Műszaki Mechanikai Tanszék

Szeretettel várjuk az érdeklődő hallgatókat a Gépészeti fejlesztő specializáció bemutatójára.

Stability and Bifurcation of Longitudinal Ground Vehicle Braking

Dr. Brian J. Olson
Johns Hopkins University
Applied Physics Laboratory


Szeretettel várjuk az érdeklődő kollégákat a 2024. május 14-én 11.00 órakor kezdődő
szemináriumi előadásra az MM Tsz. könyvtárában.



Abstract
The longitudinal braking dynamics of a rubber-tired ground vehicle are
investigated using single- and two-wheel analytical models, empirically
derived tire-to-road friction characteristics, and techniques from
nonlinear dynamics. The models are planar, incorporate the coupled
dynamics of the vehicle body and independently braked wheels, and take
into account the slip dynamics of each wheel. Qualitative behavior of
the system is completely captured by a relatively simple phase plane
problem if the dynamics are cast in terms of the vehicle speed and wheel
slip values instead of the usual formulation using wheel rotational
rates. A systematic bifurcation analysis is carried out by
quasi-statically varying the front and rear wheel torques. It is shown
how the system transitions from stable braking to the possibility of
lockup in one or both wheels, to guaranteed lockup in both wheels. In
this manner, a quite complete picture of the dynamic behavior is
obtained as a function of the two brake torques, including regions with
multiple possible steady braking outcomes, depending on the initial
conditions. The nonlinear analysis provides new insights into the
dynamics of vehicle traction, including a correction to the standard
result for critical brake torques at which the wheels undergo lockup.
Application to a U.S. automaker driveline durability/reliability
assessment is briefly discussed.


Biography
Dr. Brian J. Olson is a Fellow of the ASME and senior professional staff
at The Johns Hopkins University Applied Physics Laboratory with 18 years
of experience in the Aerospace and Mechanical Engineering group within
the Air and Missile Defense Sector. He holds B.S. (1999), M.S. (2001)
and Ph.D. (2006) degrees in Mechanical Engineering from Michigan State
University. His applied research is in the areas of dynamics, vibration,
and shock of mechanical systems, linear and nonlinear, with emphasis on
multi-physics modeling and simulation, test and evaluation, engineering
measurements, and digital signal processing. His fundamental research
encompasses several areas including vibration reduction in cyclic
vibratory systems, nonlinear dynamics of ground vehicle traction, and
stereoscopic methods for velocimetry in fluid diagnostics.

Frissítve: 2024.05.09. 10:48:02