Quad-copter Design
Summary
The University of Alberts Aerial Robotics Group (UAARG) designed a new quad-copter aircraft to compete in a competition in 2023 (the SUAS competition presented by AEAC). The project underwent requirements setting, conceptual design and detailed design & analysis, followed by manufacturing. Members were encouraged to submit concepts for evaluation, and were evaluated on different metrics including ability to meet competition requirements, manufacturability and aesthetics (also graded at competition). Team members were then assigned roles in the detailed design and analysis, before parts were ordered and manufacturing began. The timeline was tight since competition requirements were released at the end of September 2022, and manufacturing had to be complete in February to allow for time to tune the aircraft control system before submitting proof of flight for the competition in March; team members had to balance full courseloads with a heavy extracurricular load.
Design Criteria
The quadcopter design must meet the following criteria:
A minimum range of 30 km
Able to withstand 24 mph winds
A status LED visible from 360 degrees
A modular payload system capable of carrying and delivering packages or passenger cabins
Undermounted cameras and sensors
Arming/disarming switch clear of propellers
Max takeoff weight of 15kg
Aesthetically pleasing
Technical Details
There were 7 stages in the development of PhoenX1:
Conceptual Design
All members of the club were encouraged to submit concept sketches, which were reviewed to asses which designs best fit the design criteria.
The concept I submitted, consisting of a skeletal frame made of carbon fiber tubes for a stretch-X quadcopter was selected as the best design, and proceeded to the following stages of analysis.
Detailed Design & Analysis
During the detailed design and analysis, tasks were split up amongst the willing members of the airframe team.
My task during the design analysis was designing the finalized geometry of the frame, and analyzing the strength of the frame under the expected loads.
Other tasks involved the design of the air-taxi cabin payload, design of the propulsion system, etc.
Design Review & Purchasing
Upon completion of the frame, propulsion system, and electrical design, a design review was conducted where each design was presented in thorough detail for the faculty advisor, and the any interested members of UAARG
Design Validation & Prototyping
All structural joints for this build were 3D printed, and held together by either fasteners or epoxy resin; all of these joints were validated using destructive testing (since a replacement is easy to make) to ensure the actual strength is above the desired strength.
Once the frame was assembled, the entire structure was assessed using Non-Destructive Testing (NDT). NDT was tested up to the designed load including safety factor to ensure the system will not break under any expected conditions.
Manufacturing & assembly
The rest of the manufacturing and assembly was conducted to create bracketry to hold the electronics components, and motors onboard.
The payload system (air-taxi cabin) was also manufactured during this stage, but legs were mounted in it's place to begin aircraft tuning.
Tuning
Tuning was attempted within a few weeks of competition; since the team only has permission to fly on weekends, this left the team to the mercy of the weather. Due to high wind, the aircraft had large difficulties in tuning correctly, but in the last weekend, was tuned to be fairly stable.
Deployment
PhoenX1 was disassembled to ship to competition, where it's systems were put to the test autonomously.
Results
PhoenX1
The end result of the analysis and manufacturing is shown in this photo where PhoenX1 is sitting at competition. The team placed third in one category at the competition, despite a crash due to an improperly tuned PID controller. The team has since rectified the tuning issues, and this aircraft remains active for testing subsystems and as a back-up aircraft for the 2024 competition.
UAARG is always continuously updating PhoenX1 with improvements where possible, including extra vibration isolation for telemetry and imaging, and custom machined aluminum structural parts.