1. THÔNG BÁO TUYỂN ADMIN DIỄN ĐÀN 2013
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    HÃY TÌM KIẾM Ở ĐÂY TRƯỚC KHI ĐẶT CÂU HỎI
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X by Wire

Thảo luận trong 'Điều khiển tự động ô tô' bắt đầu bởi bmnhy, 24 Tháng chín 2006.

  1. bmnhy Giảng Viên

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    Mình post một ít thuật ngữ mới về X by wire (Một loạt hệ thống mới ứng dụng điện tử và điều khiển tự động trong các hệ thống của xe hơi)
    Hiệ tại các xe cao cấp như: BMW 3 Series, Mercedes Benz C class, Audi A4/S4, BMW 5 Series, Peugeot 607, Saab 9-5 đã trang bị các hệ thống này. Và tới đây chúng ta sẽ thấy Hệ thống lái không còn thước lái, Hệ thống thắng không còn Các xylanh thủy lực, và các đường ống dầu,... và chiếc xe sẽ là một cổ máy với những hệ thống mới hiện đại - hiệu quả - an toàn có tên gọi chung là X by Wire:

    hãy bắt đầu làm quen với Acronym trước nhé:

    Tiêu đề: Thuật ngữ:

    Nội dung:
    Opel Adam Opel AG (includes Saab unless other wise specified)
    ASR Anti Slip Regulation
    ABS Antilock Braking Systems
    ADB Automatic Differential Brake
    BA Brake Assist
    CAGR Compound Annual Growth Rate
    CBC Cornering Brake Control
    DaimlerChrysler Daimler Chrysler (Mercedes Benz and Chrysler and MCC Smart)
    DBC Dynamic Brake Control
    DSC Dynamic Stability Control
    EHB Electro Hydraulic Braking
    EMB Electro Mechanical Braking
    EBA Electronic Brake Assist
    EBD Electronic Brake-force Distribution
    EDL Electronic Differential Lock
    ESC Electronic Stability Control
    ESP Electronic Stability Program
    EWB Electronic Wedge Brake
    Fiat Fiat Group (Fiat, Lancia and Alfa Romeo)
    Ford Ford Motor Company (Ford, Jaguar and Volvo)
    HDC Hill Descent Control
    HBA Hydraulic Brake Assist
    MSR Modulate System Regulation
    OEM Original Equipment Manufacturers
    PDC Park Distance Control
    RSC Rollover Stability Control
    TCS Traction Control Systems
    TRW TRW Automotive
    VDIM Vehicle Dynamics Integrated Management
    VM Vehicle Manufacturer
    VSC Vehicle Stability Control


    Tiêu đề: Brake by wire:

    Nội dung:

    When traveling on a motorway at speeds exceeding 100 kmph, imagine the car in front of you skidding off its path and hitting the barriers hard enough to block the whole road and to force you to make a sudden complete halt. The technologies that allowed you to come to a complete halt, are the brakes and the stability control systems of the vehicle. Brakes are the
    first to come to your rescue, however, even if the brakes are highly efficient, it is extremely difficult for any driver to maintain the stability and control over the vehicle when braking at high speeds. With this major challenge in mind, over the years the industry has put considerable research efforts into the development and continuous improvement of Stability control systems such as Antilock Braking Systems (ABS), Traction Control Systems (TCS) and ultimately Electronic Stability Program (ESP) which by 2012 are expected to be implemented in over 98 percent of passenger vehicles in Europe. Furthermore, and following the increasing importance the industry has been placing on the development of advanced solutions, stability
    control systems are expected to be integrated with active and passive safety systems such as adaptive cruise control, pre crash sensors and airbags and seat belt pretensioners.

    As analysed more in detail in this study, OEMs such as Fiat and Renault are expected to offerESP systems as a standard, whilst OEMs such as General Motors and DaimlerChrysler are likely to opt for the implementation of advanced ESP systems that offer features such as integration to Adaptive Cruise Control (ACC), integration to pre crash systems and steering intervention. By 2015, advanced ESP systems are expected to be present on over 20 percent of the passenger vehicles market in Europe. With the launch of BBW systems such as EWB and EMB systems around 2009/2010, integrated chassis control systems will start penetrating the market.

    Amongst braking systems, although over 95 percent of the market is currently equipped with hydraulic braking systems, the industry is expected to gradually shift towards more advanced braking systems such as electro mechanical braking (EMB) systems and electronic wedge brake (EWB) systems post 2009/2010. Premium OEMS such as BMW and Audi are expected to opt for EMB systems, with penetration rate expected to cross 3 percent in BMW by 2012 whilst, OEMs such as Toyota are ( [IMG] (có vẻ chổ này sai chính tả - nhưng mình vẵn post nguyên văn original file) likely to prefer Electronic Wedge Brake (EWB) systems on high end models such as the Lexus LS Series. Frost & Sullivan estimates that by 2020 OEMs such as DaimlerChrysler, Volkswagen and BMW will introduce a complete Brake-By-Wire system and to shift towards a global integrated chassis control system with By-Wire chassis systems. By 2020, the conventional hydraulic braking system is expected to be present mainly on A and B segment vehicles, reaching a maximum penetration of approximately 30 to 35 percent on these segments.
  2. toyo Guest

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    Ông bạn muốn cho sv học av chuyên ngành luôn huh? lỡ các bạn khác nhìn thấy English ngán wá không muốn đọc thì box này ai ghé thăm [IMG]
  3. bmnhy Giảng Viên

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    Ý của bạn cũng hay, nhưng kiếm được bài, đọc, lọc ra chổ quan trọng, post. Vậy nên Tôi mong các bạn hãy cố gắng vượt qua rào cản Ngoại ngữ, nhất là trong tình hình hiện nay: tài liệu đa phần viết bằng TA. và Hầu hết anh em ngành kỹ thuật đều phải gặm các bài này dưới dạng này thôi, Nói vậy thì cũng hơi quá. nên tôi sẵn sàng giải đáp những cụm từ hoặc danh từ chuyên môn (với khả năng của tôi) nếu anh em nào gặp khó khăn. Chứ không thể dịch hết tất cả. Mình cũng đã nêu nhập đề bằng tiếng việt để anh em thấy có tí hứng thú để xem đó thôi
    ví dụ câu này: When traveling on a motorway at speeds exceeding 100 kmph: thì mình nghĩ có nên tốn thời gian ngồi gõ lại bằng tiếng việt? Ở trình độ anh văn 2 trường mình là đọc hiểu dc rồi bạn ạ!
    Chúng ta cũng cần nghĩ thoáng hơn một chút dc không? Anh văn là cầu nối để chúng ta đến với tri thức nhân loại! Vậy nên cũng không nên cầu kỳ quá.
    Tất nhiên sẽ có bài tôi tóm tắt lại bằng tiếng việt, nhưng việc chưa thể ngay hôm nay, vì tôi cũng phải đọc thêm nhiều, làm nhiều mới hiểu dc mà viết chứ, đúng không ông bạn!
  4. bmnhy Giảng Viên

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    Thêm một số khái niệm cụ thể làm tiền đề hiểu X by wire

    X-by-wire systems and
    time-triggered protocols

    The benefits of the fly-by-wire technique have
    gotten the automotive companies to investigate the use of a similar technique in vehicles.
    In the automotive industry, the dependability of a system is not the only requirement. The
    cost of manufacturing has a big part of production.


    When you replace the mechanical parts of a system by electronics, you can think that
    a setback of the safety of the system. But the electronics can indeed help to make the
    system safer. The x-by-wire technology is aiming towards fault tolerant control systems
    that completely replace the need for mechanical backup. These systems cannot only
    control the vehicle; they can assist the driver in difficult situations on the road.

    A Safety related system is one by which the safety of equipment or plant is assured.- Tin chac


    One of the most desired properties of a safety related system is predictability. If the
    system is predictable you can foretell the systems behavior.

    Most safety-related systems can be categorized as either a Control System or as a
    Protection System.

    In a safety critical system the calculations must be in an interval (khoang thoi gian giua 2 su kien) small enough to recognize that a message hasn’t arrived in time, so the fault recovery can start
    immediately.

    Fault avoidance
    Fault avoidance techniques aim to prevent faults from entering the system in the first
    place. This is the primary aim of the entire development. Techniques as formal
    methods are great fault avoidance techniques when they can be applied. [23]
    2.6.2 Fault removal
    Fault removal is the techniques where you try to find all faults introduced into the
    system during the design phase. This is done before the system is taken into use.
    Extensive testing of both hardware and software is fault removal methods. [23]
    2.6.3 Fault detection
    The fault detection methods are applied to systems in use, to try to detect fault before
    they lead to errors to minimize the effects on the system. A system that uses fault
    detection algorithms is more suitable for safety critical systems because they
    continuously try to find faults in the system. The methods include among others
    functionality testing that checks that the hardware still are performing according to its
    specification. Information redundancy aims to reveal errors in the data by using CRC,
    checksums and error correcting codes. [23]
    2.6.4 Fault tolerance
    Many techniques for fault tolerance are dependant on the existence of fault detection
    techniques. Fault tolerance is a property associated with the ability of a system to
    endure fault without changing the behavior of the system. There are many techniques
    for fault tolerance including hardware and software redundancy. [23]

    X-by-wire
    An x-by-wire system is a safety related fault tolerant electronic system in vehicles
    without mechanical backup. The x stands for different safety related applications, e.g.
    steer- and brake-by-wire.
    [IMG] The purpose of an x-by-wire system is to assist the driver in different situations and to
    make it safer for all road-users. This increases the overall vehicle safety, as the driver
    doesn’t have to be concerned of the routine tasks anymore. Another advantage is the
    lower cost for production of this type of system. An x-by-wire system is also called a dry
    system, as the hydraulic fluids are no longer necessary. This leads to a simpler and more
    easily maintained system.

    Many car manufacturer already have some kind of x-by-wire system in their latest
    models and they are all very interested to develop this technique because it’s a cost
    effective way to make the cars safer than today. The x-by-wire system also gives the
    opportunity to monitor the activity of the system during operation or you can write data
    to a log (bang ghi) for later.

    [IMG] There are several benefits of x-by-wire systems.
    The controlling electronics in steering system can be placed anywhere. It’s no longer needed to be under the steering wheel. In fact, the wheel can be replaced with a joystick. When you can place the steering unit anywhere, it’s simpler to adapt the car to both right and left hand steering.
    An x-by-wire system can also be easily upgraded (cai tao) or adjusted to different needs as the dynamics of the system is in the software. You just download the new software into the controllers. No parts must be replaced!

    Electronics in automotive systems increase. When moving from body-electronics to
    vehicle control the need for a secure transmission is greater. When your steering wheel
    is connected to the tires only by electronics, you have to be able to trust the system. The
    x-by-wire systems are often safety-critical and must be built on a reliable network
    architecture.

    The currently used transfer protocols don’t have the level of security that’s
    needed. This is the reason why automotive manufacturers want to develop new secure protocols, the time-triggered protocols.

    Today, the industry has divided into two major groups developing two versions of a
    time-triggered protocol. Both groups agree that there is a great need for a standard in
    this field, but they disagree on which protocol that should set that standard.

    The Time Triggered Architecture Group, which includes PSA Peugeot Citroen, Audi, Volkswagen, Honeywell and Delphi Automotive Systems, employs the Time Triggered Protocol (TTP) originally developed at the university of Vienna, Austria. TTP is based on the strict TDMA scheduling.

    The other group is the FlexRay Consortium and they have developed its own protocol, FlexRay, based in part on the Byte flight system and on the time-triggered architecture. This protocol offers flexibility apart from the time-triggered communication. The members of this group are General Motors, DaimlerChrysler, BMW, Motorola, Philips Semiconductors and Bosch Automotive Group



    [IMG] Time-triggered architecture
    Future automotive systems seem to need more and more distributed computing. It’s not a
    single CPU doing all calculations, but a network of many micro controllers working
    together. This increases the demands on a dependable communication system.
    A real-time requirement is that a task reacts on an event in a predictable way and within
    it’s given time limit. The network latency (ngam ngam) is an important factor when analyzing a
    system. If a communication medium should be used in a hard real-time system the
    latency must be predictable. In CAN (Controller Area Network ) the latency is depending on the busload and the priority of the task. A low priority task will have to wait for all tasks with higher priority.
    Run time calculations are especially difficult for low priority tasks and in networks with many nodes and a high message frequency. In a safety critical system the calculations must be in an interval (khoang thoi gian giua 2 su kien) small enough to recognize that a message hasn’t arrived in time, so the fault recovery can start
    immediately.

    [IMG] Event-triggered protocols
    The currently used protocols in vehicles are event-triggered.
    This means that all activity is invoked by the occurrence of an event. For example, a sensor that senses a changing value immediately sends an event message to the controller of the sensor.
    predicted. CAN is an event triggered communication channel and is in more detail described in chapter 5. [7]
    The event-triggered approach is good for many real-time applications. These systems require a different architecture. The CAN bus is a good communications channel for soft real time systems, but for hard real-time systems time-triggered protocols have been developed.

    [IMG] Real-time Systems
    A real-time system is a computer system where not only the correct computation is important.
    The time when the result is produced is equally important. For example if a traffic-light turns to green after yellow, it’s a correct behavior but if both direction of a crossing get a green light at the same time it could lead to a disaster.
    Soft and hard real-time systems
    Real-time systems can be divided into soft and hard systems. The difference between these two types is how strict (chat che) the deadlines for the processes are. If a missed deadline only decreases the performance but does no harm the system is said to be a soft real-time system. If it, on the other hand, is very important that all deadline will be met, and the consequences (hau qua) if they don’t are harmful to people or property, it’s a hard real-time system. A control system in a nuclear power plant is a hard real-time system. A safety critical system is often a hard real-time system.


    [IMG] Time-triggered protocols
    The time-triggered architecture was a result of the Time Triggered Architecture (TTA)
    All nodes should be synchronized in time and every activity on the network is
    time stamped using the global time. The message-schedule can be made prior to system
    start because all messages are allocated time on the bus at the design level. This makes

    the time-triggered systems deterministic (hoc thuyet), as they always send the messages in the same
    order. The static schedule is downloaded into the controllers. The communication subsystem knows then when to send messages and when a message on the bus is of interest for its own node. One of the main advantages for a time-triggered architecture are the composability (ket hop), that reduces the need for testing when integrating a new part into the system. Composability means that a part of the system is isolated in the time and
    value domain in such way that it’s not affected by other parts of the system when they
    are put together. This is an important factor when designing safety critical systems. If
    The time triggered architecture is designed to tolerate any single physical fault in any of
    the nodes without causing damage to the system. [8] If an error does occur, it must be contained in that subsystem and not propagate through the system. This means that each
    unit must provide its own fault avoidance and fault tolerance procedures. If a unit can’t
    produce right output anymore it must close down silently so it doesn’t causes any harm
    to the rest of the system. This is known as a fail-silent architecture.
    The transparent fault tolerant structure of the time triggered architecture is based on
    Redundant fail silent units that makes it an acceptable architecture for safety critical
    systems.
    [IMG] A summary of the characteristics of each type of protocol

    Event-triggered Time-triggered
    Soft real-time Hard real-time
    Non deterministic Deterministic
    Low bandwidth for discretemessages Low bandwidth for continuous signals

    Fault tolerant
    [IMG] The protocols
    The main part of this thesis is to study three promising time-triggered protocols. TTP and
    Flexray are each supported by a large group of automotive companies and TTCAN is
    developed by Bosch. Bosch is the company that in 1985 developed the CAN protocol,
    which is now a very common communications architecture in modern vehicles.
    In this section the protocols will be described and compared. TTCA Nis a higher level
    protocol on top of CAN, so it’s neccesary to describe the CAN protocol also.

    Chúc vui vẻ!
  5. bmnhy Giảng Viên

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    BBW system:

    Beneath the hood of a Ford hybrid vehicle is a system of electronic controls that continuously monitors the interaction between the driver, the vehicle and the road to deliver class-leading fuel economy.
    Utilizing drive-by-wire (or direct drive) technology, the hybrid's electronic controls add a new degree of precision to the communication between driver and vehicle.
    Drive-by-wire technology refers to the replacement of mechanical components with electronic controls. While the technology itself is not new, drive-by-wire has gained a newfound importance in hybrid technology.
    "In the Ford hybrids we use a brake-by-wire system," said Tom Gee, manager, Hybrid Controls. "It's part of the regenerative braking system that uses friction from braking to recharge the hybrid's battery. Normal braking in the hybrid does not involve a traditional hydraulic system."
    Brake-by-wire means there is no mechanical connection between the brake pedal and the brakes during normal operation. This lets the system electronically optimize braking for maximum fuel economy and braking performance.
    "When the driver steps on the brake in our hybrids, the pedal is attached to a spring to provide the feel of braking," Gee said. "A sensor monitors the amount of pedal movement and relays the information to the Vehicle System Control. The control monitors the amount of torque needed for the powertrain and the brakes and based on the situation adjusts the braking."
    If enough power is available for safe braking, the residual energy caused by the braking is channeled back to recharge the battery.
    Whether in a hybrid or conventional powertrain, the benefits of drive-by-wire systems are greater precision in controlling the vehicle's performance. The greater precision results in better fuel efficiency and the related benefits of reduced emissions.
    Along with the braking system, the hybrids utilize another form of drive-by-wire technology, the electronic throttle control. As with the brake pedal, when the driver steps on the gas pedal, a sensor monitors the movements. In turn, the Vehicle System Control balances the driver's input with the amount of energy required by accessories like air conditioning that are running.
    "Unlike a typical transmission, the hybrid's transmission contains no hydraulics except for an oil pump," Gee said. "The Vehicle System Control sets the gearing and engine performance to the optimum setting for fuel efficiency based on what the driver is doing."
    In developing the Escape Hybrid, Ford's engineers examined different types of hybrid systems before settling on the current technology. "For this type of system, you need a torque based throttle by wire system," Gee said.
    Since the vehicle is making so many decisions affecting the vehicle's performance, Ford's engineers created a number of fail safe measures in case the electronics should malfunction.
    For example, that spring mentioned earlier that is attached to the brake pedal does more than give the driver the feel of stepping on the brakes. If the electronics were to fail, the driver stepping on the brakes would press through the spring and shift into normal hydraulic braking.
    Similar fail-safe mechanisms monitor the vehicle and take action if the hybrid's actions go out of the normal range.
    If all this sounds like robocar taking control away from the driver, the reality is quite different.
    "The driver's actions influence the efficiency of the system," Gee said. "That's why we encourage drivers of a hybrid to use a very smooth touch on the brake pedal. Normally most of the friction caused by braking is absorbed into the battery. Hitting the brakes hard, however, sends the vehicle into regular friction braking, which affects fuel economy."
    Drive-by-wire technology may be essential to the hybrid's functioning, but the technology has also found a home in some of Ford's non-hybrid vehicles. For instance, the 04 Ford Explorer introduced electronic throttle control with the 4.0-liter V-6 and the 4.6-liter V-8 engines while the redesigned F-150 also incorporated electronic throttle control.
    In Europe, a number of Ford vehicles have utilizing drive-by-wire throttle controls for a number of years on both gas and diesel engines.
  6. thuanckd Guest

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    Anh cung cấp nhiều thông tin rất thú vị. Trong đó, em quan tâm nhiều đến hệ thống phanh phục hồi năng lượng(regenerative brake system).
    Em có một vài thắc mắc về hệ thống này: khi mà bình đã nạp đầy thì hệ thống có hoạt động không? nếu có, vậy năng lượng phục hồi sẽ sử dụng vào mục đích gì?
    Nếu có thể, anh có thể cung cấp cho em một vài trang web nói rõ hơn về hệ thống này nha. em đã tìm nhiều mà chỉ toàn thấy nói chung chung thôi.
    cám ơn anh nhiều
  7. bmnhy Giảng Viên

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    regenerative brake system theo anh nghĩ cũng có nhiều phương án. Em hãy tìm một số ebook về điều khiển trong ô tô để đọc thêm!

    Chúc em may mắn!
  8. thuanckd Guest

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    Nhưng mà em tìm hoài mà không thấy, đặc biệt là phần hoạt động của hệ thống này, sự kết hợp hoạt động của hệ thống này với hệ thống phanh dầu truyền thống. Các ebook chứa thông tin hay đều có tính phí.
  9. hongthai1986vn Member

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    <div class='quotetop'>QUOTE (thuanckd @ Nov 5 2008, 02:48 AM) <{POST_SNAPBACK}></div><div class='quotemain'>Nhưng mà em tìm hoài mà không thấy, đặc biệt là phần hoạt động của hệ thống này, sự kết hợp hoạt động của hệ thống này với hệ thống phanh dầu truyền thống. Các ebook chứa thông tin hay đều có tính phí.[/b][/quote]
    em muốn hỏi ko biết cảm biến góc lái trong X by Wire sử dụng là cảm biến gì nhỉ??
  10. bmnhy Giảng Viên

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    <div class='quotetop'>QUOTE (hongthai1986vn @ Nov 11 2008, 11:05 PM) <{POST_SNAPBACK}></div><div class='quotemain'>em muốn hỏi ko biết cảm biến góc lái trong X by Wire sử dụng là cảm biến gì nhỉ??[/b][/quote]


    Sử dụng encoder Maxon 4096 pulse/vòng.

    Gắn trực tiếp vào DC motor 250 watt (grear 18 lần) hoặc 60 watt (Gear 36 lần)

    Em tính làm đề tài này à?

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