Abstract: A compact hybrid actuator has a fluid pump (20) arranged to supply fluid to an actuator (44). The pump has at least one electrically-powered solid-state pump driver (21) provided with a displacement element (22). The position of this displacement element modulates the volume of a fluid chamber (23). A driven valve (24) is operatively arranged to control the flows of fluid with respect to the pump chamber, and has one member (29) movable relative to a body (28) to modulate the opening of ports (25, 26) so as to form at least one three-way valve. A valve driver (31) is operatively arranged to operate the driven valve. Electrical power is provided to each valve and to the valve driver so as to operate these various elements in synchronism with one another. The improved pump driver and driven valve may be operated at frequencies in excess of 1 kHz.