Self-Excited Full-Vehicle Oscillations Caused by Tire–Road Interaction: Virtual and Real-World Experimental Investigation
In this article, self-excited full-vehicle oscillations (power-hops) are introduced. Initially, results of full-vehicle measurements are shown followed by the presentation of a specially build test rig (longitudinal dynamics test rig). Subsequently, these oscillations are investigated by using simulation-based tools within multibody simulation–related full-vehicle modeling. Tire–road interaction is evaluated in this process either by characteristic curves or by a proprietary quasistatic tire model that returns overall tangential forces by evaluating the state of every discretized element within the footprint area.ABSTRACT

Test vehicle (left); measurement setup for clearance studies (right) [2].

Placement of used measurement equipment.

Displacement of M1 in x-direction with and without power-hop [2].

Mechanical models to describe self-excited oscillations (right side; [4]).

Measured wheel speed signals and TCS intervention [1].

Overview of identified types of excitation [2].

Estimated slope in μ-slip characteristic.

CAD model of the developed test rig (front view) [2].

CAD model of the developed test rig (isometric view) [2].

Comparison of signals in vehicle testing and test rig: a) throttle signal; b) engine rpm.

Comparison of results in vehicle testing and test rig: a) velocities; b) drive shaft torque.

Test rig results for different wheel load signals.

Road surfaces: mastic asphalt D47 0/11 (left) and concrete C20/25 (right) [2].

Derived μ-slip curves on asphalt (left column) and concrete (right column) [2].

Influence of road surface texture (concrete: new vs worn) [2].

LDP with transparent road surface (left); principal setup (right).

Postprocessing results (screenshots): rolling tire (left); Power-Hop maneuver (right).

Model interaction in MBS [2].

Comparison of wheel speed: measurement, tire characteristic curve, xTire.

Block diagram of control algorithm (feed forward) [2].

Proof of concept in full-vehicle simulation [2].

Section view of measured tire on rim and geometry representation of tire model.

Contact patch data: wheel load Fz = 3 kN (left); wheel load Fz = 6 kN (right).

xTire result: time signal (first row, Fx; second row, ΔFz) and contact patch data.
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