The optimization design of kinematic rules for programmable mechanism is studied.The mechanism of traditional fatigue tester is modified and optimized and the 2-DOF planar mechanism is adopted to hybrid-drive

thus the on-line adjustment of the kinematic rules is realized.The forward kinematic model of the mechanism is established and then the difference between kinematic result and standard test wave is compared.Then

based on Newton-Raphson method

the inverse kinematic analysis is conducted.Therefore

the difference is eliminated and the input of servomotor is obtained.The workability of the dynamic adjustment of the amplitude is testified

and this method can be used to help the realization of kinds of kinematic rules.