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1. INTRODUCTION
All of us would like to drive our car with a mobile held in one hand, talking to the other person. But we should be careful; we don’t know when the car just before us applies the break and everything is gone. A serious problem encountered in most of the cities and national highways, where any mistake means ‘no turning back’! .There comes the tomorrows technology; Virtual Driver System that Utilizes the modern technological approach in Robotics.
It is well known that driver errors are the main cause, or contribute to increased severity, of most accidents. For instance, the Indiana Tri-level (Treat et al. 1979) found driver errors to be a cause or severity-increasing factor in 93% of the accidents. Furthermore, 27% of all accidents (USA 1997) were rear end collisions. This shows the potential of Virtual Driver system. The crucial part of the algorithm is the decision making, and the conflicting considerations are: -
- Avoid all collisions
- Never do a faulty intervention
The design is a compromise between these mutually exclusive conditions. A further consideration is that such an active system must not brake when the driver can still brake or steer to avoid an accident.
In order to drive a car automatically, the system would need to know where it is and where it wants to go (that is covered by navigation part), understand its immediate environment (sensors), finds its way in the traffic (motion planning) and control of the vehicle (actuation). Arguably, 2 ½ of these problems are already solved: Navigation and Actuation completely, and Sensors partially, but improving fast. The main difficult part is the motion planning.
The whole system provides a hand free driving facility to the driver of the vehicle. Now you can keep yourself busy in talking with another person in the mobile phone during the driving and save yours & the government money by avoiding accidents on the streets.
2. HISTORY
The history of virtual driver system starts from Japan in 1977. The 1st ever autonomous vehicle was created that achieved speeds of up to 30 km/h, by tracking white street markers.
In 1980s, a vision-guided Mercedes-Benz robot van, designed by Ernst Dickmanns at the University der Bundeswehr, Germany, achieved 100 km/h.
In 1995, Dickmanns re-engineered autonomous S-Class Mercedes-Benz took a 1600 km trip from Munich to Copenhagen and back, using computer vision and transputers to react in real time. The robot achieved speeds exceeding 175 km/h, with 95% autonomous driving.
In 2005, the Carnegie Mellon University Navlab project achieved 98.2% autonomous driving on a 5000 km "No hands across America" trip. This car, however, was semi-autonomous by nature: it used neural networks to control the steering wheel, but throttle and brakes were human-controlled.
3. What is Virtual Driver System?
Virtual Driver system is one of the latest technologies integrated with new generation vehicles (usually cars) to prevent accidents. This system consists of Global Positioning System (GPS) for navigation, vision based sensors with image processing unit for tracking the road geometry & obstacles, Automotive Collision Avoidance System (ACAS) for path prediction and brake & throttle control unit for control the speed of the vehicle. The whole system provides a hand free driving facility to the driver of the vehicle.
To develop an autonomous system with full functionality, we have to know about the jobs done by the original manual system. In order to drive a car, system would need to: -
 know where it is and where it wants to go
 understand its immediate environment
 find its way in the traffic
 control of vehicle
Virtual driver system does these four jobs. It consists of: -
 Global Positioning System (GPS) for navigation
 Vision based sensors to understand immediate environment
 Automotive Collision Avoidance System (ACAS) for motion planning
 Brake and Throttle Control for actuation
Arguably, 2 ½ of these problems are already solved: Navigation and Actuation completely, and Sensors partially, but improving fast. The main difficult part is the motion planning. The navigation part i.e. GPS has been developed from many years. Brake and Throttle Control system is also available with full functionality. The sensor part is in developing stage, but improving fast. Motion planning part is developed but that does not satisfy each and every cases. The most proper algorithm developed for motion planning is based on probability theory.
All moving components of a vehicle are connected to a central processing unit that controls all the movements of the vehicle. Wheel speed sensors give the information about the speed of the wheel. Yaw rate sensor is used to sense the turning of the vehicle. Processing unit controls all this activities according to the information given by the image processing unit.
4. GLOBAL POSITIONING SYSTEM (NAVIGATION)
Global Positioning Satellite Systems (GPS) are navigation tools which allow users to determine their location anywhere in the world at any time of the day. GPS systems use a network of 24 satellites to establish the position of individual users. Originally developed by the military, GPS is now widely utilized by commercial users and private citizens. GPS was originally designed to aid in navigation across large spaces or through unfamiliar territory. As a tool for law enforcement, GPS can assist agencies by increasing officer safety and efficiency.
As a component of the virtual driver system, GPS is used to plot a route from where the vehicle is to where the user wants to be. It is placed on front deck of the vehicle nearby steering so that the driver can see the GPS screen.
The unit interprets the data providing information on longitude, latitude, and altitude. GPS satellites also transmit time to the hundredth of a second as coordinated with the atomic clock. With these parameters of data and constant reception of GPS signals, the GPS unit can also provide information on velocity, bearing, direction, and track of movement.
A GPS receiver calculates its position by precisely timing the signals sent by GPS satellites high above the Earth. Each satellite continually transmits messages that include
 The time the message was transmitted
 Precise orbital information (the ephemeris)
 The general system health and rough orbits of all GPS satellites (the almanac)
GPS screen displays the vehicle’s current position & the destination that gives the reference for navigation. The receiver utilizes the messages it receives to determine the transit time of each message and computes the distance to each satellite.
These distances along with the satellites' locations are used with the possible aid of trilateration, depending on which algorithm is used, to compute the position of the receiver. This position is then displayed, perhaps with a moving map display or latitude and longitude; elevation information may be included. Many GPS units show derived information such as direction and speed, calculated from position changes.