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

Semi-active Suspension Control provides an overview of vehicle ride control employing smart semi-active damping systems. These systems are able to tune the amount of damping in response to measured vehicle-ride and handling indicators. Two physically different dampers (magnetorheological and controlled-friction) are analysed from the perspectives of mechatronics and control. Ride comfort, road holding, road damage and human-body modelling are studied. Mathematical modelling is balanced by a large and detailed section on experimental implementation, where a variety of automotive applications are described offering a well-rounded view. The implementation of control algorithms with regard to real-life engineering constraints is emphasised. The applications described include semi-active suspensions for a saloon car, seat suspensions for vehicles not equipped with a primary suspension, and control of heavy-vehicle dynamic-tyre loads to reduce road damage and improve handling.

With the new advancements in the vibration control strategies and controllable actuator manufacturing, the semi-active actuators (dampers) are finding their way as an essential part of vibration isolators, particularly in vehicle suspension systems. This is attributed to the fact that in a semi-active system, the damping coefficients can be adjusted to improve ride comfort and road handling performances. The currently available semi-active damper technologies can be divided into two main groups. The first uses controllable electromagnetic valves. The second uses magnetorheological (MR) fluid to control the damping characteristics of the system. Leading automotive companies such as General Motors and Volvo have started to use semi-active actuators in the suspension systems of high-end automobiles, such as the Cadillac Seville and Corvette, to improve the handling and ride performance in the vehicle. But much more research and development is needed in design, fabrication, and control of semi-active suspension systems and many challenges must be overcome in this area. Particularly in the area of heavy vehicle systems, such as light armored vehicles, little related research has been done, and there exists no commercially available controllable damper suitable for the relatively high force and large displacement requirements of such application. As the first response to these requirements, this thesis describes the design and modeling of an in-house semi-active twin-tube shock absorber with an internal variable solenoid-actuated valve. A full-scale semi-active damper prototype is developed and the shock absorber is tested to produce the required forcing range. The test results are compared with results of the developed mathematical model. To gain a better understanding of the semi-active suspension controlled systems and evaluate the performance of those systems, using perturbation techniques this thesis provides a detailed nonlinear analysis of the semi-active systems and establishes the issue of nonlinearity in on-off semi-active controlled systems. Despite different semi-active control methods and the type of actuators used in a semi-active controlled system, one important practical aspect of all hydro-mechanical computer controlled systems is the response-time. The longest response-time is usually introduced by the actuator -in this case, controllable actuator - in the system. This study investigates the effect of response-time in a semi-active controlled suspension system using semi-active dampers. Numerical simulations and analytical techniques are deployed to investigate the issue. The performance of the system due to the response-time is then analyzed and discussed. Since the introduction of the semi-active control strategy, the challenge was to develop methods to effectively use the capabilities of semi-active devices. In this thesis, two semi-active control strategies are proposed. The first controller to be proposed is a new hybrid semi-active control strategy based on the conventional Rakheja-Sankar (R-S) semi-active control to provide better ride-handling quality for vehicle suspension systems as well as industrial vibration isolators. To demonstrate the effectiveness of this new strategy, the analytical method of averaging and the numerical analysis method are deployed. In addition, a one-degree-of-freedom test bed equipped with a semi-active magnetorheological (MR) damper is developed. The tests are performed using the MATLAB XPC-target to guarantee the real-time implementation of the control algorithm. The second controller is an intelligent fuzzy logic controller system to optimize the suspension performance. The results from this intelligent system are compared with those of several renowned suspension control methods such as Skyhook. It is shown that the proposed controller can enhance concurrently the vehicle handling and ride comfort, while consuming less energy than existing control methodologies. The key goal of this thesis is to employ the existing knowledge of the semi-active systems together with the new ideas to develop a semi-active suspension system. At the same time, development of an experimental simulation system for real-time control of an experimental test bed is considered. To achieve its goals and objectives, this research study combines and utilizes the numerical simulations and analytical methods, as well as lab-based experimental works. The challenge in this research study is to identify practical and industrial problems and develop proper solutions to those problems using viable scientific approaches.

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.

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 describes the procedures of developing an adaptive suspension system with examples. This book gives a thorough introduction to air suspension systems, which contain height leveling systems, electronic control systems, design fundamentals, performance superiority, etc. This book encompasses all essential aspects of suspension systems and provides an easy approach to their understanding and design. Provides a step-by-step approach using pictures, graphs, tables, and examples so that the reader may easily grasp difficult concepts. This book defines and examines suspension mechanisms and their geometrical features. Suspension motions and ride models are derived for the study of vehicle ride comfort. Analysis of suspension design factors and component sizing along with air suspension systems and their functionalities are reviewed.