Papers by Keyword: Error Compensation

Abstract: This paper proposes a new method to predict the spindle deformation based on temperature data. The method introduces ANFIS (adaptive neuro-fuzzy inference system). For building the predictive model, we first extract temperature data from sensors in the spindle, and then they are used as the inputs to train ANFIS. To evaluate the performance of the prediction, an experiment is implemented. Three Pt-100 thermal resistances is used to monitor the spindle temperature, and an inductive current sensor is used to obtain the spindle deformation. The experimental results display that our prediction model can better predict the spindle deformation and improve the performance of the spindle.

Abstract: According to the robot positioning accuracy, this paper proposed an error compensation method after updating the controller parameters based on the D-H parameters model and Dynacal system. The proposed method is effectiveand was validated on the developed robot of which the mean error was reduced to 0.092mm. The method can greatly improve the positioning accuracy of the robot.

Abstract: In this paper, we propose a signal compensation algorithm. In heterodyne laser interferometer, the unexpected error restricts the precision such as nonlinearity and environmental error. To improve the accuracy in length measurement, we use the method of Lagrange multiplier which solves the constrained optimization problem and allows to minimize an objective function. With the method of Lagrange, we apply it to a length measurement and show the result of simulation.

Abstract: The adoption of conformal optics system can evidently improve the synthetical performance of infrared missiles. Hot-pressing poly-crystal magnesium fluoride (MgF₂) is an ideal material for conformal optics dome. But many problems about machining and surface test of deep aspheric surface have not been solved at present, and there is not much research about the machining characteristics of MgF₂ material. In this paper, in-situ measurement system is designed, so positional errors that introduced by repeating installation can be avoided. Then, machining process of MgF₂ material by single point diamond turning is studied, and optimized diamond turning process is proposed by experiments in order to obtain low surface roughness. Furthermore, surface accuracy is tested by on-machine measurement system. Based on the result, error compensation process of conformal dome is carried out. Finally, the shape error of the dome is less than 0.8μm PV.

Abstract: When a missile runs under the complex situation such as high dynamic flying, receiver signal being blocked and so on, the GNSS receiver sometimes gets less than four satellites. For the loosely coupled system, the navigation accuracy will decrease over time. In this paper ,tightly coupled integrated navigation system which is based on pseudo range and pseudo range rate dynamically adjusts the dimension of the system according to the number of visible satellites, in order to achieve seamlessly navigation; a multiple step optimum precision factor satellite selection algorithm is proposed, an error compensation method which is based on the state transition is designed and implemented. Experiments show that when the number of visible satellites changes, tightly coupled system can seamlessly switch, when more than four satellites are received, the multiple step optimum precision factor selection algorithm can provide a combination of high precision satellites, by applying the error compensation method to calibrating the system, high-precision navigation can be achieved.

Abstract: In this paper, the cause of nc machine tool geometric error made a more detailed analysis, the system error compensation methods are summarized, and on this basis this paper expounds the applications of all kinds of error compensation method, in order to further realize the accuracy of machine tool software upgrade to lay the foundation.

Abstract: It is inevitable that the mechanical part has error when machining. To increasing the machining precision and decreasing the shape and position error, error compensation is one way. The geometry error parameter is necessary when the error compensation model is founded and the compensation data is calculated. The common measuring and identifying methods are introduced in this article. Their mathematic models and solutions are listed and their merits and drawbacks are compared. This method has been applied in CNC error compensation and the effect is advisable.

Abstract: In order to improve time-grating sensor’s measurement accuracy, which is influenced by stability of the components, temperature and mechanical processing in precision measuring procedure. A novel compensation method based on Fourier series approach and least square is presented. With this method, the measurement error is separate into a lot of harmonics, and the optimal parameters of compensation are evaluated by least square method. The accuracy analysis certificates that time-grating sensor’s measurement error is reduced from ±14.8′′ to ±2.5′′ by applying the error compensation method, which is compensated about 80% compared with no compensation. Sensor’s accuracy is effectively improved.

Abstract: In this study, a small 6-DOF (degree of freedom) parallel mechanism worktable for machine tool was developed. There are many factors that affect the positioning precision and the accuracy of the machine tool. The uncertainty in position is mainly due to the structural rigidity, the geometric error of the parts and the assembly errors. It is very difficult to estimate the assembly errors and the link parameter of each part. Moreover, it is necessary to make clear the relation of cross talk between each axis for parallel mechanism. In this research, a method to compensate the movement error of worktable based on the measurement result was proposed and discussed. First, in order to measure the positioning accuracy of the worktable a measuring method by using 3-dimensional coordinate measuring machine (CMM) was proposed. After the evaluation, the positioning accuracy of the parallel mechanism worktable, the error of each configuration parameter can be obtained. By the correction of the inverse kinematic program, the improvement of the positioning accuracy of the worktable was confirmed. After calibrating several times, the positioning error became stable within a constant range. It is confirmed that this method to obtain the parameter error is effective, and it is possible to improve the positioning accuracy.

Abstract: Aiming at removing interference field in the geomagnetic navigation, the technology of interference magnetic field measurement and error compensation are studied. The scheme of error measuring and compensating are designed, the compensation model is established based on the magnetic dipole theory, its calculation method is designed, experiments prove that this technology is of high accuracy and its process is simpler, it provides a new way for eliminating interference in the aeromagnetic survey.