Nonlinear H, control of active suspensions

A nonlinear H, control law based on a quadratic and quartic cost function is developed, and applied to a quarter-car, two-degree-of-freedom vehicle model. For small disturbances, the performance is similar to the system controlled by the linear H, controller, but for large disturbances, the suspension travel and wheel hop are reduced at the expense of larger body acceleration. When the vehicle strikes isolated large bumps, the nonlinear suspension provides a safer ride at the expense of higher car body acceleration and decreased ride quality.