Parallel mechanism with RRR closed-loop subchain

A parallel mechanism with an RRR closed-loop subchain comprises the RRR closed-loop subchain and an executive mechanism subchain. The RRR closed-loop subchain is capable of controlling a first rotary table to move in a plane where the RRR closed-loop subchain is located, and movement of the first rotary table can realize spatial two-degree-of-freedom motion of a movable platform. The spatial two-degree-of-freedom motion of the movable platform is realized by using the closed-loop subchain to control planar movement of the rotary plate, the parallel mechanism has the advantages of compact structure and simplicity in control, and all linear drivers are connected to a frame.