Tip control of a single-link flexible arm using a feedforward technique

Abstract This paper examines the problem of controlling the tip of a single-link flexible manipulator. A feedforward controller along with a P-D feedback controller are used to regulate the position of the arm's tip. It is shown analytically that the feedforward controller based on a precomputed torque provides an ‘almost’ pole-zero cancellation property which minimizes the residues of the dominant system poles, thus speeding up the response. Simulations are carried out to verify these properties and comparisons with standard error compensation methods (P-D) are conducted. An investigation is also conducted to determine the extent of system response degradation when the parameters of the feedforward controller are chosen inaccurately. This paper demonstrates that a combination of feedforward and feedback control is more adequate than methods based only on feedback control for controlling flexible link arms.