A toggle mechanism, which is driven by a permanent-magnet synchronous servo motor, with variable-structure model-following control (VSMFC) is proposed in this study. The rod and crank of the toggle mechanism are assumed to be rigid. The Hamilton principle and Lagrange multiplier methods are applied to formulate the equation of motion. Based on the principles of the adaptive model-following control and the variable-structure control, a VSMFC system is developed to control the position of a slider of the toggle mechanism servo system. Numerical and experimental results show that the dynamic behaviour of the proposed controller-motor-mechanism system is robust to parametric variations and external disturbances.
