The dynamic response of a sliding mode controlled toggle mechanism, which is driven by a permanent magnet (PM) synchronous servomotor, is studied in this paper. The rod and crank of the toggle mechanism are assumed to be rigid. The Hamilton＇s principle and Lagrange multiplier methods are applied to formulate the equation of motion. Reducing the differential-algebraic equation and employing the Runge-Kutta numerical method, the state variable representation is obtained. Based on the principles of the sliding mode control, a robust controller is developed to control the position of a slider of the motor-mechanism coupled system. Moreover, a fuzzy logic controller (FLC), which is based on the concept of hitting condition without using the complex mathematical model of the motor-mechanism coupled system, is designed to control the motor-mechanism coupled system for comparison. Numerical and experimental results show that the dynamic behaviour of the proposed controller-motor-mechanism system is robust to parametric variations and external disturbances.