In this paper, robust position control of a direct drive using a state spac
e model predictive control (MPC) algorithm is presented. The proposed contr
oller consists of a state feedback regulator and a feedforward controller.
Their gains are obtained by minimizing a cost function that is a sum of the
position tracking errors and the control cost over some user defined time
horizons. The effects of the controller parameters on the dynamic performan
ce and the robustness of the direct drive are investigated. To provide good
estimates of the state variables in the presence of load disturbance, a ne
w observer based on the receding horizon concept is also formulated. Experi
mental results are presented to demonstrate the effectiveness of the approa
ch.