Space four degree-of-freedom platform mechanism

The utility model discloses a spatial four degree-of-freedom platform mechanism, wherein one end of upper joints of four driving branched chains is respectively connected with one corner of an upper platform and the other end is respectively connected with the upper ends of a rectilinear motion executor. One end of lower joints of the four driving branched chains is respectively connected with one corner of a lower platform, and the other end is respectively connected with the lower ends of the rectilinear motion executor. The center points of the upper and the lower joints of the four driving branched chains form an upper and a lower rectangles. One end of an upper joint of a driven branched chain is connected with the upper platform, the other end is connected with the upper end of a driven branched chain upper end element, and a lower end element is vertically fixed with the lower platform; the center of the upper joint, and a fixation point are respectively positioned at the center of the upper and the lower rectangles and the upper end of the lower end element are connected with the lower end of the upper end element through a driven kinematic pair. The utility model has the advantages that the upper platform can rotate around the three coordinate axes of spatial coordinate systems, and can move along one of the coordinate axes. The utility model can be used for various stable tracking platforms, motion simulators, airship connectors, submarine rescuing connectors, robots and virtual shaft machine tools.