Articulated freight vehicles transmit high levels of whole-body ride vibration to the driver and high magnitudes of dynamic tire forces to the pavements. The high levels of ride vibration and tire forces are attributed to the excessive sizes and weights of these vehicles. The driver health and safety risks posed by ride vibrations, and the significant tire induced road damage caused by heavy vehicles have prompted a growing demand for design of driver- and road-friendly vehicles. Different active and passive suspension systems are thus analyzed to enhance the performance characteristics of articulated freight vehicles. The investigation is carried out in five phases: (i) development of a representative dynamic model of the vehicle; (ii) passive suspension design and optimization; (iii) ideal active suspension design; (iv) limited-state active suspension design; and (v) assessment of tire dynamic forces transmitted to the pavement. An articulated freight vehicle is characterized by an inplane nine degrees-of-freedom (DOF) dynamic system model. An analytical characterization of the randomly irregular road surface is presented and the time delays between the consecutive wheel inputs are incorporated using Pade approximation. The validity of the analytical vehicle model is asserted by comparing its response characteristics with the road measured data. A technique, based on covariance analysis, is employed to perform the multi-parameter sensitivity analysis and to design an "optimum" passive suspension. A performance index comprising ride quality, cargo safety, suspension rattle space and dynamic tire forces is formulated to derive the "optimum" suspension design. The effects of varying the suspension properties on the frequency response characteristics are investigated to further verify the conclusions drawn from the covariance analysis. Linear Quadratic Gaussian (LQG) control technique is employed to design an ideal fail-safe active suspension scheme based on full-state feedback. Passive damping and stiffness elements are incorporated in the active suspension system to yield a fail-safe configuration with minimal power requirement. The performance characteristics of the ideal active suspension are compared to those of the "optimum" passive suspension to determine their potential performance benefits. In view of the excessive hardware and signal processing requirements, high cost and poor reliability of a full-state feedback active suspension design, a thorough analysis of a more realistic active suspension scheme, based on H$\sb2$ synthesis, is undertaken. Two suspension schemes based upon limited-state measurements are investigated. The performance characteristics of the propose suspension designs are compared to those of the full-state active suspension and the "optimum" passive suspension systems. Finally, a comprehensive analysis is undertaken to assess the effects of the passive and various active suspension schemes on the dynamic tire forces. It is concluded that the reduced state active suspension systems yield performance characteristics comparable to those of an ideal active suspension

This book focuses on most recent theoretical findings on control issues for active suspension systems. The authors first introduce the theoretical background of active suspension control, then present constrained H∞ control approaches of active suspension systems in the entire frequency domain, focusing on the state feedback and dynamic output feedback controller in the finite frequency domain which people are most sensitive to. The book also contains nonlinear constrained tracking control via terminal sliding-mode control and adaptive robust theory, presenting controller design of active suspensions as well as the reliability control of active suspension systems. The target audience primarily comprises research experts in control theory, but the book may also be beneficial for graduate students alike.

This book describes the development of a new analytical, full-vehicle model with nine degrees of freedom, which uses the new modified skyhook strategy (SKDT) to control the full-vehicle vibration problem. The book addresses the incorporation of road bank angle to create a zero steady-state torque requirement when designing the direct tilt control and the dynamic model of the full car model. It also highlights the potential of the SKDT suspension system to improve cornering performance and paves the way for future work on the vehicle’s integrated chassis control system. Active tilting technology to improve vehicle cornering is the focus of numerous ongoing research projects, but these don’t consider the effect of road bank angle in the control system design or in the dynamic model of the tilting standard passenger vehicles. The non-incorporation of road bank angle creates a non-zero steady state torque requirement.

Semi-Active Suspension Control Design for Vehicles presents a comprehensive discussion of designing control algorithms for semi-active suspensions. It also covers performance analysis and control design. The book evaluates approaches to different control theories, and it includes methods needed for analyzing and evaluating suspension performances, while identifying optimal performance bounds. The structure of the book follows a classical path of control-system design; it discusses the actuator or the variable-damping shock absorber, models and technologies. It also models and discusses the vehicle that is equipped with semi-active dampers, and the control algorithms. The text can be viewed at three different levels: tutorial for novices and students; application-oriented for engineers and practitioners; and methodology-oriented for researchers. The book is divided into two parts. The first part includes chapters 2 to 6, in which fundamentals of modeling and semi-active control design are discussed. The second part includes chapters 6 to 8, which cover research-oriented solutions and case studies. The text is a comprehensive reference book for research engineers working on ground vehicle systems; automotive and design engineers working on suspension systems; control engineers; and graduate students in control theory and ground vehicle systems. - Appropriate as a tutorial for students in automotive systems, an application-oriented reference for engineers, and a control design-oriented text for researchers that introduces semi-active suspension theory and practice - Includes explanations of two innovative semi-active suspension strategies to enhance either comfort or road-holding performance, with complete analyses of both - Also features a case study showing complete implementation of all the presented strategies and summary descriptions of classical control algorithms for controlled dampers