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Automotive Architecture
Published in Patrick Hossay, Automotive Innovation, 2019
All of this also requires some form of mechanical articulation that can allow relative motion of the wheels and chassis while maintaining wheel orientation to preserve vehicle control, stability and tracking. Exactly how this is done varies significantly. Older systems included dependent suspensions that had a stiff axle housing connecting the two wheels and keeps them in a fixed relative orientation. With the exception of trucks, these systems have been largely replaced by independent suspension that allow each wheel assembly to move independently, and so better accommodate uneven road conditions and improve handling. Though, to accommodate larger cabin space or reduce cost, a semi-independent system can sometimes be used on the rear axle, with the two wheels impacting each other but allowed to move largely independently, such as a twist beam axle. Nevertheless, just about every contemporary car has independent front suspension and a growing number also have independent rear suspension.
The Systems Approach
Published in Bryan Hopkins, Cultural Differences and Improving Performance, 2016
This over- and undershooting is called hysteresis and is found in all dynamic systems. We experience it every time we sit in a car. Car suspension systems rely on two components: a spring and a shock absorber. If a car did not have a spring, the ride would be very hard, so the spring system allows the body of the car to move up and down gently as the wheels pass over holes and bumps in the road. However, the weight of the car body would cause the car body to quickly settle into a regular up-and-down motion, which would become very uncomfortable and prompt car sickness all round. So, along with the springs we have a shock absorber system, which slows the up-and-down movement. Now, the art of the car designer is in balancing the effects of the springs and shock absorbers. Cars with a ‘soft ride’, such as old American cars, are good for travelling in straight lines on good roads as the springs smooth out any slight imperfections in the road. However, when the car hits a bump it moves up and down dramatically. Conversely, a vehicle designed to go over uneven surfaces, such as an off-road four-wheel drive, has much stronger shock absorbers, but these can make travelling on smooth surfaces rather hard.
Strongly perturbed sliding mode adaptive control of vehicle active suspension system considering actuator nonlinearity
Published in Vehicle System Dynamics, 2022
Shuang Liu, Tian Zheng, Dingxuan Zhao, Ruolan Hao, Mengke Yang
The car suspension is the general term for all the force transmission between the frame and the wheel. The suspension is an important part of the car. Its main function is to transmit the force between the wheel and the frame, to reduce the impact caused by the uneven road surface, to adjust the posture of the vehicle in time and to ensure the safety and stability of the vehicle. According to whether the system generates control through the feedback signal, or more precisely depending on the active or passive nature of suspension force production [1,2], the suspension can be divided into two categories: active suspension and passive suspension. According to the different control force generation methods and the adaptability, or more precisely depending on the amount of active energy required [1,2], active suspension is divided into full active suspension and semi-active suspension.
A new state observer-based vibration control for a suspension system with magnetorheological damper
Published in Vehicle System Dynamics, 2021
The quarter car suspension system with MR damper is shown in Figure 2. is the body mass (sprung mass) of the car, is the uncertainty external mass, is the wheel mass (un-sprung mass), is the stiffness of spring, is the stiffness of tire, is the displacement of road, and are displacements of the sprung and un-sprung mass, respectively, is the tire deflection with , and is the suspension deflection with . The suspension system assumes that the tire surface keeps contacting on the road. There are two subsystems in the force balancing equation for the suspension system, one is the suspension subsystem, and the other is the tire subsystem. Thus, the force balance equation for the suspension subsystem is where is the spring force and is the exerted damping force.
Observer-based event-triggered control and application in active suspension vehicle systems
Published in Systems Science & Control Engineering, 2022
The dynamic equation of the quarter-car suspensionsystem is established as Wang et al. (2019) where is relative displacement of vehicle body, is relative displacement of vehicle wheel, is velocity of vehicle wheel vibration.Denote , , . The quarter-car suspension system is shown in Figure 1.