an actuation system includes a pump assembly configured to form a pump chamber ; an actuator having first and second chambers and a movable member and configured to convert pressures applied to the first and second chambers into a movement of the movable member ; and a valve section . a controller controls the valve section to open a first flow path between the pump chamber and the first chamber and close a second flow path between the pump chamber with the second chamber , during a discharge period during which the pump chamber is pressurized , in a first mode ; to close the first flow path and open the second flow path during an intake period during which the pump chamber is depressurized , in the first mode ; to close the first flow path and open the second flow path during the discharge period in a second mode ; and to open the first flow path and close the second flow path during the intake period in the second mode .