inverse of the linearized model of robot dynamics and contains only proportional-double-derivative (PD²) terms. This controller ensures that the manipulator joint angles track any reference trajectories. The feedback controller is of proportional-derivative (PD) type and achieves stability and pole placement. This controller reduces any initial tracking error to zero as desired. The two controllers are independent of each other and are designed separately based on the linearized robot model and then integrated in the overall control scheme.