Papers by Keyword: Error Model

Abstract: Extracting acceleration of boost phase is the key technology of establishing the ballistic profiles. An algorithm based on orthogonal curve fitting is presented to extract acceleration of boost phase, using the line of sight (LOS) measurements. Then, an error model is established and the theoretical error of the method is analyzed. The new fitting method improves the curve fitting error of the terminals. Sufficient simulations on some typical scenarios are performed, and the results indicate that the method presented is efficient.

Abstract: The precision of Multiaxial EDM is improved by a geometric and motion error model of EDM. A lower numbered body array is introduced to describe the EDM with a homogeneous coordinate transformation used to model the geometric and motion errors of a typical body in the multi-body system. Multi-body kinematics are employed to derive the structural and motion relations and the corresponding location error equation。 The motion error chain for the EDM is analyzed to develop a versatile error model. An entire Multiaxial EDM is analyzed as an example to determine its errors. The method provides a reference for Multiaxial EDM precision design.

Abstract: Error modeling and analysis can improve the manufacturing precision and the error compensation accuracy of machine tool. According to the surface of the parts topography information, this paper puts forward a kind of error model of machine tool based on cutter contacting point vector chain. Based on analyzing the cutter contacting point of one tool path which is on the surface of the parts, Based on analyzing action rules of a single cutter contacting point error, the cumulative rules of errors and calculation methods were introduced detailedly, and an application demonstration is given.

Abstract: With the continuous development of the Internet of things technology, the high-speed vehicles to prevent rear-end collision warning system which is from the traditional passive to the current vehicle-to-vehicle communication active warning also continues to develop. In this paper, a vehicle ranging system is composed of Zigbee wireless communication and GPS positioning system. Through setting maneuvering model, establishing ranging system state equation and observation equation, error model, integrating the two vehicles’ distance, relative velocity, relative acceleration and the distance error, we can get the vehicle distance estimation by using of centralized Kalman filter techniques. The simulation results show that the method can provide vehicle-to-vehicle communication ranging system with the high precision data of anti-collision distance. The system has good tracking performance.

Abstract: Star tracker is an accurate autonomous attitude measurement equipment. Multi-channel star tracker has been widely used and the accuracy of multi-channel star tracker becomes an important issue to study. In order to study this issue, an error model of multi-channel star tracker is established and analysis of accuracy of multi-channel star tracker is carried out with the model. Simulation results show accuracy of multi-channel star tracker is much higher than the single channel ones. There is great potential to develop multi-channel star tracker in the future.

Abstract: In the project of testing platform, characteristics of the measured object are framework. In view of the difficulties of non-contact high-precision measurement of the planar motion objects, an innovative measuring method is proposed which is based on the combined using of high-precision laser distance sensors. This paper presents the structure of the new sensor and its measuring principle, and established a mathematical model of the measurement object and its error model by using differential method. We use the Monte Carlo method to random sample the random sampling of random variables of the error model; finally combining with the instance; we use the Monte Carlo method to get frequency distribution histogram of the measurement error. Through analysis and calculation of this paper, we prepare for theory for the practical application of this new type of sensor.

Abstract: In this paper, a non-contact coordinate measuring machine with laser displacement sensor, which consists of three translational axes, is designed and built independently. In order to obtain the measuring precision, it needs to calibrate the coordinate measuring machine. Learning from the calibration method of contact coordinate measuring machine, a detection method is proposed for calibrating the precision of the non-contact coordinate measuring machine. Based on the homogeneous coordinate transformation theory, the error model of coordinate measuring machine is built under the condition that the positioning errors, angular errors, straightness errors and perpendicularity errors are taken into comprehensive consideration. The final error expressions of three axes can be calculated in the use of error model and homogeneous coordinate transformation theory. The final values of the errors are acquired through the analysis of the error curves, which can be obtained by using the laser interferometer system. The method proposed in this paper is using the two-dimensional ball plate to measure the errors. By locating three different positions of the ball plate in the space and using automatic centering procedure to measure the center position which is previously calibrated, the final errors of three axes can be detected directly. By comparing the two results, it testifies that the two-dimensional ball plate detection method is reasonable. Comparing with the laser interferometer method, the two-dimensional ball plate detection method reduces the workload of adjusting the optical path and the time of measuring errors, which has the vital significance in calibrating the precision of non-contact coordinate measuring machine.

Abstract: To increase the precision and the processing efficiency of large-scale marine propeller, the method of twin-tool symmetrical processing is proposed based on hybrid mechanism. With the introduction of mechanism compositions of the machine tool, the calibration method of the structural parameters is researched. The serial and parallel mechanisms of the hybrid mechanism are calibrated separately for the coupled motion. Their structural error models are established and identification methods of structural parameters are analyzed. And nonlinear equations are solved by using the Levenberg-Marquardt optimization algorithm to obtain the structural parameters. Finally, in ADAMS, hybrid machine tool model with structural parameter errors is established. And the pose errors of the tool are acquired in kinematics simulation. After that, the structural parameters errors of the machine tool are compensated by calibrating. Then, the error models and the parameter identification methods are proved to be accurate. Meanwhile, the correctness and effectiveness of the calibration method is proved.

Abstract: Research on spatial error modeling of the glass fillet machine is introduced based on the basic principles of multi-body system kinematics. Firstly, the topological structure and the low-order body arrays are described on the basis of the mechanical structure. Then, the spatial error analysis is carried out based on the theory of multi-body system. At the same time, the transformation matrix between the adjacent typical bodies is written. After that, in order to illustrate the relationship between the grinding wheel and the grinding point, the space error model of the glass fillet machine is established, which explains the effect of spatial structure on machining error and the calculation method of machining error. This model is easy to analyze the error and embodies the superiority on the error analysis and correction. Thus it provides a kind of ideal technique for the precision analysis of the glass fillet machine.

Abstract: Latest trend in increasing the performance characteristics of precision machines is reducing error in machines. Today research is focused on Machine tool accuracy. The effect of thermal error contributes to major part of 70% of volumetric error. The present study aims to establish a new compensation method for CNC Turning centre. Selection of proper temperature variables is a great task in thermal error compensation. In this paper 3 thermal process variables namely spindle speed; temperature and time are used to create thermal error models. Using ANSYS simulation experiments are created.