Four-legged robot mechanism of variable topology structure

A four-legged robot mechanism of a variable topology structure comprises a trunk unit and leg units. The bottom of the trunk unit is connected with four leg units; the legs units comprise hip leg joints, thigh leg joints and shank leg joints, coupling semiaxis are connected between the trunk unit and the hip leg joints, the hip leg joints and the thigh leg joints, and the thigh leg joints and the shank leg joints correspondingly, hip joint horizontal roller linear hydraulic actuators are connected between the hip leg joints and the trunk units, thigh pitching linear hydraulic actuators are connected between the thigh leg joints and the hip leg joints, and shank pitching linear hydraulic actuators are connected between the shank leg joints and the thigh leg joints. Three linear hydraulic cylinders are adopted by the four-legged robot mechanism to control each leg, the leg motion inertia is effectively reduced, the leg units are modularized, the structural variability is effectively increased, the maintenance d