Virtual tyre force sensors: An overview of tyre model-based and tyre model-less state estimation techniques

Abstract

This paper presents a comprehensive literature review on tyre force estimation and road grip recognition approaches. With the development of modern automotive control systems, a precise estimation of a large number of vehicle states is necessary to guarantee a robust actuation of the controller. Moreover, the estimation of these states must be carried out in a cost-effective and reliable way. The aim of this work is to provide a solid base for the development of automotive virtual sensors, and in particular, virtual tyre force sensors. An initial overview of the tyre force estimation problem is provided in the first section. Tyre and vehicle modelling, as well as observers for vehicle state estimation, are covered in detail in the second section. The third section introduces a brief discussion regarding the main limitations of direct tyre force measurement approaches. In the following sections, relevant works regarding three-axis tyre force estimation and road grip recognition are discussed. The review is structured around longitudinal force estimation, lateral force estimation, combined tyre force estimation, tyre self-alignment torque estimation and vertical tyre force estimation. Within each section, the most significant road grip identification approaches are introduced. An additional section, Road slope and bank angle compensation, describes relevant work on estimation methods for global chassis orientation. A brief summary of the presented approaches is provided in the section Summary of presented approaches. Finally, relevant conclusions and further research steps are given in the last section.

Road Friction Virtual Sensing: A Review of Estimation Techniques with Emphasis on Low Excitation Approaches

“…An EKF was also employed in Li et al [102], and a Dugoff tyre model was adopted to estimate the road friction potential. Contrary to the approached adopted by Antonov et al [8], Li et al estimated the longitudinal forces in a separated block (using a wheel rotating dynamics-based approach [53]), and limited the friction potential estimation to pure lateral dynamics events. The vehicle responses were simulated using veDYNA software and different limit double lane change manoeuvres were performed in surfaces of µ max = 0.9 and µ max = 0.5.…”

“…In addition, the analysis is restricted to the friction potential estimation. A comprehensive list of relevant tyre force estimation methods can be found in [53]. Finally, only real-time works are presented in this review.…”

“…The most extended friction models are the Magic Formula [67] presented by Hans B. Pacejka, the Dugoff [14,72] tyre model, and the Brush analytical formulation [16,17,67]. The Dugoff and Brush tyre models are often given preference in road friction recognition problems due to their implementation easiness and cost-effectiveness [53]. Other friction modelisations have been proposed in the literature (e.g., Burckhardt friction model or Lugre and Dahl dynamic tyre models) [73,74], but these are omitted in this section due to their reduced use in the reviewed works and their added complexity.…”

“…For simplicity, only the ISO convention is used here. For a more detailed discussion [53,54] can be consulted. Finally, the wheel speed evolves according to the wheel rotating dynamics, expression (7), I totẇi = T drv,i − T b,i − f res F z,i r e − F x,i r l…”

“…A linear regression was performed to obtain these values setting the maximum longitudinal slip to 2%. Ahn presents the "equivalent tyre-road stiffness" theory [42,53] to explain the differences seen on C λ . Specifically, this theory attributes the variations in slip slope to the presence of soft material (e.g., gravel, snow or wet ice) in the road-rubber interface.…”