A control method for controlling a hydraulic actuator to impart oscillatory excitation to a load, the actuator comprising at least one hydraulic chamber and a movable member capable of moving in said chamber between two extreme positions under the action of a liquid under pressure, wherein the method comprises the steps consisting in: determining an operating point for said actuator, which operating point corresponds to a rest position of said movable member; applying a hydraulic command to bring said movable member into correspondence with said rest position; and applying a hydraulic command to cause said movable member to perform reciprocating movement about said rest position, said reciprocating movement being adapted to apply a desired excitation to said load; the rest position of said movable member being selected to be significantly off-center relative to said extreme positions. Advantageously, said rest position is selected to be as close as possible to one of said extreme positions of the movable member, taking account of the movement amplitude required of the piston to impart a desired excitation to said load.