Technical Aspects of External Devices into Vehicles' Networks ...

International Journal of Applied Engineering Research ISSN 0973-4562 Volume 11, Number 10 (2016) pp 7003-7006 © Research India Publications. http://www.ripublication.com

Technical Aspects of External Devices into Vehicles’ Networks Integration Sergey Sergeevich Shadrin and Andrey Mikhailovich Ivanov Moscow Automobile and Road Construction State Technical University (MADI), Leningradskiy Pr. 64, Moscow, 125319, Russia.

Abstract The article discusses main trends of modern car manufacturing evolution. Possibilities of vehicle networks usage are considered with regard to automobile data exchange upon solution of research tasks, road test conduction, development of control system of autonomous vehicles, as well as in ITS applications (intelligent transport systems). The list of required data is given in order to implement inter-entity interaction in the scope of V2V (Vehicle-to-Vehicle) and V2I (Vehicle-to-Infrastructure) communications, reserve of network capacity of CAN buses of vehicles in operation is analyzed. Keywords: car, vehicle, CAN bus, CAN bus data usage, intelligent transport systems, ITS, V2V, V2I, V2V data set

Figure 2: Data exchange.

TRENDS OF AUTOMOBILE INDUSTRY EVOLUTION As for now, the main trends of evolution of automobile manufacturing are associated with development of intelligent transport systems (ITS) [1], technologies of autonomous driving [2-5] and conventional energy efficiency (innovative materials, hybrid transmissions, electromotive cars and others). ITS development results in the fact that modern vehicle is no longer a single wheeled vehicle and, being integrated into traffic data environment, becomes connected or cooperative entity. Application of autonomous driving systems modifies the role of a driver in the "driver-car-roadenvironment" system, and the system itself acquires new interrelations and is transformed into more complex one, our concept of such system is illustrated in Figure 1.

VEHICLE NETWORK DATA Nearly all vehicles of M and N categories manufactured at present [6] are equipped with data transfer buses, the most widely applied is CAN bus [7]. For the vehicles of N1, N2, N3, M3, and T categories the unified encoding format described in SAE J1939-71 [8] is applied in order to transfer parameters via CAN bus. European manufacturers of freight vehicles use unified data transfer protocol (FMS [9]) and install unified interface for connecting of digital tachographs, which also can be used for operation of external devices. The situation with the vehicles of M1 and M2 categories is different. The main problem upon operation with CAN bus in such types of cars and minibuses (M1 and M2 categories) is that the automobile manufacturers use their own decoding databases of CAN messages, and even more, the bases are different for different car models of one and the same manufacturer and are considered as strictly protected confidential information [10]. The manufacturers attribute this fact to additional reliability and safety of operation of vehicle electronic systems. For instance, the CAN bus of modern vehicle equipped with the systems of electronic stability program (ESP/DSC) can a priori be used for data transfer and subsequent processing by means of the methods described elsewhere [10], they are as follows: vehicle velocity; linear wheels velocities; lateral and longitudinal accelerations of gravity center; yaw rate; steering wheel angle; steering wheel angular velocity; accelerator pedal position; brake pedal position; engine RPM; and others. Moreover, data sampling intervals from HS CAN bus are individual and vary, averaging from 10 to 200 Hz, that is, they are comparable with the characteristics of professional sets of measuring equipment of vehicle motion dynamics.

Figure 1: Our concept of modern system "driver--car--road-environment".

Figure 2 illustrates data exchange in the "driver--car--road-environment" system.

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International Journal of Applied Engineering Research ISSN 0973-4562 Volume 11, Number 10 (2016) pp 7003-7006 © Research India Publications. http://www.ripublication.com Therefore, if modern vehicles equipped with numerous electronic systems and sensors, the digitized data from which can be found in vehicle networks, then it would be reasonable to use these data, for instance, in solution of research tasks, during road tests conduction, in ITS applications while providing inter-entity communication between V2V and V2I, as well as for development of control systems of autonomous vehicles with various levels of automation [2], which should at least simplify the described issues and make them more cost efficient.

minimum HS CAN reserve of68.1 %, and for MS CAN 72.2 % of maximum loading of data transfer buses, which is more than sufficient for connection of external devices. 2) Vehicle of М1 category, Ford Focus 2, 2008 MY, equipped in basic configuration with high speed CAN bus (class С, data transfer rate: 500 Kbps) and medium speed CAN bus (data transfer rate: 125 Kbps).With active ignition the HS CAN loading was about 14 % (Figure 4). After completion of the road test the engine was deactivated, the loading of HS CAN was 12 %. While analyzing the acquired data after the road tests the maximum loading of HS CAN bus amounted to 14.2 % and that of MS CAN to 9.9 %.

ANALYSIS OF RESERVE OF NETWORK CAPACITY OF CAN BUSES Prior to connection and integration of newly developed devices into vehicle networks, it is necessary to estimate approximate available reserve of network capacity and additional loading which can be generated by external devices. We performed the following tests of vehicles in operation: 1) Vehicle of М1category: Land Rover Discovery 3, 2009 MY, equipped in basic configuration with high speed CAN bus (class С, data transfer rate: 500 Kbps) and medium speed CAN bus (data transfer rate: 125 Kbps). The tests were performed withNI8473s decoder (National Instruments). With active ignition the loading of high speed CAN bus (HS CAN) was about 7 % (of 500 Kbps). With active engine, as well as during road tests, the loading of HS CAN was about 31 % (Figure 3). After completion of the road test the engine was deactivated, the loading of HS CAN was 19 %. After activation of regular vehicle alarm a single maximum loading of the bus in 94 % was recorded, possibly related with alarm algorithms but not with regular modes of vehicle driving operations.

Figure 4: HS CAN loading of Ford Focus 2 in operation.

Therefore, under traffic conditions the minimum HS CAN reserve of the considered vehicle (Ford Focus2) amounted to 85.8 %, and that of MS CAN to 90.1 % of maximum loading of data transfer buses, which is more than sufficient for connection of external devices. It should be mentioned that the studies were performed not with the latest vehicle models. It is known that in BMW vehicles of last generation the navigation data are transferred via MS CAN bus, which increases its loading. Continental Corporation performed investigations into data transfer of 3D terrain map from radar installed in vehicle front end via HS CAN bus. Nevertheless, we established that the maximum additional loading on CAN buses from external ITS devices (or control units of autonomous vehicles or loggers/analyzers) will be short-term loading and can vary from 0.1 % to 4 % of network capacity. That is, connection of external electronic devices to CAN buses of modern vehicles (with retaining of integrity of network architecture and validity of communication data exchange) cannot influence on operation safety. Let us mention the experimental estimation of safety of data transfer buses of a modern vehicle [11]. The subject of tests was a serial vehicle, all electronic control units of which were dismounted and connected to signal generating and reading devices and programmers. As a consequence, the software of control panel was decompiled and revised, control authorization algorithms of nearly all vehicle electronic systems were deciphered, including braking system, climate control system and warning alarms. In conclusion, extreme vulnerability of vehicle network was revealed with regard to illegal actions of third parties; the importance of unavailability of physical access for intruders to vehicle data transfer buses

Figure 3: HS CAN Loading of LR Discovery3in operation.

While analyzing the acquired data after numerous road tests the maximum loading of HS CAN bus amounted to 31.9 % and that of MS CAN bus to 27.8 %. Upon diagnostics involving real-time control via MS CAN bus of sound alarm, hazard warnings, passenger compartment lighting, and instrument readings the maximum loading of MS CAN was 31.8 %. Upon sending of diagnostic OBD-II requests into HS CAN for reading of 5 parameters of engine operation the loading of HS CAN increased by about 1.7 %. Therefore, under traffic conditions the considered vehicle exhibited the

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International Journal of Applied Engineering Research ISSN 0973-4562 Volume 11, Number 10 (2016) pp 7003-7006 © Research India Publications. http://www.ripublication.com was mentioned as a main reason preventing distribution of harmful programs and illegal actions. However, recent development of wireless interfaces, including ITS technologies, makes urgent the safety issues requiring for further investigations.

Table 1: Characteristics of transferred data Item

1

V2V AND V2I COMMUNICATIONS Vehicles of various levels of automation [2], integrated in cooperative intelligent transport systems, in comparison with stand-alone vehicles are characterized with significantly higher potentials of improvement of traffic safety, efficiency of road utilization and vehicles themselves. For instance, while discussing possibility to increase traffic capacity and neutralization of jams resulted from wave propagation of vehicle deceleration, it was experimentally established in [12], that in the case when about 20 % of vehicles are cooperative intelligent units, then the total traffic stream is completely controllable, and average speed increases by about 15 %, and the vehicle deceleration waves are neutralized as fast as possible. Thus, let us consider one of ITS subsystems: the system of inter-entity interaction which can be implemented in the form of V2V (vehicle-to-vehicle) or V2I (vehicle-to-infrastructure) communications. Currently numerous research centers and commercial companies of the world perform works on development, study and tests of the considered systems, including those on the basis of wireless dynamic networks DSRC (in Europe: ITS-G5) in various frequency ranges. Though, it should be mentioned that at present there is no unified approach to composition and characteristics of transferred data, for instance, from vehicle to ITS network. We believe that in the scope of V2V and V2I communications the following data set should be transferred from vehicle to ITS dynamic network: 1) geographical data of vehicle location (longitude, latitude, absolute time, course angle, elliptic height), acquired by means of vehicle hybrid navigation system; 2) kinematic parameters of motion (vehicle velocity, longitudinal and lateral accelerations, yaw rate); 3) the data of vehicle control actions, performed by the driver or by system of autonomous driving(accelerator pedal position, brake pedal position, steering wheel angle, operation mode of turning indicators, activation mode of warning alarms, control system status, that is, information of vehicle control either by the driver or by autonomous driving system, or the control is transferring from/to human-driver); 4) parameters of traffic conditions (ambient temperature, operation mode of vehicle head lighting and windshield wipers, indicators of activation of active safety systems: ABS, TC, ESP/DSC and others); 5) vehicle identifiers (vehicle category, weight, length, width, height, VIN).

2 3 4 5

6 7 8 9

10 11 12 13 14 15

16 17

Updating Measurement Data time*, range/ size ms step I) Geographical data of car location NMEA 0183 longitude 1000 [13] latitude 1000 NMEA 0183 absolute time 1000 NMEA 0183 course angle 1000 NMEA 0183 ∑≈70 elliptical height 1000 NMEA 0183 byte II) Kinematic parameters of motion 0-250 vehicle velocity 20 16 bit / 0.004 longitudinal -11-11 20 8 bit acceleration / 0.1 -11-11 lateral acceleration 20 8 bit / 0.1 -1.8-1.8 yaw rate 10 16bit / 0.003 III) Data of vehicle control actions accelerator pedal 0-100 20 8 bit position / 0.5 brake pedal 10 8bit position steering wheel -780-780 10 16 bit angle / 0.1 operation mode of 100 4 bit turning indicators alarm activation 100 4bit mode control system 4bit status IV) Parameters of traffic conditions ambient -100-100 1000 8 bit temperature / 0.1 Description

operation mode of head lighting

operation mode of windshield wipers status of active 19 safety systems 18

Units

NMEA 0183 NMEA 0183 NMEA 0183 NMEA 0183 NMEA 0183

km/h m/s2 m/s2 rad/s

% ON/OFF degrees left-0-right ON/OFF driver--system.

C OFF-low beamhigh beam-fog headlight OFF-periodiccontinuous-rapid

1000

-

4bit

1000

-

4bit

20

-

4bit

OFF-ON

V) Car identifiers

21 22 23 24

category of vehicle unladen weight overall length overall width overall height

25

VIN

20

-

-

16 bit

ASCII

-

-

kg m m m

250*3

ASCII

16 bit 8 bit 8 bit 8 bit 17 byte

ASCII

*-estimated updating time of the considered parameters on HS/MS CAN buses of modern vehicles, for reference.

It should be mentioned that the minimum updating rate of the considered data in vehicle network as well as "domestic" navigation sets is 1 Hz, and in this regard we assume that the considered data set of 25 parameters, required for provision of inter-entity interaction between intelligent transport systems, will be transferred to vehicle ITS network by means of V2V/V2I technology at the frequency of at least 1 Hz.

Table 1 summarizes the data transferred by vehicle to ITS system and their estimated characteristics.

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International Journal of Applied Engineering Research ISSN 0973-4562 Volume 11, Number 10 (2016) pp 7003-7006 © Research India Publications. http://www.ripublication.com On the basis of the data in Table 1, applying elementary calculations, we obtain that the minimum required rate of data transfer for inter-entity interaction should amount (with consideration for service information, such as identifiers, control sums, encoding and others, since Table 1 summarizes only estimated sizes of data and not of transferred packages) to about 1296bps (1.27Kbps).

Person (V2P) interface. Life Sci J 2014; 11(12s):862864 [11] Karl Koscher, Stephen Checkoway. Experimental Security Analysis of a Modern Automobile.Department of Computer Science and Engineering, University of Washington, University of California San Diego.-IEEE Symposium on Security and Privacy, 2010.-URL: http://www.autosec.org/pubs/carsoakland2010.pdf [12] Frank Engels Developing In-Vehicle Traffic Jam Alleviation Technology for Android Using Simulink URL: http://www.mathworks.com/tagteam/77455_91995v00 _developing-traffic-jam-alleviation-technology-usingsimulink.pdf [13] IEC 61162 Maritime navigation and radio communication equipment and systems-Digital interfaces.

RESULTS AND DISCUSSION 1. The article describes our concept of modern "driver-carroad-environment" system, data exchange is illustrated. 2. Possibilities of modern vehicles CAN buses usage are described upon solution of research tasks, road test conduction, development of control systems of autonomous vehicles, as well as in the ITS applications. 3. Reserve of network capacity of CAN buses of vehicles in operation has been analyzed. Additional loading on CAN buses from external devices has been estimated. Safety of such integration has been substantiated (with retaining of integrity of network architecture and validity of communication data exchange). 4. Minimum list of data is presented, which is required for implementation of inter-entity interaction in the scope of V2V and V2I communications, the minimum required channel rate equals to 1.27 Kbps according to calculations.

REFERENCES [1]

Eskandarian, A. Handbook of Intelligent Vehicles / Azim Eskandarian (Ed.) // Springer.-2012.-1628 p. [2] SAE J3016 Taxonomy and Definitions for Terms Related to On-Road Motor Vehicle Automated Driving Systems.-SAE, 2014.-12 p. [3] Buehler, M. The DARPA Urban Challenge. Autonomous Vehicles in City Traffic / Martin Buehler, Karl Iagnemma, Sanjiv Singh (Eds.) // Springer.-2009.651 p. [4] Nonami, K. Autonomous Control Systems and Vehicles. Intelligent Unmanned Systems / KenzoNonami, MuljowidodoKartidjo, Kwang-Joon Yoon, AgusBudiyono (Eds.) // Springer Japan.-2013.306 p. [5] Cheng, H. Autonomous Intelligent Vehicles. Theory, Algorithms, and Implementation / Hong Cheng // Springer.-2011.-163 p. [6] UN-ECE/TRANS/WP.29/78/Rev.3-Consolidated Resolution on the Construction of Vehicles (R.E.3).2014.-102 p. [7] Kiencke, U. and L. Nielsen, 2005. Automotive Control Systems-For Engine, Driveline, and Vehicle. Second edition. Springer-Verlag Berlin Heidelberg, pp: 512. [8] SAE STANDARD J1939-71. SURFACE VEHICLE RECOMMENDED PRACTICE. VEHICLE APPLICATION LAYER.-06/2006, 686 p. [9] FMS-Standard Working Group. FMS-Standard. Interface description. Vers.02.00, 11.11.2010. [10] Prikhodko V.M., Ivanov A.M., Shadrin S.S. The development of additional services using Vehicle-to-

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