Development of GPS and obstacle avoidance Based low altitude navigation system for a Powered parachute aerial vehicle

Abstract

Unmanned Aerial Vehicle is an aircraft with no on board pilot. UAVs can be controlled with remote or autonomously. They are used for number of different missions depending upon the application. There are different types of UAVs available like fixed wing, multi copter and Parafoil UAV. Certain characteristics like low speed, high payload carrying capability, etc. makes Parafoil UAV a versatile platform for various applications. Parafoil is entirely made of fabric and is a non- rigid wing. A Parafoil get inflated just like a parachute when dropped from a height. The wing has a low aspect ratio with an elliptical or a rectangular plan form when inflated. To act as an airfoil, the upper membrane and the lower membrane are sewn together with a gap between both. The leading edge is kept open so as to allow the air inside the cells creating air pressure, which maintains the shape of the Parafoil as a wing. The vents in the ribs allow the air pass from one cell to another which helps in maintaining uniform air pressure in the wing. To avoid the air loss the fabric is made of nonporous material. The suspension lines are used to connect the Parafoil to the newlinepayload. Addition of a Propulsion unit on the payload makes the Paraglider a Parafoil UAV. This Vehicle has a Fly-bar to which the Parafoil is connected and a motor on the Payload. Directional control is achieved by pulling the fly-bar either side, which changes the direction of the lift making the aircraft turn. The Powered Parafoil has a tendency to fly at constant airspeed. These systems have pendulum stability and oscillations, because of the mass of the airframe suspended significantly below the canopy, which allows the system to have a yaw motion rather than roll motion. Lateral control is obtained by the propulsion system which is attached to the payload. The thrust of the propulsion system is controlled to maintain the altitude, take-off or landing. Modeling of Parafoil UAV has been studied in detail in this work.