Tin whisker analysis of an automotive engine control unit

Since the 1970s, automobile manufacturers have used electronics for safety–critical automobile control systems such as acceleration, braking, and steering. These electronic systems introduced functionalities in automobiles that were not feasible in a purely mechanical framework, such as anti-lock braking systems and electronic stability control. However, failures of these electronic systems can lead to fatalities, financial losses, legal ramifications, and reputational liabilities for manufacturers. Therefore, automotive electronics must be designed to have minimum failures during use.     

Kalman Predictive Redundancy System for Fault Tolerance of Safety-Critical Systems

The dependence of intelligent vehicles on electronic devices is rapidly increasing the concern over fault tolerance due to safety issues. For example, an x-by-wire system, such as electromechanical brake system in which rigid mechanical components are replaced with dynamically configurable electronic elements, should be fault-tolerant because a critical failure could arise without warning. Therefore, in order to guarantee the reliability of safety-critical systems, fault-tolerant functions have been studied in detail. This paper presents a Kalman predictive redundancy system with a fault-detection algorithm using the Kalman filter that can remove the effect of faults. This paper also describes the detailed implementation of such a system using an embedded microcontroller to demonstrate that the Kalman predictive redundancy system outperforms well-known average and median voters. The experimental results show that the Kalman predictive redundancy system can ensure the fault-tolerance of safety-critical systems such as x-by-wire systems.      

Automotive electronics power up

People are spending increasing amounts of time in their cars. As a result, automakers are equipping vehicles with more and more power-draining creature comforts as selling points. Cup holders have given way to navigational systems, separate driver and passenger climate controls, and surround sound and compact disk players. But performance and handling improvements under the hood, such as dynamic stability controls, electronic suspensions, and precision-controlled fuel injection, also need power from the 14-V system featured in today's cars. To handle the situation, automotive manufacturers and suppliers are embracing a 42-V standard for system voltage as they design new products. The challenge for designers, however, is that the cost of the new electronics cannot prohibit the economic production of automobiles. This hurdle must be cleared before cars with 42-V systems will become available to consumers. The paper discusses why 42 Volts was chosen, how many batteries will be needed, control systems, start/stop operation, and the influence of silicon devices on cost     

Automobile electronics in the 1990s .2. Chassis electronics

There can be few topics developing faster than automotive electronics. Although the application of microcomputer-based systems is now well established for the control of automobile engines, there is still greater scope for the use of high-reliability electronic technology in other areas of vehicle operation. Amongst these are systems, such as air-bags, which improve safety, and also features which improve comfort and convenience. In this paper the operation of electronically controlled antilock braking systems (ABS) and electrically power-assisted steering (EPAS) is examined     

Automobile Brake-by-Wire Control System Design and Analysis

The 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 antislip 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.     

Mission-critical and safety-critical development

The concern in mission-critical and safety-critical systems is that you develop them thoughtfully and carefully. They need traceable evidence for every detail. Like a good journalist, you and your team must establish the "who, what, when, where, why, and how" in everything you do. Development of mission- and safety-critical systems requires a temporal progression, regardless of the development model. Generally, there are five phases to development. These are: concept; planning and scheduling; design and development; controlled release; commercial release. Another issue in mission- and safety-critical system is people. People make processes work or not work. Good, disciplined people can struggle, even under wretched conditions, and produce good results. Add reasonable processes, and these same people can produce great results. Unfortunately, outstanding processes cannot rescue a project from unruly and undisciplined people.     

Comparison between braking and steering yaw moment controllers considering ABS control aspects

Two yaw motion control systems that improve a vehicle lateral stability are proposed in this study: a braking yaw motion controller (BYMC) and a steering yaw motion controller (SYMC). A BYMC controls the braking pressure of the rear inner wheel, while a SYMC steers the rear wheels to allow the yaw rate to track the reference yaw rate. A 15 degree-of-freedom vehicle model, simplified steering system model, and driver model are used to evaluate the proposed BYMC and SYMC. A robust anti-lock braking system (ABS) controller is also designed and developed. The performance of the BYMC and SYMC are evaluated under various road conditions and driving inputs. They reduce the slip angle when braking and steering inputs are applied simultaneously, thereby increasing the controllability and stability of the vehicle on slippery roads. The SYMC performs better than the BYMC because the SYMC vehicle has four-wheel steering. However, both the BYMC and SYMC vehicles show improved performance during lane-change maneuvers.     

联协研发电动汽车最佳结构的四大基础部件以赶超世界领先

综合汽车、电机、控制、交通及其技术经济多学科的五大理论,经完备的深入分析研究,提出了可极大提高电动汽车驱动、制动和转向三大执行机构快速响应性及其性价比,和基于四大基础部件的电动汽车最佳结构的五项发明专利;优化电动汽车性能和交通管理来综合解决汽车引起的能源危机、环境污染、交通事故、道路拥堵四大负面效应;结合国情和现有技术分析了适于普及的节源环保型电动微轿车,提出尽快商品化的研发模式。为此需整合重组新汽车产业链通过联合协作攻关以赶超世界领先,从而带动国民经济腾飞,以此振兴中华。     

Mathematical Modeling and Nonlinear Controller Design for a Novel Electrohydraulic Power-Steering System

This paper is concerned with the mathematical modeling and nonlinear controller design of a novel electrohydraulic closed-center power-steering system. After a short introduction to the requirements of modern power-steering systems, the construction of the power-steering system under consideration will be described. The main advantage of this construction is the enhancement of the overall energetic efficiency of the steering system and the possibility of a variable steering assistance while keeping the good steering feeling of traditional hydraulic steering systems. Based on a detailed mathematical model of the essential components of the system, it is shown how some of the parameters of the system can be chosen to achieve an optimal dynamic behavior of the closed-loop system. The controller design proceeds in two steps: first, a nonlinear controller for the assistance force based on the differential flatness property of the system is designed, and afterwards, a steering torque controller using an impedance matching design is derived. Finally, measurement results of a test stand show the good performance and the robust behavior of the proposed control strategy     

Modeling and control of steering system of heavy vehicles for automated highway systems

This work presents modeling, analysis, and controller design of the steering subsystem of heavy vehicles as a subsystem of vehicle lateral control system for the automated highway systems. A physical model of the steering subsystem is derived where the hydraulic power assist unit is modeled as a family of static nonlinear boost curves. Based on open-loop frequency tests and analysis of the physical model structure and its dynamical characteristics, a nominal second order linear model of the steering subsystem is obtained. Then, a linear robust loop-shaping controller is designed to provide a good tracking performance of the closed-loop dynamics of the steering subsystem for varying gain cross over frequencies which is a result of the nonlinear characteristics of the hydraulic power assist. The controller has been successfully incorporated as an inner-loop controller into the nested lateral control architecture for autonomous driving and its efficacy has been demonstrated experimentally.     

关键性安全系统安全完整性概述

介绍关键性安全系统的安全与风险基本概念、安全完整性的实现,以及功能安全要求标准IEC61508：2010的结构、功能安全的要求与实现、安全完整性评估。     

Robust Yaw Stability Controller Design and Hardware-in-the-Loop Testing for a Road Vehicle

Unsymmetrical loading on a car like $mu$-split braking, side wind forces, or unilateral loss of tire pressure results in unexpected yaw disturbances that require yaw stabilization either by the driver or by an automatic driver-assist system. The use of two-degrees-of-freedom control architecture known as the model regulator is investigated here as a robust steering controller for such yaw stabilization tasks in a driver-assist system. The yaw stability-enhancing steering controller is designed in the parameter space to satisfy a frequency-domain mixed sensitivity constraint. To evaluate the resulting controller design, a real-time hardware-in-the-loop simulator is developed. Steering tests with and without the controller in this hardware-in-the-loop setup allow the driver to see the effect of the proposed controller to improve vehicle-handling quality. The hardware-in-the-loop simulation setup can also be used for real-time driver-in-the-loop simulation of other vehicle control systems.      

自适应模糊神经控制的汽车电动助力转向系统

电动助力转向是汽车动力转向的新技术和新结构,助力控制是电动助力转向的基本控制策略,并决定电动助力转向的助力特性.本文应用现代模糊神经网络理论,构建汽车电动助力转向系统模型,提出了性能较好的控制策略,并进行仿真研究.仿真结果表明,电动助力转向系统具有更好的操纵性能.实验证明,理论分析和仿真结果是正确的.     

基于磁流变制动器的自供能式汽车线控制动系统的设计与分析

磁流变液是近年来研究的热点,如今汽车线控技术的不断成熟和发展,利用传感器,控制元件,电子元件驾驶员动作转化为电信号,通过电线传递指令来操纵汽车,而不再需要传统的复杂的机械和液压连接装置.针对新型智能流体材料——磁流变液,我们将其应用于汽车线控制动系统中.利用磁流变液的这一特性设计出的制动器,再辅以合理的控制和信息反馈系统,可以实现制动力与地面附着力的快速匹配,甚至可以完成连续精准无脉动的ABS制动过程,从而代替传统液压机械式ABS,有利于实现底盘集成控制,大幅改善车辆制动性能.     

Documentation on tap

Electronic versions of documents can be more useful than their paper counterparts, by reducing costs and providing a more effective means of accessing and searching for information. Such systems can take input from a number of sources and convert it into a common form that can be browsed through, searched, and, where necessary, annotated on screen. The author describes how, when implementing an electronic system for documentation, four key activities are involved: acquisition; publication; distribution; and browsing. He details how such an implementation requires forethought and cooperation     

Thermal Monitoring of Self-Checking Systems

With the increasing power density in integrated systems resulting from scaling down, the occurrence of field failures due to overheating has considerably increased. Faulty operation can be prevented by on-line temperature monitoring. This paper deals with questions of on-line temperature monitoring in safety-critical systems. First the possible temperature sensors are reviewed and basic principles of self-checking systems including such sensors are detailed, then a new temperature sensor cell with extremely good parameters designed especially for DfTT applications is presented. The basic questions of integrating thermal sensors into self-checking systems are also discussed.     

液压动力转向系统性能分析与优化设计

液压动力转向系统其转向的轻便型和高速行车时的稳定性是一对矛盾,传统的液压动力转向系统无法实现随车速变化而作出必要的精确调节,因此无法兼顾低速时的加力效果和高速时车辆行驶的稳定性,故有必要对传统的机械液压动力转向系统进行优化设计以改善其使用性能。     

无线网络参数修改管理办法探讨

无线参数管理是一项非常重要的基础网络工作,针对目前参数修改的随意性、频次性高、修改量大、重要网络参数缺乏监管流程、不能及时发现参数异常设置等问题,制定参数分级管理制度,实施审批流程、规范参数修改制度、实施固定周期核查等方法进行参数修改的集中管理,保障网络参数设置的准确性与合理性。     

Design of a fault-tolerant IPM motor for electric power steering

This paper deals with the design of an interior permanent magnet (IPM) motor for power steering. Such an application requires an imperative fault-tolerant capability that is obtained by means of a redundant solution with two motors on the same shaft. A ball-screw system converts the rotating movement into the linear movement of the steering rack. In addition, the IPM motor has to exhibit very low braking torque after a short-circuit fault. Useful relationships between the maximum braking torque and the motor parameters are found and used in the design of the motor.     

Dynamic behavior of an electrohydraulic valve: Typology of characteristic curves

The majority of off-road vehicles employed in agriculture are equipped with a hydraulic steering. An efficient way of automating the steering mechanism of these vehicles is by controlling the electrohydraulic valve that operates the steering cylinder. Electronically-controlled hydraulic valves often behave nonlinearly and, consequently, they introduce certain complexities in the analysis of the hydraulic system. Therefore, it is necessary to understand their behavior before designing a control system that is able to auto-steer an agricultural machine safely and efficiently. The objective of this work was to characterize the performance of an electrohydraulic valve with the aid of a set of experiments conducted on a hardware-in-the-loop electrohydraulic simulator. The operation of the valve was classified in four types (I, II, III, and IV) according to the valve characteristic curves and the properties of the input signal. The phenomena of deadband, hysteresis, and saturation helped to discriminate between types. The input signal, especially its frequency, was crucial in studying the functioning of the valve. The hardware-in-the-loop simulator was fed with signals that imitated the auto-steering action. The outcomes obtained from this research provide some critically supporting information for designing high performance steering controllers for agricultural vehicles.