Unmanned Aerial Vehicle (UAV)

CHAPTER 1
INTRODUCTION
Unmanned Aerial Vehicle (UAV), also commonly known as drone is either an autonomous or remote controlled state-of-the-art aerial flying vehicle without a human onboard. During the recent years, small scale UAVs are increasingly gaining attention due to the fact that they are highly agile, capable and maneuverable apart from being cheap and can be constructed using easily available parts. Hobbyists and researchers use them as advanced and versatile platforms to implement and test new ideas in a number of different fields including, but not limited to robotics, intelligence, control systems, navigation and real-time systems.
There has been a tremendous rise towards the work of Unmanned Aerial Vehicles in the recent years.

It utilizes closed loop control feedback to maintain stability and steadiness. An electronic device called Inertial Measurement unit (IMU) which includes combination of the sensors – accelerometer, gyroscope, magnetometer and barometer (altimeter). Each of these sensor devices except the barometer can determine 3 axes of coordinates (x, y and z). For instance, combination of accelerometer and gyroscope will give 6 Degrees of Freedom (6 DoF) i.e. number of different independent parameters that describe the state or configuration of the system. If the combination of all the sensors are used, then it can achieve 10

It is obvious a UAV is sure to face obstacles either in indoor or outdoor environment or both and thus the avoidance of obstacles namely collision avoidance becomes a crucial task to overcome as cited by the United States Department of Defense [2]. Meister et.al. [3] and Moses et.al. [4] investigated collision detection and avoidance using multiple sensors. Sensors like RADAR, LIDAR, ultrasonic sensors, laser range finders, infrared sensor, etc. are used for ranging and detection of obstacles and hindrances in the flight trajectory for the UAV system. In addition to the sensors, UAVs are also capable of having on board cameras which provides the remote user a real time video feed to enable the user steer away from barriers or