Nonlinear characteristic analysis of high-speed spatial parallel mechanism

In order to grasp the nonlinear characteristic of high-speed spatial parallel mechanism, the analysis of nonlinear characteristics for spatial parallel mechanism is investigated. The nonlinear elastic dynamic equation of 4-UPS-UPU high-speed spatial parallel mechanism is derived by kineto-elastodynamics theory, the dynamic equation is solved by numerical method, the nonlinear characteristic of the parallel mechanism is analyzed by phase diagram. Numerical results show that 4-UPS-UPU high-speed spatial parallel mechanism exhibits typical nonlinear characteristic during exercise, the factors, such as the motion trajectory of parallel mechanism, the material of driving limbs, the diameter of driving limbs and the mass of moving platform, are also have effect on nonlinear characteristics of parallel mechanism. Therefore the reasonable choice of the above factors can weaken the chaos motion. This researches provide important theoretical base of the chaos suppression for spatial parallel mechanism.