Closed-form Analysis of Vehicle Suspension Ride and Handling Performance

A closed-form, analytical study that evaluates the response characteristics of a two-degree-of freedom quarter-car model using passive and semi-active dampers is provided as an extension to the results published in past studies for active suspensions. The semiactive methods that are considered include skyhook, groundhook, and hybrid control. The relationships between vibration isolation, suspension deflection, and road-holding are studied using the model. The performance indices that are used include vertical acceleration of the sprung mass, deflection of the suspension (rattle space), and deflection of the tire. The results indicate that hybrid semiactive control yields better comfort than passive suspension and the other semiactive control methods that are considered, without reducing the road-holding quality or requiring larger suspension rattle space for typical passenger cars.