Development of a micro guidance, navigation control system for quadcopters

• Main Author: Ng, Jason Kee Teck
• Other Authors: Xie Lihua
• Format: Final Year Project
• Language: English
• Published: 2015
• Subjects: DRNTU::Engineering::Electrical and electronic engineering
• Online Access: http://hdl.handle.net/10356/63909
• Institution: Nanyang Technological University

To develop a guidance and navigation of a Micro Aerial Vehicle (MAV) system, a high performance autopilot module called Pixhawk was adopted throughout the project which allows the ease of implementing existing localization methodologies onto its flight control stack, PX4. These developments were essential in providing information on the quad’s position with respect to an unknown environment or to determine a path for navigating the quad through obstacles within a GPS-denied environment. The report provides an inside view of how two different localization techniques were adopted, interfaced through an on-board embedded computer system, providing essential pose estimation measurements to the quad. A simulation program was implemented based on the Simultaneous Localization and Mapping (SLAM) techniqure in which it acquired a laser range finder and several ROS packages to link up the laser data that was obtained with a local map planner. The laser data was used to develop a pose estimation of the quad in relation to an area that was being scanned. Besides that, it was able to map out the unknown environment in a visualization tool called rviz. With rviz, a path planning process could be initiated for guiding the quad in achieving autonomous navigation capability in an unknown environment. The MAVLink extendable communication node for ROS packages known as MAVROS was established as the main communication link between the ROS operated SLAM packages and the MAVLink supported Pixhawk autopilot system It allows various control setpoints to be encoded in MAVLink messages before sending over to Pixhawk for further processing. The report will provide an extensive detail on how a set of pre-defined position setpoints could be sent to the Pixhawk via the MAVROS and subsequently publishing these setpoints on a ground control station. The Ultra-Wide Band (UWB) was implemented to produce a pose estimation of the quad with respect to a pre-defined space or coordinate system. An algorithm was implemented which utilized the Euler’s rotation theorem to perform frame transformation from the UWB Cartesian coordinate system to an earth-fixed North-East-Down (NED) coordinate system; the reference frame adopted by Pixhawk.