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AFS is initially the name of the European Eureka project that was started in 1993. Its main target was to improve regulations as the front lighting systems evolve. Since 2003, legislation has evolved to include Adaptive Front light Systems (AFS), and is starting to include additional features to improve visibility and safety. The aim of AFS is to adapt light distribution on to the road to give optimum lighting performance in a range of driving situations. The lighting systems have evolved from traditional light sources in headlamps to more complex designs using lighting modules that create several illumination profiles.
15 AFS is initially the name of the European Eureka project that was started in 1993 Its main target was to improve regulations as the front lighting systems evolve Since 2003, legislation has evolved to include Adaptive Front light Systems (AFS), and is starting to include additional features to improve visibility and safety The aim of AFS is to adapt light distribution on to the road to give optimum lighting performance in a range of driving situations AFS - Adaptive Front Lighting Systems 15.1.1 Fixed Bending Light One of the most important features of a headlamp with adaptive light distribution is the improved side illumination for driving situations in towns, at intersections and in small radius curves Fixed or static Bending Light consists of an additional complex reflective surface or elliptical module in the headlamp that is operated when turning The function is activated according to the steering wheel angle The lighting systems have evolved from traditional light sources in headlamps to more complex designs using lighting modules that create several illumination profiles 35° to 40° 15.1 Bending lights The very first generation of AFS focussed on bending lights l Fixed Bending Light (FBL) and cornering light l Dynamic Bending Light (DBL) The first FBL in the world was equipped by Valeo on the Porsche Cayenne with an additional elliptical module inside the headlamp Headlamp for Porsche - Cayenne with FBL technology 61 15 AFS - Adaptive Front Lighting Systems 15.1.2 Cornering 15.1.3 Dynamic Bending Light The cornering beam is dedicated to corner / bend visibility, it covers a wider angle than the Fixed Bending Light The function is switched on when: l The driver activates the turn indicator l Or the driver turns the steering wheel l Car speed is under 40 km/h The Dynamic Bending Light (DBL) function is operated by using a lighting module that can direct the beam pattern within an angular range according to the steering wheel angle The module rotates from left to right in the horizontal axis of the car, but the aiming of the beam (vertical axis of the car) is not part of the DBL feature The DBL is often fitted in conjunction with Xenon or LED lamps However, one Halogen DBL product is supplied by Valeo for the Opel / Vauxhall Corsa D headlamp > 60° To implement a cornering function, Valeo applies this technology in two different ways: l Inside the headlamp l Inside the foglamp Headlamp for Citroën - C5 with cornering technology in the headlamp Headlamp for Opel / Vauxhall Corsa D with DBL technology and Halogen H9B lamp Foglamp for BMW - X3 with cornering technology in the foglamp 62 With conventional headlamp High headlamp aimed at -1,5% 43m 60m 93m +44% v to Dyna In normal condition, it is considered that the visibility distance is 50 m With DBL headlamp +44% visibility in curves thanks to Dynamic Bending Light! 63 15 AFS - Adaptive Front Lighting Systems 15.2 Full Adaptive Front Lighting “Full AFS” A lot of the improvements in vehicles are based on driving comfort and safety, there have been major developments in this field, such as ABS braking systems, stability controls, air bags, etc Over the last decade there have been as well significant improvements in lighting systems to improve visibility and braking distances Since 2006 the AFS has improved a lot providing more features Traditional low beams using Halogen or Gas Discharge (HID) light sources not provide sufficient illumination to allow a safe braking distance For example, the emergency braking distance of a vehicle driving at 100 km/h (60 mph) including the human reaction time is at least 50-60 meters The system automatically adapts light distribution according to the position of the preceding and oncoming traffic A standard low beam system with a cut-off inclination of 1% can provide illumination up to a distance of about 25-30 meters A new standard was set in 2004 to cope with this need, it defined the concept of “Long-Distance Illumination without Glaring (Dazzling) Effects” The aim of long-distance illumination is a new type of low beam which enables continuous illumination for a safe braking distance of approximately 60-70 meters An adaptive “cut-off line” provides illumination for a safe braking distance, without causing any dazzling effect on other road users, and enables safe and comfortable night driving 64 Full AFS technology allows drivers to benefit from optimum visibility under all conditions, reducing the stress of driving at night and improves visual comfort and safety Full AFS introduces a new era of light distribution for several typical driving situations and adapts the beam according to: l Road type l Road conditions l Weather conditions l Drivers actions (side indicator/steering wheel) Full AFS classes of light distributions Town beam Adverse weather beam Highway beam Low beam with cornering light 15.2.1 Full AFS for the Audi Q7 Always at the forefront of technology, Valeo is supplying Audi with the range-topping 2009 version of the Q7, AFS Tri-Xenon headlights that combine high beam, low beam and highway functions with LED based DRL (Daytime Running Lamps) Valeo’s full AFS for the 2009 Audi Q7 The entire range of Audi Q7 headlights (Halogen, dual-function Xenon and AFS Tri-Xenon) is available in the aftermarket Headlamp for AUDI - Q7 with Tri-Xenon AFS technology 65 15 AFS - Adaptive Front Lighting Systems 15.2.2 Automatic operation of the AFS The first generation of adptative systems permitted to improve visibility by directing illumination on the road, complementary to this the AFS system is able to vary the beam cut-off in small increments by using electrical actuator motors Valeo’s “Full AFS” solution is based on a Tri-function module providing light beams: Lighting modules are able to create dedicated illumination profiles (classes) by combining several features such as: l Motorway beam l Right beam motion – horizontal and vertical l Low beam l High beam Horizontal rotation l Left beam motion – horizontal and vertical l Aiming control l Cut-off diversity Xenon lighting module Vertical rotation 66 15.2.3 AFS - Classes and Modes By mixing a combination of main beams and automatic levelling positions the system is allowed to create additional functions: l Town lighting l Adverse weather beam (wet road) l Tourist beam (beam adaptation to avoid glare when driving abroad) The term “class” defines main beam patterns (C/V/ E/W/T) The term, “mode” defines conditions or events when driving requires the lighting system to adapt to a class or to switch from one class to another by adapting the beam profile AFS systems continuously adapt the illumination on the road according to the ongoing mode The system is designed to be adaptive by using control signals guided by sensors which are capable of detecting and reacting to each of the following inputs: l Ambient lighting conditions l The light emitted by the front lighting and front signalling systems of oncoming vehicles l The light emitted by the rear lighting of preceding vehicles; additional sensors may be used to improve the system’s performance The changes within and between classes and their modes of AFS lighting functions are performed automatically without causing discomfort, distraction or glare, neither for the driver or for other road users Full AFs - Tri-function mechanism AFS are regulated and detailed in European regulations ECE R48 and ECE R123 The projector beam steps are basically categorized in passing beam classes and modes: A dedicated photometric chart has been issued for AFS It is based on the Xenon lighting systems initial chart with all provisions of new classes and their specific modes l “Classic” class C modes l “Town” class V modes l “Motorway” class E modes l “Wet road” class W modes l “Bending modes” T modes 67 15 AFS - Adaptive Front Lighting Systems 15.2.3.1 Classic beam This beam is the low beam; it is the default pattern of the AFS system “classic” class C modes – beam on the road The “classic” class C mode(s) of the low beam shall be activated if no mode of another low beam class is activated; it is also called “Neutral state” “classic” class C modes – H/V aiming LH axis -1% 60 lux -2% -12° 68 RH axis -9° -6° -3° -12° -VV -9° +3°° -6° 60 lux +6° -3° +9° -VV +12° +3°° +6° +9° +12° 15.2.3.2 Town beam The town beam offers a wider beam pattern for sidewalks visibility with increased foreground and reduced hot spot (less glaring effect) “Classic” class C modes – beam on the road The “town” class V mode(s) of the passing beam shall not operate unless one or more of the following conditions is/are automatically detected: l Roads in built-up areas l Vehicle’s speed not exceeding 50 km/h l Roads equipped with a fixed road illumination l A road surface luminance of cd/m2 and/or a horizontal road illumination of 10 lux being exceeded continuously “town” class V modes – H/V aiming LH axis RH axis L module moved 8° Left R module moved 5° Right -1% 60 lux -2% 60 lux -12° -9° -6° -3° -12° -VV -9° +3°° -6° +6° -3° +9° -VV +12° +3°° +6° +9° +12° 69 15 AFS - Adaptive Front Lighting Systems 15.2.3.3 Motorway beam The motorway beam offers: l An improved visibility distance, up to 120 m, without glaring other vehicles l A doubled intensity (120 lux) comparing to maximum possible intensity of the low beam l An increased light-range by 60 meters The class E mode of the passing beam (motorway light) has a higher luminous intensity and a raised cut-off offering increased forward visibility for the driver To avoid glaring other road users it is only operated on roads where the traffic direction is separated by means of road construction, or, a sufficient lateral separation of opposing traffic is identified, a typical motorway condition New technology based on sensors such as camera systems and GPS navigation can provide accurate information to determine if motorway conditions are fulfilled regardless of vehicle speed l The “motorway” class E mode(s) of the passing beam shall not operate unless the vehicle’s speed exceeds 70 km/h and the road characteristics corresponding to motorway conditions are automatically detected 70 “Motorway” class E modes – beam on the road In case of the following modes of class E, the cut-off aiming is adapted to the speed level The vehicle’s speed exceeds 100 km/h, the cut-off is set to 0.59% (0.34°) for a maximum Illumination range The vehicle’s speed exceeds 90 km/h the cut-off is adjusted to 0.78% (0.45°) for a medium Illumination range The vehicle’s speed exceeds 80 km/h the cut-off is pulled down to 1% (0.57°) to avoid glare of opposing and oncoming vehicles 1404 KSME International Journal, Vol 16 No 11, pp 1404~ 1411, 2002 Auto-Leveling of HID Headlamp Using Preview Control Boojoong Yong* School of Mechanical Engineering, Kyungil University, Kyungsan 712-701, Korea Heeyong Kang, Sungmo Yang School of Mechanical Engineering, Chonbuk National University, Chonju, Chonbuk 561-756, Korea A newly developed high intensity discharge (HID) automotive headlamp results in a high luminous gradient at the cutoff line, and proves the superior concept in safer and more comfortable nighttime driving This new headlamp technology provides drivers expanded night vision by a significantly improved light pattern However, the HID headlamp may dazzle other traffics during traversing a rough road or encountering an unexpected bump To resolve this problem, an automatic headlamp leveling device is necessary A preview control is presented for the design of the leveling system The proposed control algorithm is capable of attenuating a dynamic glare which is one of the major detractors to a driving in dark roads Computer simulations using ADAMS are carried out to confirm the effectiveness on the control system Key Words : High Intensity Discharge (HID), Vertical Cutoff, Auto-Leveling, Preview Control I Introduction For decades automobile lighting designers have tried to develop brighter and more efficient automotive headlamps A new electronic headlamp system, Litronic (light and electronic) or Xenon headlamp, has been available since 1991 (Huhn, 1995) The light from a high intensity discharge (HID) headlamp, which is closer to the hue of natural light and thus is thought to be better at illuminating a night road, comes from an electrode-ignited Xenon atmosphere Providing good quality light patterns, the HID headlamp has intrinsic advantages-high luminous efficiency as well as low power consumption Better visibility and visual guidance will essentially enhance driver's safety and comfort during nighttime driving According to Brussels-based Eureka project, a European program for the promotion of research * Corresponding Author, E-mail : yongb@asme.org TEL : -t-82-53-850-7128;FAX : +82-53-850-7601 School of Mechanical Engineering, Kyungil University, Kyungsan 712-701, Korea (Manuscript Received January 12, 2002;RevisedJuly 31, 2002) and development, the HID headlamp system is expected to be a European standard within a few years (Sharke, 2001) However, it is noted that the dynamic glare occurs as vehicles change attitude during strong braking or when traversing rough roads As lighting systems evolve, many complaints about the glare claim that the HID headlamp is too bright to those of opposing or preceding traffics Vertical aim, along with beam pattern and light source, is found to be one of the most important factors in influencing the headlamp performance The European light pattern and its philosophy are well summarized by Sharke (2001) Imagine a line that runs straight out from a headlamp to a wall, and a point where the line hits the wall Then, light patterns exhibit a sharp line at the point between the bright lower part of the beam and the dark upper part The sharp line on the light pattern is called vertical cutoff Conventional headlamps beam virtually no light above the vertical cutoff, so they are less capable of illuminating overhead signs This downward aim with respect to the sharp vertical cutoff is partly due to a desire of minimizing the dynamic glare While Auto Leveling o f HID Headlamp Using Preview Control low-glare headlamps may solve the problem, they would shorten a driver's visibility on the night road To blend the best of both conventional headlamps and HID lamps, lighting engineers introduced a new design concept in headlamp systems, that is, an auto-leveling The automatic leveling system for headlamps prevents blinding a passing motorist As European standards mandate the auto-leveling for HID headlamps, in most countries, it is expected that the self-leveling device will be a requirement for an advanced front lighting Among several control schemes, a preview control can be considered for the design of an auto-leveling system The finite preview control can be realized practically in many applications, for example, with ' l o o k - a h e a d ' sensors in robotics or in active suspensions for automotives, etc Yong (1997) applied the preview control to a contour-following of an industrial robot using a robot force control To improve the ride comfort of automobiles, several studies using a preview control method are proposed Bender (1968) found the optimal preview control by Wiener filter theory for a single degree of freedom vehicle model Tomizuka (1976) applied continuous and discrete optimal preview control to a vehicle suspension system, while Foag (1988) proposed a preview control for an active suspension Guo and Tomizuka (1997) proposed an optimization scheme for the hybrid feedforward controller in high-speed and high-precision digital motion control systems This study investigates an application of preview control to the automatic leveling of HID headlamps Preview information about the road profile ahead of the vehicle is utilized to attenuate leveling disturbances against oncoming or preceding vehicles In Section 2, we discuss HID headlamps and illuminating disturbances Next, the design of the disturbance rejection controller based on the preview control algorithm is proposed in Section In Section 4, assuming an optical preview sensor installed at the front bumper of a vehicle, computer simulations examine the preview control effects The results are compared with a conventional headlamp without an 1405 auto-leveling, and the performance is verified Finally, we conclude in Section 2.High Intensity Discharge Headlamps (Huhn, 1995 ; Hege, et al., 1996 ; Sharke, 2001) The HID headlamp uses the similar mechanical and electrical interfaces as does the standard all halogen equipped projector type headlamp Reflector, shade, lens holder, and lens itself are forming a closed and rigid cage around the HID bulb In general, the main light output is accomplished by a lens with a diameter of 60mm Adding an outer ring, reflector will enlarge the illuminated area for a more conventional signal image of the headlamp The detail structure of HID headlamp system can be found in Hege, et a1.(1996) The low beam headlamps only are equipped with the superior HID systems, as in standard traffic situations more than 90% of the driving takes place with dipped headlamps The HID light is very distinct by its different color, and the driver's eyes accept the blueish-white as white in driving practice This makes it attractive by an innovative appearance It was reported that the tested HID systems had very wide illumination angles This provided good visual guidance and good orientation to the driver in various traffic situations, such as nighttime driving, fog, snow, or rain condition Limitation of maximum illumination values together with the later-on described automatic leveling system prevents glare to other traffics For the well known conventional headlamps, there exist environmental and lighting requirements With the introduction of new HID headlamps, a complex high voltage driven system in the car's front end emerges Therefore, some new requirements have to be added such as safety, electrical conditions, and system lifetime, etc In this study, we consider only the requirement in safety aspects during driving situations, i.e., the vertical aiming in light pattern Eureka project defined requirements for advanced headlamp systems through industries At least one existing regulation already calls for European regulations governing discharge light- 1406 Boojoong Yong, Heeyong Kang and Sungmo Yang ing Among the notable results of the project, lighting that reduced glare on wet or dark roads helped both the drivers of cars equipped with HID headlamps and the drivers of opposing vehicles It was also found that the more intense a glare, the more it disturbed oncoming drivers; the size of the light source affected the level of discomfort After sources were normalized to the same luminous intensity, the researchers discovered that small areas of the glare were more disturbing than large ones As much as dynamic glare, momentary flashes also disturbed opposing drivers more as their duration increased Light pulses lasting less than a half-second were generally tolerated Those lasting longer than eight to ten seconds degraded visual performance, because it took longer time for eyes to readapt to lower light levels once the pulse ceased The efforts for reducing lighting discomfort can be realized by the auto-leveling system The hardware may comprise: sensor on the front and/ or rear axles, electronic control unit, stepper or DC motor inside of each headlamp This system prevents the glare and short visibility distances, provided that the headlamp aiming is correct Auto-Leveling using Preview Control In cars with very soft suspension, while driving a rough road or encountering a sudden bump, the oscillatory and higher vertical aiming may disturb oncoming and preceding traffics Although a stiffer suspension will reduce such effects, the better solution for the problems is to employ an automatic headlamp leveling system Furthermore, if we can apply a preview control algorithm, the controller may take into consideration the 'look-ahead' leveling disturbance source to the system The preview control prescribes the inclusion of the modes of the disturbances from the preview sensor 3.1 System description Similar to Nagiri et al (1992), Fig shows a vehicle model illustrating the concept of preview control The control system is constructed of an , PreviewLoop I C°ntr°ller ~ Conta'olSi~al~ _.x I Feedbackl IPreviewA.Sensor [ L elin ~ ,~o~Surfaee LevelingDevice Fig Auto-Leveling using preview control ordinary feedback loop and a feedforward preview loop The feedback loop consists of leveling sensors, a feedback controller, an actuator, etc The leveling sensors can be implemented on the front/rear axle or suspension system The vertical cutoff level of lighting will be controlled to attain the set value, i.e., the zero level In general, the magnitude and phase of the disturbance input to a control system are not known in advance If information about the disturbance is obtained a priori, it makes sense to use available knowledge of the disturbance signal for better disturbance rejection To realize this, the previewed road profile signal is provided to the feedforward controller, which is led to better leveling capabilities This will enhance the conventional leveling device so that the entire system achieves a better performance, e.g., good disturbance rejection properties in HID headlamp systems 3.2 An optimal preview control algorithm The basic idea of preview control, comparing with the LQ-optimal control principles (Lewis, 1986a), can be stated that the final time in the optimization problem is actually a moving time with a fixed time-to-go (a finite preview length) The preview control requires an artificial constraint for a constant solution of the associated Riccati equation, even for optimization problems over a finite time interval Using the constraint on the choice of performance measure, the resulting control system can be decoupled into a feedback part and a feedforward component Since the feedback loop concentrates on the system stability and robustness, determining the feedback component rather than the feedforward Auto- Leveling of HID Headlamp Using Preview Control loop is firstly motivated Ideally, the feedback component should contain the mapping from the disturbance signals to the corresponding control input, such that no system error occurs by applying this control input to the process However, as long as this mapping is not perfect, system errors occur and the feedforward controller is necessary to enhance the disturbance rejection capabilities Accordingly, the feedforward controller will be designed based on the determined feedback gains Theoretically, the feedforward preview control has no effect on the system stability, because it is placed outside of the basic feedback loop However, the feedforward structure also incorporates a contribution to the feedback loop, caused by the fact that any error signal will be based on measurements of a process output This means that the feedforward control with inaccurate preview information may cause stability problems a n d / o r saturation of actuators 3.3 Controller design For designing the control system, it is required to obtain the angular positioning dynamics of the leveling device Since the leveling system should compensate the leveling error caused by a pitching motion of an automobile, it is desirable that the dynamics of the leveling device is close to the pitching mode of the vehicle Therefore, we analyzed the dynamics according to Inman (1994), and the resulting model in the discrete domain can be represented by °'1464z-l+°1211z-2 Fd -l /1) G (z) : l - 1.3019z -1 +0.5694z -2 ldeg J where z indicates a Z-transform variable The preview control algorithm requires a parametric model of the plant The model of the leveling system (1) can be transformed to the discrete state-space representation such as x ( k + 1) = x ( k ) + F u ( k ) y(k) = H x ( k ) (2) where x(k) is a state vector, u(k) is a control input, y(k) is a system output, ~ is a system matrix, F i s an input vector, and H is an output vector 1407 Using a preview sensor, we anticipate the disturbance signals from a road profile such that p ( k ) - = [ p ( k + l ) p ( k + ) " p(k+Np)] r (3) where E'1 r denotes the transpose of [ 1, and Np indicates a finite preview length This preview information will be incorporated into the preview servo model The controller processing interval time will determine the duration of a preview step A performance index is also necessary to design the preview controller A typical performance index can be defined by 1(i): 1~ k=i [e2(k) Q + u Z ( k ) R (4) where e(k) represents a leveling error, R and Q are positive scalar weighting factors Q in the cost function penalizes the error quantity and R penalizes large values of the control input With the given performance index, the optimal feedback controller, K, and the feedforward preview controller, Kpr, will be designed after some mathematical manipulation presented in Yong (1997) Then, the control input, u ( k ) , for the leveling system yields u (k) = - K x (k) - K p r p ( k ) (5) The optimal feedback component assures a good system dynamic performance as well as a closed-loop system stability To determine the feedback gains, a proper choice of the weighting factor ratio, p c : Q / R , in the defined performance index provides a good transient performance The higher weighting factor ratio, the lower damping ratio - it yields higher percent overshoot, and the system presents unstable behavior Decreasing the weighting factor ratio stabilizes the control system, but implies some loss of performance as well We applied pc=6000 for the most reasonable performance in simulations, and the corresponding feedback gains and 5-step preview gains are K = [8.3646 6.54941 K : [ - -0.6761 0.5075 0.2983 0.08751 (6) The preview component is equipped to acquire and utilize the knowledge of the road profile Boojoong Yong, Heeyong Kang and Sungmo Yang 1408 disturbance signal, which is not taken into account (quantitatively) in the feedback design, so that the system performance is optimized during control In order to determine appropriate preview steps, it is necessary to repeat the design process iteratively In this investigation, 5-steps of preview is found to cancel the disturbance effectively This agrees with simulations performed in the next section Usually the full system state, x ( k ) , is not directly accessible, thus a state estimator is required in the feedback loop Considering noise effects on the system, an optimal estimator can be found by defining the following linear time-invariant discrete-time estimator model, x ( k + 1) = ~ x (k) + F u ( k ) +Fww (k) y(k) = H x ( k ) +v(k) (7) where v(k) represents an actual measurement noise, and w(k) is a pseudo process noise whose assumed intensity is used in filter tuning Suppose that w(k) and v(k) are random white noise sequences with zero mean, i.e., E [ w ( k ) ] = E [ v (k)] =0 Here, E [ ' ] denotes an expected value or mean value of E'] Also assume that w (k) and v(k) are uncorrelated with each other and normal, and have covariances defined by E[w2(k) ]=Rw, E[v2(k) l=Rv (8) Then, an optimal estimator gain will be determined corresponding to gw and gv If we feed back the error signal, e(k), we can obtain the estimated state vector i ( k ) such as ~(k) = ~ ( k ) + L { e(k) -H£(k) } +Fu(k) Fig [ Block diagram of auto-leveling system L=[0.9919 0.7105] r (ll) Figure shows an entire control system with the preview control method including the optimal estimator, where r (k) indicates the desired vertical level (zero leveling), and y ( k ) represents the actual vertical aiming The dashed lines indicate the injection and observation of the road profile through the preview controller From Fig 2, it becomes clear how the feedforward component is incorporated with a feedback loop The controller for leveling disturbance rejection herein is implemented in a 'plug-in' fashion, meaning the feedforward compensator using the preview control scheme is used to augment the conventional servo If the preview control is excluded, the control system results in a pure optimal feedback control or an LQG-controller In this case, the auto-leveling system will only take account of instant leveling error signal relative offset of the front axle with respect to the rear axle When a vehicle experiences fast acceleration or strong braking, the auto-leveler is supposed to be activated solely by the feedback compensator, since no preview information is available (9) where L is the constant estimator gain obtained by error covariance propagation (Lewis, 1986b), and ~(k) is the time updated state from z i ( k + ) = a)~(k) Preview (10) Note that the noise covariance ratio, pe=Rw/Rv, plays a major role to design the optimal estimator Since actual process noise variance is not available, the gain should be determined so that the filter removes the undesired oscillation without introducing too much lag and slowing the response In this analysis, we found pe=5000 is the appropriate ratio, which results in Simulation Results and Discussions Computer simulations using ADAMS, the commercial multibody dynamic analysis program, are carried out when a vehicle encounters bumps at the vehicle traveling speed of 20 Km/h Considering a simple two degree-of-freedom model of the passenger vehicle, we analyzed the motion in the plane of symmetry of the automobile (Inman, 1994) Although the motion of the vehicle includes both bouncing and pitching, we concerned only the pitching behavior in this investigation The profile of bumps in a paved road is described Auto- Levering o f HID Headlamp Using Preview Control t,,interv~_,_l ~ Fig !.5 1.0' width Bump profile in a road I "7" oJ 0.5 0.0' 1.5 =_ ,, :, i 1.0" 1409 -0.5 "d -1.0" 0.5 %, _ 0.0" -I 5' -2.0 ~ -0.5' •~ -1.0Fig -1.5, time (sec.) Traversing sequential bumps (interval: 1.0 m) without auto-leveler -2.0 0.3" time (see.) Fig vertical aiming using LQG-control 0.2~ Encountering a bump without auto-leveler 0.1 0.3vertical aiming using LQG-control 0.0 0.2al "-~ 0.1- -0.1' • E -0.2 0.0- vertical aiming using preview control -0.3 -0.1 J -0.2 vertical aiming using preview control -0.3 o time (see.) Traversing sequential bumps Cinterval : 1.0 m) with auto-leveler time (see.) Fig Fig Encountering a bump with auto-leveler in Fig 3, where the width and the height of bumps are 1.0 m and 0.08 m, respectively Figures present leveling responses encountering a single bump Here, the slight error profile at the earlier part of the responses reflects the aiming error caused by the vehicle acceleration The results announce that the dynamic glare without a leveling device will affect other traffics significantly On the other hand, the vertical aim- ing error is noticeably reduced by the auto-leveling system, especially controlled by the preview control The preview controller attenuates the peak amplitude by a factor of 10 12, while the LQG-controller reduces it about a factor of Figures examine the vertical aiming while a vehicle traverses sequential bumps, which have an interval of 1.0m In Fig 7, the performance of the auto-leveling system is also apparent in reducing the leveling error for this type of disturbance Comparing with the LQG-control, the Boojoong Yong, Heeyong Kang and Sungmo Yang 1410 1.5 ¸ cutoff level along with less peak aiming error, even compared with the leveling system controlled by the LQG-control Meanwhile, the headlamp without a leveling device suffers an extensive aiming error and oscillations This observation justifies the use of automatic leveling system 1.0" 0.5 o 0.0" ~_ ~m -0.5, C o n c l u s i o n s "~ -1.0-1.5, -2.0 Fig time (sec.) Traversing sequential bumps (interval: 3.0 m) without auto-leveler 0.3 vertical aiming using LQG-control 0,2' "~ 0.1, o.0 ~ -0.1 J ~ -0.2 vertical aiming using previe~ control -0.3 time (see.) Fig Traversing sequential bumps (interval: 3.0 m) with auto-leveler preview control decreased the magnitude of aiming error more effectively The results also show that the peak amplitude of leveling error by the preview control is about half of that controlled by the conventional nonpreview control Trends of cutoff level responding to a series of bumps are also illustrated in Figs 9, where the interval of bumps is 3.0 m The disturbance is rejected well by the auto-leveling under acceptable aiming error range Similar to the previous simulations, Fig shows that the auto-leveler using the preview control achieves more stable This study has investigated the usefulness of an automatic headlamp leveling in automotives The aim of auto-leveling is to reduce vertical aiming error in light pattern To achieve more efficient regulation against external leveling disturbances, the preview scheme is used to control a leveling device Computer simulations are carried out to evaluate the performance of the automatic leveling systems Two types of auto-leveler are examined: one employs the preview control, and the other uses a nonpreview control method such as the LQG-control Simulation results present the preview control in auto-leveling improves the vertical aiming performance drastically It is shown that this type of auto-leveler reduced peak leveling error in angular position by a factor of 10 12 compared with the headlamp system without an auto-leveling It is also noted that the effectiveness of the preview control is about twice higher than that of the LQG-control considering the same performance measurement This investigation demonstrates that the preview control is well suited for controlling the HID headlamp leveling system References ADAMS, User's Manual, MDI, V 10.0 Bender, E K., 1968, "Optimum Linear Preview Control with Application to Vehicle Suspension," Trans of ASME, Ser E, 90-2, pp 213-221 Foag, W., 1988, "A Practical Control Concept for Passenger Car Active Suspensions with Preview," IMeehE, pp 190 196 Guo, L and Tomizuka, M., 1997, "High-Speed and High-Precision Motion Control with an Op- A uto-Leveling of HID Headlamp Using Preview Control timal Hybrid Feedforward Controller," I E E E / A S M E Trans On Mechatronics, Vol 2, No 2, pp 110 122 Hege, G and Dahm, H., 1996, "New Reflection-Type Xenon Headlamps Using HID Technology," SAE Technical Paper series 960927, pp 153 156 Huhn W and Hege, G., 1995, "High Intensity Discharge Headlamps (HID)-Experience for More Than 3-I/2 Years of Commercial Application of Litronic Headlamps," SAE Technical Paper series 950591, pp 63 67 Inman, D., 1994, Engineering Vibration, Prentice-Hall, Inc., N J Lewis, F., 1986a, Optimal Control, John Wiley & Sons Lewis, F., 1986b, Optimal Estimation, John 1411 Wiley & Sons Nagiri, S., Doi, S., Shohno, S and Hiraiwa, N., 1992, "Improvement of Ride comfort by Preview Vehicle-Suspension System," SAE Automotive Suspensions and Steering Systems, SP917, pp 81 87 Sharke, P., 2001, "Let light be there," ASME Mechanical Engineering, Vol 123, No 6, pp 70-73 Tomizuka, M., 1976, "Optimum Linear Preview Control with Applications to Vehicle Suspensions," A SME Journal of Dynamic Systems, Measurement, and Control pp 309 315 Yong, B, 1997, "Contour-Following of a Force-Controlled Industrial Robot Using Preview Control," K S M E International Journal, Vol II, No 2, pp 115 124 Unit1 The amount of the money you pay when you buy a car Price The amountof the money you get when you sell your car Resale value How big the car is Size Items inside the car Interior features How much petrol or diesel the car uses Fuel consumption The car capacity to go fast an accelerate quickly Performance When customers always buy their cars form the same manufacturer Brand loyalty Crash tests Standard equipment Fuel consumption Diesel engine Brand image Resale value Leather seats Passenger airbags Unit2 You open the to look at the engine Bonnet The absorb small impacts in an accident Bumper Don’t forget to retract the before using the car wash Aerial Can you put my suitcases in the please? Boot When it stars raining, you need to switch on the Windscreen wiper ‘What model is that’ ‘I don’t know I can’t see the from here.’ Badge It is important to inflate the to the correct pressure for better fuel consumption tyre The Mercedes star id a well-known Logo Open the and let some sun and fresh air into the car Sun roof 10 I wish all drives would use their when they want to turn right or left Indicator This model in the new factory in Poland Is produced German cars all over the world Are sold The orders by fax or online Can be place The car by robot Assemble Spare parts from your local dealer Can be bought The interiors by computer A designed Tyres .before they wear down completely Should be replace Unit It’s so practical to have a near the steering wheel I can take a drink whenever I want Cup holder In a car with manual transmission, you need to press the when you want to change gear Clutch pedal There’s usually a cosmetic mirror on the passenger’s Sun visor I have a leather It’s not cold for my hands in the winter Steering wheel It’s against the law to phone while driving so i’ve odered a car with a Hand free telephone Could you have a look in the road atlas? It’s in the Glove compartment I don’t need a as I don’t smoke and I don’t want anyone to smoke in my car Cigarette lighter Could you close the .? I’m getting a draught Air vent Shows you how fast the car is travelling? Speedometer Warm you if the engine lubrication system gets too hot? Engine oil temperature gauge Shows that you are indicating to turn left or right? Hazard waring/indicator light Shows you how often the engine is turning over? Rev counter Shows you how much petrol you have in the tank? Fuel gauge Indicates the voltage of the car’s electrical system? Voltmeter I’m .1 to you because of a problem with the delivery which we received from you last week The order was for 1000 dashboard panels 50 of the boxes that arrived were empty Can you send us the missing items as soon as .3? We would also .4 it if you could look into the problem to make sure this does not happen again I’m .5 you a scan of the delivery note as an .6 I look .7 to hearing from you soon Writing Appreciate Unfortunately Sending Possible Attachment Forward Unit 4 10 11 12 13 14 15 16 ABS ACC ASR bhp CATS ESP FWD GDI g/km mpg mph Nm PAS RWD SI TDI Anti-block Brake system Automatic climate control Anti-Spin Regulation brake horsepower Computer Active Technology Suspension Electronic Stability Program Front-Wheel Drive Gasoline Direct Injection gramper/kilometer miles per gallon miles per hour Newton metre Power Assisted Steering Rear Wheel Driver Spark Ignition Turbo-diesel Direct Injection In an engine, linear is converted into motion by the crankshaft Rotational The power of the engine is through the clutch and the gearbox Transmission The spark plug the air/fuel mixture and sets off an Ignites – Explosion A 6-cylinder engine is more than a 4-cylinder engine Powerful Fuel and air is compressed in the chamber Combustion V-engine this layout is used for high-performance engine with a compact layout such as in the BMW 7-series The cylinders are arranged in tow banks set at an angle to one another This layout is normally more cuboid in shape than the other two Horizontally opposed engine this layout is wide and flat and givens the engine a low centre of gravity The cylinder are arranged in tow banks on opposite sides of the engine It is very practical for car with the engine located at the rear, such as the Porsche In-line engine this layout is long and narrow The cylinders are all next to each other in a single bank It is a standard, simple layout used in the Mercedes A-class, for engine Unit The has been stiffened to produce more precise steering at high speeds Front suspension We have also increased the size of the for a shorter braking distance Disc brakes I also noticed that the press release says there is improved Fuel consumption Firstly, we have enhanced the Cd value with a Chassis length We have also reduced the kerb weight of the car by over 50 kilos by using Light-weight material We have introduced a so that the engine cuts out if you stand still for more than three seconds and stars again when you take your foot off the brake Start-stop automatic This has a positive effect on the of this car and, of course, on the resale value Running costs We have also increased the to make the car more practical for families and sports people Boot capacity A measure of the car’s wind resistance, or drag coefficient Cd-value The amount you spend on petrol, tax, maintenance, etc Running costs The volume of the boot Boot capacity How much fuel you need driving around town Urban consumption Brake system which uses a caliper and rotor, or, disc, to stop or slow a vehicle Disc brakes How much you can expect to get it you sell the car after three years Resale value The connection of the axles by springs and dampers to the car body which prevents occupants from road shock Front suspension The distance between putting your foot down on the brake and the car stopping Braking distance How much the car weighs when there are no passengers in it and with half a tank of fuel Kerb weight The Audi TT has a top speed of 259 mph it is much than a fiat panda Faster Rolls-Royce makes some of the car in the world Most expensive All new car now have airbags as standard so they are than cars were years ago Safer A diesel engine is still than a petrol engine, even though they are much quieter than they used to be Noisier Volvos have the reputation of being some of the cars on the market Safest The interior of a Bentley is and luxurious than a BMW 7-series More spacious The Porsche Cayenne weighs two and a half tonnes It is .than the BMW X5 Heavies The Lamborghini Diablo is one of the cars in the world Fastest A car engine with twelve cylinders is than one with six cylinder More powerful 10 These leather seat are the seats l’ve ever sat in! Most comfortable Wood is very often used in interiors because it looks and warm Natural Aluminium and magnesium are important for car makes because they are and therefore good for weight-saving 10 Light Safety regulations require that the foam used in car seats shouldn’t be Flammable Rubber should be able to withstand great temperature differences while staying In other words, it shouldn’t become brittle Elastic Windscreens are made of a special .glass to protect drivers in accident Shatterproof Fabrics used in cars need to be and not look old too quickly Durable Steel is used in for load-bearing parts because it is Rigid Sheet metal is used for large car parts because it is and dent-resistant Malleable Ceramic, which is ., is used in the catalytic converter because of the very high temperatures Heat-resistant Aluminium is ideal for bumpers and other body parts because it is Corrosion-resistant Unit People should be able to take their driving test when the are 15 disagree Drivers who have just passed their test should have leaner plates on their car for the first six months agree Drinking and driving should be strictly against the law agree Drivers over 65 years of age should take a new test every two years agree Safety features like ABS are dangerous-they give drivers a false sense of security and encourage them to take more risks disagree Drivers should be required to have headlight on during the day disagree People shouldn’t be required to wear seat belts in car with airbags disagree Car manufacturers could make cars much safer if they wanted to agree 10 11 ABS Adaptive cruise control Crumple zone Highly rigid roof Automatic emergency braking Seat belt Airbag ESP Retractable steering wheel Shatterproof windscreen Lane departure warning system chống bó cứng phanh kiểm sốt hành trình thích ứng vùng chịu lực mui có độ cứng cao tự dộng phanh khẩn cấp đai oan tồn túi khí cân điện tử thu volang lai kính chắn gió chống vỡ cảnh báo lệch đường đèn xenon 12 Xenon headlight Unit The new version of this design classic is as charming as the original Details such as the steep windscreen and the large round headlights emphasize that this car is unconventional There’s no question that this is a fun car to drive Mini cupper Its design is a blend of retro and contemporary It has a sleek, distinctive appearance, with unique proportions and a surprisingly spacious interior The side profile is muscular and aggressive, and gives the whole vehicle a feeling of motion and direction PT cruiser This very stylish car has a striking exterior with a compact shape and bold styling It’s a very sporty car with exciting lines and powerful proportions It features eye-catching details such as the fuel filler with its exposed screws Audi TT we also produce a clay model, which has a ratio of 1:4 If it is approved, a 1:1 model is made and presented to a concept clinic If there are no knock-out factors, the concept goes to a product clinic so that marketing factors can be finalized In the concept phase Successor Derivative Concept car Predecessor Design freeze Prototypes Pre-series cars The next model A variation of the basic model A car built to show people what the future car will look like The last model The stage where no more design changes are possible Limited number of handmade cars with the necessary equipment and technology inside A limited number of cars built on an assembly line to test tooling and parts If won’t be necessary to develop new technology for this model We can what we already have Adapt We need from the Board of Directors if we want to continue with this project Approval Only models are produced in the clinic, not ‘real’ car Concept The location of the plant has an impact on the pricing of the car Assembly / production It is necessary to the final design before the prototype is made Specify Marketing factors, e.g target groups and market share, are finalized after a clinic Produce Technical requirements Ergonomics I have to take the size of the engine and other technical parts into account I have to make sure that attractive seats are also comfortable and customers have enough legroom Laws Fuel consumption Customer demands Brand identity Recycling Production requirement I have to take safety regulations into account, so I can’t put a big metal part on the bonnet which may injure pedestrians The car has to be as streamlined as possible so that it doesn’t need so much fuel If the customers want cup holders inside the car, I have to put them in I can’t design any grill I want I can’t use any material i want, no matter how attrative Have to konw if we can use it again Sometimes i think of a really great shape for the bonnet and the production guys tell me the metal can’t be formed like that We have a number of choices, but our is to lower fuel consumption Best option On the next slide, the indicates the money saved by using recycled materials Dotted line At the beginning of the year we formed a with a company in Africa We’re that this was the right decision Joint venture – Absolutely certain The most last year was in the lowering of emissions Significant development is clearly rising in the Far East as more and more people can afford vehicles and fuel Car ownership I’m not 100% sure, but it is that our is coming out with an environmentallyfriendly model within the next five years Joint venture – Main competitor Will + be/have/use Will + be going to