Four-branch-chain space six-degree-of-freedom parallel mechanism driven by moving pair

The four-branch-chain space six-degree-of-freedom parallel mechanism driven by the moving pairs comprises a base, PPPS driving branch chains and an objective table, and the four PPPS driving branch chains are arranged between the base and the objective table; the PPPS driving branch chain comprises a three-translation-pair series joint and a spherical hinge joint, the three-translation-pair series joint comprises a third moving joint, a second moving joint and a first moving joint, the second moving joint is orthogonally arranged on the third moving joint, the first moving joint is arranged on the second moving joint, and an included angle is formed between the first moving joint and the plane of the base; the spherical hinge joint is arranged on the first moving joint, the objective table is arranged on the spherical hinge joint, and the PPPS driving branch chain drives the objective table to achieve translation and rotation of the objective table in the X-axis direction, the Y-axis direction and the Z-axis