Sequential telescopic oil cylinder system and control method and equipment thereof

According to the sequential telescopic oil cylinder system, a rodless cavity of a multi-stage telescopic oil cylinder is communicated through a connecting pipeline, a rod cavity of the multi-stage telescopic oil cylinder is communicated in a one-way mode through a one-way communicated oil way, a control oil way is arranged between a sealing cavity of a sealing device and a piston rod cavity, and the upper-stage piston rod is closed before completely stretching out and is communicated after stretching out; the control on an oil return path of the next-stage telescopic oil cylinder is realized; according to the sequential telescopic oil cylinder system, through ingenious design of telescopic oil cylinder oil ways, reasonable application of hydraulic elements and control over an oil inlet oil way and an oil return oil way of the sequential telescopic oil cylinder system, sequential telescopic control over all stages of telescopic oil cylinders is achieved, and mechanical collision of control elements and positio