We present a hybrid physical-dynamic tire/road friction model for applications of vehicle motion simulation and control. We extend the LuGre dynamic friction model by considering the physical model-based adhesion/sliding partition of the tire/road contact patch. Comparison and model parameters relationship are presented between the physical and the LuGre dynamic friction models. We show that the LuGre dynamic friction model predicts the nonlinear and normal load-dependent rubber deformation and stress distributions on the contact patch. We also present the physical interpretation of the LuGre model parameters and their relationship with the physical model parameters. The analysis of the new hybrid model's properties resolves unrealistic nonzero bristle deformation and stress at the trailing edge of the contact patch that is predicted by the existing LuGre tire/road friction models. We further demonstrate the use of the hybrid model to simulate and study an aggressive pendulum-turn vehicle maneuver. The CARSIM simulation results by using the new hybrid friction model show high agreements with experiments that are performed by a professional racing car driver.

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In-situ sensing the tire-road interactions such as local contact friction force distributions provides crucial information for building accurate friction force models for vehicle safety control. In this paper, we report the development of an embedded, flexible local force sensor for measuring the tire local friction forces and their distributions. A new pressuresensitive, electric conductive rubber (PSECR) sensor is used and embedded inside the tire rubber layer to extract the multidimensional local friction forces on the tire contact patch. The low-cost, flexible PSECR sensor is oriented in certain directions, and is sensitive to multiple compressive forces. To interpret the sensor measurements, we use a beam-spring model for the tireroad interactions to extract the local contact friction forces. The experimental results of stick-slip interaction testing on a motorcycle tire demonstrate the effective and good performance of the PSECR-based tire force sensor.

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