07-03-2011, 10:30 AM
[attachment=9654]
AUTONOMOUS CAR
Abstract
The technical Brilliance and Developments in different fields has led to a drastic change especially in the communication field. Devices with intelligence rule the world. Imbibing intelligence to these devices is through a system called “EMBEDDED SYSTEMS”. It is the evolution or further development of the computing system. Its applications provide marvelous opportunities for ingenious use of computer technology. Almost every new system introduced is an example of Embedded System. These systems are more intelligent and autonomous.
Embedded Systems are combinations of hardware and software that are mounted on compact electronic circuit boards integrated into devices. They are engineered or intended to perform one specific function in a specific environment. An important decision in the design of an embedded system is the selection of the processor(s) around which the rest of the system is to be built. It is a chip that contains a microprocessor, some memory & I/O interface circuitry useful in embedded applications and is often called an ‘EMBEDDED PROCESSOR’ or ‘MICRO CONTROLLER’ chips as they perform important control functions, and are based on micro controller.
The current topic “Automation of car” that we are going to present is one of the fine examples of Embedded System.
Autonomous car: There are many paradigm shifts taking place due to information explosion and the concept of autonomous vehicle is one shift. The car, which is embedded, can simulate the human driver completely and direct the vehicle on the road. Autonomous vehicle is the drastic change in technical brilliance and developments in different fields with EMBEDDED SYSTEM as pioneer.
Introduction:
The term embedded system is quite a complex one. Simply it is a combination of hardware and software that forms the component of a larger system, this in turn is programmed to perform a range of dedicated functions usually with a minimal operator intervention. In embedded systems the hardware is normally unique to a given application, computer chips are embedded into the control electronics to manage the products functionality.
Embedded systems are rapidly becoming a catalyst for change in computing data communications, telecommunications, industrial control and entertainment sectors. New innovative applications in these as well as other areas such as home networking and car infotainment will roll out in the near feature.
The fine art of automation:
We load the code of our destination in the dashboard computer and turn the car on, while we remain seated carefree on the rear seats. Then its all the job of the ‘unknown’ to drive it on the roads, bridges, thought the bazaars, past the crossings to the destination, without getting challenged even once for traffic rule violations.
A fully computerized car capable of doing almost everything a car lover would want to. Almost all automobiles will interact with computer on dashboards. From ordering pizza to booking tickets at the nearest theatre, things would be as easy as giving orders to your servant. As a matter of fact, vehicles all over the world are now fitted with intelligent devices that make the vehicles to respond to various factors –be it climate control, sudden accelerations or braking or even self-repair of modules.
The finger print technologies have been introduced to enter and start your car with the touch of a finger. The fingerprint, which is acting as a key, would trigger a check of the mirrors, steering wheel, radio and temperature to ensure that they're the way you like them. The convenience of fingerprint recognition technology comes with heightened security. Unlike personal identification numbers, passwords and keys, each person's unique fingerprints can't be duplicated, lost or forgotten.
Description:
As stated above that a vehicle can run by itself with out the intervention of human beings by the embedded intelligence in it. For this purpose Global Positioning System (G.P.S) using satellites can provide positioning information and proves to be a versatile all-time. For still higher accuracy wide area differential GPS is used, which offers a robust system that readily deals with selective availability errors and satellite clock errors.
The models for GPS also include aiding sensors, e.g. dead reckoning, radar and camera. A computer is simply required to feed destination into a dashboard computer. Highly sensitive actuators simulate a human driver completely and direct the vehicle on the road. The vehicle transmitter broadcasts its position and velocity to other immediate participants for collision-avoidance and lane changing manoeuvres. Forward and reverse motions and u-turns are precisely achieved as per route guidance requirements. Furthermore, an accurate steering control is obtained using Pulse Code Modulation technique and acceleration/braking control is successfully implemented using learning adaptive system.
The reliability, efficiency and cost effectiveness of an autonomous vehicle depend mainly on how judiciously its navigation sensors, perception unit and computer control is incorporated.
The driver’s activity is influenced by several factors that depend on driver itself and is environment such as traffic density, traffic status, time of travel and weather. Thus the driving activity deals with a combined driver vehicle-environment system shown in figure
The vehicle is required to blend its environmental perception capabilities with its intelligent controls in order to affect optimal path-planning strategies that not only avoid obstacles but also minimize criteria such as time of travel, fuel consumption, exposure to pollution/danger, etc. however basic driving functions consists of lane-keeping, safe distance maintenance, timely lane changing and overtaking. The key to all these driving tasks is collision avoidance.
The Master Control Station (MCS) receives the positioning information from the satellite by employing WADGPS concept. The MCS is linked to GPS instrumented position location systems (PLS) installed on the autonomous vehicles through a data page link sub system (DLS). The DLS can either use VHF or UHF or L-band, incorporating time division multiple access protocol to handle on the roads. A block forward error correction code is employed to protect and maintain the message integrity.
The desired destination and starting position of the vehicle together with the time of travel, manifest an optimal route on the road network. Once the vehicle commences the journey the sensors continuously keep track of the direction and displacement of the vehicle initial calibration is a little crucial for dead reckoning performance; however a feedback calibration indicated in fig suggested obtaining distance accuracy better than 99.9 percent.
The new generation microprocessors promises further increase in system capabilities while simultaneously shrinking both volume and power consumption of the autonomous vehicle embedded system. The digital road maps, available on CD-ROM’s have substantially increased safety of automobiles. These maps along with GPS navigation provide a feasible solution to autonomous vehicle system.
