Papers by Keyword: Calibration

Abstract: Based on the former calibration data of error coefficient of inertial navigation instrumentation and environment parameters, a three-layer BP neural network is founded to predict the calibration value in current circumstances. To confirm the structure of neural network, genetic algorithm is used to seek the optimal solution, and hence the concept of genetic neural network is introduced. Also since the calibration data has small-sample characteristics; Bayes regularization method is adopted to improve the network generalization ability and predicted performance. In the end the simulated results show that it is reasonable and effective to accomplish the prediction in genetic neural network.

Abstract: For calibrating the X-band equipment in the TT&C ship based on wireless communication, we design a high gain rectangular horn antenna. Through analysing the theory of structure, the antenna’s preliminary size parameter is estimated and it is simulated based on HFSS. The antenna structure parameters are obtained after parameters optimization. The results of simulation indicate that the design of antenna indexes meet the needs completely. The structure of antenna is compact and it easy to process. The simulation method in the paper may also be referred to other related design.

Abstract: The paper deals with constructing the inertial navigation system (hereafter INS) which will be utilized for the calibration of a robotic workplace. The calibration is necessary for adapting the simulation of a production device model to real geometric conditions. The goal is to verify experimentally the proposed inertial navigation system in real conditions of the industrial robot operation.

Abstract: It is known that earthquakes generate infrasound. The frequency spectra of the infrasound signals associated with earthquakes are concentrated within a wide frequency range (0.002-0.02 Hz), and have spectral tail extending up to the frequencies 0.1-1 Hz. Therefore, the dynamic characteristics of infrasound sensors should be chosen so as to capture main features of such signals. In this paper, the characteristics of infrasound sensor InSAS2008 developed by Institute of acoustics, Chinese academy of sciences, are described. Its performance indicators are listed and its frequency response is analyzed. The special construction in the mechanical design is developed to overcome drift problem caused by temperature variations. In addition, the infrasound sensor is not affected by nonlinear effects. The calibration results show that infrasound sensor works within a wide and flat frequency band.

Abstract: A method of analyzing the Six-axis force measuring system by hybrid modeling is introduced in this paper. The mapping function of signal voltage output, which is input vectors of the Neural Network (NN) model, and measuring force signal, which is output vectors of the NN model, is represented as two parts. The determined linear part obtains the main principle and the the information of transfer matrix. The undetermined nonlinear part are estimated by neural network. The problems about nonlinear error and coupling are solved. The accuracy and feasibility of the method are displayed by the result of experiment data simulation.

Abstract: Selective Catalytic Reduction (SCR) technology is an effective measure to reduce NO_x emissions of diesel for commercial vehicles. The purifying effect of Urea-SCR exhaust gas purification device is related to calibration of the parameter of urea control system. Based on MAP diagram , the calibration method of urea spray control system in Urea-SCR system was studied on. Through verifications of ESC and ETC,it is reflected that calibrated MAP diagram can effectively reduce NO_x emissions of diesel if used in the control system and emissions could meet the standards of 4th and 5th stage national emission regulation.

Abstract: A novel and simplified method, which is useful in calibrating instantaneous acceleration and cushioning time of accelerometers after impacted by an object under different parameters’ condition, is proposed in this paper. An investigation on cushioning time, which is usually difficult to be quantified during the process of collision, has also been conducted. Firstly, by mathematical inference on a physical model, we obtained two formula conclusions. Next, numerical simulation suggests that the instantaneous acceleration and cushioning time, to different extent, are sensitive to six factors. Then, influences produced by each of them are studied one by one. By analyzing these influences, the method and results are proved to be correct and practical.

Abstract: The measurement of spray characteristics especially the droplets thermal and hydrodynamic properties is very important for many industrial applications. In this paper, a developed global rainbow thermometry method is applied to measure droplets temperature and size distribution in a flat fan air-blast atomizer spray. The spray droplets is illuminated by a continuum laser with the wavelength of 532nm and power of 14mW, and the rainbow light formed by the droplets is received by a linear CCD. To get accurate result, a calibration method for the relation of scattering angle and CCD pixels is designed, which can effectively reduce the error of the measured temperature. Experiment is taken under different temperature at a fixed gas-liquid ratio conditions, and results shows the method is feasible and has a relatively good precision.

Abstract: Three-dimensional (3D) vision scanning measurement is widely used in industry for its ability to obtain the 3D surface data of the object. Aiming at overcoming the shortcomings of 3D scanning measurement system with single structured-light sensor, such as limited measurement range and blind measurement area, a scanning system based on double structured-light sensors (DSS) is established. The object is scanned from two different directions, and the 3D surface coordinates are unified to the measurement coordinate system to obtain the 3D surface of the measured object. In this paper, the mathematical model of the DSS scanning system is established. Meanwhile, an on-site calibration approach based on planar target is proposed to complete the system calibration task. Finally, experimental results of practical data are given to show the feasibility and validity of the proposed system.

Abstract: This paper studys the feasibility of the shadow of interactive gestures on the projection screen as the control instructions in a projection interactive system. With regard to complex background of the projection screen, we put forward to detect mobile gestures and the shadows of gestures by using the way of the Gaussian mixture model. Relative to the non-rigid body interaction gestures, The shadow of gestures has a simpler two-dimensional characteristics and greater differences from the other regions of the projection screen. Based on this characteristics, we adopt Ostu threshold segmentation algorithm to remove the interference of the gestures. Then we use the mixed way of the radial symmetry transform and curvature threshold to position the interactive fingertips as interactive instruction of the projector-camera system. Conctroling the screen in a wide range without carrying any equipment is completed. The experimental results show that this method is easy to operate and has a high accuracy rate.