Abstract: According to the requirement of active reflector supporting mechanism, one type of spatial three degrees-of- freedom parallel manipulator combining two degrees rotation and one degree translation is proposed. The inverse kinematics problems are described in closed forms and the velocity equation of the parallel manipulator is given. The forward kinematics problem is investigated by number analysis method. Three kinds of singularities are presented. The position and orientation workspace for the manipulator is analyzed. The analysis results prove that the manipulator can be used as the supporting mechanism of spherical radio telescope. And the research builds the theory basis for dimensional design, trajectory planning and control of this type of manipulator.

Key words: Active reflector, Kinematics analysis, Parallel manipulator, Spherical radio telescope