Space four freedom mechanism for realizing three rotating and one moving

The present invention discloses one kind of four-freedom spatial structure realizing three rotation freedoms and one translation freedom. There are four driving branch chains, each of which has upper joint connected between one corner of the upper platform and the upper end of one linear motion executor, and lower joint connected between one corner of the lower platform and the lower end of the linear motion executor, and one driven branch chain, which has upper joint connected between the upper platform and the upper end of the driven branch member and lower end member connected to the lower platform vertically. The present invention can realize the rotation of the upper platform around three spatial coordinate axes and one transition along one axis. The present invention is used in various stably tracking platform, motion simulator, shuttle butt connector, etc.