Design and experimental testing of safe flight control system for novel vertical take-off and landing aircraft

Abstract

This paper describes the design and flight test of the control system of a novel octocopter with new topology to improve aerodynamic performance and efficiency. The article analyzes the advantages of the new configuration and analyzes the feasibility of the control method which can ensure fault-tolerant control when one rotor of the aircraft stops in theory. The feasibility verification is carried out through a prototype flight test. The power and hardware platform of the octocopter UAV was set up according to the requirements of structural and control system design. Flight tests were carried out multiple times, and the UAV's redundant actuation was able to successfully stabilize the vehicle, even after a single rotor stopped functioning. Under normal flight conditions, smooth flight and effective control could be ensured for the UAV, while under the condition of a single rotor having stopped functioning, the control method was able to effectively utilize the other seven rotors to provide a proper lift force and to control the aircraft to perform basic motions such as pitch, roll, and yaw.

Ground Effect on the Thrust Performance of Staggered Rotor System

“…Adding two isolated rotor systems as a comparison can eliminate the influence of aerodynamic interference between rotors, making it easier to compare the performance of rotor systems at different ground heights. Previous studies on unloaded flight experiments [35] indicate that the operating condition for this rotor model is approximately 1500 RPM. Considering the loaded flight of the aircraft, 2000 RPM is chosen as a typical operating condition for the subsequent study on thrust variation.…”

“…The unloaded rotor speed was referenced from previous staggered rotor UAVs [35,36], but considering the decrease in rotor speed during the landing process, speeds commonly ranging from 1000 to 3500 were selected. Under these conditions, the Reynolds number at the blade tip is between 0.26 × 10 5 -1.15 × 10 5 , the blade tip velocity is between 24 and 84 m/s, the blade tip Mach number is between 0.05 and 0.25, and the lateral distances are 0, 0.5, 1.0, 1.5, and 2.0, respectively.…”

Deep learning-based visual navigation control method for autonomous trajectory of UAVs

“…In the actual process of UAV use, the UAV is required to be in a near-hovering situation, and it is necessary to accurately control the attitude angle and landing trajectory of the UAV helicopter to overcome the ground effect so that the UAV helicopter can land smoothly, slowly, and accurately on the landing field without falling sideways and quickly to the ground [6]. This requires it to have a set of good control systems, which requires a strong resistance to external interference [7][8]. So, the visual navigation needs to select a suitable reference as the reference object, and it can only obtain information on the relative motion state of two objects [9].…”

Experimental Investigation on Thrust Performance of a Small-Scale Staggered Rotor System in Hover

“…The values for lateral distance form an arithmetic sequence between 0 and 2.4, with a common difference of 0.4 between adjacent values. In previous flight research experiments on staggered rotor unmanned aerial vehicles [31,33], corresponding reference values for rotor speed under no load operation were identified. As such, the primary testing range for rotor speed falls between the commonly encountered values of 2000 and 3500 RPM in the operational state of this type of rotor.…”

“…Staggered rotor systems, which involve multiple rotor blades that are not aligned in the same plane, can have various implications on aircraft performance and control. In the authors' previous research, significant impact of the staggered rotor power system was identified on the aircraft's overall aerodynamic performance [30], optimization design [31,32], controller design and flight quality [33]. In order to help find superior performance in multi-rotor configurations, many scholars have conducted research related to overlapping rotors to enhance and optimize aircraft design.…”