Abstract—The paper presents a two degrees of freedom
(2-dof) structure combining a dynamic feedforward approach
with a nonlinear feedback component to control the damper
valves’ currents of a semi-active suspension system. The concept
makes use of a dynamic damper model, which is able to represent
the dynamic behavior significantly more accurate than
the standard approach, where static damper characteristics are
used.While an additional force feedback path is able to enhance
force tracking even further, a measurement signal of the realized
damper force is not available for control purposes in practice.
Hence, a model-based and a signal-based estimation approach
are employed. The impact on ride performance caused by
the reduced tracking error is studied using three different
suspension controllers known from literature. The performance
potential of the force tracking controller as well as of the
entire control structure is analyzed in simulations and on a
quarter-car test rig. No matter which suspension controller
is applied and thus independently from the respective control
objective, the overall ride performance can be increased due to
the enhanced force tracking of the semi-active damper.