The Development and Implementation of Adaptive Semi-Active Suspension Control*

Experimental study on fuzzy skyhook control of a vehicle suspension system using a magnetorheological fluid damper

“…To improve vehicle ride control or handling, modified skyhook control strategies are designed for specific applications. Venhovens developed an adaptive semi-active skyhook control for suspension system by measuring or estimating vehicle states [2]. Williams et al presented a vehicle control scheme to allow nearly optimal ride and simultaneously permit modification of vehicle handing properties by combining the Lotus modal decomposition with a skyhook damper [3].…”

A New Adaptive Controller for Performance Improvement of Automotive Suspension Systems with MR Dampers

“…Now the problem has been reduced to appropriately adjusting the value of α for maximum performance improvement. An adaptive controller introduced in [12] had the basic idea that comfort is the objective, as long as the dynamic tire forces are within certain limits. The weighting parameter α varying between zero and one defines the level of this constraint violation.…”

“…To avoid unnecessary chatter in the controller, the absolute value |F tire | can be used. (12) With the two constraint equations defined for slow and fast adaptation, a way can be developed to quantify the level of constraint violation. The adaptation structure is shown in Figure 4, where the input is the dynamic tire force F tire (which will be the estimated tire force in practice) and output is the weighting parameter α.…”

High frequency energy transfer in semi-active suspension

“…Whatever the constant of the filter is, the level of the transmissibility at high frequency remains higher for the semi-active suspension than for the active (and passive for c =100 Ns/m) suspension. In practice, the time response of hydraulically powered digital servo valves lies in the range of 10 ms [8] and sometimes a little more [21]. As an alternative to an analog filter, the next section investigates if an elastic mount of the damper, using rubber bushing at both ends, could play a role of mechanical filter to smooth the control force.…”

“…Another possible modification of the algorithm is to switch the valves only in those cases where the relative velocity between sprung and unsprung mass is zero [20]. In these instances, the suspension (spring + damper) force remains unchanged independent of the damper settings because no damper force can be generated [8].…”