Ij. Fialho et Gj. Balas, Design of nonlinear controllers for active vehicle suspensions using parameter-varying control synthesis, VEH SYST D, 33(5), 2000, pp. 351-370
Nonlinear suspension controllers have the potential to achieve superior per
formance compared to their linear counterparts. A nonlinear controller can
focus on maximizing passenger comfort when the suspension deflection is sma
ll compared to its structural limit. As the deflection limit is approached,
the controller can shift focus to prevent the suspension deflection from e
xceeding this limit. This results in superior ride quality over the range o
f road surfaces, as well as reduced wear of suspension components. This pap
er presents a novel approach to the design of such nonlinear controllers, b
ased on linear parameter-varying control techniques. Parameter-dependent we
ighting functions are used to design active suspensions that stiffen as the
suspension limits are reached. The controllers use only suspension deflect
ion as a feedback signal. The proposed framework easily extends to the more
general case where all the three main performance metrics, i.e., passenger
comfort, suspension travel and road holding are considered, and to the des
ign of road adaptive suspensions.