Optimal Control of the Tractor-Semitrailer Truck

This paper is concerned with the braking performance and the handling behavior of the tractor-semitrailer truck under optimal braking. Optimal control theory is used in order to deal with the problem and a combination of the steepest descent method and the Davidon Fletcher Powell method is used to solve it numerically. Results for some chosen braking maneuvers are obtained for a nonlinear truck model which has 14 degrees of freedom. These results show that, for the chosen maneuvers an idealized anti-skid braking is close to being optimal in the sense defined in this paper. Implementation of an idealized anti-skid braking on the tractor-semitrailer truck, however, may be not desirable.     

Optimal Control of the Tractor-Semitrailer Truck

SUMMARY

This paper is concerned with the braking performance and the handling behavior of the tractor-semitrailer truck under optimal braking. Optimal control theory is used in order to deal with the problem and a combination of the steepest descent method and the Davidon Fletcher Powell method is used to solve it numerically. Results for some chosen braking maneuvers are obtained for a nonlinear truck model which has 14 degrees of freedom. These results show that, for the chosen maneuvers an idealized anti-skid braking is close to being optimal in the sense defined in this paper. Implementation of an idealized anti-skid braking on the tractor-semitrailer truck, however, may be not desirable.     

基于主动制动的半挂汽车列车横摆稳定性控制

为研究半挂汽车列车在高速大转向等极限操作工况下的横摆稳定性控制问题,建立了14自由度的半挂汽车列车非线性仿真模型;提出了牵引车与半挂车独立直接横摆力矩控制的横摆稳定性控制方案,通过牵引车和半挂车车轮的合理选择和主动制动实现横摆控制;以跟踪参考模型的稳态横摆响应为目标,设计了PI横摆稳定性控制器,对牵引车和半挂车分别设计了目标制动车轮的选择决策规则。单移线操作仿真结果表明,基于主动制动的横摆力矩控制可有效改善极限工况下半挂汽车列车的横摆稳定性,牵引车与半挂车进行独立横摆控制可以减小制动车轮选择决策的复杂性,而获得较好的控制效果。     

某轻型载货汽车制动性能分析与改进设计

将某轻型载货汽车制动系统中前制动器改为盘式制动器,对采用不同配置制动系统的整车进行路试制动性能试验,结果表明制动性能得到很大改善.在该制动系统中加装制动力自动调节装置来调整前、后轮制动器的输入压力,并对改进设计后的整车制动性能进行实车道路试验.结果表明,该轻型货车制动力分配更加合理,制动性能明显提高,制动稳定性和安全性得到改善.     

Stability Bounds of a Tractor-Semitrailer

The dynamic stability of a tractor-semitrailer is presented here on a qualitative basis. In a four-dimensional space, equilibrium states of the system are discovered which lead to suitable initial conditions for numerical integration of the system equations. The intergal solutions define the stable and the unstable regions in the state-space, and thereby reveal the system behavior. A simple example concerning the effect of a front tire blowout illustrates how the theory can expose the vehicle motion under external perturbations.     

液罐汽车直线制动稳定性的分析

对液罐汽车部分装载并直线制动时，罐内液体的质心坐标和制动稳定性进行分析讨论。部分装载的液罐汽车制动行驶时，其质心位置将向前、向上转移，使汽车的同步附着系数减小，造成后桥车轮先于前轴车轮抱死，致使后桥车轮侧向附着力下降而容易发生侧滑；同时还导致前后车轮抱死间隔时间增加。为了减小液罐汽车罐内液体质心的转移对汽车制动稳定性的影响，应在结构上采取措施，尽量控制罐内液体质心的转移量，提高同步附着系数。     

制动衬片摩擦性能对轻型货车前后制动力之比的影响

本文研究了制动衬片摩擦性能——热衰退性能、速度和压力相关性对轻型货车鼓式制动器前后制动力之比的影响及其规律。研究表明,前后制动力之比不足一固定值,而是在很大范围内变化的一个区,从而影响同步附着系数,导致前后轮抱死区的变动;研究表明,摩擦特性受热不稳定而出现的逆衰退和过恢复是影响β的主要原因。本文还讨论了前后制动力之比β的简易计算法与台试实测结果间的差异,提出由制动器台架试验确定β之方法。     

载货汽车制动跑偏原因

汽车制动系统的稳定性直接影响整车安全,而制动跑偏又是多年的老问题。文章从设计和生产加工的角度分析了引起制动跑偏的原因,并介绍了一种制动力调节机构（可调式弹簧制动气室）的工作原理,表明制动系统零部件加工及制造误差引起的积累误差是造成制动跑偏的主要原因,而这个积累误差是不可控的,也是无法消除的。指出要解决这个问题必须尽可能提高各零部件加工质量,减小积累误差;同时在制动系统中增加制动力调节机构,通过制动力的调节来弥补积累误差。     

重卡制动空气处理系统研究

目前,重卡普遍采用气制动,若制动管路空气质量差,将影响阀体的正常工作或者失效,降低制动效能。本文结合实际分析了影响制动管路空气质量的原因,提出了提高制动管路空气质量的几项对应措施,进一步提出了制动系统某些零部件匹配推荐值,对提升制动管路空气质量具有一定的参考意义。     

半挂汽车列车转向分析

研究了半挂汽车列车的最小转弯直径、转弯通道圆和直角通道宽度理论计算方法,介绍了如何分析半挂汽车列车在公路上行驶时的通过性能。     

Random Response of Tractor-Semitrailer System

This work describes an analytical study of the dynamic behaviour of a tractor-semitrailer vehicle. A digital computer simulation was used to describe the longitudinal, vertical, and pitching motions of the vehicle travelling over a stationary random road surface. A man-seat model was also incorporated into the simulation. Vehicle response to road irregularities has been studied by assuming two different roads for loaded and unloaded cases.

Numerical results are presented for vehicle, showing system eigenvalues, power spectral densities and root mean square values of the linear and angular accelerations and displacements. Vehicle acceleration response is compared with the ISO riding comfort standard. All results for the loaded and unloaded cases and for smooth and rough roads indicated that an uncomfortable ride would result from vehicle response.     

Random Response of Tractor-Semitrailer System

SUMMARY

This work describes an analytical study of the dynamic behaviour of a tractor-semitrailer vehicle. A digital computer simulation was used to describe the longitudinal, vertical, and pitching motions of the vehicle travelling over a stationary random road surface. A man-seat model was also incorporated into the simulation. Vehicle response to road irregularities has been studied by assuming two different roads for loaded and unloaded cases.

Numerical results are presented for vehicle, showing system eigenvalues, power spectral densities and root mean square values of the linear and angular accelerations and displacements. Vehicle acceleration response is compared with the ISO riding comfort standard. All results for the loaded and unloaded cases and for smooth and rough roads indicated that an uncomfortable ride would result from vehicle response.     

牵引车-半挂车列车转向稳定性分析

研究了3种用于判别牵引车-半挂车列车稳态转向特性的方法:线性系统稳态转向特性的判别方法、基于动力学仿真的非线性系统稳态转向特性的判别方法、能量相平面判别方法.运用这3种方法分别对某一牵引车-半挂车列车的稳态转向特性进行了判别.结果表明,3种方法相互补充,可以更全面地判别牵引车-半挂车列车的稳态转向特性.     

牵引车-半挂车列车动力学仿真研究

在合理的理论假设基础上建立了较为精细的牵引车-半挂车的整车动力学仿真模型。应用此模型,针对6×4牵引车拖挂2轴半挂车列车的折叠、甩尾、倾翻及转向瞬态响应进行了仿真,并对各工况的特点进行了分析。仿真结果表明该模型能够很好地模拟车辆在各种危险工况下的运动状态,从而为进一步研究牵引车-半挂车列车的性能特点提供了很好的工具。     

Tractor-Semitrailer Dynamics: Design of the Fifth Wheel*

The nonlinear equations of motion are derived for a tractor-semitrailer truck where both the itractor and the semitrailer yaw, pitch, roll, and translate. Special emphasis is placed on the constraints imposed by the fifth wheel on the vehicle motion. In particular, the effects of two proposed fifth wheel design changes on the jackknifing behavior of a vehicle in a turning, braking maneuver are studied. The results demonstrate that the tendency of the vehicle to jackknife can be reduced with a geometric modification of the fifth wheel.     

带有能量再生系统市区公共汽车制动性能的计算机仿真研究

本文提出了一种新型的制动能再生系统，对一种带有飞轮储能器的市区公共汽车的制动原理进行分析，并给出了在两种不同输入情况下制动过程中的车辆系统动态响应的计算机仿真结果。