MSRSAS - Postgraduate Engineering and Management Programme - PEMP

ASSIGNMENT

Module CodeAEL2516

Module NameReal-time Embedded systems

CourseM.Sc. in Automotive Electronics

DepartmentComputer Engg.

Name of the StudentSalman Mohideen

Reg. NoCDB0913002

BatchFull-Time 2013.

Module LeaderProf. Tracy Austina Z.

Declaration Sheet

Student NameSalman Mohideen

Reg. NoCDB0913002

CourseMSc BatchFull-Time 2013.

Batch

Module CodeAEL2516

Module TitleReal-time Embedded systems

Module Dateto18-012014

Module LeaderProf. Tracy Austina Z.

Declaration

The assignment submitted herewith is a result of my own investigations and that I have conformed to the guidelines against plagiarism as laid out in the PEMP Student Handbook. All sections of the text and results, which have been obtained from other sources, are fully referenced. I understand that cheating and plagiarism constitute a breach of University regulations and will be dealt with accordingly.

Signature of the studentDate

Submission date stamp

(by ARO)

Signature of the Module Leader and dateSignature of Head of the Department and date

Abstract____________________________________________________________________________Navigation technology is a promising technology that has applications in many aspects of life, such as in agriculture, law, sports, the automobile industry, etc. In the automobile

industry, navigation is used with GPS in many forms. In this paper, it is explained how GPS technology and accelerometer based navigation system could be used for optimal routing and location and the application status of RTES in present automotive scenario. In this way, we can reduce traffic congestion, eventually reduce travel times and air pollution, and even save money on fuel consumption. This task is accomplished by using the data collected by the car GPS navigation system, analyzing this data, and then using the data to model how optimal navigation can be achieved. A robust architecture for the integration of add-on software in ECUs can be used to effectively make use of the RTES. This reduces the complexity of the embedded system in vehicles and eases the ECU integration.Contents____________________________________________________________________________

iiDeclaration Sheet

iiiAbstract

ivContents

vList of Tables

viList of Figures

viiList of Symbols

1.Real time embedded systems11.1 Introduction11.2 Growth of RTES

21.3 Development issues

2 1.3.1 Complex safety requirements 3

1.3.2 Reuse of software 3

1.3.3 Increasing ECUs in vehicle 4

1.3.4 Complicated vehicle network architecture 2 Title of the Chapter

42.1 Subtitle 1

52.2 Subtitle 2

62.3 Subtitle 3

91. Title of the Chapter

143.1 Subtitle 1

16

3.2 Subtitle 2

17

3.3 Subtitle 3

28References

29Bibliography

31Appendix-1(Title of the Appendix)

33Appendix-2 (Title of the Appendix)

38List of Tables

____________________________________________________________________________Table No.Title of the tablePg.No.

Table 1.1Title of the table 12

Table 1.2Title of the table14

Table 2.1Title of the table18

< The table numbers have to be based on the chapter number>

List of Figures

____________________________________________________________________________

Figure No.Title of the figurePg.No.

Figure 1.1Title of the figure 13

Figure 1.2Title of the figure15

Figure 2.1Title of the figure19

< The Figure numbers have to be based on the chapter number>List of Symbols____________________________________________________________________________SymbolDescriptionUnits

ACurrentAmp

gAcceleration due to gravity - 9.81m/s2

VVoltageVolts

wWidthmm

< Arrange in alphabetical order>

PART-A

CHAPTER 1

1. Real-Time Embedded systems1.1 Introduction:

The Embedded systems create a sophisticated structure for modern automobiles which enhances the performance and quality of the vehicles on a real-time basis. Software development for automotive applications is gaining more and more importance. Today, software controls a large number of functions, which make use of linked networks. Interactions of functions in a linked network contribute to an increasing complexity, which require a strong controllability of the complexity. This scenario made the role of RTES in automobiles vital. Now each and every systems in a vehicle deals with complex tasks and efficient function flows which recalls the need of RTES and its importance in modern style.1.2 Growth of RTES

The role of software in the automobile concept has got its own evolution with tears of background. In the 70ties, mechanical systems dominated car development. In the 80ties, electronics supports mainly in the area of chassis and engine control. Infotainment functions gave software dedicated meaning in the automotive domain of the 90tiesAt the beginning of the third millennium; the automotive industry is facing a new challenge. Electronics make 90% of the innovations, 80% out of that in the area of software. This fact means a big change for the development of electronics. The evolution of OS in embedded system paved the way of systematic growth of RTES in a glory. 1.3 Development issues1.3.1 Complex safety requirements

As the year time passes, people become more vigilant about the performance of car, mainly on two parameters- safety and reliability. Requirements of the common people have followed the technology evolved from period to period, reliable but safer too. Substantial growth of technology is a bold point to be discussed when the new requirements of people are discussed. But the fact is, technology which is invented, is not that capable to satisfy the complete requirements on priority basis. This becomes a main issue in developing new technologies and the evolution line never ends.1.3.2 Reuse of software

Until recently, in the automotive industry, reuse of software has entirely been a typical activity of suppliers. They try to reduce the increasing software development costs that stem from rising complexity and size of software in the modern automobile. Lately, also the automotive manufacturers began to develop specific software with competitive relevance. Now they have to deal with the problem of reuse, too. But the re-use of the software has not become effective since then the RTES has launched. Effective tools and unawareness of the technology and variation of ECU fro from ECU make the process complex.1.3.3 Increasing ECUs in vehicle

Modern vehicles have a large number of Electronic Control Units (ECUs) inside that realize a huge number of functions. Those functions may be distributed among several ECUs. Premium cars for example have up to 70 ECUs, connected to 5 system busses, realizing over 800 functions. Standardization of the ECU architecture is needed in order to handle increasing functional complexity in a cost efficient way. BMW is working on a complex body domain ECU consisting of 3 microcontrollers, including a dual core 32Bit C and a dedicated C for safety-related applications. AUTOSAR will be used to integrate numerous functions into one ECU.1.3.4 Complicated vehicle network architecture

Early vehicles used dedicated point-to-point connections for inter-module communications. As the number of modules and features increased in vehicles, the wiring system became bulky, complex, expensive and difficult to install and maintain. A serial bus can replace all the dedicated point-to-point wiring between modules. Nowadays many vehicles are considering using a low-speed LIN bus for body electronics and a high-speed CAN bus for power-train. Future vehicles

will access internet and exchange information with other vehicles and road-side units for various reasons such as collision avoidance, message dissemination etc. These many network protocols including FLEXRAY are used in vehicles were communication algorithms becomes more and complex including the hardware. This is one of the main design issues in modern vehicles.1.4 Two future embedded systems

There are numerous embedded systems which can be incorporated in future vehicles as the part of safety and performance. Two of them are discussed below,

1.4.1 Driver Fatigue Detection system

This is a system which detects the drowsiness of driver, during driving. Most of the accidents happen due to distraction or driver in sleepy mood. If the driver is in drowsy mood, driver looses the control on the vehicle and it may lead to a major accident. So there should be a system to avoid this type of accidents by warning the driver in this situation. When vehicle is moving, a sensor which may be mostly a camera should take the picture continuously and using image processing or video graphics, the condition of drivers eye should be identified. Or a better way is to use Retina scanner to scan the condition of eye, whether it is half opened, fully opened or closed.

Sensing this parameter and the current vehicle speed, a warning (mostly a sound beep or jerk in steering wheel) signal should be generated in order save the driver from accidents. The sensors can be placed on the windshield as a micro structure. Video graphics and retinal scan hardware are readily available throughout. Integrating these in a single car will be challenge. The warning range should be depended upon the relative vehicle speed to enhance the safety. These requirements are already being claimed in some of the countries.1.4.2 Phone call detection

This can be explained as excel concept system because of the complexity in implementation. There are accidents happening all over the globe because of the cell phone usage of driver while driving. If the driver is using cell phone or making a call, there should be a system to detect this activity and save the driver life by controlling the vehicle speed automatically. This can be achieved using a full-fledged telematics system. The telematics system should be capable of communicating with the drivers phone which is already configured, and in turn the system should communicate with the vehicle ECU. Whenever driver makes a call, the telematics system detects the function using the frequency used, saves in memory, compares with the phone frequency configuration and sends signals to ECU. The ECU in turn reduces the vehicle speed to a threshold of a less speed which is already saved. Or there can be a system where this system connects with the ACC (Adaptive Cruise Control) and reduces the speed when any obstacle comes in front. Any warning signals can be given before reducing the speed. Or it can be incorporated with Automatic Brake Assist.1.5 Conclusion

RTES in automotive systems has gone through so many innovations and steps, since it holds the important part of vehicle performance. The consistent user requirements have paved the way of development of software throughout the period. Complexity of different systems which follows these requirements raises the issues in implementing integrating RTES in automobiles. Increasing complexity doesnt affect the growth much, but in turn enhanced the growth of embedded software. It can be concluded that wherever requirement is there, growth of technology starts.

PART-B CHAPTER 2________________________________________________________________________________

2. Vehicle navigation systems2.1 Introduction:

Anautomotive navigation systemis asatellite navigation systemdesigned for use inautomobiles to locate the vehicle location, direction to the vehicle is moved, angle, orientation etc. It typically uses aGPS navigation deviceto acquire position data to locate the user on aroadin the unit's mapdatabase. Using the road database, the unit can give directions to other locations along roads also in its database.Dead reckoningusing distance data from sensors attached to thedrive train, agyroscope and anaccelerometercan be used for greater reliability, as GPS (Global Positioning System) signal loss and/ormultipathcan occur due tourban canyonsortunnels. Any system that can provide intelligent vehicle location and navigation information will let us avoid congested freeways and find more efficient routes to our destinations, maintaining economy.2.2 Survey on existing navigation systems

Recently In-car navigation systems have integrated various functions allowed the connection of different devices, and it is likely that in-car navigation system will incorporate elements of other functions. Present in-car navigation systems are integrated systems that mainly consist of navigation function, audio and video function and communication function. The technology used in navigation includes evolution of various systems which explains about GPS navigation, inertial navigation system or inertial measurement unit. Two systems are explained which has wide application on existing automotive systems. 2.2.1 GPS based navigation system Fig.2.1 GPS navigation system A GPS receiver calculates its position by precisely timing the signals sent by 3 or more GPSsatelliteshigh above the Earth. The receiver uses the messages it receives to determine the transit time of each message and computes the distance to each satellite using the speed of light. Each of these distances and satellites' locations defines a sphere. The receiver is on the surface of each of these spheres when the distances and the satellites' locations are correct. These distances and satellites' locations are used to compute the location of the receiver using thenavigation equations. This location is then displayed, perhaps with amoving map displayorlatitudeandlongitude; elevation or altitude information may be included. The Micro controller unit in the car acquires these signals via UART (Universal Asynchronous Receiver Transmitter), processes and displays through LCD or any other media, may include any other actuators depending upon the application (Fig.2.1).2.2.2 Inertial Navigation system (INS) Fig.2.2 Inertial Navigation System

Inertial navigation is based on the principle that an object will resist in its current state (stationary or in uniform motion), unless it is disturbed by a force which causes an acceleration. Measuring this acceleration allows us to determine its motion. A mathematical integration with respect to time leads us to the velocity, and through a second integration, we obtain the relative position. To determine the direction it is crucial to consider the actual attitude. Fig.2.2 shows the block diagram of a basic INS. It consists of a measurement unit called IMU or Inertial Measurement Unit, CPU and actuator. IMU consists of the various types of sensors like accelerometers (mostly 3-axis accelerometers), gyroscopes to measure the angles and optionally some other sensors like pressure and temperature sensors for relevant information

The acceleration is measured with an accelerometer. These sensors not only measure the acceleration due to external force, but also the acceleration due to the local gravity. Given that we know the altitude of the accelerometers, we can mathematically remove the local gravity component. In order to determine the altitude, an angular velocity sensor, ie gyroscope can be employed. Mathematically integrating these values allows us to determine the rotation of the platform and therefore the change in its altitude. These calculations enable us to calculate the position of the vehicle with distance travelled, location, direction.2.3 Design of simplified navigation system

Fig.2.3 A simplified navigation system

The navigation system should be capable to provide location data at real time with relevant information and very less amount of errors. Fig.2.4 shows the block diagram of a simplified navigation system which provides basic information of the position and location of the car on real the time basis. The system includes basic components for the navigation which is communicated through serial communication. The basic components are, GPS Satellites Fig. 2.4 GPS satellites trackingThe readymade data of the location is provided by the GPS satellites. There are around 24 satellites revolving around the earth on its orbit, which is used only for sending GPS data, basically the satellite name, time when it sent and position of the satellite. Minimum of 3 GPS satellites are used by forming a triangle and locates the unknown position with its known location of the satellite. Fig.2.4 is the diagram of navigation using satellites forming triangles. The data is sent 24 hours irrespective of the location of the user. GPS Receiver Fig.2.4 shows the GPS receiver used in the system. It can receive the data at the rate of 9600bps. GPS satellites send the data in a format called NMEA (National Marine Electronics Association) format which is unique for all satellites and locations. The receiver captures these signals through antenna which is attached with module and the module converts these signals to RS232 format using MAX232 IC. 2-axis accelerometer Accelerometer used in the system is ADXL202. The proper acceleration measured by an accelerometer is not necessarily the coordinate acceleration (rate of change of velocity). Instead, the accelerometer sees the acceleration associated with the phenomenon ofweight experienced by any test mass at rest in theframe of referenceof the accelerometer device. The ADXL202 is a low cost, low power, complete dual axis accelerometer with a measurement range of 2 g. The ADXL202 outputs analog and digital signals proportional to acceleration in each of the sensitive axes. PIC microcontroller CPU is the other main component of the system. The analog accelerometer data should be converted to digital in order to process by the processor, at the same time there should be a system which contains a UART system to communicate GPS signals with the controller. So the best option is to use a PIC microcontroller. Here in this system PIC18f458 is the MCU used. The PIC18F458 Microcontroller includes 32kb of internal flash Program Memory, together with a large RAM area and an internal EEPROM. An 8-channel 10-bit A/D converter is also included within the microcontroller, making it ideal for real-time systems and monitoring applications. It contains inbuilt SPI (Serial Peripheral Interface) system for communication. PIC based systems are relatively fast and easy to debug. LCD display The Liquid Crystal Display is used in this navigation system to display the position information in fast and reliable way. LCDs are low cost displays which can be programmed according to the application and basic information can be displayed without the usage of graphics.

Fig. 2.5 Liquid Crystal Display Fig.2.5 shows a basic LCD display and its pin diagrams. It needs a 5v supply and 4 pins to control the display. This navigation system uses a 5*7 matrix LCD.2.4 Accelerometer based position calculation Before going in details of the position calculation, it is helpful know about the use of accelerometers in this system. In this particular system accelerometers replaces GPS through a method called Dead reckoning. To get inertial frame velocities and positions, it is first necessary to obtain the physical acceleration of the sensor in the inertial frame. To convert the accelerometer measurement into actual physical acceleration of the sensor, it is important to first understand exactly what the accelerometer is measuring.2.4.1 Dead reckoning

As said, GPS system is already used as primary navigation system for the overall system. But even though GPS data can be used to locate the position without any additional calculation, GPS has got its own drawbacks. If the vehicle is passing through a tunnel or at extreme weather conditions like fog etc. there is a chance of GPS data getting lost. So there is an additional method called dead reckoning. It is the process of calculating one's current position by using a previously determined position, orfix, and advancing that position based upon known or estimated speeds over elapsed time and course. Dead reckoning is subject to cumulative errors. Advances innavigational aidswhich give accurate information on position, in particularsatellite navigation using theGlobal Positioning System, have made simple dead reckoning by humans obsolete for most purposes. However,inertial navigation systems, which provide very accurate directional information, use dead reckoning and are very widely applied. It enables to keep high accuracy positioning by using information from various sensors (gyro sensor, accelerometer, wheel ticks, etc.) to calculate the current position, even when GPS only positioning is difficult. Dead Reckoning solution is widely utilized in automotive navigation systems.2.4.2 ADXL202, 2-axis accelerometer

The ADXL202 is a true accelerometer, easily capable of shock/vibration sensing with virtually no external signal conditioning circuitry. Since the ADXL202 is also sensitive to static (gravitational) acceleration, tilt sensing is also possible. Tilt sensing requires a very low noise floor which usually necessitates restricting the bandwidth of the accelerometer, while shock/vibration sensing requires wide bandwidth. The ADXL202 is a low cost, low power, complete dual axis accelerometer with a measurement range of 2 g. The features can be listed as, Measurement range of 2 g/10 g.

It can measure both dynamic and static acceleration. 2-Axis Acceleration Sensor on a Single IC Chip +3 V to +5.25 V Single Supply Operation 1000 g Shock Survival Low Power