Rotor Craft Research Articles

Robust Hybrid Control Algorithm for Tuning the Altitude and Attitude of Unmanned Aerial Vehicle

In this article, a new and novel robust hybrid control algorithm is designed for tuning the parameters of unmanned aerial vehicle (UAV). The quadrotor type UAV mathematical model is taken to observe the effectiveness of our designed robust hybrid control algorithm. The robust hybrid control algorithm consists of H∞ based regulation, pole-placement and tracking (RST) controller along with mixed sensitivity function is applied to control the complete model of UAV. The selected rotor craft is under-actuated, nonlinear and multivariable behavior in nature along with six degrees of freedom (DOF). Due to all these aforementioned issues its stabilization is quite difficult as compared to fully actuated systems. For the tuning of nonlinear parameters of the UAV, we designed, robust hybrid control algorithm is used. Moreover, the performance of the designed controller is compared with robust controller. The validity and effectiveness of the designed controllers are simulated in MATLAB and Simulink, in which the designed controller shows better steady state behavior, robustness and converges quickly in specific amount of time as compared to robust controller.

A Study on the Design of Blimp Type Rotor Craft Blade according to Pitch Angle

A Study on the Design of Blimp Type Rotor Craft Blade according to Pitch Angle

社会インフラ点検用のための新しいロータ・クラフトの開発および天井への吸着制御

社会インフラ点検用のための新しいロータ・クラフトの開発および天井への吸着制御

Experimental and 3D CFD analysis on optimization of geometrical parameters of parallel vortex tube cyclone separator

The air separators or vortex tubes are widely used in rotor craft engines. The air separators are used to provide an appropriate air stream (clean air) to helicopter engines. Vortex tubes are normally categorized according to direction of exiting flows. This article focuses on some results (both experimental and numerical) into the optimization and analysis of the separation performance/efficiency and fluid patterns in parallel vortex tubes (PVTs) as one of the most interesting types of air separators. Regarding the Ranque–Hilsch vortex tubes, the separated fluids (gas or liquid) or hot and cold streams (dirty and clean) leave the vortex tube at two different sides, in the case of parallel vortex tubes, both exhausts are located in one side (control valve position). In this research the effects of a new nozzle position (parallel injector), throttle orifice diameter (6.5–9.5 mm) and length of parallel main tube (180–220 mm) on the quality of the separation process in the Ranque–Hilsch and the parallel air separator (PVT) are analyzed. The results show that the parallel vortex tube with optimized length, injection angle and orifice diameter provides 66.08% (14.83 K) and 58.61% (13.88 K) higher thermal separation performance as compared to the initial parallel vortex tube.

A Preliminary Design Tradeoff Study for an Advanced Propulsion Technology Rotorcraft at Mission Level

This paper aims to present an integrated rotorcraft (RC) multidisciplinary simulation framework, deployed for the comprehensive assessment of combined RC–powerplant systems at mission level. The proposed methodology comprises a wide-range of individual modeling theories applicable to RC performance and flight dynamics, as well as the gas turbine engine performance. The overall methodology has been deployed to conduct a preliminary tradeoff study for a reference simple cycle (SC) and conceptual regenerative twin-engine-light (TEL) and twin-engine-medium (TEM) RC configurations, modeled after the Airbus Helicopters Bo105 and Aérospatiale SA330 models, simulated under the representative mission scenarios. The installed engines corresponding to both reference RC are notionally modified by incorporating a heat exchanger (HE), enabling heat transfer between the exhaust gas and the compressor delivery air to the combustion chamber. This process of preheating the compressor delivery air prior to combustion chamber leads to a lower fuel input requirements compared to the reference SC engine. The benefits arising from the adoption of the on-board HE are first presented by conducting part-load performance analysis against the reference SC engine. The acquired results suggest substantial reduction in specific fuel consumption (SFC) for a major part of the operating power range with respect to both RC configurations. The study is further extended to quantify mission fuel burn (MFB) saving limit by conducting an extensive HE tradeoff analyses at mission level. The optimum fuel burn saving limit resulting from the incorporation of on-board HEs is identified within realistically defined missions, corresponding to modern RC operations. The acquired results from the mission analyses tradeoff study suggest that the suboptimum regenerated RC configurations are capable of achieving significant reduction in MFB, while simultaneously maintaining the respective airworthiness requirements in terms of one-engine-inoperative. The proposed methodology can effectively be regarded as an enabling technology for the comprehensive assessment of conventional and conceptual RC–powerplant systems at mission level.

1A1-F03 クアッドコプターの位置・姿勢運動に対するロバスト制御(飛行ロボット・メカトロニクス(1))

This paper deals with a control system of a quad-copter. Since quad-copters can hover in air, they are useful for surveillance. Furthermore, their dynamics is much simpler than single rotor helicopters. On the other hand, rotor craft is sensible for disturbance and modeling error. Thus, this paper designs two types of controllers based on PID control and a sliding mode control for an experimental quad-copter. The performance including robustness for the two controllers is examined through numerical simulations in this paper.

Applications for PMI foams in aerospace sandwich structures

Hermann Seibert of Rohm GmbH & Co KG discusses the use of PMI foams in large sandwich components in state-of-the art satellite launchers and in structural applications for rotor craft and civil aircraft.

A globally convergent tracking controller for the X4 flyer rotor craft for reference trajectories with positive thrust

In this paper we present a globally convergent and ultimately exponentially convergent tracking controller for an X4 Flyer rotor craft. The desired or reference trajectory is restricted in one way: its scalar thrust must be uni signed and bounded away from zero. The proposed controller is a two phase one. Phase I converges the attitude (orientation) error and thrust error to zero globally and ultimately exponentially. Phase II is a position tracking and relative yaw angle tracking controller, which is not globally convergent by itself. By carefully postponing a switch from Phase I to Phase II, we are able to assure that Phase II will ultimately drive the position error and relative yaw angle error to zero exponentially. In problem-statement/theorem/proof format, we define the system, the control objective, the proposed controller, and a rigorous proof that the controller maintains boundedness of all closed loop signals and provides global convergence of the tracking error to zero and also ultimately exponential convergence of the tracking error to zero.

The Negative Information Problem in Mechanical Diagnostics

Condition-based maintenance (CBM) is an emerging technology, which seeks to develop sensors and processing systems aimed at monitoring the operation of complex machinery such as turbine engines, rotor craft drivetrains, and industrial equipment. The goal of CBM systems is to determine the state of the equipment (i.e., the mechanical health and status), and to predict the remaining useful life for the system being monitored. The success of such systems depends upon a number of factors, including: (1) the ability to design or use robust sensors for measuring relevant phenomena such as vibration, acoustic spectra, infrared emissions, oil debris, etc.; (2) real-time processing of the sensor data to extract useful information (such as features or data characteristics) in a noisy environment and to detect parametric changes that might be indicative of impending failure conditions; (3) fusion of multi-sensor data to obtain improved information beyond that available to a single sensor; (4) micro and macro level models, which predict the temporal evolution of failure phenomena; and finally, (5) the capability to perform automated approximate reasoning to interpret the results of the sensor measurements, processed data, and model predictions in the context of an operational environment. The latter capability is the focus of this paper. Although numerous techniques have emerged from the discipline of artificial intelligence for automated reasoning (e.g., rule-based expert systems, blackboard systems, case-based reasoning, neural networks, etc.), none of these techniques are able to satisfy all of the requirements for reasoning about condition-based maintenance. This paper provides an assessment of automated reasoning techniques for CBM and identifies a particular problem for CBM, namely, the ability to reason with negative information (viz., data which by their absence are indicative of mechanical status and health). A general architecture is introduced for CBM automated reasoning, which hierarchically combines implicit and explicit reasoning techniques. Initial experiments with fuzzy logic are also described.

A feasibility study of using smart materials for rotor control

Rotor actuation in the rotating system promises a quantum jump in overall rotor craft performance. Smart material actuator technology for operation `on the blade' is now becoming available and has the potential to overcome the size, weight, and complexity issues of hydraulic and electric on-rotor actuation. The present paper is based on the results of a feasibility study to investigate the use of smart materials for primary and active control on the AH-64 helicopter. Based on the results of the study, it is seen that imbedded actuator concepts, i.e. pitch, twist, and camber control, are not practical at this time. Servoflap control, using hinged control surfaces driven by discrete actuators emerges as the most suitable candidate for smart material actuation. Preliminary data show that rotor control using smart materials might be feasible if a combination of smart materials is used and the rotor design is driven towards low control loads and motions.

Dynamic analysis of rotor blades with root retention design variations

Kinematic and elastic couplings are often provided in rotor blade root retention systems to improve aeroelastic or flight stability. This paper uses the generalized coordinates approach and Lagrange Multiplier variational method to arrive at a unified formulation in which it is unnecessary to repeat the structural part of the analysis when root boundary conditions change. Such a method has advantages for evaluating design variations of blade retention systems. Two idealized rotor hub-hinge system models, with many features typical of advanced blade retention designs, are examined here. The in vacuo, free vibration characteristics of rotor blades with masselastic properties outboard of the attachment point typical of present-gener ation rotor craft are calculated, as influenced by these retention systems. Trends with variations of root retention system parameters are presented for natural frequencies, damping ratios, and the amount of blade pitch induced by root flapping or lagging motions. A well-known static instability, which could be insidious in advanced rotor retention system design, is also reviewed.

Helicopter accident survivability.

Army Air Corps accident and fatality rates have now reached levels which compare favourably with data from other civilian and military sources. This improvement is the result of enhanced helicopter design and parallel progress in aircrew training. The introduction of new generations of turbine powered rotor craft has largely eliminated mechanical failure as the cause of accident. As a result 75% of Army Air Corps accidents are due to pilot error. This contribution is likely to increase in the future as the pilot's task is made more difficult by the incumberance of personal equipment. Methods whereby occupant protection and aircraft crashworthiness can be improved are reviewed and it is concluded that it would make sound economic sense to implement some of these well proven design features.

Twenty‐sixth International Air Show

The 26th International Aerospace Show at Le Bourget will undoubtedly be the largest that has ever been held. Inevitably, at a time when the European industries are attempting to consolidate their positions and the United States industry is pushing hard to improve its own sales and technical standing throughout the world, there will be a highly competitive air about the whole Exhibition. At the same time, many companies will be emphasizing their international links—in terms of collaborative developments, licence production or sales. Organized by the French equivalent of the S.B.A.C. in Britain—the Union Syndicate des Industries Aeronautiques et Spatiales—this year's Salon will follow traditional lines in that each day of the Show will be devoted to a particular facet of aerospace activities thus: June 10 Press Preview; June 11 Official Inauguration by President de Gaulle; June 12 Philately; June 13 Light, Executive and Commercial Aviation; June 14 Space Activities; June 15 Electronics; June 16 Systems and Equipment; June 17 Rotor craft; June 18 French and Foreign Missions; June 19 International Air Display; and June 20 International Flying Display. The Russians will send a number of space exhibits as well as a selection of civil aircraft—including the world's largest helicopter. The British industry will be represented by approximately fifty companies as well as Ministry of Aviation, Ministry of Defence and S.B.A.C. presentations. This preview of the show is concerned solely with the British exhibits, beginning with the major airframe and engine industries.