Abstract: A wind tunnel test was conducted to compare the characteristics of low speed stability and control for aircraft with conventional tail and V-tail configurations. Comparison was made in terms of static directional stability at selected test speed of 40 m/s, which corresponds to Reynolds number of 0.1622 x 106 based on the chord. Three types of simplified tail-only model were tested in Universiti Teknologi Malaysia's Low Speed Wind Tunnel (UTM-LST). Results show that the V-tail configuration greatly affects the aerodynamic characteristics in directional stability as the side force and yaw moment tends to vary linearly with yaw angles up to 25 degrees, compared to conventional tail that has linear characteristics up to only 10 degrees yaw
Abstract: One of the key challenges of designing low-cost Unmanned Aircraft Systems (UAS) is to ensure acceptable and certifiable reliability factors for the adopted Commercial-off-the-Shelf (COTS) components since their reliability is often not quantified. In this paper, the experimental results obtained for quantifying the reliability of mini Unmanned Aircraft (UA) servomotors (by recording their time-to-failure on a defined set of test runs) are presented. The Weibull prediction model is adopted for quantitative analysis and the associated key mathematical models. The methodology adopted for performing the reliability analysis including the test bench setup used for the experiments is described. The results indicate a level of reliability expected for low-cost servos. Such servos could be used for low-risk UAS operations (e.g. small UA operating over sparsely populated regions) and where the economics of the business case permitted higher loss rates.
Abstract: Effective control of an elastic space vehicle is possible only on the basis of exact information on its elastic oscillations. Exact estimation of these oscillations is possible via a distributed system of measuring instruments installed in different points of the elastic design. In recent years, new types of inertial measuring devices came into use like micro-electro-mechanical (MEMS) gyroscopes and accelerometers. Significant progress in the development of on-board computers allows the use of modern means of filtering algorithms, based on numerical integration of a large number of differential equations in real time. Miniaturization of sensors and the decrease of their power consumption increases admissible quantity of used sensitive elements and reduces restrictions for their placement. This article presents new results on optimization of placement of system of sensors on an elastic controlled object.
Abstract: Autonomous aerial hard docking is the process where an aircraft approaches and forms a rigid connection with another aircraft. After the docking process is complete, it is not necessary for the lift and propulsion system of the docked aircraft to be operating. Docking allows the larger aircraft to carry the small aircraft outside its airframe, thereby extending the range of endurance of the smaller aircraft. In this paper, we investigate specific scenario where docking occurs between a rotary wing aircraft and a fixed wing aircraft. To perform the above procedure, a guidance system on each platform has to ensure interception while satisfying the primary interception condition of velocity vector co-linearity at the moment of intercept of the two trajectories or flight paths. Pursuit guidance and proportional navigation were assessed as candidates for further development for the terminal docking phase. Since the platforms are in quasi-perfect knowledge of each other, the pursuer evader scenario is replaced by the pursuer-pursuer scenario. The novelty of this work lies in the formulation of terminal constraints, as well as the findings obtained. This paper concludes that contrary to the missile guidance scenario, pursuit based guidance laws provide superior baseline laws from which AAHD guidance and navigation laws can be developed.
Abstract: In this study, the Auxiliary Power Unit (APU) and the Ground Power Unit (GPU) that are required meet the energy demand in ground operations of aircraft were compared in terms of their damages –human health (disability adjusted life years- DALYs), ecosystem quality (PDF.m2.yr) and resources (MJ Surplus). These damages were calculated with gate-to-gate method of Life Cycle Assessment (LCA). This assessment was held on three main stages; capital investment, operation and maintenance. SimaPro 7.2.4 was used for this calculation. Human Health Damages (HHDs) of APU were found to be (0.0557 -disability adjusted life years- DALYs) 20.34 days/year while HHDs of GPU were calculated as (0.0411 -disability adjusted life years-DALYs) 15 days/year. While Ecosystem Quality Damages (EQDs) of APU were calculated as 103366.37 PDF.m2.yr, EQDs of GPU were found to be 82651.23 PDF.m2.yr. In other words, although the use of APU gives rise to loss of 0.1 species –1 year, 1 square kilometer area, the use of GPU gives rise to loss of 0.083 species. With regards to Resources Damages (RDs), 62125 MJ surplus energy needed for future extractions of minerals and fossil fuel considering APU, one the other hand 36002 MJ surplus energy needed for future considering GPU. As a result, the use of APU effects on human health, ecosystem quality and resources was determined greater than the use of GPU for 30 minute. The use of GPU has less impact on human health, ecosystem quality and resources in ground operations.
Abstract: In this paper, the author looks at certain areas of maintainability prediction process where missteps or misapplications most commonly occur. This research attempts to utilise the aircraft maintenance historical data and information (i.e. feedback information systems). Aircraft feedback information such as Service Difficulty Reporting System (SDRS) and Air Accidents Investigation Branch (AAIB) contains various types of information that could be used for future improvement rather than just the failure elements, as well as to help identify the critical and sensitive components that need more attention for further improvement. The study shows that the aircraft maintenance related feedback information systems analyses are very useful for deciding the maintainability effectiveness; these include planning, organizing maintenance and design improvement. There is no doubt that historical data information has the ability to contribute an important role in design activities. The results also show that maintainability is an importance measure that can be used as a guideline for managing efforts made for the improvement of aircraft components.
Abstract: This paper focuses on the capabilities of equipment known as Mass Properties Measurement (MPM) to calculate the center of gravity (CG) of a jig or an adaptor, which is used for mounting a structural model of Malaysian satellite, RazakSAT on POI-1000M Spin Balance Machine. The adaptor needs to be designed accurately to precisely accommodate the bolt sizes in both sides of the Device Under Test (DUT) side and the rotary plate side. In other words, the adaptor must be able to act as a good interface plate. A Malaysian research institute, SIRIM Berhad was chosen to undertake the design and manufacturing of the adaptor according to the specifications made by ANGKASA. The list of requirements of MPM should be considered during measurement to have optimum results, so that the satellite fixture onto the rotary table can be preceded for further calculations. Space Electronics (SE), the manufacturer for this MPM machine, has provided the control system for operators to calculate the required measurement such as CG, moment of inertia (MOI) and Product of Inertia (POI). Results confirmed that the simulation and experimental values are successfully obtained.
Abstract: This paper presents a variable deflection control of a fiber glass composite plate system using shape memory alloy (SMA) actuators. The technique on changing the camber of plate needs to be developed as it is the most investigated approach of shape morphing. Gradual changes of the camber along the span can create controllable twisting of the composite plate. The necessary camber change is pursued either by reconfiguration of the underlying structure or the shape changing of the composite plate or smart composite. In this proposed platform, strain gauges are used to measure the strain of the plate in a single cantilever mode while nickel titanium (NiTi) Shape Memory Alloy (SMA) wires are used as actuators to actuate the composite plate, which are controlled using Proportional-Integral-Derivative (PID) controller. In this research six strain gauges were placed at different location of the plate: tip, mid and root part of the plate. From the experimental result, it was found that the mid part of the plate had the highest change in strain value and the control system using input from the strain gauge located there produced the best performance compared to those located at the tip and root of the plate.
Abstract: This research focuses on the electrical noise coming from the sensor: load cell which is being used in rocket thrust measurement system. The aim is to investigate the noise contained in the measurement data. Fast Fourier Transform (FFT) is used as an indicator for appropriate cut off frequency in filtering data. Low Pass Filter is used as the measurement of thrust for it produces steady-state signal and acceptable transient response. Results confirmed that there are significant differences for Signal Noise Ratio (SNR) value between filtered and unfiltered data. Data noise has an impact to the true value of the expected results that affects data interpretation. It is shown that the influence of noise on the measurement data has been successfully reduced by the method used.
Abstract: Transportation has already become a huge necessity in people's life today. As the world progresses, transportation systems will have to undergo paradigm shifts to adapt with the changing requirements. Personal transportation is typically preferred to the public transportation and to date, most domestic travels have been made on the ground through roads. However, with the increasing traffic volume, the average time spent travelling on roads has significantly increased for the same amount of distance travelled. It has been proposed that utilization of the possible third dimension of transportation system, which is the air transportation, can aid personal transportation and alleviate this problem. This notion gives birth to the design concepts of the personal air vehicle (PAVE) that is envisioned to operate synergistically with the existing ground and air infrastructures. This paper aims to preliminarily study and analyze the potential benefits of having PAVE option in Malaysia for domestic travel and how its performance fares in comparison to existing transportation options. The results of travel time and cost comparisons highlight the potential of PAVE application for the domestic transportation in Malaysia, particularly for personal travel need.