CONSTANT-SPEED CONTROL OF A MOTOR DRIVEN MECHANISM SYSTEM

One of the basic assumptions in both the synthesis and analysis of man y four-bar mechanisms is that the angular velocity of the input crank is constant. However, this assumption may not be valid when an electri c motor is connected to drive the mechanism. In this study, the motor- mechanism combination is treated as a single system, and control strat egies are developed to efficiently reduce the crank angular speed fluc tuation of a four-bar linkage. A complete mathematical model for the c ontroller-motor-mechanism is developed, using a state space representa tion. Based on the principles of conventional PID control and the info rmation obtained from steady state constant speed analyses, several mo dified PID type control strategies are developed. Nonlinear programmin g techniques are utilized for the determination of optimal controller gains. Numerical simulations show that, by using feedback control, the crank speed fluctuation can be reduced substantially.