Research Staff, Ford Research Laboratories
Dearborn, MI 48124
Motor vehicles behave well when operated under typical conditions such
high friction roadways, moderate speeds, and well behaved driver inputs.
when operated outside of the typical condition range, vehicles can
become difficult to
control, especially for non-professional drivers under extreme emergency
such as can occur while trying to avoid an unexpected obstacle on a
slippery road. By
providing a vehicle with a means of monitoring and controlling its
response to inputs, it
can be made to operate more robustly, providing safer and more enjoyable
driving over a
wider range of operating conditions and inputs. Several means of
vehicle behavior have emerged from the automotive industry. These
braking systems, traction control, yaw control through active braking,
steering, active and semi-active suspensions, and others.
This presentation focuses on several of these systems, including
advanced suspensions, yaw control using active braking, and related.
Traction control is
presented by introducing the force-producing capability of a tire,
showing how tire slip is
targeted to produce a desired vehicle response to driver inputs,
methods including actuator and control system partitioning, and showing
between choices of actuation and overall system performance. Advanced
systems are presented by discussing the fundamental tradeoff between
ride comfort and
vehicle handling, and presenting controls and actuation methods. Yaw
active braking is presented by showing how vehicle body yaw moment is
through active differential braking and by presenting a control
accomplishing closed-loop yaw control.
In addition to presenting vehicle dynamic control subsystems, methods
and tools for
developing these systems are also discussed. Different development
stages are presented
including developing an understanding of desired vehicle response,
desktop modeling of
the system hardware and controls, man-in-the-loop simulations, and open
and closed loop
in-vehicle testing. The tools used in each stage are also discussed.
The presentation ends
with a discussion of future possible directions for advanced vehicle
controls and related
development and testing methodologies.