Make your own mini-quadcopter

• Main Author: Wong, Kwek Yuen.
• Other Authors: Wang Jianliang
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Control and instrumentation::Control engineering
• Online Access: http://hdl.handle.net/10356/55209
• Institution: Nanyang Technological University

A quadcopter is a four-rotor helicopter which can be used as an Unmanned Aerial Vehicle (UAV) for surveillance, search and rescue, and inspection purposes. Quadcopters are normally controlled by microcontrollers from a remote station or programmed for autonomous operations. Different sensors can be installed on the quadcopters to carry out its tasks in confined and hazardous areas. The objectives of the project are to design and build a mini-quadcopter of 200 mm in diameter, calibrate and align the camera attached to the quadcopter, and compute the height of a moving quadcopter using optical flow. With the understanding of quadcopter dynamics and kinematics, a suitable controller, motors, propellers and battery were selected for the quadcopter based on its size, a total weight of 300g and a flight time of 5 minutes. Following that, the quadcopter frame was designed and fabricated using carbon fiber material. Then, control tuning on the quadcopter was conducted and the stability of the quadcopter was subsequently verified. Next, a micro wireless camera was acquired and installed onto the quadcopter. Camera calibration was conducted using the Matlab Camera Calibration Toolbox to obtain the coordinate relationship between the camera, quadcopter and the inertia frame. With the installed camera, an experiment was conducted to compute the height of a moving quadcopter. The experiment was done in two steps. Firstly, a video of a simulated moving quadcopter was captured with the camera optical axis pointing towards the ground. Then the height of the quadcopter was computed using optical flow based on Lucas-Kanade method with Pyramid in Matlab code. The three objectives of the project were achieved. Firstly, the mini quadcopter was built and able to fly stable using a transmitter. Secondly, the camera calibration was conducted and the physical orientation and location of the camera to the quadcopter was verified to be accurate. Lastly the experimental result from optical flow computation has shown feasibility to obtain height information of a moving quadcopter. In the future project, a mathematical model of a quadcopter can be developed for control and stability simulations. In addition, real time height measurement of the quadcopter can also be done by computing instantaneous optical flow.