scholarly journals Invariant points of semi-active suspensions

2018 ◽  
Vol 10 (7) ◽  
pp. 168781401877731 ◽  
Author(s):  
Shida Nie ◽  
Ye Zhuang ◽  
Fan Chen ◽  
Jie Xie

The invariant points of the quarter vehicle model shape many properties concerned in vehicle suspension design. Although they have been studied for years, the invariant points are still confusing for their different traits. Hence, the existing invariant points are sorted and analysed. Meanwhile, the invariant points of the semi-active suspension were introduced. In this article, a further study on the invariant points of the semi-active suspension is conducted, which provides insight for suspension optimization. In detail, an equivalent linear approximation model, derived from the transformation of the semi-active suspension model, is utilized to analyse the invariant points of the semi-active suspension. With the equivalent linear approximation model, the invariant points of the sky-hook semi-active suspension are proved to be highly dependent on the adjustable damping range. In fact, the frequencies and magnitudes of the invariant points, as the limit of the semi-active suspension, are determined by the adjustable damping range. Consequently, the influence rule of the adjustable damping range on semi-active suspension performance is revealed, which provides insight for the optimization of the damping for different demands. Experimental study shows that the invariant points are real, not just exist in the theoretical analysis.

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
Yan-yang Wang ◽  
Yi-nong Li ◽  
Wei Sun ◽  
Chao Yang ◽  
Guang-hui Xu

The vibration of SRM obtains less attention for in-wheel motor applications according to the present research works. In this paper, the vertical component of SRM unbalanced radial force, which is named as SRM vertical force, is taken into account in suspension performance for in-wheel motor driven electric vehicles (IWM-EV). The analysis results suggest that SRM vertical force has a great effect on suspension performance. The direct cause for this phenomenon is that SRM vertical force is directly exerted on the wheel, which will result in great variation in tyre dynamic load and the tyre will easily jump off the ground. Furthermore, the frequency of SRM vertical force is broad which covers the suspension resonance frequencies. So it is easy to arouse suspension resonance and greatly damage suspension performance. Aiming at the new problem, FxLMS (filtered-X least mean square) controller is proposed to improve suspension performance. The FxLMS controller is based on active suspension system which can generate the controllable force to suppress the vibration caused by SRM vertical force. The conclusion shows that it is effective to take advantage of active suspensions to reduce the effect of SRM vertical force on suspension performance.


2012 ◽  
Vol 479-481 ◽  
pp. 1355-1360
Author(s):  
Jian Guo Chen ◽  
Jun Sheng Cheng ◽  
Yong Hong Nie

Vehicle suspension is a MIMO coupling nonlinear system; its vibration couples that of the tires. When magneto-rheological dampers are adopted to attenuate vibration of the sprung mass, the damping forces of the dampers need to be distributed. For the suspension without decoupling, the vibration attenuation is difficult to be controlled precisely. In order to attenuate the vibration of the vehicle effectively, a nonlinear full vehicle semi-active suspension model is proposed. Considering the realization of the control of magneto-rheological dampers, a hysteretic polynomial damper model is adopted. A differential geometry approach is used to decouple the nonlinear suspension system, so that the wheels and sprung mass become independent linear subsystems and independent to each other. A control rule of vibration attenuation is designed, by which the control current applied to the magneto-rheological damper is calculated, and used for the decoupled suspension system. The simulations show that the acceleration of the sprung mass is attenuated greatly, which indicates that the control algorithm is effective and the hysteretic polynomial damper model is practicable.


1995 ◽  
Vol 7 (4) ◽  
pp. 295-300 ◽  
Author(s):  
Antonio Moran ◽  
◽  
Tomohiro Hasegawa ◽  
Masao Nagai

This paper presents a new design method of semi-active suspensions based on the integration of neural networks and bilinear systems. It is known that semi-active suspensions with ideal linear components have a bilinear structure. However actual semi-active suspensions with nonlinear components have an structure which is not purely bilinear. In order to improve the performance of semi-active suspensions, neural networks and bilinear systems are integrated and used for the identification and optimal control of nonlinear semi-active suspensions. The validity and applicability of the proposed method are analyzed and verified theoretically and experimentally using a semi-active suspension model equipped with piezoelectric actuators.


2015 ◽  
Vol 759 ◽  
pp. 77-90 ◽  
Author(s):  
Tomasz Nabagło ◽  
Andrzej Jurkiewicz ◽  
Janusz Kowal

In the article, a new solution of a semi-active suspension system is presented. It is based on a sky-hook strategy model. This solution in 2S1 tracked platform is applied to improve body vehicle stability and driving comfort. The solution is applied in two versions of the 2S1 vehicle suspension model. First one is a basic model. This suspension is based on existing construction of the 2S1 platform suspension. It is based on torsion bars. Second one is a modified model, based on spiral torsion springs. In this model a new solution of idler mechanism is applied. It provides constant tension of the tracks. Semi-active suspensions simulations results are compared with results of models with passive versions of the suspension to highlight the improvement level. Simulations are conducted in the Yuma Proving Ground conditions. Results of all models simulations are compared and analyzed to improve stability and comfort level in conditions of the modern battlefield. Stability level is analyzed for weapon aiming tasks. Comfort level is analyzed for the vehicle crew efficiency.


2011 ◽  
Vol 141 ◽  
pp. 319-322
Author(s):  
Jun Zhong Xia ◽  
Zong Po Ma ◽  
Shu Min Li ◽  
Xiang Bi An

This paper focuses on the influence of various vehicle suspension systems on ride comfort. A vehicle model with eight degrees of freedom is introduced. With this model, various types of non-linear suspensions such as active and semi-active suspensions are investigated. From this investigation, we draw the conclusion that the active and semi-active suspensions models are beneficial for ride comfort.


2014 ◽  
Vol 602-605 ◽  
pp. 1372-1377 ◽  
Author(s):  
Yi Zhang ◽  
Li Li Sun

In order to improve the control effect of vehicle suspension, the simplified Seven-DOF active suspension model was created in ADAMS/View by applying the dynamics theory, and classical PID control principle was utilized to design an active suspension controller for vehicle. The vehicle model was imported into the PID controller established in MATLAB as a module to create a vehicle active suspension control model. According to the simulation results, compared with passive suspension, the PID control of active suspension can control effectively the vertical vibration acceleration (VVA),roll and pitch acceleration (RAA&PAA) of body ,which improved vehicle ride comfort performance.


2020 ◽  
Vol 25 (4) ◽  
pp. 532-541
Author(s):  
Shailendra Kumar ◽  
Amit Medhavi ◽  
Raghuvir Kumar

Passive suspensions are designed to satisfy the conflicting criteria of riding comfort and vehicle handling. An active suspension system attempts to overcome these compromises to provide the best performance for vehicle control. Different types of mathematical models have been used to study the suspension system of a vehicle. The quarter vehicle model is used for initial investigation. Later, the half vehicle and full vehicle models are used for the study, which is closer to the actual model of a vehicle suspension. In this paper, the behavior of a suspension system is analyzed using the full vehicle model. In the current work, the dynamic equation and their state-space formulation are presented for the full vehicle model to understand the system prior to the controller design. The open-loop response of the full vehicle suspension system, when subjected to various road excitations, is also studied. The procedure of modeling a SIMULINK model for passive suspensions system is discussed in detail. Design of the simple Proportional Integral Derivative (PID) feedback and feed-forward controller is presented for the active suspension system using transfer functions. Closed-loop transfer functions are also derived and their responses are plotted. To analyze the rollover behavior simulation for cornering is also performed in the current study.


2018 ◽  
Vol 211 ◽  
pp. 02004
Author(s):  
Matheus Melo ◽  
Suzana Avila

The vehicle suspension isolates the chassis from road irregularities, reacting to forces produced by the tires and the braking torques, always keeping the road tire contact, providing stability and safety. Stability and safety are two antagonistic characteristics in suspension design, when improving one the other is impaired and vice versa. The semi-active suspension is a type of vehicle suspension that can change its stiffness and/or damping in real time depending on the vehicle response to the actual road profile. The On-Off semi-active suspension changes its damping coefficient between two fixed limit values. This work proposes an On-Off semi-active suspension model, in which the damping coefficient changes its values considering the road profile function frequency. A control strategy is proposed in a way to improve performance keeping the same simplicity, without any structural change of the semi-active suspension. On the proposed control strategy one of the damping coefficients is obtained through the linear quadratic regulator (LQR) algorithm, with the aim to set the coefficient from the gain matrix associated to the velocity of the suspended mass. This model is compared to anothers found in literature.


2013 ◽  
Vol 456 ◽  
pp. 14-17
Author(s):  
Jian Guo Chen ◽  
Xia Feng ◽  
Xiao Ling Zhang

Vehicle suspension is a MIMO coupling nonlinear system; its vibration couples that of the tires. For the suspension without decoupling, the vibration attenuation is difficult to be controlled precisely. In order to attenuate the vibration of the vehicle effectively, a nonlinear half vehicle model with active suspension is established and a differential geometry approach is used to decouple the nonlinear suspension system. The decoupled system becomes independent linear subsystems, though pole assignment, the vibration attenuation of the sprung mass is achieved. The simulations show that the vertical and the pitching motion of the sprung mass are attenuated greatly, which indicates that the control algorithm is effective.


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