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Chassis systems
Published in Tom Denton, Advanced Automotive Fault Diagnosis, 2020
An active suspension system (also known as computerised ride control) has the ability to adjust itself continuously. It monitors and adjusts its characteristics to suit the current road conditions. As with all electronic control systems, sensors supply information to an ECU which in turn outputs to actuators. By changing its characteristics in response to changing road conditions, active suspension offers improved handling, comfort, responsiveness and safety (Figure 7.39).
Nature Inspired Optimization for Controller Design
Published in Jitendra R. Raol, Ramakalyan Ayyagari, Control Systems, 2020
Jitendra R. Raol, Ramakalyan Ayyagari
In this section we will describe another case study where the suspension systems are designed to be active, which requires a power source to generate suspension forces according to some prescribed criterion. With such a strategy, ride comfort and track holding ability can be enhanced simultaneously. For further ride comfort improvements, active suspension systems can adjust the system energy to control the vibration of the vehicle body, leading to increased ride comfort. We do not debate here whether semi-active is better or active suspension is better; we just describe the design methodologies, which were hugely benefited by the intelligent control techniques.
Active Suspensions
Published in Simon Iwnicki, Maksym Spiryagin, Colin Cole, Tim McSweeney, Handbook of Railway Vehicle Dynamics, 2019
It is clear from the preceding chapters that railway vehicle dynamics has developed principally as a mechanical engineering discipline, but an important technological change is starting to occur through the use of active suspension concepts. Advanced control on rail vehicles has been common for many decades in the power electronic control of traction systems, and it is now firmly established as the standard technology, which has yielded substantial benefits, but its application to suspensions is much more recent. Although the term ‘active suspension’ is commonly taken to relate to providing improved ride quality; in fact, it is a generic term that defines the use of actuators, sensors and electronic controllers to enhance and/or replace the springs and dampers that are the key constituents of a conventional, purely mechanical, ‘passive’ suspension; as such, it can be applied to any aspect of the vehicle’s dynamic system.
Application of semi-active yaw dampers for the improvement of the stability of high-speed rail vehicles: mathematical models and numerical simulation
Published in Vehicle System Dynamics, 2022
Xu Wang, Binbin Liu, Egidio Di Gialleonardo, Ivo Kovacic, Stefano Bruni
An alternative solution is to employ an adjustable damper, capable of adapting to the variation of the wheel-rail contact conditions. The adjustable damper can be semi-active or full-active. The concept of active yaw damper has been studied both theoretically and experimentally in labs on roller rigs and in field on real vehicles [2–4,7,8]. Many control strategies are available for the control of the active yaw damper, e.g. modal control, LQG, H∞, skyhook, and fuzzy control where H∞ and LQG are model-based control strategy which generally produces better performances than non-model-based ones while it suffers from unmodelled behaviours and parameters uncertainties. Although many advantages of the active yaw damper in the railway application have been demonstrated through these research works, no commercial application has been reported yet. This is due to the high complexity and cost implied by this application and also to concerns about the effect of failures in the active suspension.
H∞ optimal control of vehicle active suspension systems in two time scales
Published in Automatika, 2021
In order to pursue the comfort and safety of vehicles, more and more researchers have focused on the design and control of active suspension in the past decades [1–3]. As we all know, suspension is the general term of all force transmission connecting devices between the vehicle frame (or load-bearing body) and the axle (or wheel). Its function is to transfer the force and torque between the wheel and the frame, buffer the impact force transmitted from uneven road surface to the frame or body, and reduce the vibration caused by it, so as to ensure the smooth running of the car. Specifically, active suspension systems, also known as active guidance suspension systems and dynamic variable suspension systems, can control the vibration and height of vehicle body by changing the height, shape and damping of suspension system. It can mainly improve the performance of vehicle operation stability and riding comfort. Therefore, active suspension represents the development direction of automobile suspension in the future and a large number of scholars have carried out a lot of research on the key control problems, e.g. LQG control [4], adaptive control [5], sliding mode control [6], robust control [7], backstepping control [8], etc. The control of active suspension systems, however, poses a major challenge due to the unknown road input, high order and strong coupling characteristics. On the other hand, from the perspective of practical application in vehicles, the potential poor transient response (e.g. overshoot, sluggish convergence) of the above control methods may result in performance degradation, hazards and even cause hardware damage.
Simultaneous dynamic system estimation and optimal control of vehicle active suspension
Published in Vehicle System Dynamics, 2019
Tamer Attia, Kyriakos G. Vamvoudakis, Kevin Kochersberger, John Bird, Tomonari Furukawa
The state-space assignments rewrite (1)–(3) as follows (see Appendix for more details), where, The active suspension system is designed to improve ride comfort and road holding stability within the limits of the suspension deflection. Hence, three aspects are going to be considered in our work: Ride comfort which is related to the sprung mass bounce, roll and pitch accelerations. By reducing these accelerations, good ride comfort will be experienced by the passengers.Road holding stability which is defined by the tire dynamic load; where to ensure vehicle stability, the dynamic tire load should not exceed its static load to maintain uninterrupted contact with the road, which can be expressed as the relative tire loads and is given by, where are the relative tire loads at front left, front right, rear left and rear right, and g is the gravitational acceleration.And finally, the suspension deflection which is limited by the available rattle space as follow, where are the relative suspension deflections at front left, front right, rear left and rear right, and is the maximum rattle space hard limit.