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Automotive Chassis Components
Published in Don M. Pirro, Martin Webster, Ekkehard Daschner, Lubrication Fundamentals, 2017
Don M. Pirro, Martin Webster, Ekkehard Daschner
The suspension systems mentioned up to this point are simple mechanical systems that respond to vehicle dynamics and road loads with fixed set of springs and levers. Many high-performance cars can now respond actively to these driving loads. Suspension position and acceleration sensors can vary spring rates and shock absorber damping rates to improve vehicle performance. Shock absorber damping rates can be altered using electrically controlled variable valves, or by using a magnetorheological damper. The fluid in these types of shock absorbers contain ferromagnetic particles that can change the fluid properties in reaction to an induced magnetic field. A significant safety feature in many cars today is the use of active vehicle dynamics control. The vehicle can identify driving situations such as where the car begins to skid when cornering. The vehicle computers will then adjust throttle, suspension, and braking as required to retain control of the vehicle.
Optimal control of vehicle semi-active suspension considering time delay stability
Published in Domenico Lombardo, Ke Wang, Advances in Materials Science and Engineering, 2021
The above research results have done theoretical research from different aspects. However, these research papers are mainly aimed at the control ways. The reference [4] proposed a quasi-linear-parameter-varying algorithm. In reference [5]: an adaptive optimal control constraining semi-active vehicle suspension system is presented. The reference [6] researched on performance of semi-active suspension which ued magnetorheological damper based on LQG algorithm strategy. In this paper, the application of LQG algorithm in semi-active suspension control is emphatically studied.
Seismic Response Control for Bridge Piers with Semi-Active MR Damper Based on Displacement Feedback
Published in Journal of Earthquake Engineering, 2023
Zou Shuang, Hei-Sha Wenliuhan, Yan-Hui Liu, N Inoue, Zhi-Peng Zhai
In order to avoid the pounding of adjacent structures of a bridge under an earthquake, various devices and engineering measures have been proposed to reduce the excessive displacement of the main beam of the bridge under an earthquake (Lee and Chen 2011a). In recent years, a structural vibration control has been developed rapidly, in which the semi-active control system can achieve the control effect close to that of the active control system because it only needs a small amount of energy (Jansen and Dyke 2000; Lee and Chen 2011b; Li, Liu, and Guan 2007). In particular, the (magnetorheological) damper have many advantages, such as the simple device, low energy consumption, large damping force, strong temperature adaptability, fast response speed and strong controllability. It becomes an ideal element for structural semi-active control (Chang and Loh 2006; Choi et al. 2007; Guo et al. 2009; Ok et al. 2006; Li et al. 2016; Yang, Chen, and Hua 2011). Many recent studies have used MR dampers for the anti-pounding of bridges. Ok et al. (2006) studied the semi-active fuzzy control technology of an MR damper for a cable-stayed bridge and explained that the control system can effectively mitigate the seismic response and enhance the robust performance of a semi-active control system. Through the damping performance test of an MR damper of a suspension bridge, Yang, Chen, and Hua (2011) made it clear that the MR damper can effectively reduce the longitudinal seismic response of the suspension bridge. Sanjay (2005) analyzed and experimentally studied the performance of a 1:20 scaled bridge model employing semi-active controllable MR dampers under near-fault earthquakes. The results showed that the smart MR damper reduced the bearing displacements while maintaining the isolation level forces. Heo et al. (2017) conducted an analytic study on an MR damping system in a three-span bridge to verify its effect on the pounding prevention of the bridge and the reduction in the relative displacement of the bridge structure. Lee and Chen (2011a) considered the nonlinear behavior of piers in the analysis. They verified that the displacement control effect of the MR damper on the main beam is obvious. Therefore, many studies have discussed the effectiveness of MR dampers in reducing the seismic response of bridges and preventing the pounding between adjacent structures of bridges.