Advanced Materials Research Vols. 433-440

Abstract: For the problem of determination of maintenance time in demonstration phase of materiel, analysis method based on maintenance concept and maintenance function is put forward. Maintenance concept gives the constraints for maintenance time By analysis of maintenance function, the relation between a function system of materiel and a maintenance level, and the relations of maintenance actions of levels are clarified. To describe determination of maintenance time for convenience, taking example for intermediate-level maintenance, on the basis of the given maintenance concept, models of maintenance time are built, and flow-processes of maintenance function are given. According to above analysis result, mean maintenance time of intermediate-level is determined. It provides an important basis for trading off the relation of impacting among maintenance concept, maintainability requirement, and design of materiel.

Abstract: Radar non-contact measurement technology, the microwave signal transmission does not need the media, feature-rich, with a wave of false learning function. It is not subject to any process in the steam, pressure, dust or temperature. And therefore suitable for high viscosity, corrosive, high temperature, high pressure, high dust and other occasions, the level measurement, level measurement methods routine at this time will not be achieved. Radar level meter in the high dust, slurry particles, pellets Level available non-contact continuous measurement of very good use of effects.

Abstract: In this paper, dynamic pricing and ordering policy for non-instantaneous deteriorating items is developed. Shortage is allowed and partially backlogged where as the backlogging rate is variable and dependent on the waiting time for the next replenishment. The major objective is to determine the optimal selling price and the optimal ordering policy simultaneously such that, the total profit is maximized. We first show that for any given selling price, optimal ordering policy schedule exists and unique. Then, we show that the total profit is a concave function of price. Next, we present a simple algorithm to find the optimal solution. Finally, we solve a numerical example to illustrate the solution procedure and the algorithm.

Abstract: This paper deals with the mathematical formulation of tolerance analysis. The mathematical formulation presented simulates the influences of geometrical deviations on the geometrical behavior of the mechanism, and integrates the quantifier notion. We propose a mathematical formulation of tolerance analysis which simulates the influences of geometrical deviations on the geometrical behavior of the mechanism, and integrates the quantifier notion. To compute this mathematical formulation, two approaches based on Quantified Constraint Satisfaction Problem solvers and Monte Carlo simulation are proposed and tested.

Abstract: The electrical energy consumption is rising and there is a steady increase in the demand of power generation. To meet the demand fuel reserves are not sufficient. So, we can go to non-conventional energy sources like solar, tidal, wind and etc. In that wind generating system is rapidly growing one. The wind speed is not constant at all times they can using variable speed wind turbine (VSWT) or Doubly Fed Induction Generator (DFIG). The DFIG wind turbine is recently most used turbine, because it maintains fixed voltage and frequency at variable wind speeds using power electronics equipments like RSC and GSC. In this paper discus the stability of a DFIG wind turbine connected to grid, during unbalanced loads and grid faults. Dynamic analysis and fault analysis to find the stability of system were going to carry out in this work. And to improve stability of system during abnormal conditions STATCOM is proposed.

Abstract: This paper considers the problem of formation control and obstacle avoidance for a group of non-holonomic mobile robots in a leader referenced model based on reactive switching control strategy. Three important issues related to the multi robot formation namely distributed formation control framework, dynamic role switching algorithm and real time implementations are investigated. The switching control strategy combines together formation planning, navigation and active obstacle avoidance in a layered control framework composed of functional behaviors based on the relative motion states of the robots employed in the group. Dynamic role switching mechanism incorporated in this work to tackles the problem of obstacle avoidance in the follower path. The proposed approach is validated through laboratory experiments using commercially available robot research platforms and the results obtained are discussed.

Abstract: The objective of this paper is to investigate longitudinal flight dynamics of the said aircraft at loitering flight condition near sea level. Three mathematical dynamic models are used to compute transient response of Baseline-II E-2 BWB along with a proposed model known as Model-N. Model-N is derived to incorporate as many important derivatives, including gravitational and pitch angle factor, as possible. While all these four dynamic models are different in a sense where one model is more simple or complex than the others, the basic architecture of all these models are the same. This paper shows the short-period mode needs serious attention. A control algorithm is needed to overcome its handicap which is below Level 3 damping ratio according to MIL-F-8785C. Improvement to phugoid can be considered secondary, but one must ensure that bringing short period mode to Level 1 flying quality does not make phugiod mode response worse than it is now.

Abstract: This paper presents exergy analysis of Micro Gas Turbine (MGT) system. It is proposed to use hot MGT exhaust gases heat in a heat recovery steam generator to produce steam. Absorption chillers can help to increase the performance of MGT tri generation plants. MGTs are fuelled with natural gas and their waste heat is used to drive absorption chillers and other thermal energy users. Based on a steady-state model of the processes, exergy flow rates are calculated for all components and a detailed exergy analysis is performed. The components with the highest proportion of irreversibility in these systems are identified and compared.

Abstract: Current research trend in mobile robot is to build intelligent and autonomous systems that enables mobile robot to plan its motion in static and dynamic environment. In this paper, Genetic Algorithm (GA) is utilized to come out with an algorithm that enables the mobile robot to move from the starting position to the desired goal without colliding with any of the obstacles in the environment. The proposed navigation technique is capable of re-planning new optimum collision free path in the event of mobile robot encountering dynamic obstacles. The method is verified using MATLAB simulation and validated by Team AmigoBotTM robot. The results obtained from MATLAB simulation and real time implementation are discussed at the end of the paper.

Abstract: Trajectory optimization problem for spacecraft proximity rendezvous with path constraints was discussed using direct collocation method. Firstly, the model of spacecraft proximity rendezvous in elliptic orbit optimization control problem was presented, with the dynamic equations established in the target local orbital frame, and the performance index was minimizing the total fuel consumption. After that the optimal control problem was transcribed into a large scale problem of Nonlinear Programming Problem (NLP) by means of Hermite-Simpson discretization, which was one of the direct collocation methods. Then the nonlinear programming problem was solved using MATLAB software package SNOPT. Finally, to verify this method, the fuel-optimal trajectory for finite thrust was planned for proximity rendezvous with elliptic reference orbit. Numerical simulation results demonstrate that the proposed method was feasible, and was not sensitive to the initial condition, having good robustness.