A fully active automotive suspension based on a rotary hydraulic valve

Active suspensions are commonly used in high-end vehicles to improve ride comfort and road holding. Commercial hydraulic active suspensions for cars typically employ directional solenoid valves to control hydraulic fluid flow, thereby modifying the dynamic behavior of output actuators. However, these valves require fast, accurate actuation, which is often hindered by their intrinsic nonlinear behavior. This research presents a fully active suspension based on the use of a novel rotary valve. The proposed design is compact and highly integrated with a permanent-magnet synchronous machine for precise position control. To test its validity, a prototype of the actuation system is simulated, built and tested. Experiments on the position control loop of the valve spool demonstrate that the proposed system is able to fulfill the necessary actuation bandwidth for an automotive suspension. Static and dynamic experiments on the actuator output validate the ability to yield forces in the four quadrants of the force-speed plane.