Active suspension with structural actuator

A strut actuator for a vehicle suspension, comprising:

• a hydraulic motor-pump with a first port and a second port;
• an electric motor-generator drivingly connected to said hydraulic motor-pump;
• a strut actuator comprising a cylinder divided into a rebound volume and a compression volume by a piston, with an attached piston rod, slidably received in said cylinder wherein said rebound volume is in fluid communication with said first port and said compression volume is in fluid communication with said second port;
• a fluid reservoir;
• and
• a flow control system means for fluidly connecting said reservoir to one of said first port and said second port with lower pressure;
• wherein said strut actuator is configured to withstand forces applied in a direction that is transverse to the longitudinal axis of said actuator.

An active strut system of a vehicle, comprising:

• a wheel assembly of said vehicle attached to said strut system;
• a vehicle body of said vehicle attached to said strut system;
• a hydraulic actuator comprising a rebound volume and a compression volume divided by a piston attached to a piston rod;
• a hydraulic motor-pump with a first port in fluid communication with said rebound volume and a second port in fluid communication with said compression volume configured to control rebound and compression of said hydraulic actuator;
• an electric motor-generator drivingly coupled to the hydraulic motor-pump;
• and
• a controller electrically coupled to the electric motor-generator, wherein said controller is configured to operate said hydraulic actuator in at least three of four quadrants of a force velocity domain of said hydraulic actuator;
• wherein said strut is configured to tolerate side-loading applied by said wheel assembly and said body.

A method of operating a strut of a vehicle, comprising:

• installing a strut actuator between a vehicle body and a wheel assembly;
• filling a first volume on one side of a piston in said actuator and a second volume on an opposite side of said piston with hydraulic fluid;
• generating a force on said piston in response to a hydraulic fluid pressure;
• displacing a quantity of hydraulic fluid contained within said first volume;
• receiving at least a portion of said displaced fluid at a first port of a hydraulic motor-pump;
• passing at least some of said portion through said hydraulic motor-pump from said first port to a second port of said motor-pump;
• returning at least some of said fluid passed through said motor-pump to said second volume;
• using a control system to determine which of said first port and said second port has a lower pressure;
• and
• providing fluid communication between a reservoir and one of said first port and said second port with said lower pressure.