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Parameter Optimization of Genetic Algorithm Utilizing Taguchi Design for Gliding Trajectory Optimization of Missile
Full text linkThe present study aims to establish a genetic algorithm (GA) method to optimize gliding trajectory of a missile. The trajectory is optimized by discretizing the angle of attack (AOA) and solving optimal control problem to achieve maximum gliding range. GA is employed to resolve the optimal control problem to achieve optimized AOA. A Taguchi’s design of experiments was proposed contrary to full factorial method to ascertain the GA parameters. The experiments have been designed as per Taguchi’s design of experiments using L27 orthogonal array. Systematic reasoning ability of Taguchi method is exploited to obtain better selection, crossover and mutation operations and consequently, enhance the performance of GA for gliding trajectory optimization. The effects of GA parameters on gliding trajectory optimization are studied and analysis of variance (ANOVA) is carried out to evaluate significance factors on the results. Crossover function and population size are observed as highly impacting parameter in missile trajectory optimization accompanied by selection method, crossover fraction, mutation rate and number of generations. Artificial neural network (ANN) method was also applied to predict the significance of GA parameters. The results show that the gliding range is maximized after GA parameter tuning. Simulation results also portrayed that with optimal AOA, gliding distance of missile is improved compared to earlier one. The numerical simulation shows the efficiency of proposed procedure via various test scenarios
An Architecture for On board Frequency Domain Analysis of Launch Vehicle Vibration Signals
Full text linkThe dynamic properties of the airborne structures plays a crucial role in the stability of the vehicle during
flight. Modal and spectral behaviour of the structures are simulated and analysed. Ground tests are carried out with environmental conditions close to the flight conditions, with some assumptions. Subsequently, based on the flight telemetered data, the on-board mission algorithm and the auto-pilot filter coefficients are fine tuned. An attempt is made in this paper to design a novel architecture for analysing the modal and spectral random vibration signals on-board the flight vehicle and to identify the dominant frequencies. Based on the analysed results, the mission mode algorithm and the filter coefficients can be fine tuned on-board for better effectiveness in control and providing more stability. Three types of windows viz. Hann, Hamming and Blackman-Harris are configured with a generalised equation using FIR filter structure. The overlapping of the input signal data for better inclusiveness of the real-time data is implemented with BRAM. The domain conversion of the data from time domain to frequency domain is carried out with FFT using Radix-2 BF architecture. The FFT output data are processed for calculating the power spectral density. The dominant frequency is identified using the array search method and Goldschmidt algorithm is utilised for the averaging of the PSDs for better precision. The proposed architecture is synthesised, implemented and tested with both Synthetic and doppler signal of 300 Hz spot frequency padded with Gaussian white noise. The results are highly satisfactory in identifying the spot frequency and generating the PSD array
A Comparative Study on various Flight Termination System Technologies
Full text linkIn a test range, a Flight Termination System (FTS) plays a prominent role in protecting range and flight personnel along with surrounding area population in case the flight vehicle is out of its trajectory range and possesses a threat to surrounding. An efficient FTS should posses high Signal to Noise Ratio, link robustness to ensure reliable communication between ground transmitting and onboard receiving systems and should be immune to interference. This article presents a detailed report on the requirement and features of FTS & technologies used in it. Techniques such as tone based, code based and Code Division Multiple Access (CDMA) are considered. Analysis of RF spectrum, gain and noise figure measurement and channel power are presented. Advanced methods like Enhanced Flight Termination System (EFTS) and Autonomous Flight Termination System (AFTS) are considered which show supportable and upgradable technologies, better range understanding, unique vehicle id & higher data rate. AFTS being self-reliant provides superior performance in terms of GPS, launch responsiveness, multiple flight vehicle control and auto pilot
Ethernet Over Coaxial (EoC) Cable Telemetry Over High Voltage Dc And High Power Ac For Airborne Sonar Applications
Full text linkWe have proposed a new passive component-based coupling scheme to simultaneously transmit high power AC, high voltage DC and high speed data through a long, single core coaxial cable, particularly for Airborne Sonar applications. This method is intended to replace the bulky multicore cables with single core coaxial cables that are compact and effective for transmitting data over long distances. This coupling scheme consists of three couplers to superimpose high power AC, high voltage DC and high speed data at the onboard end of the cable, and three decouplers to separate them at the remote end. The long cable, couplers, decouplers and the acoustic transducer are represented by their corresponding equivalent circuits that are cascaded together to construct the complete network. Power loss in the circuit is minimised by providing impedance matching networks in the form of a T-network transmission line and a tuning coil. The Ethernet over Coaxial (EoC) module can transmit high speed Ethernet data at the rate of 10/100 Mbps for telemetry from onboard to remote units and vice versa. DC voltages up to 300 V are coupled to the single core coaxial cable from the onboard unit and superimposed with high power AC signals and high-speed data. Passive filter-based coupling and decoupling schemes are demonstrated. Network simulation studies and experimental studies are carried out to verify and validate the equivalent circuit model. The transfer functions of each set of couplers and decouplers are determined independently as well as collectively and their effects on the underwater acoustic performance of the system are studied. The model resuls are found to agree with experiments. The proposed system is capable of generating an acoustic Source Level of about 195 dB with the supply of 125 V continuous wave (CW) AC signals, with simultaneous transmission of data at 10 Mbps and DC supply of 260 V from the on-board unit to the remote unit at the end of a coaxial cable of 200 m length. Introduction of impedance matching network is found to increase the source level by about 12 dB
Realization of High Pressure Turbine Blades of a Small Turbo Fan Engine through Investment Casting Process
Full text linkTurbo-fan gas turbine engines, or simply turbo-fan engines (STFEs), are used for powering both manned aircrafts and unmanned air vehicles (UAVs). The high pressure turbine section of such engines use Ni-base superalloy cast rotor blades because of their good mechanical properties at high operating temperatures. The present paper provides the technical/technological details of the various aspects associated with development and manufacturing of high pressure turbine blades (HPTBs) for utilization in an indigenously-developed small turbo-fan engine. Vacuum investment casting process has been adopted for realization of the above equiaxed components using a Ni-base superalloy
 
Effect of Vanadium Addition On Structure And Soft Magnetic Properties of Nanocrystalline FeCoZrBCu Melt Spun Alloys
Full text linkIn this report, glass forming ability, structure and soft magnetic properties of melt spun ribbons of (Fe1-xCox) 88-yVyZr7B4Cu1alloys with compositions x0.1y2, x0.1y4 and x0.1y6 & x0.35y2, x0.35y4 and x0.35y6 have been investigated. All alloys were found to be fully amorphous after melt spinning. Annealing of amorphous ribbons of x0.1 series alloys leads to the formation of bcc α-Fe(Co) phase and Fe2Zr phase in the amorphous matrix, while annealing of amorphous ribbons of x0.35 series alloys, leads to the formation of only bcc α-Fe(Co) phase in the amorphous matrix. High precision lattice parameter calculation revealed that V addition influences the phase formation in low Co containing x0.1 alloys. It leads to low volume fraction of bcc α-Fe(Co) phase and promotes Fe2Zr phase. A higher Co content increases the Curie temperature of amorphous phase, while V addition decreases the TC of amorphous phase in both x0.1 and x0.35 series of alloys. Saturation magnetization (Ms) of x0.35 alloys are higher than of x0.1 alloy due to higher Co content and the Ms decreases with increasing V content due to its non-magnetic nature. Coercivity was found to be increased with annealing in x0.35 alloys due to the low volume fraction formation of bcc α-Fe(Co) phase and Fe2Zr phase. The coercivity decreases with increasing V addition in x0.35 alloys as spun ribbons and a lowest coercivity of 0.13 Oe has been obtained in x0.35y6 alloy which is one of the lowest among FeCoZrBCu alloys reported
Development of Lead Free Magnetoelectric Materials for Magnetic Field Sensor applications
Full text link(100-x) Na0.5Bi0.5TiO3 (NBT)-(x) NiFe2O4 (NFO)(x = 0, 20, 40, 60, 80 and 100) composites are synthesized using conventional solid state reaction method. Crystal structure studies are performed by using X-ray Diffraction technique (XRD) and the Rietveld analysis of XRD patterns confirms the co-existence of cubic (NFO) and rhombohedral (NBT) symmetry with Fd- 3m and R3c space groups, respectively. Micro-structural study reveals the formation of combination of composite phases and its inter-coupling grains. The average grain sizes and area percentage of each phase for the composites are calculated using Image J software. The Magnetisation versus Magnetic field (M-H) hysteresis loops show soft magnetic behavior of composites with variation in Saturation magnetization (MS) and Coercivity (HC). A maximum MS (34 emu/g) and low HC (15 Oe) is obtained for (80) NFO - (20) NBT composite.The Polarization – Electric field (P-E) analysis shows that the maximum saturation polarization (PS) is obtained for (60)NBT-(40)NFO sample and is attributed to the leakage current generated by conductive NFO phase. The coupling between the ferrite and ferroelectric phase is studied based on the magnetoelectric voltage coefficient(αME). The maximum (αME) of 1.82 mV/cm-Oe is obtained for (80)NBT -(20)NFO sample and this is almost 80% higher than the previously published literature on NBT-NFO composites. This can be attributed to the uniform distribution of grains with each ferroelectric phase surrounded by ferrite phase as shown in the morphological study
Feasibility Study of Lithium Ion Batteries for Torpedo Applications
Full text linkA comprehensive study on the feasibility of Lithium (Li)-ion battery technology for Light Weight Torpedoes (LWT) and Heavy Weight Torpedoes (HWT) applications are reported in this article. The global scenario of Li-ion battery technology for torpedo applications and current Indigenous Li-ion battery developments in India are studied. Configuration study of Li-ion battery for LWT and HWT with commercial cells was carried out and it is found feasible to partially meet the required power for LWT and HWT applications. A comparison of the cost per cycle of Li-ion battery versus AgO-Zn battery indicates that Li-ion batteries work out to be cheaper beyond 100 cycles of use and by an order of magnitude cheaper on average. The detailed survey on Indigenous developments reveals that cell-level development is predominant in public sector agencies, whereas the private sector is mostly focussed on the assembly of imported cells and BMS
Nomographs for Polymeric Material Selection for Environmental Conscious Design of Industrial Products
Full text linkEnvironmentally-conscious product design using Life Cycle Assessment (LCA) deserves the utmost attention to save and sustain our planet’s lives, flora and fauna. The choice of materials during the design stage needs to address environmental concerns from their sourcing to production and ultimately going up to the disposal stage. A good majority of industrial products are still not designed, focusing the environmental concerns. The inclusion and practice of the LCA approach during product designing are in a nascent stage not only in India but even over the rest of the world. Nowadays, polymers share a major chunk of the volume of goods produced worldwide and thus have a significant effect on the environment. The available design books or nomographs guide the selection of materials considering several criteria but not considering the related environmental issues. This paper attempts to bridge this gap only for the selection of polymeric materials by providing some easily interpretable and visually ready reckoners in the form of 3-D nomographs. These 3-D nomographs, graphical representations developed using the Solidworks software, echo the material’s Environmental Impact (EI) potential on an axis with some two material properties (e.g., tensile strength and density) on the other two axes. 3-D nomographs are suitably transformed into 2-D nomographs without the loss of any information. EIs on these nomographs were computed using SimaPro software. The potential EI of any product and the overall environmental burden due to them can be significantly reduced, and more so when they are mass-produced, by selecting the right materials using these nomographs. Such an approach will help in fulfilling long-term sustainable development goals of society and the globe
A Novel Goal oriented Sampling Method for Improving the Convergence Rate of Sampling based Path Planning for Autonomous Mobile Robot Navigation
Full text linkAutonomous Mobile Robots' performance relies on intelligent motion planning algorithms. In autonomous mobile robots, sampling-based path-planning algorithms are widely used. One of the efficient sampling-based path planning algorithms is the Rapidly Exploring Random Tree (RRT). However, the solution provided by RRT is suboptimal. An RRT extension known as RRT* is optimal, but it takes time to converge. To improve the RRT* slow convergence problem, a goal-oriented sampling-based RRT* algorithm known as GS-RRT* is proposed in this paper. The focus of the proposed research work is to reduce unwanted sample exploration and solve the slow convergence problem of RRT* by taking more samples in the vicinity of the goal region. The proposed research work is validated in three different environments with a map size of 384*384 and compared to the existing algorithms: RRT, Goal-directed RRT(G-RRT), RRT*, and Informed-RRT*. The proposed research work is compared with existing algorithms using four metrics: path length, time to find the solution, the number of nodes visited, and the convergence rate. The validation is done in the Gazebo Simulation and on a TurtleBot3 mobile robot using the Robotics Operating System (ROS). The numerical findings show that the proposed research work improves the convergence rate by an average of 33% over RRT* and 27% over Informed RRT*, and the node exploration is 26% better than RRT* and 20% better than Informed RRT*