Abstract:Based on the existing mechanisms, a new kind of two degreeoffreedom planar parallel manipulator with planar translational motion and small inertia was improved and taken as the object of study. Unlike the traditional study method, not only the geometric parameters but also the input of the manipulator are consider as the kinematics parameters, and the design space was obtained by utilizing the theory of geometric model of the solution space. The global velocity indices were calculated in the design space, the velocity atlases of the manipulator were plotted, and the relationship between the velocity and the kinematics parameters of the manipulator was discussed. The results show that: the minimum and maximum velocity indexes ηvmin and ηvmax are inverse to r1, that is r1 is shorter, the velocity performance is better; The ηvmin and ηvmax are proportional to r2, that is r2 is longer, the velocity performance is better; While 0