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2023 | Book

Control of Variable-Geometry Vehicle Suspensions

Design and Analysis

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About this book

This book provides a thorough and fresh treatment of the control of innovative variable-geometry vehicle suspension systems. A deep survey on the topic, which covers the varying types of existing variable-geometry suspension solutions, introduces the study. The book discusses three important aspects of the subject:

• robust control design;

• nonlinear system analysis; and

• integration of learning and control methods.

The importance of variable-geometry suspensions and the effectiveness of design methods implemented in the autonomous functionalities of electric vehicles—functionalities like independent steering and torque vectoring—are illustrated. The authors detail the theoretical background of modeling, control design, and analysis for each functionality. The theoretical results achieved through simulation examples and hardware-in-the-loop scenarios are confirmed. The book highlights emerging ideas of applying machine-learning-based methods in the control system with guarantees on safety performance. The authors propose novel control methods, based on the theory of robust linear parameter-varying systems, with examples for various suspension systems.

Academic researchers interested in automotive systems and their counterparts involved in industrial research and development will find much to interest them in the eleven chapters of Control of Variable-Geometry Vehicle Suspensions.

Table of Contents

Frontmatter
Chapter 1. Introduction
Abstract
In the last decade, several new focuses for research and development have arisen in the automotive industry. These focuses are on urban mobility and transport, alternative fuels and the electrification of the vehicle safety applications in co-operative systems; see EUCAR (1992). Self-driven vehicles, smart urban solutions and electric driveline systems have increased influence on the actual direction of automotive and transportation-oriented research. The motivation of these fields is the growing transportation demand in cities, where limitations on road traffic flow capacities can be found. Furthermore, the importance of electric vehicles with enhanced economic driveline control solutions is to reduce emissions in urban regions. The design of autonomous electric-driven vehicles with their connection to the highly automated transportation systems can help to overcome these issues. Nevertheless, it requires the use of V2X communication topologies, especially vehicle-to-vehicle and vehicle-to-infrastructure solutions. The requirements of small and light vehicle chassis for urban autonomous vehicles lead to the limitation of actuator numbers, but, similarly, the maneuverability of the vehicle cannot be reduced (Piyabongkarn et al. 2004). It motivates the coordination and design of automotive smart actuators, especially for urban vehicles, with which the requested vehicle control functionalities can be realized.
Balázs Németh, Péter Gáspár

Variable-Geometry Suspension for Wheel Tilting Control

Frontmatter
Chapter 2. LPV-Based Modeling of Variable-Geometry Suspension
Abstract
This chapter proposes model formulation and analysis methods for variable-geometry suspension systems. Thus, the formulation of enhanced methods is proposed, which are based on the extensions of existing lateral vehicle models, and, furthermore, new methods for modeling and analysis are also provided.
Balázs Németh, Péter Gáspár
Chapter 3. LPV-Based Control of Variable-Geometry Suspension
Abstract
This chapter deals with the design of variable-geometry suspension, i.e., suspension structure along with the control design and their interactions are examined, while a simultaneous design method is introduced.
Balázs Németh, Péter Gáspár
Chapter 4. SOS-Based Modeling, Analysis and Control
Abstract
In various vehicle control problems, the modeling of vehicle dynamics in linear form can be adequate to create control systems. Nevertheless, the understanding of operation in detail can require nonlinear methods. Especially, in the case of variable-geometry vehicle suspensions, the nonlinear characteristics of lateral tire forces request enhanced synthesis and analysis methods. In this chapter, a system analysis method based on the Sum-of-Squares (SOS) programming technique is applied, which is able to involve polynomial formulation in vehicle modeling. The focus of this chapter is to approximate Controlled Invariant Sets, which provide information on the effectiveness of the control intervention, i.e., on the maximum of the control forces for each wheel.
Balázs Németh, Péter Gáspár

Independent Steering with Variable-Geometry Suspension

Frontmatter
Chapter 5. Modeling Variable-Geometry Suspension System
Abstract
This chapter focuses on the model formulation for achieving independent steering functionality. In the model, the motion dynamics of the suspension and the orientation of the wheel are formulated, i.e., the lateral motion model of the vehicle, in which the variations of camber angle and scrub radius are considered.
Balázs Németh, Péter Gáspár
Chapter 6. Hierarchical Control Design Method for Vehicle Suspensions
Abstract
It has been revealed from the previous section that numerous subsystems are required for providing an accurate model formulation of variable-geometry vehicle suspensions. Since the dynamics of these systems can be different, e.g., time response, delay, fastness and mathematical structure, it can be beneficial to join them in a hierarchical framework; see Sename et al. (2013) and Németh et al. (2015). Accordingly, the control functionalites of variable-geometry suspension are designed independently, i.e., suspension control on each wheel, their control on steering and on lateral dynamics. As Fig. 6.1 shows, the control systems are linked through control signals and references. In the suggested scheme, the steering and suspension controls on the left and right sides have similar construction. Furthermore, stability and performance must be ensured in the hierarchical design method.
Balázs Németh, Péter Gáspár
Chapter 7. Coordinated Control Strategy for Variable-Geometry Suspension
Abstract
In the former chapters, various controller designs have been introduced in a hierarchical structure. While the introduced control systems ensure performance and stability, effective coordination of torque vectoring and independent steering can be accomplished through the distribution of steering/force and reconfiguration of the actuators. This chapter suggests methods, which are formed through a polynomial analysis on variable-geometry vehicle suspension.
Balázs Németh, Péter Gáspár
Chapter 8. Control Implementation on Suspension Test Bed
Abstract
This chapter introduces the implementation of steering control on variable-geometry vehicle suspension, using a one-wheel test bed, which is integrated with a Hardware-in-the-Loop (HiL) framework. A hierarchical control algorithm has been created as a contribution of this chapter, the efficiency of which has been shown during implementation. Control systems on low and high levels have been involved in the hierarchical control structure. A high-level controller has a role in trajectory following, whose functionality has been evaluated in a CarMaker high-fidelity simulator. A low-level control operation, i.e., generating steering angle, using a linear actuator in the test bed has been performed. The present chapter shows that the introduced approach of variable-geometry suspension control is capable of realizing steering functions.
Balázs Németh, Péter Gáspár

Guaranteed Suspension Control with Learning Methods

Frontmatter
Chapter 9. Data-Driven Framework for Variable-Geometry Suspension Control
Abstract
This chapter has been motivated the providing of high-precision models for low-level dynamics of variable-geometry vehicle suspensions. The precise positioning of the wheel, such as performing a steering angle, requires precise control-oriented modeling of the test equipment that can be utilized for design purposes.
Balázs Németh, Péter Gáspár
Chapter 10. Guaranteeing Performance Requirements for Suspensions via Robust LPV Framework
Abstract
In this chapter, a control design structure for variable-geometry suspension systems is proposed, in which structure non-standard control elements, such as neural networks, can be included. The essential of this structure is that the minimum performance level of selected performances can be guaranteed, even at the undesired operation of the unconventional element. Because of the motivation of automated vehicle systems, the unconventional element in this book is the machine learning-based controller. In the proposed control strategy two control elements are considered. First, it is given a non-conventional control, e.g., a neural network, which can be formed as follows: \( u_L=\mathscr {F}(y_L),\) in which relationship \(\mathscr {F}\) denotes the learning-based control. The controller has \(m_L\) number of inputs in the vector \(y_{L}\), and its output, i.e., control input from the learning-based control, is \(u_L=\begin{bmatrix} u_{L,1}&u_{L,2}&\ldots&u_{L,n} \end{bmatrix}^T\) with n outputs.
Balázs Németh, Péter Gáspár
Chapter 11. Control Design for Variable-Geometry Suspension with Learning Methods
Abstract
In this chapter of this book, the method of providing performance guarantees on the variable-geometry suspension with an unconventional control agent is proposed. Two types of applications are provided, i.e., the unconventional control agent is a neural network or a direct intervention of the driver. In both applications, guarantees on the lateral dynamics are formed as the primary performance, and, thus, this chapter focuses on the control design of the high level. The dynamics and control of the low level, i.e., variable-geometry suspension dynamics, are approximated through the characteristics of a simplified model. In the design of variable-geometry suspension control, the proposed method of Chap. 10 is applied. Thus, in this section the design of the robust control and the supervisor for the specific lateral trajectory tracking problem is presented.
Balázs Németh, Péter Gáspár
Backmatter
Metadata
Title
Control of Variable-Geometry Vehicle Suspensions
Authors
Balázs Németh
Péter Gáspár
Copyright Year
2023
Electronic ISBN
978-3-031-30537-5
Print ISBN
978-3-031-30536-8
DOI
https://doi.org/10.1007/978-3-031-30537-5

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