| Abstract [eng] |
This project examines the possibility of controlling the direction of propeller thrust using flexibly attached blades and precise control of propeller rotation. The suggested method allows for control of the thrust direction without direct mechanical control. A propeller mechanism with flexible blades was designed in this study, allowing the blade pitch to be adjusted according to the direction of angular acceleration. A 10x6 Direct Drive propeller was selected for the blades, and a propeller mechanism was designed with a total diameter of 336 mm. Strength analyses were performed when the mechanism is rotated at a frequency of 2000 RPM. Also the factors of safety for the mechanism components were also calculated. To evaluate the propeller characteristics, an experimental testing stand was built to measure thrust and its direction. A Raptor Pro 30A electronic speed controller with the DShot300 protocol was used for precise control of the propeller rotation. An AS5600 magnetic angle sensor was selected to accurately determine position during performance. National Instruments Ni-9238 and cDaq-9173 equipment was used to collect data. As the mechanism rotates, the operating loads are transmitted to the middle section of the test stand, so displacement and frequency analyses were performed. During the analysis, displacements of 0.21 mm were detected in the central part of the test stand attached to the load cells, and the propeller rotational frequency was significantly lower than the resonance frequency of 301 Hz. An algorithm was developed to control the propeller mechanism, which allows the signal values to be adjusted according to the rotor angle of rotation. The control signal is generated based on a sinusoidal wave, with the control angle used to adjust the starting point. Diagrams of the algorithm operation and its program have been created, and an electrical functional diagram has been drawn. An alternative control method has been developed in which the maximum and minimum values are maintained for a longer period, thereby creating a longer acceleration and deceleration interval. To obtain results in SI units, the sensors were calibrated prior to the measurements. To change the direction of thrust in the plane, the control angle was varied (0°, 90°, 180°, and 270°). Based on the sinusoidal control signal, the maximum thrust was obtained when the maximum amplitude value was 24%, and the minimum at 18%, and with a longer deceleration – 1 N. Thrusts and torques were evaluated while maintaining a constant rotational frequency but varying the difference between amplitudes in percentage terms. The thrust at a 25% difference was 0.142 N, and the torque was 0.0013 Nm. At a 100% difference, the thrust was 0.112 N, and the torque was 0.0055 Nm. This demonstrates that better control can be achieved by reducing the thrust and increasing the percentage difference between the amplitudes. |
