IAVSD Colloquium on
Stability and Bifurcations of Vehicle and Driver System

Date: 4 March 2022, 13:00-16:00 (CET)
Venue: Politecnico di Milano, Italy (online)
Chairmen: Prof. G. Mastinu and Prof. M. Ploechl

Scientific topic

After a severe lane change, a wind gust or other disturbing occurrences, drivers could be unable to recover the intended motion even if the vehicle is stable and understeering. This fact is very well known by any driver, but it appears that the scientific investigation of this phenomenon is just at its beginning. In the literature, different mathematical models of car and driver have been used for the description of the car motion after a disturbance. Theoretical topics referring to non-linear dynamics, bifurcations and global stability analysis had to be tackled. Since accurate mathematical models of drivers are still object of scientific investigation, driving simulators need to be used to assess the influence of the human action on vehicle motion. Classic unstable motions like Hopf bifurcations – almost disregarded by automotive engineers, but very well known by mathematicians – should be  further brought to the attention of the scientific and industrial community and used for future enhancements of vehicle technology. Unstable limit cycles seem to be at the base of the dynamic behaviour of both understeering and oversteering vehicles driven by humans. At a certain high speed, chaotic motion has been found as well. The delegates of the Colloquium will discuss how to avoid destabilisation of the motion of the car by the driver after a respective disturbance. Future automated vehicles are prone to the same problems of human-driven cars.  


The general aim of the colloquium was to address a scientific community, that sets the proper theoretical basis for

  • understanding the nonlinear behaviour that underpins the motion of car and driver in critical situations, like the response to a disturbance, and
  • studying stable or unstable limit cycles, saddles, bifurcations pertaining to vehicle and driver system motion.

Due to the covid19 pandemic, the colloquium was held online in a shortened format. Invited speakers motivated the topic from different points of view with short presentations. At the end, a discussion among the speakers and the participants took place and possible future activities for a wider interested community were addressed.

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