US Patent 11065931 Active suspension system

A suspension system includes a primary actuator, an inertial actuator, and a controller. The primary actuator applies force between a sprung mass and an unsprung mass of a vehicle to control movement therebetween. The inertial actuator applies force between the unsprung mass and a reaction mass to damp movement of the unsprung mass. The inertial actuator has a threshold capacity. The controller controls the primary actuator and the inertial actuator. The controller determines a required damping of the movement of the unsprung mass, and apportions the required damping between the primary actuator and the inertial actuator.