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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(12):1535-1550
The paper is concerned with modelling car drivers. The context of the work presented is explained. Then, previous research on the application of optimal linear preview control theory to driving road vehicles with only modest excursions from a straight-running equilibrium state is extended into the general large-lateral-motion arena. Optimal controls are found for steady-cornering trim states of an exemplary car at a given speed as a function of cornering effort, up to the practical limit. The manner in which the optimal controls change as the cornering vigour changes is discussed. Simulations of the virtual driver-controlled car are shown to demonstrate the closed-loop system following lateral path demands and the advantages of employing gain-scheduled adaptive control over a fixed-control scheme are demonstrated. 相似文献
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FlexRay is a reliable and hard real-time in-vehicle communication protocol that is strongly promoted by car manufacturers as the de facto standard in the automotive domain. The protocol offers both a time-triggered and an eventtriggered architecture. This paper focuses on the optimal scheduling of the time-triggered component of FlexRay known as the static (ST) segment using a two-dimensional bin-packing technique. To maximize the bandwidth utilization in the ST segment, a fast heuristic as well as an efficient integer linear programming approach are proposed. Our methods directly schedule signals into slots including frame packing, according to signal-based data scheduling and the slot/ cycle multiplexing mechanisms presented by the latest version of the FlexRay protocol. The benefits of our proposed methods are demonstrated by extensive experiments on synthetic and an automotive X-by-wire system case study. An additional test case is examined to emphasize the superior performance of the proposed approach relative to that of existing optimal scheduling approaches. 相似文献
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由高速ON/OFF阀操作的主动悬架系统及控制方法研究 总被引:4,自引:1,他引:4
主动悬架能使车辆的乘坐舒适性和操纵安全性同时得到改善,但系统复杂性及成本的提高使其普及受到影响,本文提出一个以价格低廉的高速ON/OFF阀取代目前使用的压力比例控制阀的系统方案,并应用天棚阻尼器控制,最优控制,最优预见控制等方法进行控制系统设计及实验研究,结果表明,所提的系统是可行的,控制效果是令人满意的。 相似文献
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S.M. Ei-Demerdash D.A. Crolla 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1996,25(5):369-386
In this work, the preview control problem is considered for fully active and hydro-pneumatic slow-active systems. Based on the quarter car model, linear optimal control theory is used to derive the control laws. The Pade approximation technique is used to represent the preview time resulting from a preview sensor mounted at the front bumper to measure the road irregularities ahead of the front wheels. The results for the slow-active system with preview showed that there is 15% improvement in ride comfort compared to slow-active without preview and 28.5% improvement over passive system at similar root mean square (r.m.s) dynamic tyre load and suspension working space. The performance gains are, however, lower by about 15% than those obtainable with the theoretically ideal, fully active system with preview. The power results for slow active with and without preview showed that a 2kW fixed displacement hydraulic pump is enough for full vehicle requirements. 相似文献
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Vijay K. Garg Yun Lung Wang Kuang-Han Chu 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1984,13(2):73-92
The dynamic performance of a flat car is studied herein. The performance indices include roll angles, lateral accelerations, center plate loads, side bearing loads, wheel loads and spring deflections. These variables are maximum when the car is running at its critical speed, corresponding to either the rock and roll, or the bounce mode. The Association of American Railroads' (AAR) Flexible Carbody Model was used. The input for vertical track irregularities used in the simulation was generated from published spectra for U.S. Federal Railroad Administration (FRA) Class 4 track. After studying the car's performance with various column loads and spring suspensions, it was found that the most commonly used column load of 4,000 lbs. (17.8 kN) should be used. The spring suspension used in the original car design should also be adopted, in order to avoid spring. bottoming. 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(3):185-210
Summary The research and development (R & D) of maglev technology had made a great progress in China since the early 1980s. Especially, a 35 km-long Shanghai high-speed maglev railway employing the German Transrapid system began to be constructed on March 1, 2001. Based on the Transrapid system, the paper develops a 10-degree-of-freedom model of maglev vehicle running over three types of guideways with constant speed. Random guideway irregularities are discussed and taken into account for simulation of the vehicle response and for evaluation of the ride comfort. Using the direct time integration method and the discrete fast Fourier transform (DFFT), random responses of the maglev vehicle-guideway systems are obtained and analyzed. Numerical results show that the resonant frequency of car body acceleration response is 0.5–1 Hz, and there is a 2.2 Hz periodic vibration due to the periodic configuration of rigid piers when the maglev vehicle travels over the elevated-beam guideway. The car body acceleration power spectral density (PSD) curves meet well the ride quality criterion of the urban tracked aircushion vehicle (UTACV) and the maximum acceleration of car body is less than 0.05 g. Moreover, the Sperling ride index values are less than 2.5 as long as the operational speed is less than 450 km/h. It is concluded that the maglev vehicle ride quality is quite well. 相似文献
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C. F. Zhao W. M. Zhai 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2002,38(3):185-210
Summary The research and development (R & D) of maglev technology had made a great progress in China since the early 1980s. Especially, a 35 km-long Shanghai high-speed maglev railway employing the German Transrapid system began to be constructed on March 1, 2001. Based on the Transrapid system, the paper develops a 10-degree-of-freedom model of maglev vehicle running over three types of guideways with constant speed. Random guideway irregularities are discussed and taken into account for simulation of the vehicle response and for evaluation of the ride comfort. Using the direct time integration method and the discrete fast Fourier transform (DFFT), random responses of the maglev vehicle-guideway systems are obtained and analyzed. Numerical results show that the resonant frequency of car body acceleration response is 0.5-1 Hz, and there is a 2.2 Hz periodic vibration due to the periodic configuration of rigid piers when the maglev vehicle travels over the elevated-beam guideway. The car body acceleration power spectral density (PSD) curves meet well the ride quality criterion of the urban tracked aircushion vehicle (UTACV) and the maximum acceleration of car body is less than 0.05 g. Moreover, the Sperling ride index values are less than 2.5 as long as the operational speed is less than 450 km/h. It is concluded that the maglev vehicle ride quality is quite well. 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(12):1461-1474
A numerical method for the time-optimal control of the race car is presented. The method is then used to perform the role of the driver in numerical simulations of manoeuvres at the limit of race car performance. The method does not attempt to model the driver but rather replaces the driver with methods normally associated with numerical optimal control. The method simultaneously finds the optimal driven line and the driver control inputs (steer, throttle and brake) to drive this line in minimum time. In principle, the method is capable of operation with arbitrarily complex vehicle models as it requires only limited access to the vehicle model state vector. It also requires solution of the differential equation representing the vehicle model in only the forward time direction and is hence capable of simulating the full vehicle transient response. 相似文献
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Vijay K. Garg Yun Lung Wang Kuang-han Chu 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1986,15(2):73-92
The dynamic performance of a flat car is studied herein. The performance indices include roll angles, lateral accelerations, center plate loads, side bearing loads, wheel loads and spring deflections. These variables are maximum when the car is running at its critical speed, corresponding to either the rock and roll, or the bounce mode. The Association of American Railroads' (AAR) Flexible Carbody Model was used. The input for vertical track irregularities used in the simulation was generated from published spectra for U.S. Federal Railroad Administration (FRA) Class 4 track. After studying the car's performance with various column loads and spring suspensions, it was found that the most commonly used column load of 4,000 lbs. (17.8 kN) should be used. The spring suspension used in the original car design should also be adopted, in order to avoid spring bottoming. 相似文献
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现今的发动机技术虽然相当的成熟,但燃烧的效率也仅达25%—30%而已,因此积炭主要是由机械本身所造成的现象,以及汽油品质不佳所引起,汽车行驶一段时间后,燃油系统就形成一定积炭。行驶在二万公里以上汽车积炭特别严重,就会出现发动机怠速不稳、忽高忽低;加油时,加速不良,有发闷的现象;行驶无力,尤其超车时,提速反应慢,无法达到原车动力;尾气刺眼、刺鼻,严重超标;油耗也比以往增加。 相似文献
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汽油车改装成汽油/LPG双燃料车后,由于汽油和LPG的物化性质和燃烧特性有较大的差别,因而使用同一个点火提前角是不合理的。本文以桑 塔纳LX型轿车发动机为对象,通过台 试验得出燃用LPG时的最佳点火提前角,在原车点火系统的基础上,研制出一套能根据不同的燃料自动切换点火提前角的点火装置,该装置在台架和整车道路试验中都获得较好的结果。 相似文献
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I. Kageyama R. Nagai 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1995,24(4):313-327
This study aims to stabilize the trailer at high speed. The behavior of passenger cars with four wheel steering system, vehicles with rear wheel steering and of trailer and passenger car are similar. This is regarded as an optimal regulator problem with linear equation of motion, and a state variables feedback control system is adopted. The problem of stability at high speed on a straight course can be solved. Therefore, the passenger car-trailer system can be stabilized. Furthermore, this study indicates the way forward to stabilize a passenger car-trailer system. 相似文献