MicroCARTMicroprocessor Controlled Aerial Robotics Team

AbstractMicroCART is a group of EE/CprE students tasked with developing an autonomous helicopter platform. The project originated several years ago with the goal of competing in the International Aerial Robotics Competition, a competition for autonomous unmanned aerial vehicles (UAVs). The completion of Level 1 of IARC required the UAV to takeoff, fly to several GPS waypoints up to 3 km away, and maintain a hover at the last waypoint. Accomplishing these tasks is the current objective of the MicroCART team. The helicopter system will be designed to be extensible and to allow for various other missions that will require this functionality, including survey work and remote monitoring.

Problem StatementOur goal is to create the hardware and software components of an auto-pilot for a small unmanned helicopter. The requirements are meant to coincide with the Level 1 Objectives of the International Aerial Robotics Competition.

Solution• X-Cell 60 RC helicopter modified to carry an electronics bay• Single board computer running a distribution of the Linux operating system• Sensor package consisting of Inertial Measurement Unit (IMU), GPS, Compass, Altimeter, and Sonar• Servo Controller to allow the autopilot to control the helicopter’s servos• Manual override system to switch between manual and autonomous control

Semester Goals• Finish implementation of manual override system• Implement missing functionality in ground station protocol• Improve reliability of flight control software• Finish sensor implementation• Achieve autonomous hover on all 5 channels independently• Achieve autonomous hover on all 5 channels simultaneously

Concept Sketch

System Block Diagram

Semester ResultsWe have accomplished a significant amount on the project this semester. Below is a breakdown of our progress on our goals.•Finish implementation of manual override system• Manual override system completed and tested

•Implement missing functionality in ground station protocol• Added command to hover at current position• Improved logging capabilities

•Improve reliability of flight control software• Discovered and fixed several issues in sensor code• Integrated GPS position data into algorithm

•Finish sensor implementation• GPS: Fixed code and moved hardware to tail to achieve a more reliable fix• Compass: Shielded w/ aluminum box, calibrated, tested w/ engine running• Sonar: Purchased new Analog to Digital Converter to improve reliability• Altimeter: Prototype completed and tested, awaiting final circuit board

•Achieve autonomous hover on all 5 channels independently• Awaiting flight testing for verification

•Achieve autonomous hover on all 5 channels simultaneously• Awaiting flight testing for verification

SummaryThis semester we made a great deal of progress on the project. We greatly improved the stability of the flight control software, implemented and improved nearly all of the helicopter’s sensors, and gave future MicroCART teams a stable, reliable hardware and software platform.

Development and TestingDue to the complexity and long-termnature of the project, we utilize the following continuous development cycle.

Comparison graph of various compass filters. The red filter was chosen.

Ground Test

Flight Test

Analyze Results

Analyze Results

Implement, Bug Fixes,Lab

Testing