For the dynamic analysis, Hamilton's principle and Lagrange multiplier method are applied to formulate the equations of the motion of a quick return mechanism driven by a DC motor. The coordinate partitioning theorem is applied here to provide a theoretical reduction of differential-algebraic equations to differential equation form. In this work, we are concerned with the analysis and design a modified proportional-integral-derivative(PID)controller which was based on the principles of conventional PID controller to keep the driving crank with a constant angular velocity. Results of numerical simulations show that the angular velocity fluctuation can be reduced substantially and this modified PID controller also can give reasonably good results whatever it have or not considered cutting force in the system.