The system (11) has four pivot articulations (41-43, 45) defining four quadrilateral vertices (Q11) arranged in a plane (P11) perpendicular to an axis (X42). Extension and retraction units comprising rigid support arms (21-24) and a hydraulic cylinder (31) deform the vertices of quadrilateral by moving a wheel (15) and one of the arms along a circular translatory movement. Oscillation units comprising hydraulic cylinder (32) deform the vertices of quadrilateral in the plane by moving the wheel and one of the arms according to rotational movements (D15, M15) around the axis.
