  PID control is commonly utilized in an active suspension system to achieve
desirable chassis attitude, where, due to delays, feedback information has much
difficulty regulating the roll and pitch behavior, and stabilizing the chassis
attitude, which may result in roll over when the vehicle steers at a large
longitudinal velocity. To address the problem of the feedback delays in chassis
attitude stabilization, in this paper, a feedforward control strategy is
proposed to combine with a previously developed PID control scheme in the
recently introduced Parallel Active Link Suspension (PALS). Numerical
simulations with a nonlinear multi-body vehicle model are performed, where a
set of ISO driving maneuvers are tested. Results demonstrate the
feedforward-based control scheme has improved suspension performance as
compared to the conventional PID control, with faster speed of convergence in
brake in a turn and step steer maneuvers, and surviving the fishhook maneuver
(although displaying two-wheel lift-off) with 50 mph maneuver entrance speed at
which conventional PID control rolls over.
