Coupled four-freedom-degree parallel connection vibration isolation platform

A coupled four-freedom-degree parallel connection vibration isolation platform mainly comprises an upper platform, a lower platform, four main part branches and a middle constraint branch, wherein the four main part branches are identical in structure and used for connecting the upper platform and the lower platform. The tails of actuators of the main part branches are connected with the lower platform through universal joints, telescopic rods of the actuators are connected with the upper platform through ball joints, one end of a lower connecting rod in the middle constraint branch is connected with the lower platform through a universal joint, the other end of the lower connecting rod is connected with an upper connecting rod in a bell socket mode to form a sliding pair, namely the upper connecting rod can expand and retract in the lower connecting rod, the upper connecting rod of the sliding pair is sleeved with a spring, the other end of the upper connecting rod is connected with the upper platform through a rotating pair, and the axis of the rotating pair is parallel to one axis of the universal joint in the middle constraint branch. Lower hinge points of the four main part branches are symmetrically arranged in a square shape, upper hinge points are arranged in a trapezoid shape, and the trapezoid is symmetrical about the axis of a rotating pair of the middle constraint branch. The coupled four-freedom-degree parallel connection vibration isolation platform is simple in structure, large in bearing capacity and good in dynamic response characteristic.