Quadcopters in flight

INTRODUCTION

UAV is termed as Unmanned Aerial Vehicle, popularly known as drone. It is also known as unpiloted aerial vehicle by International Civil Aviation Organization. It is an air vehicle without human pilot. Quadcopter (UAV) also known as Quadrotor is a four propeller system having an arrangement of four independent rotors on it. This arrangement removes the concept of swash plates which were used earlier for more usage of degrees of freedom. The control of this type of quadcopter is next to impossible without the integration of electronics system in it. Quadcopters has 6 degrees of freedom and four independently working rotors with their rotor speeds. These UAVs use an electronic control system and electronic devices and sensors to stabilize the structure. Being small size and easy manoeuvres, these quadcopters can be flown indoors as well as outdoors. Quad-rotor consists of total four motors, with fixed-pitch blades located at the four corners. Quadcopters do not require any complex type of mechanical control linkages for motor actuation. It makes both the design and maintenance of the vehicle very convenient. The use of four rotors ensures that individual rotors are smaller in diameter than the equivalent main rotor on a helicopter, compared to the airframe size. The individual rotors, hence store less kinetic energy during flight.

 DESIGN AND CONFIGURATION

The common quadcopter has four rotating angles and four input power, each motor giving its own power. The configuration can move and remain in vertical direction. This configuration helps the quadcopter to land in any conditions. That means no specific landing platform is needed. The main components manufactured for quadcopters are the centre frame supports, landing gears and crash absorbers, and the arms. The centre piece is created from two flat pieces of carbon to obtain desired shape and characteristics. These helps in holding the electronic devices. 

There are 2 types of configurations: 1) "+"     2) "x"

The stable configuration is considered to be x type. The 1 and 3 rotates clockwise (CW) and 2 and 4 rotates Counter Clockwise (CWW). For the movement of a Quadcopter, pitch angle is very necessary to be considered. For stable forward movement, the speed of forward rotors is increased and on the same time the speed of rear rotors is decreased. This action changes the pitch angle. 

For the direction part, the quadcopter structure is divided into 3 axes; x, y, z. The rotor will point towards z direction and the arms will point towards x and y directions. The three Euler angles of roll angle (Φ), pitch angle (θ), and yaw angle (ϕ) are used for determining the position of quadcopter. The pitch angle θ helps in finding the rotation of the quadcopter about the y-axis. Roll angle ϕ finds the rotation about the x-axis and the yaw angle ψ about the z-axis.

By changing the speed of propellers , we get gives equations of yaw, roll, and pitch quadcopter:

 

Yaw = ky (( ω1 + ω3) – (ω2+ ω4))

Roll =kr (( ω1 + ω3) – (ω2+ ω4)) 

Pitch = kp (( ω1 + ω3) – (ω2+ ω4)) 

So, a decrease of rotor velocity of 2nd and an increase in rotor velocity of 4th acquires roll movement.   On the same hand, reducing rotor velocity 1st and increasing rotor velocities of 3rd gives pitch movement. Increasing the angular velocities of the two opposing rotors and reducing the velocities the other two determines yaw movements.

MODELLING OF QUADCOPTER USING CATIA

                      

SCOPE OF QUADCOPTERS

1) Construction:

Drones in this sector are used to survey building sites, progress, 3D mapping, examine construction materials, and check security functions.

2) Agriculture:

It helps in Aerial investigation of land to identify and manage potential crop threats, like pests or plant infestations. Irregularities in soil can also be found. Aerial drones may scan fruits and crops for temperature change to hunt out ongoing issues.