8 Introduction solutions to the problems of California’s surface transportation systems. Current PATH research projects are divided into four program areas: Policy and Behavioral Research, Transportation Safety Research, Trafc Operations Research, and Transit Operations Research. CALM Continuous Communications for Vehicles CALM (2008) is under ISO TC 204 Working Group 16 Wide Area Communications-Protocols and Interfaces. The scope of CALM is to provide a standardized set of air interface protocols and parameters for medium and long range, high speed ITS communication including V2V and V2I communications. AUTOSAR AUTomotive Open System ARchitecture (AU- TOSAR, 2008) is a partnership of automotive manufacturers and suppliers working together to develop and establish an open and standard auto- motive software architectures. Its core partners are BMW, Bosch, Continental, Daimler, Ford, OPEL, GM, PSA Peugeot Citroën, TOYOTA, and Volkswagen. The AUTOSAR project plan was released in May 2003 and the rst AUTOSAR Open Conference held in October 2008. JasPar JasPar (2008) is formed by the Japanese automo- tive companies and its board members include TOYOTA MOTOR CORPORATION, Nissan Motor Co., Ltd, Toyota Tsusho Electronics, Honda R&D Co., Ltd and DENSO CORPORATION. The aim of JasPar is to reduce technology develop- ment costs and promote technology development by encouraging Japanese companies to collab- oratively develop pre-competitive technologies such as automotive LAN enabling technology, middleware and software platform, and contribute to development of global standards. Internet ITs Consortium (Japan) Internet ITS Consortium (2008) is developing a common Internet ITS platform and aims for promotion of a standardized global Internet ITS specication. It is formed by Japanese companies and has 11 companies as Executive Members, 12 companies as Regular Members and 69 companies as Supporting Members. A*CAR in Singapore With the rapid growth in the global automotive population, the A*STAR (Agency for Science, Technology and Research) Capabilities for Automotive Research (A*CAR) began as a task- force with the aim of establishing an initiative to address technical challenges in the automo- tive area and provide technical leadership to the automotive supplier industry in Singapore through R&D (Yong, 2008). A*CAR taskforce has launched an automotive consortium to bring together automotive OEMs, suppliers and R&D community to work hand in hand in addressing key research areas in automotive technology. The consortium is driven by 7 A*STAR research institutes namely, Data Storage Institute (DSI), Institute for Infocomm Research (I²R), Institute of Chemical and Engineering Sciences (ICES), Institute of High Performance Computing (IHPC), Institute of Materials Research and Engineering (IMRE), Institute of Microelectronics (IME), and Singapore Institute of Manufacturing Technology (SIMTech) (A*CAR, 2008). FUTURE TRENDS The global automotive industry is the world’s largest manufacturing industry and most industry 9 Introduction analysts predict that there will be a year-on-year growth till 2012 (PwC Automotive Institute, 2008). The overall market for automotive network- ing will grow at a 10% annual rate through 2011 and the components for the automobile networking market will nearly triple between 2005 and 2011. Driving this trend is the introduction of more electronics in every vehicle, and that accounts for the much faster annual growth rate than the auto industry’s 2 to 3% (Regt, 2007). In the future, more and more control modules will be attached into the high-speed data network- ing backbones embedded in a vehicle. Vehicular networks will simplify the operation of control systems and allow more features to be deployed within automobile. For example, information and direction displays will be embedded directly into windshields. Another example is that instead of self-parking being a service that is offered only on luxury cars, it will soon become a standard feature on every car. With the advances in sen- sors, control, GPS (Global Position System) and networking technologies, “self-driving cars” will become possible in the future (Uldrich, 2008). Neurotechnology that studies drivers’ brain patterns and brain computers that read drivers’ intentions from their brainwaves through electro- encephalogram (EEG) will help keep them alert and monitor sleepy driver syndrome. Vehicular networks still plays a vital role in enhancing the automotive industry for safety, security and entertainment. In the future, as more and more information is streamed onto the Internet, vehicular networks will allow driv- ers and passengers to enjoy their journey more than ever before with entertainment and area information. CONCLUSION This introduction chapter presents the emerging area of vehicular networks in the forms of Intra- Vehicle (InV), Vehicle-to-Vehicle (V2V), and Ve- hicle-to-Infrastructure (V2I) communications. It briey surveys the car communications, potential applications, potential wireless technologies, and specially designed technologies DSRC standards and communication stack for data exchange. As the emerging area of vehicular networks has at- tracted a number of R&D groups in the world, this chapter then introduces the consortiums and initiatives working on advanced automotive tech- nologies in Europe, the U.S., Japan and Singapore. In the future, vehicular networks certainly play a vital role in enhancing the automotive industry for safety, security and entertainment. REFERENCES Armstrong, L. (2008). What is DSRC? Retrieved September 2, 2008, from http://www.leearm- strong.com/DSRC/DSRCHomeset.htm A*CAR. (2008). Automotive @ A*STAR. Bro- chure from Agency for Science, Technology and Research (A*STAR). AUTOSAR. (2008). Retrieved September 2, 2008, from http://www.autosar.org California PATH. Retrieved September 2, 2008, from http://www.path.berkeley.edu CALM. (2008). CALM Continuous Communica- tions for Vehicles. Retrieved September 2, 2008, from http://www.calm.hu/ Car 2 Car Communication Consortium. (2008). 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Retrieved September 2, 2008, from http://www. standards.its.dot.gov/fact_sheet.asp?f=80 Yong, M. S. (2008). A*CAR. A*STAR Program Proposal. 12 Copyright © 2009, IGI Global, distributing in print or electronic forms without written permission of IGI Global is prohibited. Chapter II Drive by Wire Systems: Impact on Vehicle Safety and Performance Sohel Anwar Indiana University-Purdue University Indianapolis, USA INTRODUCTION Drive by wire (DBW) systems are relatively new technology that are increasingly nding their place in modern automobiles. A drive by wire system is an automotive system that interprets driver’s inputs and executes the commands to produce desired vehicle behavior, typically via a microprocessor-based control system. A typical drive-by-wire system comprises of redundant sensors, actuators, microprocessors, and com- munication channels for fault tolerance. There are no mechanical or hydraulic connections be- tween driver’s input interface (e.g. throttle, brake, steering) and vehicle system (e.g. engine/traction motor, brake/steering actuators) in a drive by wire equipped vehicle. A broadened denition of drive by wire sys- tems will include other microprocessor based automotive control systems such as anti-lock braking system (ABS), traction control system (TCS), yaw stability control (YSC), etc. These systems are designed to enhance the safety of the vehicle by continuously monitoring various ABSTRACT An overview of the drive by wire technology is presented along with in-depth coverage of salient drive by systems such as throttle-by-wire, brake-by-wire, and steer-by-wire systems, and hybrid-electric propul- sion. A review of drive by wire system benets in performance enhancements and vehicle active safety is then discussed. This is followed by in-depth coverage of technological challenges that must be overcome before drive-by-wire systems can be production ready. Current state of the art of possible solutions to these technological hurdles is then discussed. Future trends in the drive-by-wire systems and economic and commercialization aspects of these system are presented at the conclusion of the chapter. 13 Drive by Wire Systems vehicle states and taking corrective action and / or warning the driver upon detection of an im- pending unsafe vehicle condition. The rst such system came into commercialization is ABS in early 1970’s. It was followed by traction control system and electronic stability control in the 1980’s and 1990’s (Margolin, 1997; Stanton & Marsden, 1997; Wagstaff, 1999; Davis, 2001; Higgins & Koucky, 2002; Anon, 2003; Fowler, 2003; Ross, 2003; Lee, 2003; Daniels, 2005; Kendall, 2005). The rst true drive by wire system to come to the market was Throttle By Wire (TBW) which was incorporated in high end vehicles such as Audi A6, Mercedes Benz, Lexus, and BMW models in the late 1990’s and early 2000’s. The TBW systems were advantageous in stability control applications where the throttle deactivation may be needed in order to improve the traction so that sufcient brake torque can be generated. Electro-hydraulic brake (EHB) system, a form of brake by wire (BBW), was rst introduced in Mercedes Benz SL series in 2001-02 (Higgins & Koucky, 2002). Although hydraulically actuated, these brakes operate on commands from sensors at the brake pedal and generate the necessary brake pressure at the wheel cylinders via a set of electronically controlled valves and a pump. However, the brake by wire system was decom- missioned and removed from the vehicle due to a number of eld problems a few years later. Work on the electro-mechanical brakes (EMB), another form of brake by wire system that does not use hydraulic uid, was done in the late 1990’s by number of automotive companies such as Bosch, Continental, and TRW. However, issues related to their reliability and fault tolerance still remain which must be addressed before these system can be used in an automobile. Steer by wire (SBW) system is by far the most complex drive by wire system which is also the most safety critical by-wire system in an automo- bile. In a pure steer by wire system, the steering column is eliminated. Sensors mounted on the steering wheel are interpreted by the controller to generate the correct amount of road wheel angle using electric motors based on the vehicle velocity. If a sensor stops functioning properly, the controller will not be able to actuate the motors to generate the correct road wheel angle, potentially causing hazardous situation. Figure 1 shows a brief chronology of the drive by wire system introduction into the modern automobile with the broadened denition (Iser- mann et al, 2002). As shown, the steer by wire system will likely be the last of the drive by wire system to be introduced in the automobile due to its complexity and safety criticality. In an even broader denition, hybrid electric vehicles, electric vehicles, and plug-in hybrid electric vehicles can also be classied as drive by wire equipped automobiles due to the electronic control of various subsystems in these vehicles. Electric vehicles (EV) by their very nature are drive by wire that is propelled by electronic control of the electric traction motor based on the sensor information from the throttle pedal. However, the steering and brakes of an EV may still be hydro- mechanically operated. In case of hybrid electric vehicle (HEV), a sophisticated microprocessor based control system channels the power ow between the internal combustion (IC) engine, the battery, the electric motor / generator, and the vehicle wheels (Lu & Hedrick, 2005). All of these functions are done via a central controller for optimal performance. Plug-in hybrid electric vehicles are very similar to hybrid electric vehicle, except that a more powerful battery extends the vehicle range in pure electric mode. This chapter is organized as follows: A more detailed coverage on drive by wire system is covered in the next section. The performance and safety benets of the drive by wire systems are il- lustrated in the following section. This is followed by the section on technological challenges and possible solutions associated with DBW system. Future trends for the DBW system is presented in the next section. Lastly, some nal thought will be presented in the conclusion section. 14 Drive by Wire Systems DRIVE BY WIRE SYSTEMS: CURRENT STATE OF THE ART Figure 2 shows a pictorial view of a number of drive by wire systems in a concept automobile. In addition to standard drive by wire systems, this concept vehicle also includes a 42V converter which is used to power the by-wire systems. With all the drive by wire systems in the vehicle which use electrical power for actuation, the electric power demand must be met using higher voltage systems. 42V power source is thought to be a compromise between high voltage requirement and safety. However, the power demand for hy- brid electric vehicles is signicantly higher due to propulsion need and hence uses a 240-300V DC power bus. An extra layer of safety in the design of such systems must be incorporated to eliminate the possibility of electrocution. In addition, for fault tolerant architecture, at least two or more such power sources are required for a DBW equipped vehicle. Figure 1. Hazard severity of failures in advanced automotive control and drive by wire systems Figure 3 illustrates the rst commercialized brake by wire system by Daimler Benz (Higgins & Koucky, 2002). This is an electro-hydraulic brake (EHB) system with mechanical backup that was installed in SL 500 model. The brake pedal displacement sensor output is used to determine the desired wheel cylinder pressure which is generated via a closed loop control system that includes a set of electro-hydraulic valves and an electric motor driven pump. This system was later recalled due to reliability issues. Since then no automakers have incorporated brake by wire systems in any of their vehicles. Figure 4 shows another concept vehicle that incorporates drive by wire systems on a hybrid electric vehicle. This concept is based on the synergy of combining a DBW system with HEV. The DBW systems can easily be powered by the HEV battery pack or the high voltage power bus. The IC engine along with the motor generator will ensure that power is always available for the DBW systems. 15 Drive by Wire Systems Figure 2. Concept drive by wire equipped vehicle Figure 3. Brake by wire equipped Mercedes Benz model SL 500 (source: Daimler Benz) 16 Drive by Wire Systems Figure 4. A drive by wire equipped hybrid electric concept vehicle Figure 5. General Motors’ HyWire concept vehicle (source: GM) 17 Drive by Wire Systems Another concept vehicle that incorporates drive by wire system in a Fuel Cell HEV (FCHEV) is illustrated in Figure 5. The concept vehicle was designed by General Motors and was codenamed “HyWire” (“Hy” for hydrogen fuel cell and “Wire” for drive by wire). GM later renamed this vehicle “FX-3” and built a prototype of this vehicle in 2006. This vehicle has fuel cell propulsion system with four wheel electric traction motors. Vehicle steering, braking, and suspension are all controlled electronically (drive by wire). Drive-By-Wire systems offer a number of benets when incorporated on a vehicle. Some of the benets are as follows: • D BW sys tems can easily be congured (via software updates) for added or tunable features such as brake pedal feel / enhanced safety via stability control. • DBW syst ems can enhance vehicle perfor- mance by prepositioning brake calipers for fast brake actuation or allowing for over- steering to enhance maneuverability. • DBW sy stems can improve fuel economy via better engine / motor / powertrain control and via regenerative braking. • DBW syst ems can offer better ergonomics such as adjustable feel at driver’s interface (steering wheel, brake / accelerator ped- als). • DBW syst ems offer better fault detection and warning to the driver which enhances the safety, reliability, and maintenance of the vehicle. • DBW syst ems are able to incorporate multi- functionality in a single system thereby mak- ing today’s advanced features (e.g. stability control systems via active steering) more cost effective in these automobiles. • SBW syst ems can not only provide these additional features, but also can free up premium packaging space by eliminating the steering column thereby enabling easy assembly of the instrument panel. • SBW syst ems also offer variable steering ratio at different vehicle speeds for additional safety. • Automa tic line keeping is possible for SBW equipped vehicle on the automated highways of the future. This feature will further en- hance safety and comfort of the driver. • Haptic steering for improved ergonomics and operator safety & performance is possible with SBW vehicles. • DBW syst ems will offer reduced overall production cost for steering systems via standardized modules and software. • BBW syst ems offers improved brake noise, vibration, and harshness (NVH) since there is no direct mechanical or hydraulic link from the pedal to the wheels. ABS pulsation in normal hydraulic brake will disappear in a BBW system. • BBW sy stems also allows for Better Comfort Level ○ Anti-Dive Algorithm • Better fuel economy through regenerative braking • Easier m aintenance ○ Less wear and tear ○ No need to turn those rotors • Extended brake life ○ No need to replace brake shoes, pads, or rotors • Better c old performance than wet brake systems • Better bra king-in-a-turn performance • Enhanced safety ○ Stability control algorithms ○ Reduction of brake fade • Enhanced cruise control on a down hill However, there are a number of challenges that a DBW system must address before full commer- cialization. These challenges are discussed in the “Technological Challenges” section. In this section, the following drive by wire systems are presented in more detail: [...]... ENHANCEMENTS AND ACTIVE SAFETY VIA DRIVE BY WIRE SYSTEMS Drive by wire systems can significantly enhance the design and performance of the vehicle active safety systems such as the collision avoidance systems, adaptive cruise control, active front steering, stability control, road condition warning Figure 10a-b illustrates trend of incorporation of various active safety systems in automobiles and driver... WIRE SYSTEMS AND POSSIBLE SOLUTIONS The explosion of the usage of the electronic control systems is nowhere more apparent than in the modern automobiles During the last two decades, advances in electronics have revolutionized many aspects of automotive engineering, especially in the areas of engine combustion management and vehicle safety systems such as anti-lock brakes Drive by Wire Systems (ABS) and. .. friction brake system Steer B y Wire (SBW) Systems Steer by wire systems are in the early stage of development Major automakers are yet to decide if and when such system will be incorporated in a vehicle Similar to the brake by wire systems, SBW systems use microcontrollers to actuate the road wheel in the lateral direction based on the hand wheel steering angle and vehicle speed information Figure 9 illustrates... improved performance, safety and reliability with reduced manufacturing and operational costs However, only recently has the electronic revolution begun to find its way into automotive chassis systems in the form of electronically controlled variable assist and, within the past few years, fully electric power assist The complexity of the DBW systems arises from the fact that these systems must incorporate... to the market Cost and reliability are two major challenges facing these systems While reliability of these systems can be improved via increased redundancy and fault tolerant control algorithms and communication protocols, the physical redundancy of components makes these systems prohibitively expensive In this section, we highlight the major challenges facing the drive by wire systems including cost,... Systems Figure 7 TBW system interface with ABS / TCS / YSC active safety systems Brake B y Wire (BBW) Systems Brake by wire systems can be classified in three main categories, based on the type of actuation system, as stated below: 1 2 3 Electro-hydraulic (EH) BBW systems Electromechanical (EM) BBW systems Electromagnetic (EMg) BBW systems (Regenerative braking via electric generator or Eddy Current braking)... controllers, and communications networks to achieve fault tolerance The fault tolerant control of these systems is accomplished via appropriate fault detection, isolation, and accommodation (FDIA) algorithms However, the total number of redundant components makes the DBW systems prohibitively expensive Also, in order to accurately detect and isolate a component failure without raising any false alarms, fast and. .. obviously by design which ensures a fault tolerant operation Of the three drive by wire systems presented above, both BBW and SBW systems are considered safety critical systems which 22 means that any failure of the system may lead to catastrophic consequences As a result, these systems must be designed to withstand multiple faults or failures within the system, before reaching conditions of catastrophic... sample failures or by the use of some more complex logical procedure One major difference between pure DBW systems and other electronically controlled vehicle systems is that even if these control systems fail, the basic functionality of the brake and steering system remains intact In case of DBW systems, a component failure can result in loss of function- ality unless the DBW system has redundancy in... basic mechanical system (e.g steering or braking) and hence cannot be justified from a cost standpoint Following the example of fly by wire systems, it is only natural to focus on drive by wire system without mechanical backup However, DBW systems are microprocessor-based control system based on sensor inputs and electronically controlled actuation systems (via communication bus) which call for fault . communications. AUTOSAR AUTomotive Open System ARchitecture (AU- TOSAR, 2008) is a partnership of automotive manufacturers and suppliers working together to develop and establish an open and standard auto- motive. drive by wire systems are presented in more detail: 18 Drive by Wire Systems 1. Throttle By Wire Systems 2. Brake By Wire Systems 3. Steer By wire Systems Throttle by Wire (TBW) Systems For traction. drive by systems such as throttle-by-wire, brake-by-wire, and steer-by-wire systems, and hybrid-electric propul- sion. A review of drive by wire system benets in performance enhancements and vehicle