5/1/2023 0 Comments Variable pitch quad copter![]() ![]() The control law and trajectory generation algorithms are implemented on a custom variable-pitch quadrotor. A nonlinear, quaternion-based control algorithm for controlling the quadrotor is also presented with an accompanying trajectory generation method that finds polynomial minimum-time paths based on actuator saturation levels. This analysis is supported with experimental testing to show that variable-pitch propellers, in addition to allowing for generation of reverse thrust, substantially increase the maximum rate of thrust change. A detailed analysis of the potential benefits of variable-pitch propellers over fixed-pitch propellers for a quadrotor is presented. This paper shows that many of these limitations can be overcome by utilizing variable-pitch propellers on a quadrotor. This simplicity, however, places fundamental limits on the achievable actuator bandwidth and the possible flight maneuvers. UAM, HQ, handling qualities, NASA, quadrotor, air taxi operations, urban air mobility National CategoryĪerospace Engineering Identifiers URN: urn:nbn:se:ltu:diva-76146 OAI: oai:DiVA.Fixed-pitch quadrotors are popular research and hobby platforms largely due to their mechanical simplicity relative to other hovering aircraft. Place, publisher, year, edition, pages2019. Lastly, comparing the RPM controlled version of the quadrotor to the contemporary blade-pitch controlled version, one can see that the latter is more inherently responsive compared to its successor. There are still some unknowns on how the ESC should be considered according to general standards and aircraft standards. The ESC correlates to the general stability of the aircraft, making the ESCs aggressive enough will inherently make the aircraft unstable. The motor limits in this thesis was set to +/- 200V which corresponds to an effect of a single electric motor of approximately 54 hp or 40kW. ![]() It is seen that with a fast tune on the ESC the likeliness of spiking the motor voltage increases which implies that the motor power saturates. Controlling the aircraft through rotor RPM is slower than varying the blade-pitch angle, spinning up the rotors require more power from the motors than keeping a fixed RPM, hence the motor power determines how fast the quadrotor can respond and better cope with sudden disturbances and turbulence. Also, the control axis rate command, e.g, roll, has a strong correlation to motor power. The results prove that the aircraft is fully controllable using a variable RPM configuration, but that it has a spin-up region that impacts the control response and manoeuvrability mainly due to rotor inertia and lagging of the controller. Lastly, the two models are compared, the variable RPM quadrotor case is considered mostly whereas the variable blade-pitch angle acts as a reference model. Further more, it describes a process of designing a motor speed controller, which goes by the name Electronic Speed Controller (ESC), that connects to the Flight Control System (FCS). This thesis will act as a guidance on how the control system can be designed, as well as some aspects of variable RPM rotorcraft. The aircraft geometries are essentially identical with the exception of propulsion method and weight. ![]() One, is based on constant rotor RPM - variable blade-pitch angle, and the other is based on variable rotor RPM - constant blade-pitch angle. CONDUIT is then used to optimise a control system specifically designed for two similar quadrotor, but with different control systems. FlightCODE imports sized parameters from the vehicle design and calculates a point model linear state-space matrix governing the Equation of Motion (EOM). This thesis article investigates controls aspects of a single-passenger quadcopter prototype by using the programs SIMPLI-FLYD (now by the name FlightCODE), and CONDUIT. NASA, which is acting as a leader through the UAM Grand Challenge, is dedicated to conduct research facilitating the development of key areas associated with the leap of technology. These vehicles are capable of Vertical Take-Off and Landing (VTOL) operations. ![]() It is no longer feasible to let traffic flow on the ground level, instead technology is leading towards a network of "flying cars" that are given the name air taxis. Companies including aerospace, transportation, and others endeavour to shape the next era of public transportation. With an exponentially growing demand for Urban Air Mobility (UAM) capable vehicles directly related to traffic congestion in large cities around the world. 2019 (English) Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE credits Student thesis Abstract ![]()
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