DEVELOPMENT OF THRUST VECTORING SYSTEM FOR STORMPETREL
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AbstractTo overcome the limitations that existing VTOL RPAS (Vertical Take-Off and Landing Remotely Piloted Aircraft System) imposes on range and high wind capabilities, a new type of RPAS platform is investigated. A mathematical model for this new platform and its control system has been developed and implemented in MATLAB and Simulink prior to this thesis. A 2020 mm long glass fibre wing with a NACA 2412 profile has also been produced prior to this report. In this attempt, to overcome the limitations of today s VTOL RPAS, a new full thrust vectoring system has been developed for the drone platform called StormPetrel. The system is designed as a fully actuated flying wing, using four equally sized electrical thrusters in combination with thrust vectoring. Thrust vectoring means the possibility of pointing the propellers, thereby the thrust, in arbitrary directions. This is a key property in this RPAS design. The platform will hover with attitude control like a conventional quadcopter. For translation in hover, the thrusters themselves will tilt and/or twist to generate thrust in the desired direction, instead of the whole platform is altering attitude. This gives the vehicle improved stability and maneuverability in strong wind situations. To obtain forward flight like a fixed wing aircraft, the thrusters are tilted 90° forward. To achieve the tilt and twist motion of the thrusters (full thrust vectoring), a mechanical tilt and twist mechanism has been developed, implemented and partially tested. The overlying goal is an improvement of a proof of concept. There is one tilt axis, which goes through the wing from tip to tip. There are two individual twist axes, one in each end of the wing. The axes are orthogonal to the tilt axis, and the directions are dependent on the tilt angle. All tilt and twist motion is achieved by utilization of Dynamixel servos exchanging power/torque by pulleys and belts. Carbon fibre tubes in different dimensions form all axes. The mechanisms are embraced by carbon fibre plates, which work as a frame, retaining all moving parts. As few parts as possible are implemented into the airfoil itself. Most machine components, e.g. pulleys and ball bearing supports, are custom made from lightweight aluminium to minimize mass. In all chosen and considered concepts the issue of weight, price, complexity, function, geometry and availability have been considered. All solutions have been summarised and discussed after simplified trials. The next step and the planning of the next prototype has been featured in light of test results. 78 individual custom made parts were produced or modified by the master candidate for direct use in the result, in addition to prototype parts for testing. All sub systems work adequately according to what is demanded for the StormPetrel second prototype. The thrust vectoring system ended up weighing 860 g.