Monday, 10 December 2012

Design Process


Design Process
The design process for the quadcopter is best described by first explaining the mechanical design and then following up with the electrical design. The following subsections will describe in detail the steps taken to design the quadcopter.

Mechanical Design
The unique nature of a flying machine requires a frame design that is both strong and lightweight. However, most materials that exhibit both of these characteristics are expensive, and also difficult to process. Therefore, aluminum was selected as the primary frame material due to its ready availability, relatively low cost, and reasonable strength to weight properties. Any components that were not major structural members were designed to be plastic, which is generally more expensive but lighter.
The original frame design involved mounting all four engines near the center of the flying machine, and extending driveshafts out to the four rotors. This design had the disadvantage of being very heavy (close to 15 lbs), and the drivetrain design was complex and difficult to build. The basic quadcopter design requires two of the four rotors to spin in the opposite direction as the other two. In the first generation frame design, this was accomplished through gearing, adding to the complexity of the design. The main reason for mounting the engines near the center was a perceived increase in stability due to most of the mass of the machine being located near the center of mass, decreasing the potential moment on the machine.



Electrical Design
A complex electrical system had to be designed in order to gather and process information in order to control the quadcopter. A top-level block diagram containing all of the major components of the electrical system is shown in Figure. 



The main part of the entire electrical system is the Controller board (which in our case was the Ardu-IMU V2 board). Controller board accepts input from various other electrical devices (Sensors) which it processes and provides output to the motors, for controlling the quadcopter.

2 comments: