GPS GUIDED DRIVERLESS CAR

Majo G Mattam

Viswajyothi college of engineering & technology

IT department

ABSTRACT

The GPS(Global positioning system) technology is growing fastly, not only in the science purposes but also in the field of electronic systems and other purposes. Using the advantage of this topic we advise a low cost automobile GPS guidance system controlled by an 8-bit MCU (micro controller unit) (MCS-51) which support the functions like GPS guiding ,obstacle avoidance and wireless communication. We only accomplished the aim in a toy car as the cost and time is so consuming .The advantage of motion sensing is also implemented in the system.

Keywords: GPS,MCS 51

1. INTRODUCTION

The driverless car concept was developed before 30 years. The driverless car concept helped the field of automobile in a very advantageous way with automatic driving technology with application of motion sensing, obstacle avoidance, GPS guiding and so on. The 2005 DAARPA grand challenge and the 2007 DAARPA urban challenge [5] are two excellent driverless cars of the recent events. Both the system that is our model and the DAARPA system receive the signals from the satellites. Our model is an innovation in the cost of the system when compared to the beginners.

2. ARCHITECTURE

2.1 Mechanical

Due to the budget limit we advise a toy car which is capable of moving at a speed over 2m/s on a flat surface and a turning angle of 30 degree for the front wheel. A toy car which can be moved forward/backward and turn left and right can be used.

2.2 Electrical and Electronic

Most of the working side of the system is based on the electronic and electrical components.

The block diagram of the guidance system consists of an electronic compass, ultra-sonic sensor, an H-bridge driver for enhancing the movement and turning, an optical sensor, a wireless transceiver. The whole system is controlled by an 8-bit MCU. This is shown in fig 1.

pwm

pwm

fig 1. System block diagram of a guidance system [1]

Ultrasonic sensor H-bridge driver(moving)

GPS module

Electronic compass

Optical sensor

8-bit MCU

H-bridge driver(turning)Wireless transceiver

PWM

PWM

Fig 2. System block diagram of proposed guidance system

Off Road Driving Road Roughness Traffic Signals

Ultra-Sonic Sensor

Electronic Compass

8-bit

MCU

Optical Sensor

s

Wireless Transceiver H-bridge Driver

(turning)

H-bridge Driver

(moving)

GPS

Module

Sensing Capasity

3. SUBSYSTEM3.1 Driving the DC motor: H-bridge driver + PWM

We only need to replace the drivers of the motors since the toy car already has two small dc motors respectively for moving and turning. Using H-bridge driver it is easy to drive a dc motor and with the proper PWM signals added it makes it easy to implement the speed and direction control on a dc motor. The PWM signals are generated using the MCS-51 based MCU.

3.2 Sensing the movements of car: homemade optical – rotary encoder

In this section the movement of the car is discussed. An ultrasonic sensor is implemented for sensing the obstacles nearby and to avoid the stuck sitiation a reflective photo interrupter is used nearby the rear wheel. It will output “on” whenever it is right above the reflective sticker,otherwise outputs “off”. When the car is kept moving it will generate frequent on/off signal from the photo interrupter. Usually, this is an effective approach for escaping the situation. So, the MCU can make a rough measurement of speed with this signal.

3.3 Guiding the car: GPS + compass module In the guidance system GPS receiver and the compass module plays the most important role. The signal is received from the satellite and the information is used by the GPS receiver and is retransmitted to MCU through serial port once every second.The compass module is used to derive the direction of the car. According to this application the car is moving in the specific direction.

3.4 Obstacle avoidance The obstacle avoidance is carried out by the use of ultra sonic sensor. We can avoid the obstacles by using different ultrasonic sensors.The obstacle avoidance is carried out according to the distance between the car and the obstacles and the speed of the car.

3.5 Wireless Communication Wireless communication provides the destination setting and provides certain codes to change the path to the destination according to the distance. We can implement different codes for different paths.

4. PROBLEM DEFINITION4.1 Traffic signals cannot be captured.

In this system traffic signals cannot be captured or the application for that technique is not implemented.

4.2 Off road driving is not possible The proposed system doesnot accomplish the off road driving instead it only allows the driving in a flat surface.

4.3 GPS data may not be precise GPS system may not give the accurate data at every time.

4.4 Parking assistance is not implemented Parking assistance is not provided in the system.

4.5 Sensing limitations Sensing is limited in certain situations.

5 PROBLEM SOLUTION

5.1 Traffic signals

The system for capturing traffic signals can be enabled by using road profile recognition for car navigation and navstar GPS support. [3]

5.2 Off road driving.

Off road driving must be enabled by using online speed adaptation technique [2] [4]

5.3 GPS data

By using road profile recognition we can get accurate GPS data. [3]

5.4 Parking assistance

Parking assistance can be implemented using autonomous fuzzy parking control of a car-like mobile robot. [6]

5.5 Sensing capacity

Sensing capacity can be implemented by designing the sensor with certain specification. [7]

6 CONCLUSION

The prototype model which is intended to guide a car using GPS navigation system. The system also features on the obstacle avoidance by using the ultrasonic sensors. The destination point is set using the wireless transceivers.

7.REFERENCE

[1] Ray-Shine Run,Jui-Cheng Yen,Cheng-Yu Tsai A Low Cost Implementation of GPS

Guided Driverless Cars

[2] Sebastian Thrun, Mike Montemerlo, Andrei Aron, “Probabilistic TerrainAnalysis For High-Speed Desert Driving”.

[3] W. Holzapfel, M. Sofsky, U. Neuschaefer-Rube, ” Road profile recognition for autonomous car navigation and Navstar GPS support”,

Aerospace and Electronic Systems, IEEE Transactions on Volume 39,Issue 1, Jan. 2003, pp. 2-12.

[4] David Stavens, Gabriel Hoffmann, and Sebastian Thrun, “Online SpeedAdaptation using Supervised Learning for High-Speed, Off-RoadAutonomous Driving”.

[5] http://en.wikipedia.org/wiki/DARPA_Grand_Challenge[6] Tzuu-Hseng S. Li, and Shih-Jie Chang, “Autonomous fuzzy parking control of a car-like mobile robot”, IEEE Transactions on Systems, Man, and Cybernetics—Part A: Systems and Humans, Vol. 33, No. 4, July 2003.[7] Tzuu-Hseng S. Li, Chih-Yang Chen, et. al., “Design and Implementation of Sensor Fusion Based Behavior Strategies for a Surveillance and Security Robot Team”, in Proc. of SICE 2008, August 2008, Japan