Showing papers in "Canadian Aeronautics and Space Journal in 2010"

Alternative technologies and coatings for electroplated cadmium and hard chromium

Abstract: Electroplated cadmium and hard chromium have been used extensively as protective coatings for the most demanding aerospace applications. Despite excellent technical performance and low deposition c...

Robust thrust-only control of a civil transport aircraft with vertical tail damage

Abstract: Thrust-only control of a jet transportation aircraft is also referred to as propulsion-controlled aircraft (PCA). It may be adopted as an alternative to using propulsive force to provide a certain level of control capability in case of failure of the aircraft's conventional control system. Previous PCA research was mainly concerned with control surface malfunctions such as free-floating and locked-in-place situations. On the other hand, structural damage to the aircraft control surfaces makes it necessary for PCA study and results in significant challenges due to the damage-induced aerodynamic and geometric parameter deviations. This paper presents a damage-tolerant control system design for aircraft with vertical tail damage. An H∞ loop transfer recovery (LTR) technique is applied to address the stability recovery and robustness of performance in maintaining safe flight operation of a damaged aircraft. Modelling of the damaged flight dynamics and control design is presented followed by numerical...

Conceptual design of wrap-around-fin rockets using the MDO methodology

Abstract: The conceptual design of rockets is a system engineering that involves configuration, aerodynamics, engine, dynamic stability, and coupling effects. To obtain benefits from the synergistic effects, the latest research achievements, and the most powerful analysis tools efficiently, this paper focuses on how to apply the multidisciplinary design optimization (MDO) technology to the conceptual design of the long-range, large length to diameter ratio wrap-around-fin (WAF) rockets. The software iSIGHT was employed as the MDO framework, the multidisciplinary feasible (MDF) method as the MDO architecture, and the multi-island genetic algorithm combined with sequential quadratic programming as the search algorithm. By maximizing the payload ratio, the structural analysis, aerodynamics, engine, trajectory, and dynamic stability were considered comprehensively. A case study demonstrated that MDO could improve the rocket performance effectively.

Investigation of using neuro-fuzzy and self-tuning fuzzy controller to improve pitch angle response of twin rotor MIMO system

Abstract: The neuro-fuzzy based fuzzy subtractive clustering method (FSCM) and self-tuning fuzzy proportional-derivative (PD) like controller (STFPDC) were used to solve nonlinearity and trajectory problems of pitch angle control of the twin-rotor multi-input–multi-output (MIMO) system (TRMS). The control objective is to make the vertical beam of the TRMS reach a desired position quickly and accurately. The proposed adaptive network-based fuzzy inference system (ANFIS) – STFPDC is designed to improve the fuzzy logic controller (FLC) response and overcome the high demands for computation resources. To simplify the complexity of STFPDC, ANFIS-based FSCM was used to simplify the controller and improve the response. The proposed controller achieved satisfactory objectives under different input signals. Simulation results using MATLAB Simulink demonstrated an improvement in response and the superiority of simplified STFPDC compared with the FC.

An experimental investigation of the flow field between two radial plates

Abstract: The flow field in a radial diffuser downstream of a radial impeller is highly complex, as the flow is turbulent, unsteady, viscous, and three-dimensional. Depending on the initial conditions at the...

Preliminary design of a university laboratory hybrid rocket engine

Abstract: This paper gives an overview of the preliminary design of a small hybrid rocket engine (HRE) that is being built in support of propulsion research activities at Ryerson University. The initial desi...

Damage tolerance analysis of the North American SNJ-6 wing lower attachment angle

Abstract: This paper presents the damage tolerance analysis (DTA) work undertaken by the National Research Council Canada Institute for Aerospace Research (NRC–IAR) for the SNJ-6 wing lower attachment angles and the recommendations on a suitable repeat inspection interval for different usage and nondestructive inspection (NDI) capabilities. NRC–IAR carried out flight and laboratory testing to support the DTA work. Crack growth predictions were conducted using two different MIL-A-008866B spectra (basic and advanced trainer class spectra), three initial crack sizes (0.60, 0.40, and 0.25 in.), and four spectrum clipping values (5.67g, 5.00g, 4.50g, and 4.00g). A total of 24 crack growth scenarios were analyzed. A critical input to the analysis was the aspect ratio of surface crack length to crack depth, which was determined from fractographic images of the failed component. The crack growth and residual strength evaluations estimated the remaining time to failure in a broad range from 1572 h (advanced trainer; maximum...