![]() The drawback of adding actuators to adjust pitch angles is that it increases the mechanical complexity and hence may increase the fault rate. Secondly, as the thrust magnitude of a VPP is controlled by adjusting the pitch angle, the control bandwidth is much higher than with spinning speed control, the method used by conventional fixed pitch propellers to adjust their thrust magnitude. It also enables VPP quadcopters to recover swiftly from largely disturbed attitudes back to stable hovering conditions, which is important considering the safety of the system. For example, a VPP quadcopter will be able to fly upside down steadily, which is not possible to achieve with a conventional quadcopter. This novel property brings benefits to the flight control performance. ![]() Firstly, a VPP can generate forces in either upward or downward directions. Adding such actuators remarkably enhances the flight capability of a quadcopter in a number of ways. The difference between a VPP and a fixed pitch propeller is that an actuator is used to control the pitch angle. Hence, they inherit the simplicity of the overall dynamical structure from fixed pitch propeller quadcopters, and therefore have the potential to be widely applied in practice. One advantage of them is that they have the same overall control structure as conventional fixed pitch propeller quadcopters. ![]() They have attracted increasing attention in recent years,. Variable pitch propeller (VPP) quadcopters are generalised variants of fixed pitch propeller quadcopters. Many of these tasks are safety-critical and require UAVs to achieve high flight performance in terms of both agility and safety, ,. In the future, quadcopter UAVs are expected to be routinely utilised in common, day-to-day tasks, such as parcel delivery or passenger transportation. Due to the simplicity and low cost of their mechanical and dynamical systems, quadcopter UAVs have been successfully applied in many domains. Recent years have witnessed the rapid development of commercial micro unmanned aerial vehicles (UAVs) across the world. Simulation results are presented to verify the theoretical findings. Our analysis could contribute to the development of high-performance quadcopters that are both agile and robust with respect to faults. The relationship under certain parameter conditions is analysed and the parameter conditions that lead to zero self-spinning are identified. It is also discovered that the quadcopter exhibits different and favourable behaviour, such as slow self-spinning speed. It is shown that the yaw angle and angular velocity become uncontrollable in the presence of a VPP fault, yet the quadcopter can still accurately track a desired trajectory. Finally, a linear controller is proposed. The uncontrollable mode is identified next. ![]() In this paper firstly the balance trajectory is analysed. This problem has not been studied in the literature. In this paper, the flight control of a centrally-powered VPP quadcopter in the presence of a propeller fault is studied. Adding actuators to control the pitch angles of the propellers increases the mechanical complexity and hence may increase the risk of faults. Several flight tests are shown, which highlight the benefits of a variable-pitch quadrotor over a standard fixed-pitch quadrotor for performing aggressive and aerobatic maneuvers.Research into variable pitch propeller (VPP) quadcopters has seen a marked increase in recent years which is due to their enhanced dynamic capabilities compared to conventional fixed pitch propeller quadcopters. 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. Fixed-pitch quadrotors are popular research and hobby platforms largely due to their mechanical simplicity relative to other hovering aircraft. ![]()
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