1、 毕业设计说明书（英文翻译）英文 Rollover countermeasures; Intersection collision countermeasures; Rear impact countermeasures; Backup/parking assist; Pedestrian detection and warning; Degraded driving; Driver impairment monitoring; Road surface condition monitoring; Precrash; Prearming airbags; Occupant sensing (t
2、o inform airbag deployment); Seatbelt pretensioning; Precharging of brakes; External vehicle speed control.1.1.1 Assisting Driver PerceptionIV systems can enhance the drivers perception of the driving environment, leaving any interpretation or action to the drivers judgment. Adaptive headlights prov
3、ide better illumination when the vehicle is turning; night vision provides an enriched view of the forward scene; roadside systems can alert drivers to the presence of wildlife; and headway advisory provides advice to the driver regarding following distance.Adaptive Front Lighting (AFS) Adaptive hea
4、dlights illuminate areas ahead and to the side of the vehicle path in a manner intended to optimize nighttime visibility for the driver. Basic systems, already on the market, take into account the vehicle speed to make assumptions as to the desired illumination pattern. For instance, beam patterns a
5、djust down and outward for low-speed driving, while light distribution is longer and narrower at high speeds to increase visibility at farther distances. More advanced systems also incorporate steering-angle data and auxiliary headlights on motorized swivels. In the case of a vehicle turning a corne
6、r, for example, the outer headlight maintains a straight beam pattern while the inner, auxiliary headlight beam illuminates the upcoming turn. The system aims to automatically deliver a light beam of optimal intensity to maximize the illumination of oncoming road curves and bends. Next generation ad
7、aptive lighting systems will use satellite positioning and digital maps so as to have preview information on upcoming curves. Headlights are then aimed into the curve even before the vehicle reaches the curve, at just the right point in the maneuver, to present the driver an optimal view.Night Visio
8、n Night vision systems help the driver see objects such as pedestrians and animals on the road or the road edge, far beyond the view of the vehicles headlights. Typically this is displayed via a heads-up display. Advanced forms of night vision process the image to identify potential hazards and high
9、light them on the displayed image.Animal Warning Obviously, not all cars have night vision systems. To provide alerts to wildlife near roads for all drivers, road authorities are experimenting with roadside sensors that detect wildlife such as deer and elk in areas where they are known to be frequen
10、tly active. If animals are present, drivers are advised by electronic signs as they approach the area.Headway Advisory The headway advisory function, also called safe gap advisory,monitors the distance and time headway to a preceding vehicle to provide continuous feedback to the driver. Gap threshol
11、ds can be applied to indicate to the driver when safety is compromised. Fundamentally, headway advisory performs the sensing job of ACC without the automatic control.1.1.2 Crash PreventionThe following sections describe crash prevention systems in various stages of development.Some are in the R&D st
12、ages, while others have been introduced to the public as optional equipment on new cars.Forward Collision Warning/Mitigation/Avoidance IV safety systems augment the drivers monitoring of the road and traffic conditions to detect imminent crash conditions. Systems to prevent forward collisions rely o
13、n radar or lidar sensing, sometimes augmented by machine vision. Basic systems provide a warning to the driver, using a variety of means such as audible alerts, visual alerts (typically on a heads-up display), seat vibration, or even slight seat-belt tensioning to provide a haptic cue. More advanced
14、 systems add automatic braking of the vehicle if the driver is not responding to the situation. An initial version of active braking systems is termed “collision mitigation system.” These systems primarily defer to the drivers control; braking serves only to reduce the impact velocity of a collision
15、 if the driver is not responding appropriately to an imminent crash situation. Collision mitigation systems were originally introduced to the market in Japan in 2003. The next functional level, forward collision avoidance, represents the ultimate crash avoidance system, in which sufficient braking i
16、s provided to avoid the crash altogether.Lane Departure Warning Systems (LDWS) LDWS use machine vision techniques to monitor the lateral position of the vehicle within its lane. Computer algorithms process the video image to “see” the road markings and gauge the vehicles position within them. The dr
17、iver is warned if the vehicle starts to leave the lane inadvertently (i.e., turn signal not activated). A favored driver interface is to emulate the “rumble strip” experience by providing a low rumbling sound on the left or right audio speaker, as appropriate to the direction of the lane departure.
18、LDWS were initially sold in the heavy truck market; they were first introduced to the public in Japan and entered the European and U.S. automobile markets in 2004.Lane/Road Departure Avoidance (RDA) Lane departure avoidance systems go one step farther than LDWS by providing active steering to keep t
19、he vehicle in the lane (while alerting the driver to the situation). In the case of RDA, advanced systems assess factors such as shoulder width to adjust the driver alert based on the criticality of the situation. For instance, a vehicle drifting onto a wide, smooth road shoulder is a relatively ben
20、ign event compared to the same situation with no shoulder. Prototypes of such RDA systems are currently being evaluated.Curve Speed Warning Curve speed warning is another form of road departure avoidance that uses digital maps and satellite positioning to assess a safe speed threshold for an upcomin
21、g curve in the roadway. The driver is warned if speed is excessive as the vehicle approaches the curve. Prototypes of curve speed warning systems have been built and evaluated.Side Object Warning Side object monitoring systems assist drivers in changing lanes by detecting vehicles in the “blind spot
22、” to the left rear of the vehicle (or right rear for countries such as Japan with right side driver positions and left-hand road driving). Blind spot monitoring using radar technology has been used by truckers in the United States for many years and is expected to enter the automobile market soon. F
23、igure 3.2 shows detection zones for side object awareness, as well as other applications. This is a good example of “bundling” such applications.Lane Change Support Lane change support systems extend monitoring beyond the blind spot to provide rearward sensing to assist drivers in making safe lane c
24、hanges. Advanced systems also look far upstream in adjacent lanes to detect fast approaching vehicles that may create a hazardous situation in the event of a lane change. This is especially important on high-speed motorways such as the German Autobahn. These systems are in the advanced development p
25、hase.Rollover Countermeasures Rollover countermeasures systems are designed to prevent rollovers by heavy trucks. While electronic stability control to avoid rollovers of passenger cars is becoming widely available, the vehicle dynamics for tractor trailers are very differentthe truck driver is unab
26、le to sense the initial trailer “wheels-up” condition that precedes a rollover, and rollover dynamics change with the size and consistency of the cargo. Rollover countermeasure systems approximate the center of gravity of the vehicle and dynamically assess the combination of speed and lateral accele
27、ration to warn the driver when close to a Figure 3.2 Detection zones for side object awareness and other applications. (Source: Visteon.) rollover threshold. Systems currently on the market automatically slow the vehicle to avoid the rollover event. Rollover countermeasures systems recently became a
28、vailable in the heavy truck market.Intersection Collision Countermeasures Intersection collisions represent a disproportionate amount of the fatal collisions since vehicles often collide at right angles and with significant speed. Development of intersection collision countermeasures systems represe
29、nts a significant challenge, as threat conditions often cannot be detected by vehicle sensors alone. This is because, at many intersections, crossing traffic may be obscured by buildings near the road or other vehicles. In such cases, cooperative road-vehicle systems are used: Roadside systems detec
30、t dangerous situations, such as a vehicle violating a traffic signal, and communicate that information to drivers. Initial systems will warn drivers via roadside signs, and more advanced future systems will also provide the information on in-vehicle displays when communications connectivity is avail
31、able in vehicles. Another approach to ICA calls for vehicles to communicate their direction and speed to each other as they approach an intersection, with processing and interpretation of that data occurring onboard each vehicle to assess any hazards. In this case, no roadside infrastructure is invo
32、lved. All such intersection collision countermeasures are currently in the research stage.Rear Impact Countermeasures Rear impacts are a particular problem for transit buses that make passenger stops on busy city or suburban streets where other traffic would not normally stop. These buses are suscep
33、tible to being struck from behind by following vehicles whose drivers are inattentive. Since the bus is most at risk, rear impact countermeasures rely upon sensing hardware on the rear of the bus to detect fast closing vehicles. When this situation is detected, vivid warning flashers are activated t
34、oit is hopedattract the following drivers attention in time to avoid a crash.Backup/Parking Assist Backup/parking assist systems were described in the convenience systems section, but they can also play a role in avoiding the tragic accidents that occur when small children, who cannot be seen by the
35、 driver, are struck by a backing vehicle. Backup assist systems under development use radar or infrared technology to detect children or animals behind the vehicle and highlight this on a video display of the rearward view. Such systems are still several years away from market introduction.Pedestria
36、n Detection and Warning Pedestrian detection systems are most useful in urban city centers, where pedestrians are walking near traffic and could decide at any time or place to cross the street. In these situations, sensing systems, typically based on machine vision, must perform real-time processing
37、 to detect pedestrians, monitor their movements, and assess the potential danger when pedestrians enter the roadway. Robust detection of pedestrians while avoiding false alarms presents a major challenge to the technical community; nevertheless, steady progress is being made, and first generation sy
38、stems are in advanced development.1.1.3 Degraded DrivingIn degraded driving conditions, the driver is impaired (due to alcohol or fatigue, for example), or the road surface may be degraded, typically due to inclement weather. Driver Impairment Monitoring Impaired driver detection has been the subjec
39、t of extensive scientific study. Basic systems that can detect severe drowsiness have been developed using various methods. Monitoring of lane-tracking behavior, steering inputs by the driver, head movements, and eyelid movements are among the primary methods examined. A key challenge is to detect t
40、he early signs of the onset of drowsiness, so that a driver can effectively respond to a warning before drowsiness is severe. These systems can take the form of a “fatigue meter” that provides continuous feedback to the driver, or a warning that sounds when dangerous fatigue conditions are detected.
41、 Basic driver drowsiness monitors were on the market in Japan for a short time during the 1980s. First generation products targeted at long-haul truck drivers are currently being sold in the aftermarket, and driver-monitoring products are currently in development for the automobile market.Road Surfa
42、ce Condition Monitoring Knowledge regarding degraded road surface conditions, such as wet or icy pavement, is obviously important to the driver. This information can also enable ACC systems to adjust intervehicle gaps and crash countermeasures systems to adjust warning timing based on lower traction
43、, for instance. Spot conditions can be detected to some degree by vehicle systems such as anti-lock braking and traction control, but the ideal case is to have advance knowledge. Such advance warning can be provided by roadside detectors that send messages to the vehicle, or from other vehicles thro
44、ugh floating car data techniques or vehicle-vehicle communications.1.1.4 PrecrashThe precrash domain refers to the case where sensing systems (typically using ACC sensors) have determined that a crash is inevitable; therefore, action is taken to optimally protect the vehicle occupants via seatbelt p
45、retensioning and prearming or prefiring airbags. In addition, the braking system can be precharged so that maximum braking force is provided immediately upon initiation by the driver. Precrash systems are generally seen as precursors to more advanced collision avoidance systems, as a bridge between
46、occupant protection measures, which are very mature technologically, and crash avoidance measures, which are in earlier stages of development and product maturity.1.1.5 External Vehicle Speed Control (EVSC)EVSC, also called intelligent speed adaptation (ISA), assists drivers in keeping the vehicles
47、speed to the government-defined speed limit.Proponents of EVSC include residents of small towns through which highways pass. Too often, long-distance drivers do not slow down sufficiently when entering the town, creating safety concerns for residents. Residents of urban neighborhoods have similar co
48、ncerns when their roads are used as “shortcuts” by commuters to avoid traffic jams on major roadways. More generally, government initiatives to totally eliminate traffic fatalities include a strong component to keep vehicle speeds to the legal limit.The emerging EVSC approach is to use onboard satel
49、lite positioning working in conjunction with a digital map database that includes speed limits for the road network. Via an active accelerator pedal, the vehicle will automatically “resist” attempts to drive faster than the speed limit; however, the system can be overridden in the case.中文防止车翻转的措施;防止十字路口碰撞的措施;防止后部冲击碰撞的措施；备份/停车协助;行人检测和预警;退化驾驶;驱动减值监测;路面状态监测;碰撞预警;Prearming安全气囊;乘员感应（告知安全气囊）;安全带预拉伸；预加压的制动器；外部车速控制。1.1.1 提高驾驶员的觉察力IV系统可
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