Microsoft Word - A_47_Jakab_R.doc HUNGARIAN JOURNAL OF INDUSTRIAL CHEMISTRY VESZPRÉM Vol. 39(1) pp. 91-94 (2011) BYCICLE ABS PROTOTYPE DEVELOPMENT R. JAKAB1, K. ENISZ1, V. HAUPTMANN2, F. SPEISER1 , D. FODOR1 1University of Pannonia, Faculty of Engineering, Institute of Mechanical Engineering H-8200 Veszprém, Egyetem str. 10., HUNGARY E-mail: ferenc.speiser@gmail.com 2Continental TEVES Kft., H-8200 Veszprém, HUNGARY The passive and also the active safety systems of the vehicles were developed in the last decades. Beside the safety system of cars and trucks the smaller vehicles (like the motorbikes, scooters, e-bikes and bicycles) were developed as well. By emergency or persistent braking the wheel can lock making it impossible to steer the vehicle. [1, 2]. The aim of the project was to create and develop a prototype bicycle that uses a hydraulic type anti-lock braking system called ABS. Keywords: ABS, hydraulic brake system, bicycle Introduction Nowadays more and more efforts are taken to make the road traffic safer. On the traffic side not even for the cars and trucks, but also for the motorbikes and bicycles there are extra safety products as well to avoid or at least to reduce the harms and injuries. Car manufacturers have already developed several built-in safety functions such as pedestrian and bicyclist recognizer camera system or distance estimation with radar system. For motorbikes there are also active protective systems such as airbag, ABS (anti-lock braking system), rear wheel lift off protection, hill start assist and so on. If the wheel of bicycle is locked, then the motor bicycle became uncontrollable and it can slip off the road. This can be handled by ABS, since the system does not let the wheel lock. There is no need to have a driving license for a bicycle therefore it is reachable for everyone as means of traffic. In the last years more and more people choose to use bicycle and thus the number of accidents caused by bicyclist and suffered by bicyclist raised in Hungary. A lot of people use it without the minimum protection, for example helmet, knee- and elbow-protector. By a simple fall serious injuries can happen. The only solution to protect the rider is to have the safety function on the bicycle itself. This is the reason why Continental TEVES started the project together with the University of Pannonia as a pilot project for developing hydraulic ABS for a bicycle. The primary aims were to: – develop a new control algorithm for low weight vehicles with two wheels, and optimize this algorithm for use only the data from the wheel speed sensors as input parameters – create a prototype from existing components and a test environment which is suitable for testing new algorithms. Existing methods Results of the market and research survey in the bicycle ABS field shows that there is no widespread active safety product for bicycles nowadays. For electric motor aided or hybrid bicycles are already present, but regular bicycles are still not supported. There are some simple solutions by modifying the brake-pad shape, using springs in the brake wires and also exist more complex methods such as brake force distribution or balancing. Although could not be found any ready to buy product that uses some kind of intelligence, there are a few proof of concepts. The idea to apply some intelligent decision aiding mechanism is relatively new. The following methods are used: – mechanical brake force distribution, – pneumatic aided ABS, – ABS realization with electronic stepper motor, – hydraulic ABS, only one controlled wheel. Structure of the system The difference between the previously mentioned methods and this pilot project is the concept. The ABS control algorithm is able to run on a separate SBC (single board computer) and not only on the ECU (electronic control unit), the bicycle has hydraulic brake system and the algorithm is able to actuate both of the wheels independently but in synchronized manner. The system consists of three main parts (Fig. 1): – a PC to observe and modify the parameters of the bicycle and the control algorithm – a SBC to run the control algorithm and make log from the internal parameters of the algorithm and the data from the sensors – the control units and the sensors 92 Figure 1: Structure of the system (where V1 and V2 are the wheel speed sensors, the P1,2,3,4 are the pressure sensors) The PC and the monitoring software An External laptop was utilized to continuously monitor the ABS, download measurement data, monitoring the operation (Fig. 2) and upload Matlab/Simulink control model. The external PC connects to the SBC with standard wireless communication. Figure 2: Bicycle monitoring client software The SBC and the control algorithm The SBC is a small PC with an Intel Atom processor (Z530P) and with the standard interfaces. On this small computer runs the control algorithm and collects the data from the ECU. The single board computer On the SBC an embedded Windows XP is running as an operating system with limited functions, optimized for running the MATLAB/Simulink program and enabled network connections. As there is no direct connection to the SBC an application is used, that is able to function as a diagnostic, control and file transfer tool. On the SBC the module shall run as a server application independently. This module shall observe the status of the control model, such as running, activating the valves, in failure. This should be able to communicate with the external computer (client side), to send new control commands to the SBC, and to receive the log files and monitoring information back to the client side to display them during tests. The SBC does not have any peripheral device such as display, keyboard, pointer device when it is on the bicycle. There is only a feedback led that is indicating the SBC is powered up and the OS is running. The connection and control to the SBC is made over a wireless connection. Analogue to Digital converter Beside the SBC there is an A/D converter for the logging of the pressure values. The converter reads the data from the pressure sensors and forwards it to the single board computer. Communication For onboard communication system the Controller Area Network system was chosen. The main reason for using this system was that the ECU and the sensors support this kind of communication system, and other components of the system can be adapted to be able to communicate on CAN. Defined CAN nodes in the onboard network (Fig. 1): – Hydraulic and Electronic Control Unit (HECU) – Single Board Computer (SBC) via converter – Pressure signal adapter (P1,2,3,4) 93 The control algorithm The control algorithm was implemented in Matlab/ Simulink. The algorithm is based on the comparison of the wheel speed and a calculated ideal speed. false true Measured data ABS data Calculation of ideal speed ABS data = RELEASE release wheel ideal K V V ≥ hold wheel ideal K V V ≥ ABS data = HOLD ABS data = INCREASE false true Figure 3: ABS control flowchart The calculation of the ideal speed value is based on a linear function defined by a speed slope value and the initial speed value. startideal VSNV +∗= (1) where: Videal – ideal speed value defined by linear function N – elapsed time from measurement of initial speed (the number of steps) S – defined speed slope Vstart – initial speed (offset, the last valid speed value, before the actuation) The comparison of speed and the calculated ideal speed is based on the Eq. 2 and Eq. 3. 1−=ABSdata if dif wheel ideal K V V max≥ and itideal VV lim> (2) 1=ABSdata if dif wheel ideal K V V max< or itideal VV lim< (3) where: ABSdata – is the actuation request (normally the -1 is the release, the +1 is the increase state of the ABS) Vwheel – actual speed value of the wheel Kmax dif – is a defined maximum “difference” Vlimit –speed limit for ABS actuation The algorithm calculates the Vstart value in every loop (Eq. 4, Eq. 5) wheelstart VV = if wheelideal VV ≤ (4) startstart VV = if wheelideal VV > (5) The current algorithm has only two states (the release and the increase state), because it is the simplest and the fastest version of the actuation, but in the control part there is a third state, the hold, which will be used in the future for the more effective braking. The HECU / ECU and the sensors The HECU is a modified motorbike HECU, which currently works as a dummy ECU without a control algorithm, thus an external controller has to send the control messages for valves and pump states. Figure 4: Speed and pressure sensors on the bicycle To create the connection between the hydraulic system of the motorbike ABS and the brake system of the bicycle was hard, because these parts were designed for different pressure intervals and were designed for different filling methods. For monitoring the different parameters of the bicycle, some sensors were mounted. The pressure sensors were connected to the inlet and outlet lines of the ABS, and four different wheel speed sensors (Fig. 4) were mounted to test which one is the most suitable for this application. Test and measurements The first test was made on dry asphalt with the manoeuvre of emergency braking from 15 km/h speed and the results are promising. The diagram on Fig. 5 shows the data for the rear wheel. When the difference between the ideal and filtered wheel speed were increasing the ABS decreased the brake pressures and the wheel was accelerated near to the ideal speed. 94 Figure 5: Braking maneuvre (Rear wheel) Conclusions In many countries all around the world a lot of people use bicycle not just for spare-time activity but also as part of their everyday life to commute to the workplace. During these times accidents can happen to anybody, so it is important to prevent the bicycle riders from injuries. With this prototype the aim of the project team is to show that the ABS technology is also a solution for bicycles. After testing and further improvements of the software should be realized that can help the riders in dangerous situations to mitigate collision or just to stop in a safe way. For car industry it started the same way and now it is a compulsory supplement in every produced car in Europe and America also. Though the anti-lock braking system theory is the same for cars and bicycles the circumstances are really different. The point of later development shall be to keep the focus on the helping the rider to run in a safe way. In the future if the development of the bicycle brake assist system evolves as the brake systems for the car, in some-ten years the ABS for high-end bicycles or mopeds may be compulsory also. The first concept of electrical and hydraulic components are mounted on the bicycle (Fig. 6), the control model can be tested and tuned now on. In automotive industry the ABS system tuning for a vehicle is a long process based on the experience of the drivers and engineers. For the bicycle it is even more specific because there is no previous test result. In a later development phase beside ABS other safety and comfort control functions can be added to the system (e.g.: lift-off protection, hold-and-go function, brake-by-wire). Figure 6: The bicycle ACKNOWLEDGEMENT We acknowledge the financial support of this work by the Hungarian State and the European Union under the TAMOP-4.2.1/B-09/1/KONV-2010-0003 project. REFERENCES 1. V. CERONE, D. ANDREO, M. LARSSON, D. REGRUTO: Stabilization of a Riderless Bicycle A Linear- Parameter-Varying Approach, IEEE Control Systems Magazine, October (2010) 2. K. J. ÅSTRÖM, R. E. KLEIN, A. LENNARTSSON: Adapted bicycles for education and research, IEEE Control Systems Magazine, August (2005) << /ASCII85EncodePages false /AllowTransparency false /AutoPositionEPSFiles true /AutoRotatePages /None /Binding /Left /CalGrayProfile (Dot Gain 20%) /CalRGBProfile (sRGB IEC61966-2.1) /CalCMYKProfile (U.S. Web Coated \050SWOP\051 v2) /sRGBProfile (sRGB IEC61966-2.1) /CannotEmbedFontPolicy /Error /CompatibilityLevel 1.4 /CompressObjects /Tags /CompressPages true /ConvertImagesToIndexed true /PassThroughJPEGImages true /CreateJobTicket false /DefaultRenderingIntent /Default /DetectBlends true /DetectCurves 0.0000 /ColorConversionStrategy /CMYK /DoThumbnails false /EmbedAllFonts true /EmbedOpenType false /ParseICCProfilesInComments true /EmbedJobOptions true /DSCReportingLevel 0 /EmitDSCWarnings false /EndPage -1 /ImageMemory 1048576 /LockDistillerParams false /MaxSubsetPct 100 /Optimize true /OPM 1 /ParseDSCComments true /ParseDSCCommentsForDocInfo true /PreserveCopyPage true /PreserveDICMYKValues true /PreserveEPSInfo true /PreserveFlatness true /PreserveHalftoneInfo false /PreserveOPIComments true /PreserveOverprintSettings true /StartPage 1 /SubsetFonts true /TransferFunctionInfo /Apply /UCRandBGInfo /Preserve /UsePrologue false /ColorSettingsFile () /AlwaysEmbed [ true ] /NeverEmbed [ true ] /AntiAliasColorImages false /CropColorImages true /ColorImageMinResolution 300 /ColorImageMinResolutionPolicy /OK /DownsampleColorImages true /ColorImageDownsampleType /Bicubic /ColorImageResolution 300 /ColorImageDepth -1 /ColorImageMinDownsampleDepth 1 /ColorImageDownsampleThreshold 1.50000 /EncodeColorImages true /ColorImageFilter /DCTEncode /AutoFilterColorImages true /ColorImageAutoFilterStrategy /JPEG /ColorACSImageDict << /QFactor 0.15 /HSamples [1 1 1 1] /VSamples [1 1 1 1] >> /ColorImageDict << /QFactor 0.15 /HSamples [1 1 1 1] /VSamples [1 1 1 1] >> /JPEG2000ColorACSImageDict << /TileWidth 256 /TileHeight 256 /Quality 30 >> /JPEG2000ColorImageDict << /TileWidth 256 /TileHeight 256 /Quality 30 >> /AntiAliasGrayImages false /CropGrayImages true /GrayImageMinResolution 300 /GrayImageMinResolutionPolicy /OK /DownsampleGrayImages true /GrayImageDownsampleType /Bicubic /GrayImageResolution 300 /GrayImageDepth -1 /GrayImageMinDownsampleDepth 2 /GrayImageDownsampleThreshold 1.50000 /EncodeGrayImages true /GrayImageFilter /DCTEncode /AutoFilterGrayImages true /GrayImageAutoFilterStrategy /JPEG /GrayACSImageDict << /QFactor 0.15 /HSamples [1 1 1 1] /VSamples [1 1 1 1] >> /GrayImageDict << /QFactor 0.15 /HSamples [1 1 1 1] /VSamples [1 1 1 1] >> /JPEG2000GrayACSImageDict << /TileWidth 256 /TileHeight 256 /Quality 30 >> /JPEG2000GrayImageDict << /TileWidth 256 /TileHeight 256 /Quality 30 >> /AntiAliasMonoImages false /CropMonoImages true /MonoImageMinResolution 1200 /MonoImageMinResolutionPolicy /OK /DownsampleMonoImages true /MonoImageDownsampleType /Bicubic /MonoImageResolution 1200 /MonoImageDepth -1 /MonoImageDownsampleThreshold 1.50000 /EncodeMonoImages true /MonoImageFilter /CCITTFaxEncode /MonoImageDict << /K -1 >> /AllowPSXObjects false /CheckCompliance [ /None ] /PDFX1aCheck false /PDFX3Check false /PDFXCompliantPDFOnly false /PDFXNoTrimBoxError true /PDFXTrimBoxToMediaBoxOffset [ 0.00000 0.00000 0.00000 0.00000 ] /PDFXSetBleedBoxToMediaBox true /PDFXBleedBoxToTrimBoxOffset [ 0.00000 0.00000 0.00000 0.00000 ] /PDFXOutputIntentProfile () /PDFXOutputConditionIdentifier () /PDFXOutputCondition () /PDFXRegistryName () /PDFXTrapped /False /CreateJDFFile false /Description << /ARA /BGR /CHS /CHT /CZE /DAN /DEU /ESP /ETI /FRA /GRE /HEB /HRV (Za stvaranje Adobe PDF dokumenata najpogodnijih za visokokvalitetni ispis prije tiskanja koristite ove postavke. Stvoreni PDF dokumenti mogu se otvoriti Acrobat i Adobe Reader 5.0 i kasnijim verzijama.) /HUN /ITA /JPN /KOR /LTH /LVI /NLD (Gebruik deze instellingen om Adobe PDF-documenten te maken die zijn geoptimaliseerd voor prepress-afdrukken van hoge kwaliteit. De gemaakte PDF-documenten kunnen worden geopend met Acrobat en Adobe Reader 5.0 en hoger.) /NOR /POL /PTB /RUM /RUS /SKY /SLV /SUO /SVE /TUR /UKR /ENU (Use these settings to create Adobe PDF documents best suited for high-quality prepress printing. Created PDF documents can be opened with Acrobat and Adobe Reader 5.0 and later.) >> /Namespace [ (Adobe) (Common) (1.0) ] /OtherNamespaces [ << /AsReaderSpreads false /CropImagesToFrames true /ErrorControl /WarnAndContinue /FlattenerIgnoreSpreadOverrides false /IncludeGuidesGrids false /IncludeNonPrinting false /IncludeSlug false /Namespace [ (Adobe) (InDesign) (4.0) ] /OmitPlacedBitmaps false /OmitPlacedEPS false /OmitPlacedPDF false /SimulateOverprint /Legacy >> << /AddBleedMarks false /AddColorBars false /AddCropMarks false /AddPageInfo false /AddRegMarks false /ConvertColors /ConvertToCMYK /DestinationProfileName () /DestinationProfileSelector /DocumentCMYK /Downsample16BitImages true /FlattenerPreset << /PresetSelector /MediumResolution >> /FormElements false /GenerateStructure false /IncludeBookmarks false /IncludeHyperlinks false /IncludeInteractive false /IncludeLayers false /IncludeProfiles false /MultimediaHandling /UseObjectSettings /Namespace [ (Adobe) (CreativeSuite) (2.0) ] /PDFXOutputIntentProfileSelector /DocumentCMYK /PreserveEditing true /UntaggedCMYKHandling /LeaveUntagged /UntaggedRGBHandling /UseDocumentProfile /UseDocumentBleed false >> ] >> setdistillerparams << /HWResolution [2400 2400] /PageSize [612.000 792.000] >> setpagedevice