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!【包含文件如下】【机械类设计类】CAD图纸+word设计说明书.doc【需要咨询购买全套设计请企鹅97666224】.bat
A0-转向桥总成装配图.dwg
A3-右转向节臂.dwg
A3-左转向节臂.dwg
A3-横拉杆.dwg
中英文翻译.doc
设计说明书.doc
目 录
摘 要 III
Abstract IV
1 绪 论 1
1.1 汽车转向桥的发展状况 1
1.2 汽车从动桥的结构形式 4
2 转向桥的设计结构参数 7
2.1 结构参数选择 7
2.2 从动桥的总体结构选择 7
2.3 确定前桥各部分的具体结构形式 7
3 前轴的设计 8
3.1 前轴强度的计算 8
3.2 前轴的弯矩及扭矩计算 10
3.3 断面系数的计算 11
3.4 各工况下的应力计算 15
3.5 前轴的材料及许用应力 17
4 转向节的设计 18
4.1 计算截面系数 18
4.2 计算弯矩 18
4.3 计算应力 18
4.4 转向节的材料及许用应力 19
5 主销设计 20
5.1在紧急制动时的计算数据 20
5.2 在发生侧滑时的计算数据 21
6 转向传动机构的设计 23
6.1 计算推力轴承和止推垫片 23
6.2 杆件的设计结果 24
7 转向梯形机构的优化设计 25
7.1 转向梯形机构概述 25
7.2 整体式转向梯形结构分析 25
7.3 整体式转向梯形机构优化分析 26
7.4 整体式转向梯形机构的优化设计 28
8 结 论 31
参考文献 32
致 谢 33
3吨载重跃进货车转向桥总成的设计
摘 要
本人毕设题目为3吨载重货车的转向桥总成设计，设计出的转向桥要求在不同速度与路况下都能够稳定的行驶，因此对前桥的设计要求较高。本次设计的主要内容包括：确定设计方案，转向节的设计，主销的设计，前轴的设计，轴承的选择和转向梯形的设计。同时，在进行汽车设计时，应制定出既具有优异的承载能力，还能实现耐用经济性的方案。此外，节约生产成本也应作为设计原则之一，那么也就是说本次设计出的结构就应在满足要求的前提下尽可能的简单。
本次设计中需满足的要求有：（1）保证各部件有足够的强度：可承受车架与车轮之间相互的作用力。（2）保证各结构有足够的刚度：使得车轮的定位参数能始终保持不变。（3）保证汽车的转向轮有适合的定位角度：使得转向轮运动时更加的稳定，操纵起来也能更轻便并且可减轻轮胎磨损。（4）保证转向桥质量尽量小：可以提高汽车在行驶时的平顺性。
关键词: 转向桥；转向节；主销；前轴；轴承；转向梯形
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外文原文Automobile Brake-by-Wire Control SystemDesign and AnalysisAbstractThe automobile brake-by-wire (BBW) system, which is also called the electromechanical brake system, has become a promising vehicle braking control scheme that enables many new driver interfaces and enhanced performances without a mechanical or hydraulic backup. In this paper, we survey BBW control systems with focuses on fault tolerance design and vehicle braking control schemes. At first, the system architecture of BBW systems is described. Fault tolerance design is then discussed to meet the high requirements of reliability and safety of BBW systems. A widely used braking model and several braking control schemes are investigated. Although previous work focused on antilock and antis lip braking controls on a single wheel basis, we present a whole-vehicle control scheme to enhance vehicle stability and safety. Simulations based on the whole-vehicle braking model validate a proposed fuzzy logic control scheme in the lateral and yaw stability controls of vehicles.Key wordsBrake-by-wired, braking model, fault tolerance, networked control systems, stability control.I. INTRODUCTION ABRAKE-BY-WIRE (BBW) system consisting of electro-mechanical actuators and communication networks, in-stead of conventional hydraulic or electro hydraulic devices, has emerged as a new and promising vehicular braking control scheme. It offers enhanced safety and comfort, cuts off cost associated with manufacturing and maintenance, and eliminates environmental concerns caused by hydraulic systems. The BBW system has recently invoked a lot of interest for both industry and academia worldwide.In a BBW system, brake force is initiated by a driver and applied to the electronic motor-driven actuators at four wheels. The BBW system offers easy connection with other vehicular systems, enabling a simple integration of vehicle traction and stability control. The BBW systems provide better control of pedal stiffness, vehicle stability, and brake force distribution than a conventional hydraulic or electro hydraulic system. The advantages of the BBW systems are listed as follows:1) elimination of complex and heavy mechanic or hydraulic parts;2) improved efficiency and stability of brake control due to the quick and accurate generation of brake torques by electric motors;3) enhanced diagnostic capability of braking system;4) easier adaptation of assistance systems e.g., anti-block system and electronic stability program (ESP) without additional mechanical or hydraulic components;5) cost reduction in the phases of design, construction, assembly, and maintenance;6) space saving and less weight;7) elimination of environmental concerns associated with traditional hydraulic braking systems.Although the BBW system promises benefits and efficiency, its reliability and safety is the most important concern that necessitates a fault tolerance and fail-safe system architecture. To enhance safety, the BBW systems naturally require redundancies in power supply, sensors, actuators, and information processing and delivery and have provisions for error detection and fault tolerance management.This paper examines the effectiveness of a BBW system adopting differential brake torques for lateral and yaw stability controls. The lateral motion control of a moving vehicle is an important component of intelligent vehicle highway systems. Losses of lateral control and yaw stability for a traveling vehicle may result from side wind force, tire pressure losses, or braking in diverse road and vehicle situations. Under some situations, drivers could not respond to the yaw instability in time, which make it meaningful to have automatic lateral and yaw stability controls. The vehicle yaw stability control compensates for drivers controls during the panic reaction time by generating instant and corrective yaw moments. The BBW systems could easily produce a yaw moment by using differential braking.This paper is organized as follows. The brake system architecture is presented in Section II. Section III discusses the fault tolerance design to meet the requirements of reliability and safety of the BBW systems. A typical whole-vehicle model is presented in Section IV. II. BBW SYSTEM ARCHITECTUREA BBW system architecture is proposed and shown in Fig. 1. It consists of four electro-mechanical brake (EMB) modules, an EMB pedal module, a duplex communication network, a centralFig. 1. Proposed BBW system architecture.Brake control and management (CBCM) module, and power supplies. Each EMB consists of an actuator, a local electric control unit (ECU), and a communication interface (CI). The CBCM unit has an ECU and a CI. On each wheel, a wheel speed sensor (WSS) is used to detect wheel speed, the message of which is sent to the corresponding EMB. A vehicle speed sensor (VSS) is adopted to detect vehicle speed. Sensors, actuators, and control nodes communicate with each other through a real-time network with a hot backup, which is not shown in the figure for the sake of simplicity.The main components of EMB are the motor-driven actuators at four wheels and associated control units. In the case of disc brakes, the task of these components is to generate press brake pads against brake discs firmly when braking. The information of braking time and strength is extracted from a brake pedal box. The pedal box does not differ from a conventional one in the view of drivers. A nonlinear controller was proposed in 10 for the implementation of EMB pedal box. The braking information is sensed by multiple sensors within a pedal box, each individually working to probe one type of message such as the force and speed of brake pedal. The messages are delivered to local ECU as well as the main ECU. The main ECU is capable of controlling the stability of vehicle based on the messages of vehicle speed, wheel turn angle, and wheel rotation speeds. In case of a failure of either a local ECU or the main ECU, another ECU will adaptively take its place.Fig. 2 depicts the block diagram of the proposed BBW system. The central braking controller receives signals of pedal braking, steering angle, vehicle velocity, wheel rotation speeds, and other messages related to vehicle motion and safety. The central controller calculates the brake forces of actuators based on the detected brake Fig2.Block diagram of proposed BBW systemMessages. The values of the braking forces are then sent to wheel brake control units over a real-time communication network. The wheel braking controllers perform the braking according to control algorithms. The values of the brake torques are sent to actuators for braking control. Meanwhile, the wheel sensors feed back the wheel status to the wheel braking controllers. Brake controllers monitor the operations of the components, detect failures, and deal with them with fail-safe approaches.III. FAULT TOLERANCE ANALYSIS OF BBW SYSTEMSThe BBW systems do not have mechanical or hydraulic backups, and the reliabilities of electronic and electrical com-opponents are inherently lower than mechanical components. All aspects of reliability, availability, maintainability, and safety of the BBW systems need to be carefully reconsidered. A BBW system with increased safety integrity requirement needs to 1) adopt redundancy in power supplies, sensors, actuators, data processing units, and communication networks and 2) enable error checking and fault management strategy.Many works that are related to the fault tolerance design of X-by-wire systems have been recently completed. A whole overview of fault-tolerant drive-by-wire systems was provided in 1. The application of the time trigger protocol (TTP) communication network on the BBW systems are discussed 2, 3. Some methods of fault detection and diagnostics for the BBW systems have been proposed 59.A suggestion of redundancy degrees of the main components in a BBW system is listed in Table I. Three sensors are used to measure the brake pedal force, and two replicated busses are suggested to correctly guarantee communications between components. Power supply is backed up to guarantee the system operation. All safety-related signals such as vehicle velocity and wheel rotation speed are feed back to monitor vehicle status. In the meantime, the historic values of sensors are used. However, there is no redundancy for actuators since only the losses of two or more actuators may cause a safety critical situation.There are two categories of real-time networks: event trig-Gering network e.g., control area network (CAN) and TTP network. However, none of them meets the safety requirement of the BBW systems since they both lack deterministic and fault-tolerant characteristics. The combination of the above two networksTTCAN 3seems to be a good choice for the automobile BBW systems. The TTCAN protocol is realized in software in a high layer on the top of CAN, which allows the messages to be transmitted in either an event-triggered or a time-triggered mode.IV. BRAKING CONTROL SCHEMES Antilock braking systems (ABS) are now gradually accepted as standard safety components for vehicles. ABS could prevent the lockup of the car wheels during hard or emergency braking. Wheel lockup is an undesirable situation because the friction force of the locked wheel is considerably less due to sliding on the road. When the wheels are locked, steering becomes impossible, leading to less control of the vehicle. ABS ensures optimal vehicle control and minimizes stopping distance by maintaining wheel slip ratio at a possible highest value. In conventional vehicles, ABS is achieved through the use of hydraulic systems. ABS is complicated and sometimes may not be effective due to its nonlinear characteristics and unknown environmental parameters. ABS systems use velocity and acceleration information of wheels saved in a look up table to generate braking torque. Optimal slip ratio may not be guaranteed by using this predicated control method due to the uncertainties and disturbances of practical situations. A number of advanced control approaches have been proposed for ABS and antis lip controllers, namely fuzzy logic control 1519,neural network 20, 21, sliding mode 2224, iterative learning control (ILC) 25, and others 26, 27. Fuzzy logic control using linguistic information can model the qualitative aspects of human knowledge with advantages including robustness, universal approximation theorem, and rule-based algorithm. A fuzzy-logic-based controller used to control the wheel slip of electric ABS was presented 16, 17. The robustness of the fuzzy logic slip regulator was tested by a wide range of operating conditions. The results indicated that fuzzy-logic-based ABS/tracking control could substantially improve steady-state longitudinal performance and offer a potential for optimal control of driven wheel under icy road conditions. Lee and Zak 19 proposed an ABS controller that employs a no derivative neural optimizer and fuzzy logic control. The role of the no derivative optimizer is to identify the road surface and then search for the optimal wheel slip that corresponds to the maximal road adhesion coefficient. The desired braking torque is obtained by using fuzzy logic controller that uses the optimal slips from the no derivative optimizer. Although fuzzy logic is an effective method, the major drawback of fuzzy logic control is that the fuzzy rules should be previously tuned by a time-consuming trial-and-error procedure.Sliding mode control is usually introduced to tolerate some uncertainties. There are usually chattering control efforts in sliding mode control. To reduce this phenomenon, the sign function in switching control is always replaced by a saturation function with a cost of a reduced accuracy. The application of sliding mode control is justified by the natural properties of ABS actuators such as the discontinuity of operation mode. Dacono et al. 22 proposed an ABS control scheme based on sliding mode control. The scheme achieved the maximal value of the tire/road friction force during emergency braking without a priori knowledge of optimal slip. In 23 and 24, a hybrid discrete time controller utilizing the strength of fuzzy logic, sliding mode control and linear control was proposed. The combination is stable and shows robustness against some uncertainties.ILC is an effective control scheme to deal with repeated tracking control or periodic disturbance rejection. ILC sys-tem improves the performance by a self-tuning process. An ILC scheme was proposed for an ABS system under various road conditions 25. Through iterative learning process, motor torque is optimized to keep tire slip ratio corresponding to the peak traction coefficient during emergency braking. The advantage of ILC was that, once learned, the controller has the ability to automatically adjust to various road conditions, particularly in wet and icy road conditions.Previous work on brake control mainly focused on antilock and antis lip braking controls based on single-wheel models that are suitable for hydraulic braking systems. The ABS control schemes are normally based on the checking tables that are calibrated and predicted in an offline mode. The lookup table methods generated variable control performances, depending on the BBW system that are employed, road conditions, and drivers responses. It is vital to develop a whole-vehicle con-troll scheme fitting various vehicle types and environmental conditions.中文译文汽车制动控制系统的设计与分析摘要 汽车制动系统，又叫做机电制动系统，已成为很有前途的车辆制动控制方案，支持许多新驱动程序接口和增强的性能没有机械或液压备份。在本文中，我们用基于容错设计与车辆制动控制方案调查汽车制动系统。首先，描述汽车制动系统的系统架构，然后讨论了容错设计以满足BBW系统的高可靠性和安全性的要求。研究一种广泛使用的制动模型和一些制动控制方案，以前的工作集中在单轮的基础上的防抱死和防滑刹车控制，我们现在提出一个全车控制方案来提高车辆的稳定性和安全性，模拟基于制动模型验证提出的模糊逻辑控制方案在横向和偏航稳定控制的车辆。关键词：TermsBrake-by-wired，制动模型，容错，网络化控制系统，稳定性控制I 介绍ABRAKE-BY-WIRE(BBW)是由机电致动器和通信网络组成的系统,而不是传统的液压或电动液压设备，已成为一个新的、有前途的车辆制动控制方案。它提供了增强安全性和舒适性，减少成本与制造和维护，并消除环境问题造成的液压系统。BBW系统最近提起了各个行业和全球学术界的广泛兴趣。在BBW系统中，制动力是一个被驱动发起，并应用于由电子电动执行机构的四个轮子。BBW系统提供与其他车辆系统简单的连接，用于使一个简单的集成车辆的牵引力和稳定控制。BBW系统比传统液压或电动液压系统提供更好的控制刚度、车辆稳定性和制动力分配。BBW系统的优点如下：1) 消除复杂的重型机械或液压部分;2)因为快速和准确的一代制动扭矩的电动马达提高了制动控制的效率与稳定;3)增强制动系统诊断功能;4)更容易适应的辅助系统(如anti-block系统和电子稳定程序(ESP)没有额外的机械或液压元件;5)在设计、建设、组装、和维护阶段降低成本;6)节约空间，更少的重量;7)消除与传统的液压制动系统有关的环境问题。尽管BBW系统承诺效益和效率，其可靠性和安全性是最重要的问题，需要一个容错和故障安全系统架构来实现。加强安全、BBW系统自然需要冗余电源，传感器，执行器，信息处理和交付，提供错误检测和容错管理。本文用差动制动扭矩横向和偏航稳定控制检测BBW系统有效性。车辆的横向运动控制是智能车辆高速公路系统的重要组成部分。在不同道路和车辆的情况下，一个旅游车辆的横向控制和偏航稳定损失的原因可能来自风力，轮胎压力损失或不同道路和车辆制动情况。在某些情况下，司机不能及时应对偏航的不稳定，这使自动横向和偏航稳定控制的存在有一定的意义。车辆偏航稳定控制通过生成即时和纠正偏航时刻补偿司机在恐慌反应的时间。BBW系统可以很容易地通过使用差动制动产生偏航力矩。本文组织如下：制动系统架构的提出在II部分，第III部分探讨了容错设计，以满足BBW系统的可靠性和安全性的要求，一个典型的模型出现在第IV节。II BBW系统架构BBW系统体系结构展示在了图1中。它由四个电闸(EMB)模块，一个EMB踏板模块，双工通信网络，一个中央制动控制和管理(CBCM)模块和电力供应组成。每个EMB由执行机构、当地电控单元(ECU)，和一个通信接口(CI)组成。图1.BBW系统体系结构CBCM单元有一个ECU和CI。在每一轮中，车轮速度传感器(WSS)是用于检测车轮速度，它的信息发送到相应的EMB。汽车速度传感器(VSS)用来检测车辆的速度。传感器、执行器和控制节点相互通信都是通过用热备份的实时网络，为了简单起见这是没有显示在图中的。EMB主要组成部分是四个轮子的电动执行机构和相关的控制单元。在盘式刹车的情况下，当刹车时，这些组件的任务是立刻用制动片对抗刹车光盘。制动时间和力量的信息是从一个刹车踏板框中提取的。踏板框在司机视图中不同于传统的踏板框，提出了一种非线性控制器EMB踏板框。制动踏板框内信息是由多个传感器感觉到，每个传感器单独工作为了调查一个类型的消息，例如制动踏板的力量和速度。消息传递到本地ECU以及主要的ECU，主要ECU能够基于车辆速度、车轮转角和轮旋转速度的信息控制车辆的稳定性。以防本地的ECU或主要的ECU失败，另一个ECU将自适应取而代之。图2描绘了BBW提出系统的框图。中央制动控制器收到踏板制动信号，方图2.BBW系统的框图向盘角度，车辆速度，车轮转动速度，和其他与车辆运动和安全有关的消息。中央控制器基于检测的制动消息计算制动器的制动力量。刹车力的值随后通过实时通信网络发送到车轮制动器控制单元。车轮制动控制器通过控制算法执行制动。为了制动控制，制动力矩的值被发送到执行器。与此同时，车轮传感器给车轮制动控制器反馈车轮状态。制动控制器监控组件的操作，检测故障，并用自动防故障装置的方法处理。III，BBW系统的容错分析BBW系统没有机械或液压的备份，同时，电子和电器元件的可靠性本质上低于机械部件。所有BBW系统的可靠性、可用性、可维护性和安全性的这几
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