The position control of the slider of a slider-crank mechanism, which is driven by a permanent magnet (PM) synchronous motor, using an adaptive computed torque technique, is studied. First, the mathematical model of the motor mechanism coupling system is described, where the Hamilton principle and the Lagrange multiplier method are applied to formulate the equation of motion. Secondly, assuming that the parameters of the system are well known, according to the computed torque technique, a robust controller is designed to control the slider-crank mechanism. Then, considering the existence of the uncertainties of the system, an adaptive computed torque controller is designed based on the Lyapunov stability. Moreover, to increase the execution rate of the control algorithms, a digital signal processor (DSP)-based control computer is devised to control the motor mechanism coupling system.