Advanced Materials Research Vols. 488-489

Abstract: Proper operation of a hydraulic system used in a fatigue test machine (FTM) is crucial. This is because a fatigue test may take well over hours and is not necessarily supervised. Any system failure may result in specimen destruction or experiment failure. In this study experimental data is collected and analyzed to prognoses the hydraulic system. Prognosis may be used to set an alarm level when the predicted values of failure fall within the warning region. This paper presents an approach to predict the operating conditions of a hydraulic system a few increments ahead in time, otherwise known as multi-step ahead (MS). The approach is further validated using experimental data. To do this, applied force on standard aluminum specimen is recorded in time series. Wavelet soft thresholding is used to filter and reduce the effect of noise and sharp edges in the measured applied force data (time series). Embedding dimension and time delay are determined using Cao's method and auto mutual information (AMI) technique, respectively. These values are subsequently utilized as inputs for constructing prediction models to forecast the future values of the machines’ operating conditions. The results show that the neural network (NN) prediction model can track the change in machine conditions and has the potential to be used as a machine fault prognosis tool.

Abstract: Effect of HVDC transmission lines in a power system on different optimal power flow (OPF) objective functions is discussed in this paper. In this study differential evolution optimization algorithm is applied in AC-DC OPF problem, and compared with OPF in the same power system with no HVDC transmission lines to demonstrate the effect of this type of transmission line on the objective functions. In OPF problem definition, generator fuel cost considering valve effect is considered as objective function. The results of the proposed method on IEEE 30-bus power system illustrate that HVDC transmission lines improves the OPF from fuel cost point of view.

Abstract: This paper proposes a new method for designing a fuzzy adaptive controller for a class of non-affine nonlinear chaotic systems in which functions of the systems are unknown. The proposed method is aimed on a class of non-canonical non-affine nonlinear chaotic systems. The stability of the closed loop system is guaranteed based on Lyapunov’s theory. The proposed controller is robust against uncertainties and external disturbances. The simulation results show the effectiveness of the proposed method.

Abstract: This paper proposes a new method for designing both nonlinear observer and adaptive controller for a class of non-affine nonlinear systems with unknown functions of the system. The states of the nonlinear system are assumed to be unavailable for measurement. The merits of this paper is as: asymptotic convergence of the observer and tracking error to zero, boundedness of all signals involved, and robustness. The simulation results illustrate the promising performance of the proposed algorithm.

Abstract: In this paper a satellite with two flexible appendages and the piezoelectric layers which are attached to them and a central hub is considered. The piezoelectric layers are used as actuators. The governing equations of motion are derived based on Lagrange method. Using Rayleigh-Ritz technique ordinary differential equations of motion are obtained. A robust passivity based control is applied to the system to not only control the three axes maneuver of the satellite but also suppress the vibrations of the flexible appendages. Finally, the system is simulated and simulation results show the good performance of this controller.

Abstract: Fatigue failure has become a major concern in the automobile and aircraft industry, heavy machinery etc. Failures by fatigue are especially dangerous because they are unpredictable; giving no prior notification of the imminent failure they occur suddenly. Front axle of tractor is one of the major and very important components that undergo severe load conditions and it fails unexpectedly causes unrecoverable losses. The objective of this study is to analyze the existing design of the front axle of the tractor for service load conditions and redesign to its functional requirements and to increase its life expectations. Finite element simulation is carried out for the existing front axle using ANSYS. The critical location of the front axle has to be identified and redesigned to ensure the safety. The existing geometry of the front axle is modified to the optimum size which suits for functional requirements with increased life and minimum cost. In this analysis, the geometry of the front axle is modified and a new design is proposed. The life expectancy of the front axle was predicted for the dynamic load using ANSYS fatigue design module.

Abstract: The general objective of this work is to analyze the failure of HVAC components in metro trains by using reliability assessment techniques. Various failure causes with respect to the electronic, electrical, hydraulic, pneumatic, software and mechanical components were identified. To improve upon the reliability characteristics of the system, in depth qualitative analysis of all HVAC units is carried out using Root cause analysis (RCA) and failure modes and effect analysis (FMEA) by listing all possible failure modes and their possible causes. Based on FMEA of components, Risk Priority Number (RPN) is calculated.

Abstract: This paper proposes localization using sensor fusion with a laser navigation and an inertial navigation system for indoor mobile. The laser navigation is a device that measures angle and distance between the robot and the reflectors. Although it is the high-precision device for indoor global positioning, there is a problem that the accuracy of laser navigation significantly drops while moving at high speed and rapid turning. To solve this problem, the laser navigation was fused to inertial navigation system through Kalman filter. For experiment, we use omnidirectional robot with Mecanum Wheels and analyze the positioning accuracy according to driving direction of the robot.

Abstract: In this paper, we make a theoretical analysis for the two-mass feeder. The dynamic model of the two-mass feeder is established. According to the analysis of vibration equations, the reasons that lead to forward and backward swing of the feeder are found. We collect a large number of experimental data in order to verify the correctness of the theoretical analysis, and give the corresponding improvements. The results provide a strong scientific basis for the examiner and the improvement of structural design, making the design become more rational.

Abstract: In order to get the accurate traffic flow parameters, it often takes too long time and a lot of manpower and material resources. So, combined with GPS vehicle positioning system and the characteristics of traffic flow parameters, the transformation model of traffic parameters in intelligent acquisition system of traffic flow parameters is designed and the data processing and error recovery method are present. The results show that the system, integrated fully the advantage of GPS, can transform GPS coordinates into the features of traffic flow parameters directly, which has an intuitive guide to the traffic management department.