Embedded system in_automobiles_seminar_report_1234Document Transcript
WHAT ARE EMBEDDED SYSTEMS? We read in newspapers that a doctor had successfully transplanted a cardiacpacemaker in his patient’s chest by sitting around 200kilometres away. Also we know aboutdriverless cars that could take us to the destiny by using its inbuilt navigation systems.Embedded microprocessors or micro controllers are the brain behind these. An embedded system is any device controlled by instructions stored on a chip. Thesedevices are usually controlled by a micro processor that executes the instructions stored on aread only memory(ROM) chip. The software for the embedded system is called firmware. The firmware will bewritten in assembly language for time or resource critical operations or using higher levellanguages like C or embedded C. The software will be simulated using micro code simulatorsfor the target processor. Since they are supposed to perform only specific tasks, theseprograms are stored in read only memories(ROMs).Moreover they may need no or minimalinputs from the user, hence the user interface like monitor, mouse and large keyboard etc,maybe absent. Embedded systems are computer systems that monitor, respond to, or control anexternal environment. This environment is connected to the computer system through sensors,actuators, and other input-output interfaces. It may consist of physical or biological objects ofany form and structure. Often humans are part of the connected external world, but a widerange of other natural and artificial objects, as well as animals are also possible. Embedded systems are also known as real time systems since they respond to an inputor event and produce the result within a guaranteed time period. This time period can be fewmicroseconds to days or months. The computer system must meet various timing and other
constraints that are imposed on it by the real-time behavior of the external world to which it isinterfaced. Hence comes the name real time. Another Name for many of these systems isreactive systems, because their primary purpose is to respond to or react to signals from theirenvironment. A real time computer system may be a component of a larger system in which itis embedded; reasonably such a computer component is called an embedded system. Embedded systems control engine management systems in automobiles, monitor homeheating systems and regulate the quiet operation and the even distribution of laundry inwashing machines. They are the heart of toys like Furby and Tamagotchi, of golf balls thatcannot get lost and of gas pumps at gasoline stations that advertise nearby restaurants onvideo. Above all, state-of-the art communications equipment like WAP mobile telephones,MP3 players, set-top boxes and Net devices would not be possible without these powerfulminiature brains. Applications and examples of real time systems are ubiquitous and proliferating,appearing as part of our commercial, government, military, medical, educational, and culturalinfrastructures. Included are:• Vehicle systems for automobiles, subways, aircraft, railways and ships.• Traffic control for highways, airspace, railway tracks and shipping lanes.• Process control for power plants, chemical plants and consumer products such as soft drinks and beer.• Medical systems for radiation therapy, patient monitoring and defibrillation• Military uses such as firing weapons, tracking and command and control.
• Manufacturing systems with robots.• Telephone, radio and satellite communications.• Computer games.• Multi media systems that provide text, graphic, audio and video interfaces.• House holds systems for monitoring and controlling appliances.• Building managers that controls such entities as heat, light, Doors and elevators.
IN THE DRIVING SEAT There are several tasks in which real time OSs beat their desktop counterparts hands-down. A common application of embedded systems in the real world is in automobilesbecause these systems are cheap, efficient and problem free. Almost every car that rolls off theproduction line these days makes use of embedded technology in one form or theother.RTOSs are performed in this area due to their fast response times and minimal systemrequirements. Most of the embedded systems in automobiles are rugged in nature, as most of thesesystems are made up of a single chip. Other factors aiding their use are the low costs involved,ease of development, and the fact that embedded devices can be networked to act as submodules in a large system. No driver clashes or ‘system busy’ condition happen in thesesystems. Their compact profiles enable them to fit easily under the cramped hood of a car. Embedded systems can be used to implement features ranging from adjustment of thesuspension to suit road conditions and the octane content in the fuel to anti lock braking
systems (ABS) and security systems. Speaking of the things nearer home the ‘computer chip’that control fuel injections in a Hyundai Santro or the one that controls the activation of airbag in a Fiat in a weekend in nothing but an embedded system. Right from brakes toautomatic traction control to air bags and fuel/air mixture controls, there may be upto 30-50embedded systems within a present-day car. And this is just a beginning. THE DOCTOR WILL SEE YOU NOW Imagine a time when body transplants like cardiac pacemakers will be able to monitorand manage themselves remotely. These systems will be so compact that the patient wouldn’t
even be aware that they are embedded in his body. Another point in favor of RTOSs is theirstability, instantaneousresponse and efficiency. No OS crashes or delay in responding, as in the case with mostdesktop OSes. After all, which patient can rest easy with the thought of his life literallyhanging by a thread due to the time taken by the OS to load!
Embedded technology advances are pointing towards the use of pace makers that canbe transplanted in or near the heart itself. The pacemaker will be able to monitor parameterslike blood pressure, blood flow, pulse rate, temperature, etc, using micro sensors planted invarious parts of the body. This capability will enable the pace maker to automatically vary itsoperation to suit the changing body conditions. It will also transmit data using wirelesstransmission, thus enabling a doctor to constantly monitor its operation. In most cases,wireless transmitter implanted near the surface of the skin. In case any abnormality is detectedthe doctor will be able to take remedial actions even from a remote location. WIRED WEARABLES
A mobile phone in the form of a ring or an ear ring? What about cool sunglasses withstreaming video displays built into them? All these can soon be a reality. Embedded systemshave a small foot print and consume very little power which makes them ideal for wearablecomputing applications.The minimal system requirements of these devices ensure that thehardware is almost microscopic. IBM is already working on the prototype of a mobile phone that can be worn asjewellery.The components of the phone will be distributed among different pieces of jewelleryear ring, necklace, ring and bracelet. The phone is likely to have blue tooth capability built into it. The ear rings will haveembedded speakers and will act as the receiver. The necklace will have embedded microphones that will act as a mouth piece user can talk into. IBM called the ring part of the phonethe decoder ring. Light emitting diodes (LEDs) will flash to indicate an incoming call. Thering will also have features that will enable it to be programmed to flash different colors for aparticular user or to indicate the importance of a call. A video graphics array (VGA) will bebuilt into the bracelet, which will display the name and phone number of the caller. Thebracelet will also integrate the keypad and the dialing functions in it. IBM plans to incorporatevoice recognition technology for dialing a number. The phone may also have features toindicate new email. DON’T KEEP YOUR EYES ON THE ROAD
Embedded systems can also make driverless vehicle control a reality. Majorautomobile manufacturers are already engaged in work on these concepts. One suchtechnology is Adaptive Cruise Control (ACC). ACC allows cars to keep safe distances from other vehicles on busy highways. Thedriver can set the speed of his car and the distance between his car and others. When trafficslows down, ACC alters vehicle speed using moderate braking. This ensures that a constantdistance is maintained between cars. As soon as traffic becomes less, ACC moves up to thedesired cruise speed that has been set by the driver. The driver can over ride the system anytime he wants to be breaking. Each car with ACC has a micro wave radar unit or laser transceiver fixed in front of itto determine the distance and relative speed of any vehicle in the path. The ACC computer(What else but an embedded system or a grouped system of embedded system) constantlycontrols the throttle and brakes of the car. This helps to make sure that the set cruise speed oradapted speed of traffic at that time is not exceeded. THE WORKING PRINCIPLE OF ADAPTIVE CRUISE CONTROL
As already mentioned each car with ACC have a micro wave radar unit fixed in frontof it to determine the distance and relative speed of any vehicle in it’s path. The principlebehind the working of this type of radar is- the Doppler Effect.Doppler Effect: Doppler Effect is the change in frequency of the waves when there is a relative motionbetween the transmitting and receiving units. The two figures below clearly show the DopplerEffect.1. Higher Pitch Sound In this case the vehicle is speeding towards the stationary listener. The distancebetween the listener and the car is decreasing. Then the listener will hear a higher pitch soundfrom the car, which means the frequency of sound, is increased.2. Lower pitch sound
In this case the vehicle is moving away from the listener. The distance between andthe car is increasing. Then the listener will hear a lower pitch sound from the car, whichmeans the frequency of sound, is decreased. So that is the Doppler Effect in case of soundwaves. Similarly the radar unit in ACC will be continuously transmitting radio waves. Theywill be reflected and echo singles (reflected waves) will be having the same frequency ordifferent frequency depending on speed/position of the object due to which the echo singlesoriginate. If the echoes singles have the same frequency it is clear that there is no relativemotion between the transmitting and receiving ends. If the frequency is increased it is clearthat the distance between the two is decreasing and if the frequency is decreased it means thatthe distance is increasing. The figure below shows a car having ACC transmitting and receiving radio waves.
In the above case, the gun transmits the waves at a given frequency toward anoncoming car. Reflecting waves return to the gun at a different frequency, depending on howfast the car being tracked is moving. A device in the gun compares the transmission frequencyto the received frequency to determine the speed of the car. Here, the high frequency or thereflected waves indicate the motorist in the left car is speeding. The embedded system is connected to the radar unit and its output will be sent tobreaking and accelerating unit as early mentioned the embedded system is a device controlledby instructions stored in a chip. So we can design the chip or ACC having an algorithm suchthat it will give output only when the input signals are less than the corresponding safedistance value. So only when the between the car and the object in front of it is less then thesame distance value the embedded system will give output to the breaking and theaccelerating units. Thus the safe distance will be kept always. That’s how the ACC works. ABOUT THE BEAUTY OF ADAPTIVE CRUISE CONTROL As the driver in the next lane swerves in front of you, you feel that gas back off andthe brakes grab in the car you’ re driving- a Mercedes Benz S-class luxury vehicle, the first
passenger car equipped with a technology called adaptive cruise control. The technologymakes these adjustments even though you haven’t touched the brake or gas pedal. At a safe distance behind, your Mercedes settles to a speed matching that of the driverin front of you. That’s too slow, so after a look in your rear view mirror you pull into theempty outside lane and feel the acceleration as your car speeds up to the preset cruising speed.You still haven’t press the accelerator pedal. That’s the beauty of this racing star of the autoindustry, a millimeter- wave radar technology that promises not only to make driving easier,but to ignite a market for gallium arsenide and other compound semi conductor components. Although grey hound buses and some heavy- goods vehicles have been fitted withautomotive radar systems, the Mercedes is reckoned to be the first passenger automobile tosport this advanced use of electronics, and observers say it is likely to lead a proliferation ofthe technology. The Mercedes Benz system uses a 77-GHz Doppler radar linked into theelectronic control and braking system to maintain a safe distance between a car with thesystem and the vehicle in front of it. Daimler Benz Aero space has completed the design of ahybrid 77-GHz radar, called Tempo mat, which is being considered for deployment. Holger Meinel, senior researcher at Daimler Benz Aerospace AG (Ulm, Germany),was quick to make a point stressed by all the companies working in this field. “This is notanti- collision radar” he said. “It’s not a safety feature, it’s a comfort feature”. The source of this distinction is concerned that if adaptive cruise control is marketedas a safety feature, the first accident that occurs involving a vehicle equipped with millimeter-wave radar will bring a damaging liability suit. That’s why companies are at great pains topoint out that the driver retains control and responsibility.
CONCLUSION Most of the microprocessors in the world are not in pcs, they are embedded in deviceswhich control traffic for highways, airspace, railway tracks, and shipping lanes tomanufacturing systems with robots. An embedded system is any device controlled byinstructions stored on a chip. These devices are usually controlled by a microprocessor thatexecutes the instructions stored on a read only memory (ROM) chip. This the topic of myseminar. Embedded systems can be used to implement features ranging from the waypacemakers operate and mobile phone that can be worn as jewellery to adaptive cruisecontrol(ACC). In this seminar I will explain one such technology that uses the embeddedsystems- The Adaptive Cruise Control.
ACKNOWLEDGEMENT I express my sincere and heartfelt gratitude to PROF: AGNISHARMAN NAMBOODIRI , Head of Department of InformationTechnology and computer science , for giving me an opportunity to present this seminar. Ialso express my sincere thanks to ASSISTANT PROF: SANGEETHA for providing theexpert guidance and help needed for successfully presenting the seminar and for thecompletion of this report there after. I also thank profoundly, the services of Miss. Deepa.S.S. , coordinator of seminar activities. I also thank Ms Anees Philip, Mr.Lino Varghese,Mrs.Shajila Beegam, Department of Information Technology , for their guidance in thepresentation of this seminar. Last but not least, I thank all of my friends who helped me for the successfulpresentation of the seminar. SHAHID MOHAMED
ABSTRACT Most of the microprocessors in the world are not in pcs, they are embedded in deviceswhich control traffic for highways, airspace, railway tracks, and shipping lanes tomanufacturing systems with robots. An embedded system is any device controlled byinstructions stored on a chip. These devices are usually controlled by a microprocessor thatexecutes the instructions stored on a read only memory (ROM) chip. This the topic of myseminar. Embedded systems can be used to implement features ranging from the waypacemakers operate and mobile phone that can be worn as jewellery to adaptive cruisecontrol(ACC). In this seminar I will explain one such technology that uses the embeddedsystems- The Adaptive Cruise Control.
CONTENTS1. What are embedded systems? 12. In the driving seat 43. The doctor will see you now 64. Wired wearables 85. Don’t keep your eyes on the road 96. The working principle of Adaptive cruise control 107. About the beauty of Adaptive Cruise Control 138. Conclusion 15