A robust controller, which combines the merits of integral-proportional (LP) position control and adaptive control, is designed for a permanent magnet (PM) synchronous motor (SM) drive in this study. First, an IP position controller is designed according to the estimated plant model to match the time-domain command tracking specifications. Second, an adaptive uncertainty observer, which is implemented to estimate the lump of uncertainty of the controlled plant, is described. Then, a robust controller is formulated using the adaptive uncertainty observer to increase the robustness of the motor drive system. The effectiveness of the proposed controller is demonstrated by both simulation and experimental results.