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A Survey of Modelling and Identification of Quadrotor Robot
A quadrotor is a rotorcraft capable of hover, forward flight, and VTOL and is emerging as a fundamental research and application platform at present with flexibility, adaptability, and ease of construction. Since a quadrotor is basically considered an unstable system with the characteristics of dynamics such as being intensively nonlinear, multivariable, strongly coupled, and underactuated, a precise and practical model is critical to control the vehicle which seems to be simple to operate. As a rotorcraft, the dynamics of a quadrotor is mainly dominated by the complicated aerodynamic effects of the rotors. This paper gives a tutorial of the platform configuration, methodology of modeling, comprehensive nonlinear model, the aerodynamic effects, and model identification for a quadrotor.
Journal Article
I can make fantastic fliers
\"Introduces the reader on how to make flyers\"-- Provided by publisher.
Book
Air pressure in mini hovercraft
calculate the pressure on the mini hovercraft experiments by using the formula by knowing the mass of large balloon is 20,49 gr with a force of 0,2045 N was counted after balloon filled by air. The surface area was 0.011304 m2 so the obtained pressure was 18.09 Pa. Calculation of a small balloon pressure with a mass of 20.3 g calculated after the balloon is filled with air by the force of surface area 0.203 the N of the surface area 0,011304 m2 then the pressure of Pa is 17.95. A simple mini hovercraft that used for physics learning media on the pressure principal explains the utilization of air pressure on the mini hovercraft. The making of this mini hovercraft as a learning media is aimed to show the concept of pressure. From the results of observation and analysis of the data, it was proved that air pressure generated can produce bigger lift than the mini hovercraft weight. The air flowing out from the balloon in the bottom caused the mini hovercraft to be pushed upward.
Journal Article
Kinetic contraptions : build a hovercraft, airboat, and more with a hobby motor
This handy resource guide teaches you how to build two dozen contraptions using low-cost or free recycled materials, batteries, and a single motor. Some of the projects include constructing a hovercraft out of a Styrofoam plate, two corks, and binder clips; building a double-paddle wheeler out of paint stirrers, plastic bottles, and a pair of disposable knives; and, turning bamboo skewers, checkers, and a drinking straw into a three-wheeled motorcycle.
Book
Shape-form of Air Cushion Vehicle’s Flexible Skirt under Partial-cushion Blown State
Sometimes, Air Cushion Vehicle (ACV) needs to operate in the off-cushion (afloat) state with lowly rotating lift fans. In above case, the flexible skirt is at bubble state, which is partially blown into inflating shape to reduce resistanc and water draft. Research on bubble skirt shape-form is still a blank. Through observation of full-scale ACV’s bubble skirt shape-form, based on structure of typical skirt sect, an analytical method was firstly presented to calculate the bubble skirt shape-form of the afloat ACV under the partially inflated state. A program was developed in MATLAB based on this analytical method, and its results agree well with those obtained by FEM method in Abaqus, also with phenomenon of the afloat full-scale ship’s skirt shape in the bubble state. Based on the branch and boundary cutting method, program for bubble skirt shape-form using Visual LISP in AutoCAD. Compared with the FEM method in Abaqus, the presented analytical method can significantly reduce the time required for 3D modeling, FEM analysis, and calculations. On the other hand, the analytical program developed in Visual LISP can be translate into VBA to be embedded into the CATIA framework for ACV intact/damaged stability analysis with the bubble skirt. The program can deal with alomots all typical skirt sect, such as bag-finer type, double-lobe-finger type, bag-cone tupe, double-bag-cone type.
Journal Article
Investigation of resistance performance of anti-icing wave-plate separators for marine gas turbines intake system
Due to their high power and efficiency, gas turbines are commonly used propulsion systems in hovercraft propulsion systems. In polar and cold marine environments, when a hovercraft rises, a significant number of droplets are generated on the water surface and are drawn into the gas turbine’s air intake with the cold air. This paper takes the structure of the original wave-plate separator as a reference and designs two structures: the rhombic anti-icing wave-plate separator (RAWS) and the streamlined anti-icing wave-plate separator (SAWS). Experimental and numerical simulation methods are employed to calculate the air intake resistance of the two structures at speeds ranging from 1 to 10 m/s. The results show that the K-ε standard enhanced wall function turbulent model is the closest to experimental measurements, with all calculated results having an error below 5%, demonstrating reliability. Compared to RAWS, the calculated total pressure loss for the SAWS structure decreases by 200 Pa under a designed air intake velocity of 7 m/s, representing a relative reduction of 40.8%. This provides a valuable reference for the design and resistance optimization of ship air intake anti-icing devices.
Journal Article
Lift System Design of Air Cushion Vehicle
Lift system plays key role to Air Cushion Vehcile overall performance, whose design includes cushion flow demanding analysis, lift fan design, airflow distribution and pressure control. The method to calculate cushion flow exit velocity variation with craft speed was firstly presented based on cushion induced wave. Through application development in CATIA, a full solution was presented to check if craft keeps in safety flight boundary at maximum calm water speed. Through analysis, current cushion flow demanding method based on statistic former ACVs seems conservative for particular ACV with super high cushion density, which was adviced to decrease by 10%∼15%. New double discharge lift fan for polar hovercraft was developed through CFD simulation, model test, full-scale utilizing. To reach designed bag-cushion pressure ratio, polar ACV model skirt feed holes was added by 1/3 more than simple geometrical scale. Larger bag feed holes and lower bag-cushion pressure ratio are effective means to lower lift power.
Journal Article
Trajectory Tracking Control for Under-Actuated Hovercraft Using Differential Flatness and Reinforcement Learning-Based Active Disturbance Rejection Control
This paper proposes a scheme of trajectory tracking control for the hovercraft. Since the model of the hovercraft is under-actuated, nonlinear, and strongly coupled, it is a great challenge for the controller design. To solve this problem, the control scheme is divided into two parts. Firstly, we employ differential flatness method to find a set of flat outputs and consider part of the nonlinear terms as uncertainties. Consequently, we convert the under-actuated system into a full-actuated one. Secondly, a reinforcement learning-based active disturbance rejection controller (RL-ADRC) is designed. In this method, an extended state observer (ESO) is designed to estimate the uncertainties of the system, and an actorcritic-based reinforcement learning (RL) algorithm is used to approximate the optimal control strategy. Based on the output of the ESO, the RL-ADRC compensates for the total uncertainties in real-time, and simultaneously, generates the optimal control strategy by RL algorithm. Simulation results show that, compared with the traditional ADRC method, RL-ADRC does not need to manually tune the controller parameters, and the control strategy is more robust.
Journal Article
Numerical prediction of noise reduction solution on hovercraft propellers using LES and FW–H methods
Hovercrafts are known to produce excessive noise during operation, and the experimentally measured overall sound pressure level (OASPL) noise of the propeller is as high as 115 dB, which causes significant disturbances to surrounding residents and the environment. To address the research gap concerning noise issues associated with air-ducted propellers used in hovercrafts and other related fields, this article aims to investigate the impact of the clearance between the blade tips and the ducted on the aerodynamic and acoustic characteristics of the air propeller in the hovercraft. The aerodynamic and acoustic performance of the air propeller is evaluated using large eddy simulation (LES) and the Ffowcs Williams–Hawkings (FW–H) acoustic model, and the difference between numerical calculations and experiments is less than 3 dB. Results suggest that smaller tip clearance effectively reduces propeller noise without sacrificing aerodynamic performance. The maximum overall sound pressure level is reduced by 9.7 dB, while a reduction of 4.84 dB is observed at the blade passing frequency (BPF). However, increasing the tip clearance amplifies the downstream evolution of propeller wake vortices, resulting in a deterioration of the aerodynamic and acoustic performance of the propeller. This finding explains the mechanism by which tip clearance affects propeller noise and offers significant guidance for the future design and optimization of air propellers.
Journal Article