Active vehicle suspension

An active suspension system comprising:

• a hydraulic actuator including an extension volume and a compression volume, wherein the hydraulic actuator is disposed between a wheel mount and a vehicle body;
• a hydraulic motor-pump in fluid communication with the extension volume and the compression volume of the hydraulic actuator;
• an electric motor operatively coupled to the hydraulic motor-pump;
• a piston, with a first side and a second side, disposed within the actuator and separating the compression volume and the extension volume, wherein the first side of the piston is adjacent to the compression volume and the second side of the piston is adjacent to the extension volume;
• and
• a sensor to sense wheel events;
• and
• a controller, wherein in response to a first sensed wheel event the controller operates the electric motor using electrical energy from an energy storage facility to drive the motor-pump to create a pressure differential between the first side and the second side of the piston to apply a force in a direction selected from the group consisting of a compression direction and an extension direction independent from a direction of travel of the piston, and wherein in response to a second sensed wheel event the controller operates the electric motor to generate electrical energy.

A method of on-demand energy delivery to an active suspension system, comprising:

• operating an active suspension system in at least three of four quadrants of a force/velocity domain, wherein the active suspension system is disposed between a vehicle body and a wheel, and wherein the active suspension system comprises a hydraulic actuator, an electric motor, a hydraulic motor-pump operatively coupled to the electric motor, at least one sensor, and at least one energy storage facility;
• sourcing electrical energy from the at least one energy storage facility in a first operating mode;
• providing at least a portion of the sourced electrical energy to the electric motor to drive the hydraulic motor-pump and alter a pressure in a volume in the actuator to change a force applied by the actuator between the wheel and the vehicle body during the first operating mode;
• using relative motion between the wheel and the vehicle body during a second operating mode to displace a quantity of fluid from the volume in the actuator;
• causing the displaced fluid to pass through the hydraulic motor-pump to produce a torque and drive the electric motor to generate electric current in the second operating mode.