Real-Time Vehicle Dynamics Parameter Estimation

Dynamic Systems and Control, Parts A and B ◽

10.1115/imece2005-79224 ◽

2005 ◽

Cited By ~ 1

Author(s):

Kwang-Keun Shin

Keyword(s):

Parameter Estimation ◽

Control Systems ◽

Real Time ◽

Vehicle Dynamics ◽

Estimation Method ◽

Vehicle Control ◽

Simulation Software ◽

Tire Pressure ◽

Vehicle Simulation ◽

The Stability

Vehicle dynamics parameters such as understeer coefficient are very important factors to determine the stability and dynamic handling behavior of a vehicle. These parameters vary during the lifetime of a vehicle according to different loading, tire pressure/wear or vehicle-to-vehicle variations of suspension characteristics, etc. The parameter deviations from nominal values may cause performance degradation of chassis/vehicle control systems, which is often designed based on the nominal values. Therefore, if the vehicle dynamics parameters can be estimated and monitored in real-time, the performance of chassis/vehicle control systems could be further enhanced. This paper presents a real-time vehicle dynamics parameter estimation method that estimates vehicle understeer coefficient and front/rear cornering compliances. The algorithm is implemented using Simulink, and analyzed, and validated using VehSim, which is a PC windows-based vehicle simulation software for vehicle dynamics controls and integration. The simulation results show that the developed algorithm is well capable of estimating vehicle dynamics parameters of VehSim, and, therefore, is highly feasible for in-vehicle applications.

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Development of a Smart Tire System and its Use in Improving the Performance of a Collision Mitigation Braking System

Volume 11: Transportation Systems ◽

10.1115/imece2012-88628 ◽

2012 ◽

Cited By ~ 2

Author(s):

Kanwar Bharat Singh ◽

Mustafa Ali Arat ◽

Saied Taheri

Keyword(s):

Parameter Estimation ◽

Friction Coefficient ◽

Control Systems ◽

Real Time ◽

Vehicle Control ◽

Slip Conditions ◽

Model Based ◽

Road Friction ◽

Collision Mitigation ◽

Road Friction Coefficient

At present, the commercially available tire monitoring systems are not equipped to sense and transmit high speed dynamic variables used for real-time active safety control systems. Hence, today’s vehicle control systems are limited by the lack of knowledge of critical tire-road states (i.e. the kinematic conditions of the tire to its dynamic properties). From aforementioned discussion, it is clear that some method of estimating tire-road contact parameters would be greatly desirable. Existing tire-road friction estimation approaches often require certain levels of vehicle longitudinal and/or lateral motion to satisfy the persistence of excitation condition for reliable estimations. Such excitations may undesirably interfere with vehicle motion controls. This paper presents a novel development and implementation of a real-time tire-road contact parameter estimation methodology using acceleration signals from a smart tire. The proposed method characterizes the terrain using the measured frequency response of the tire vibrations and provides the capability to estimate the tire road friction coefficient under extremely lower levels of force utilization. Under higher levels of force excitation (high slip conditions), the increased vibration levels due to the stick/slip phenomenon linked to the tread block vibration modes make the proposed tire vibrations based method unsuitable. Therefore for high slip conditions, a tire-road friction model-based parameter estimation approach is proposed. Hence an integrated approach using the smart tire based friction estimator and the model based estimator gives us the capability to reliably estimate friction for a wider range of excitations. Considering the strong interdependence between the operating road surface condition and the instantaneous forces and moments generated; this real time estimate of the tire-road friction coefficient is expected to play a pivotal role in improving the performance of a number of vehicle control systems. In particular, this paper focuses on the possibility of enhancing the performance of collision mitigation braking systems.

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Estimating Pacejka (PAC2002) Tire Coefficients for Pneumatic Tires on Soft Soils With Application to BAJA SAE Vehicles

Volume 4: Dynamics, Vibration, and Control ◽

10.1115/imece2019-10682 ◽

2019 ◽

Author(s):

Amanda Saunders ◽

Darris White ◽

Marc Compere

Keyword(s):

Vehicle Dynamics ◽

Integration Method ◽

Simulation Software ◽

Dynamics Simulation ◽

Road Vehicles ◽

Traction Forces ◽

Soft Soils ◽

Vehicle Performance ◽

Vehicle Simulation ◽

Stress Integration

Abstract BAJA SAE is an engineering competition that challenges teams to design single-seat all-terrain vehicles that participate in a vast number of events, predominately on soft soils. Efficient performance in the events depends on the traction forces, which are dependent on the mechanical properties of the soil. To accurately model vehicle performance for each event, a model of the tire traction performance is required, and the tire model must be incorporated with a vehicle dynamics simulation. The traction forces at the soil-tire interface can be estimated using the Bekker-Wong stress integration method. However, commercially available vehicle dynamics simulation software, with a focus on on-road vehicles, does not utilize Bekker-Wong parameters. The Pacejka Magic Tire (MT) Formula is a common method for characterizing tire behavior for on-road vehicles. The parameters for the Pacejka MT Formula are usually produced by curve fitting measured tire data. The lack of available measured off-road tire data, as well as the additional variables for off-road tire performance (e.g. soil mechanics), make it difficult for BAJA SAE teams to simulate vehicle performance using commercial vehicle simulation tools. This paper discusses the process and results for estimating traction performance using the Bekker-Wong stress integration method for soft soils and then deriving the Pacejka coefficients based on the Bekker-Wong method. The process will enable teams to use the Pacejka Magic Tire Formula coefficients for simulating vehicle performance for BAJA SAE events, such as the hill climb, (off-road) land maneuverability, tractor pull, etc.

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Static WCET Analysis of Real-Time Task-Oriented Code in Vehicle Control Systems

Second International Symposium on Leveraging Applications of Formal Methods, Verification and Validation (isola 2006) ◽

10.1109/isola.2006.63 ◽

2006 ◽

Cited By ~ 15

Author(s):

Daniel Sehlberg ◽

Andreas Ermedahl ◽

Jan Gustafsson ◽

Björn Lisper ◽

Steffen Wiegratz

Keyword(s):

Control Systems ◽

Real Time ◽

Vehicle Control ◽

Wcet Analysis ◽

Time Task ◽

Task Oriented

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Off-Road Vehicle Dynamics Mobility Simulation With a Compaction Based Deformable Terrain Model

Volume 7B: 9th International Conference on Multibody Systems, Nonlinear Dynamics, and Control ◽

10.1115/detc2013-13152 ◽

2013 ◽

Author(s):

Justin Madsen ◽

Andrew Seidl ◽

Dan Negrut

Keyword(s):

Vehicle Dynamics ◽

Transfer Functions ◽

Soil Mechanics ◽

Three Dimensional ◽

Interaction Model ◽

Simulation Software ◽

Repeated Loading ◽

Model Parameters ◽

Vehicle Simulation ◽

Terrain Model

This paper discusses the terramechanics models developed to incorporate a physics-based, three dimensional deformable terrain database model with vehicle dynamics mobility simulation software. The vehicle model is contained in Chrono, a research-grade C++ based Application Programming Interface (API) that enables accurate multibody simulations. The terrain database is also contained in a C++ based API, and includes a general tire-terrain interaction model which is modular to allow for any tire model that supports the Standard Tire Interface (STI) to operate on the terrain. Furthermore, the ability to handle arbitrary, three dimensional traction element geometry allows for tracked vehicles (or vehicle hulls) to also interact with the deformable terrain. The governing equations of the terrain are based on a soil compaction model that includes both the propagation of subsoil stresses due to vehicular loads, and the resulting visco-elastic-plastic stress/strain on the affected soil volume. Non-flat, non-homogenous and non-uniform soil densities, rutting, repeated loading and strain hardening effects are all captured in the vehicle mobility response as a result of the general 3-D tire/terrain model developed. Pedo-transfer functions allow for the calculation of the soil mechanics model parameters from existing soil measurements. This terrain model runs at near real-time speed, due to parallel CPU and GPU implementation. Results that exercise the force models developed with the 3-D tire geometry are presented and discussed for a kinematically driven tire and a full vehicle simulation.

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