A method is proposed to improve the performance of the conventional G eneva mechanism. R ather than driving the input crank at a uniform speed, this method uses optimal control theory to synthesize the speed of the crank. In this paper, design criteria are rst developed based upon the elimination of the impact loading at the beginning and end of the motion cycle. In addition, three approaches to program the crank speed are introduced. In the rst approach, the crank speed is designed to be optimal so as to minimize the output acceleration. In the second approach, the crank speed is determined by minimizing the input motor torque. The third approach uses the degree of wear between the crank pin and wheel slot as the index to optimize the crank speed. All design objectives are formulated as a parameterized optimization problem and solved via an ef cient numerical method. F urthermore, trade-offs among the desired characteristics are taken into account by formulating the problem as a multiobjective optimization problem. Two examples are given to illustrate the design procedure.