Abstract: Dynamics of a type of 3-HSS parallel kinematic machine is dealt with, and the research on the trail tracking control method is also done at the same time. First, the reverse solution model of position, velocity and acceleration of parallel kinematic machine is deduced including parallelogram strut structure and the outer translation pair driving fashion. Based on the above, its rigid dynamic model is set up by using the virtual work principle. Considering the gravity of moving part and error of dynamic model, a robust trail tracking controller is adopted to ensure the tracking precision, which guarantees the uniform and ultimate bound of the tracking error. At last, the stability and validity of above controller are proved through the simulation on the circular trail in the whole workspace.

Key words: Dynamic model, Parallel kinematic machine, Robust control, Trajectory control