Active Safety Measures to Improve Vehicle Stability After Minor First-Events

Principal Investigator
Huei Peng (U. of Michigan)

Industry
Jianbo Lu (Ford Motor Company)

Government
David Gunter (TARDEC)

Student
Youseok Kou (U. of Michigan)

The main goal of this project is to study the effectiveness and design of active safety measures using practical chassis controls such as active brakes, augmented/mitigated steering, magneto-rheologic fluid semi active suspension, controlled driver-train, etc. to mitigate the abnormal motions of a vehicle induced by exogenous inputs. Example exogenous inputs include unexpected road bumps/potholes, or a minor crash with another vehicle. The focus of this project is to deal with minor exogenous inputs—so that the vehicle motion is significantly disturbed but is in working condition. In civilian traffic safety terminologies, these accidents can be said to have a non-harmful first event, but a harmful second/third event. These minor first events frequently lead to major crashes because the vehicle motions after the non-harmful event experience discontinuous jump within a short period of time (typically 150 msec or less). After the incident, the vehicle's lateral/yaw/roll motions are suddenly near the stability boundary, and the vehicle has so much slip or roll, it becomes difficult to be controlled by a human driver. In addition, a driver in those situations frequently panicked and the improper steering and braking actions escalated the overall vehicle/driver system instability and finally result in a harmful/fatal crash. The main goal of this project is to study the nature of these incidents, build proper models to predict their effects on vehicle motion, and seek to mitigate these incidents using active safety technologies.

The army will benefit in several ways from this proposed research. First, there are a few vehicles currently experiencing high rollover or lateral stability issues, such as the up-armored HMMWV and FMTV M1088 with LSAC armored cab. Due to the increased weight and elevated center of gravity, the vehicles are more difficult to control after a minor first-event. The need for active safety systems was self-evident in military safety data. The Secretary of the Army and Chief of Staff of the Army recently reorganized the Army Safety Center into the Army Combat Readiness Center (CRC) in January 2005 and chartered it as the focal point for all Army loss. Traffic safety is an assigned top priority. In FY2004-2006, there are a total of 785 Ground Class-A Accidents—defined as accidents that result in damage costs of $1,000,000 or more and/or destruction of an Army aircraft, missile or spacecraft and/or fatality or permanent total disability (https://rmis.army.mil/stats/prc_fy_ground_stats). Out of these 785 Class-A Accidents, 398 occurred on POV (Privately owned vehicles), 175 were associated with Army Motor vehicles or Army Combat vehicles, and 12 were caused by explosives. The modeling, simulation and analysis capabilities produced by this project help to directly address safety issues related to these accidents.

The developed incident models (especially the crash model), post-incident models (especially the driver model), and the chassis control concepts can also be applied to civilian vehicles, through our partnership with Ford Motor Company in an ongoing project.