Editorial Type:
Article Category: Research Article
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Online Publication Date: 01 Jul 2019

Tire Lateral Vibration Considerations in Vehicle-Based Tire Testing

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Page Range: 211 – 231
DOI: 10.2346/tire.18.460411
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ABSTRACT

Vehicle-based tire testing can potentially make it easier to reparametrize tire models for different road surfaces. A passenger car equipped with external sensors was used to measure all input and output signals of the standard tire interface during a ramp steer maneuver at constant velocity. In these measurements, large lateral force vibrations are observed for slip angles above the lateral peak force with clear peaks in the frequency spectrum of the signal at 50 Hz and at multiples of this frequency. These vibrations can lower the average lateral force generated by the tires, and it is therefore important to understand which external factors influence these vibrations. Hence, when using tire models that do not capture these effects, the operating conditions during the testing are important for the accuracy of the tire model in a given maneuver.

An Ftire model parameterization of tires used in vehicle-based tire testing is used to investigate these vibrations. A simple suspension model is used together with the tire model to conceptually model the effects of the suspension on the vibrations. The sensitivity of these vibrations to different operating conditions is also investigated together with the influence of the testing procedure and testing equipment (i.e., vehicle and sensors) on the lateral tire force vibrations. Note that the study does not attempt to explain the root cause of these vibrations. The simulation results show that these vibrations can lower the average lateral force generated by the tire for the same operating conditions. The results imply that it is important to consider the lateral tire force vibrations when parameterizing tire models, which does not model these vibrations. Furthermore, the vehicle suspension and operating conditions will change the amplitude of these vibrations and must therefore also be considered in maneuvers in which these vibrations occur.

Keywords: tire testing; vehicle dynamics; tire out-of-plane vibrations; vehicle-based tire testing
FIG. 1
FIG. 1

Lateral force vs time from wheel force transducers for eight ramp steer maneuvers. Force in TYDEX-W System.

FIG. 2
FIG. 2

Lateral force and camber angle signals bandpass filtered at 50 Hz for one ramp steer maneuver. The low-pass filtered sideslip angle signal for the same tire is also plotted together with a line showing the approximate sideslip angle at which the lateral force reaches its maximum.

FIG. 3
FIG. 3

Discrete Fourier transform of lateral force at different slip angles.

FIG. 4
FIG. 4

Discrete Fourier transform of lateral force at different slip angles.

FIG. 5
FIG. 5

Topology of the model used in the simulations. The constant a is set to 0.1.

FIG. 6
FIG. 6

Lateral force vs time, oblique cleat, 60 km/h, static wheel load 6020 N, tire pressure 240 000 Pa, Ftire compared with measurements.

FIG. 7
FIG. 7

Vertical force vs time, oblique cleat, 60 km/h, static wheel load 6020 N, tire pressure 240 000 Pa, Ftire compared with measurements.

FIG. 8
FIG. 8

Longitudinal force vs time, oblique cleat, 60 km/h, static wheel load 6020 N, tire pressure 240 000 Pa, Ftire compared with measurements.

FIG. 9
FIG. 9

Lateral force vs time, oblique cleat, 60 km/h, static wheel load 9570 N, tire pressure 240 000 Pa, Ftire compared with measurements.

FIG. 10
FIG. 10

Lateral force vs slip angle (top) and moving average filtered (0.05 seconds) normalized lateral force vs slip angle (bottom), with fixed rim.

FIG. 11
FIG. 11

Lateral force vs slip angle with fixed rim on a smooth road.

FIG. 12
FIG. 12

Lateral force vs slip angle, with lateral degree of freedom for the rim, with and without damping.

FIG. 13
FIG. 13

Discrete Fourier transform of lateral force from Ftire, with lateral degree of freedom of the rim without damping.

FIG. 14
FIG. 14

Lateral force vs slip angle, with lateral degree of freedom for the rim, with a damping coefficient of 3500 N/m/s and 80 and 120% of the nominal lateral suspension stiffness.

FIG. 15
FIG. 15

Lateral force vs slip angle, with lateral degree of freedom for different rim masses. With thermal model.

FIG. 16
FIG. 16

Lateral force vs slip angle, with lateral degree of freedom for different rim masses. Without thermal model.

FIG. 17
FIG. 17

Lateral force vs slip angle, with lateral degree of freedom for the rim, with different amplitudes of driving torque.

FIG. 18
FIG. 18

Lateral force vs slip angle, with and without thermal model.

FIG. 19
FIG. 19

Lateral force vs slip angle, with nominal slip angle sweep rate of 0.0126 rad/s (nominal) and 0.0504 rad/s (four times nominal).

FIG. 20
FIG. 20

Lateral force vs slip angle, different camber angle ±0.0175 rad (1°) offsets. Positive camber angle offset means top-in for the tire.

FIG. 21
FIG. 21

(Top) Sequence of the loaded cross section from high force in the top left corner to a low force at the bottom left corner. Top left cross section corresponds to the left tire in the bottom plot, and the bottom right cross section corresponds to the right tire in the bottom plot. (Bottom) Two snapshots from the simulation animation in Ftire, taken 0.0109 seconds apart at around 19.5 seconds for the nominal suspension and operating condition with medium tire damping. Note that the forces do not represent the exact extreme values of the vibrations.

Contributor Notes

2 Corresponding author. Email: anton.albinsson@chalmers.se
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