Papers by Keyword: Nonlinear Characteristic

Abstract: Temperature sensors are widely used in different industrial and scientific applications. These sensors commercially available in various type and configurations allow the enhancement of automotive systems. The manufactures need to improve and upgrade the technology by research activities regarding the accuracy of temperature measuring using sensors. In this paper will analyze the trends, applications and technologies in automotive temperature sensors. PTC/NTC thermistors are measured and characteristics curves are determined as expression of mathematical functions.

Abstract: Focusing on a complicated metro station with shallow depth, its three-dimensional calculation model was established, which includes not only the main station structure, but also includes the subsidiary structure such as the entrances and detailed structures such as the holes in the floor. The Davidenkov model was employed to simulate the nonlinear characteristics of the soil. The three-dimensional nonlinear seismic responses were analyzed. it can be shown from the calculation that: (1) the metro station structure can satisfy the demand under given seismic motion; (2) it is more important for structural concept design and structural measures design than the strength and deformation design for complicated underground structures.

Abstract: Nonlinear characteristic hinder the effective use of piezoelectric smart materials in sensors and actuators. In this paper, the intelligent fuzzy PID controller is designed in the Matlab-Simulink environment. The piezoelectric smart actuator model is built. An adaptive fuzzy PID control scheme was proposed. The proposed control scheme was implemented in Matlab. The results of simulation and experiment indicate that the control method has good control ability.

Abstract: A method for compensating nonlinear characteristic of thermocouple vacuum gauge is proposed. Least squares support vector machine (LS-SVM) is adopt as compensation model, of which parameters are optimized using particle swarm optimization (PSO) algorithm. Experimental results using data obtained on-site show that the proposed approach effectively compensates the nonlinearity characteristic, and the accuracy of this method is higher than those obtained by SVM model.

Abstract: A bridge health monitoring system based on neural network technology is proposed in this paper. Two major ground excitations recorded in Taiwan were used to establish the NARX-based system. Analytical results from different methods including transfer function, ARX-based model, and the proposed neural network-based system were used to evaluate the efficiency in health monitoring. The result shows that the proposed system can be used successfully with superior advantages after major earthquakes for bridge health monitoring.

Abstract: Based on chaotic characteristics in vertical direction of vibrating screen sides, nonlinear methods were proposed to diagnose crack of vibrating screen. First phase space maps were got in different conditions of vibrating screen, and the correlation dimension of signals were calculated. Through the comparison, the author proved that the equipment had different nonlinear characteristics in different work condition. Meanwhile, a three-dimensional spectral analysis method was proposed and validated based on neural network identification model.

Abstract: The additive of Al(NO3)3 was doped into ZnO varistors in order to reduce their residual voltages. Some of doped Al3+ enter the ZnO grains and infill into the vacancies of Zn2+ ions in the crystal lattice. Then, the resistances of ZnO grains decrease, which finally results in lower residual voltages of varistor samples. However, when most of Zn2+ vacancies inside the ZnO crystal lattice are filled with Al3+, redundant Al3+ ions inside ZnO grains will increase the grains’ resistances contrarily. In this paper, ZnO and Al(NO3)3 binary ceramics sintered at 1300 °C for 2, 4 and 8 hours were studied. The J-E curves of the investigated samples exhibit weak non-linear characteristics which may be due to the formation of grain boundary. Moreover, The resistivity dependence of ZnO ceramics on Al addition behaves as a U-type curve and the lowest resistivity of ZnO ceramics is obtained with doping 0.25mol% Al3+.

Abstract: The nonlinear dynamic behavior of a rotor-bearing system is analyzed with its finite element model based on the analysis of the discrete model, with considering some other important influencing factors such as, material damping, gyroscopic effect, inertia distribution, shear effect and so on, which make the description of the system more embodiment avoiding the casualness of selection with system parameters. With the comparison of the results on the bifurcation map and three-dimensional spectrum, significant difference is appeared with the addition of the considered factors. It is suggested that the substitution of continuum model for the discrete ones can get more accurate and abundant results. Furthermore, these results can provide more accurate verification and reference for the experiment and nonlinear dynamic design of the complex rotor system.

Abstract: Tracking solar-power devices often employ photovoltaic position sensors to detect the angle of misalignment between the axis of mounted solar panels and that of sunlight. The nonlinear input-output characteristics of this type of sensors tend to complicate controller design in such systems. This paper presents a nonlinear mathematical model of the photovoltaic position sensor. A three-layer feedforward neural network was trained to linearise the characteristics of the sensor. The MATLAB neural network tool (nntool) was used for neural network training. A final error of was obtained after training. Simulation of the neural network showed that linear sensor characteristics could be reproduced throughout the domain of sensor operation.

Abstract: Double-crank ring-plate-typed pin-cycloid gear planetary drive conquers shortcomings of a traditional pin-cycloid gear planetary drive, whose load-capacity is restricted by rotation-arm bearing dimension. The load-capacity of this kind of new drive is improved greatly and the efficiency of whole machine is 94%. In order to know dynamics reliability of this drive , nonlinear characteristics of double-crank ring-plate-typed pin-cycloid gear planetary drive are analyzed from two sides of transmission error and dynamic meshing process in this paper. A sensitive analytic mathematic model of rod dimension error is set up by kinematics theory. Based on ring-plate-type cycloid drive dynamic meshing characteristics, a rigidity-flexibility combined model of pin-cycloid planetary drive is set up by ANSYS/LS-DYNA module. Meshing process between pin-cycloid gear is simulated by FEM. Instantaneous stress, distortion and dynamic meshing rigidity are computed. Analytical results show that nonlinear meshing rigidity and transmission errors are two main dynamic exciters which cause prototype to vibrate. So, rod dimension error should be reduced in order to increase meshing accuracy, and meshing rigidity of new prototype should be increased in order to reduce vibration. Nonlinear characteristics of the drive can offer some theoretical bases for design of new prototype.