Abstract: This paper reviews the present status and future prospects of the levitation mass method (LMM), which is a precision mechanical measurement method. The LMM has been proposed and improved by the author for 10 years. The force generated by the actuator is measured as the inertial force of the mass levitated with sufficiently small friction using an aerostatic linear bearing and connected to the moving part of the actuator. During the measurement, the Doppler shift frequency of the laser beam reflected by the mass is measured with a high accuracy with the help of an optical interferometer. Subsequently, the velocity, position, acceleration, and inertial force of the mass are calculated using based on this frequency. Simultaneously, the current and voltage supplied to the actuator are measured.
Abstract: Thermal error modeling method is an important field of thermal error compensation on NC machine tools, it is also a key for improving the machining accuracy of machine tools. The accuracy of the model directly affects the quality of thermal error compensation. On the basis of multiple linear regression (MLR) model, this paper proposes an autoregressive distributed lag (ADL) model of thermal error and establishes an accurate ADL model by stepwise regression analysis. The ADL model of thermal error is established with measured data, it proved the ADL model is available and has a high accuracy on predicting thermal error by comparing with MLR models.
Abstract: An observation scheme, which is designed several frequencies suited over the natural audio electric field frequency range, is used to qualitatively understand the electrical structure of underground geological body. Weak signal detection technology has been used to amplify and filter the weak natural electric field signal, and read out them after selecting corresponding frequencies and integrating. This instrument can observe eight natural electric field signal at frequency of 8Hz, 16Hz, 32Hz, 64Hz, 128Hz, 256Hz, 512Hz, 1024Hz. Several reliable technologies have been used in the hardware design and software development to improve both the anti-interferences capability and system stability. Compared with field work instance, we conclude that natural audio electric field frequency selecting instrument can get the underground geological information within a certain depth, and therefore it can be used for fast survey in geology and mineral resources, and in engineering geophysical and water resources.
Abstract: In order to avoid the useless tunneling and the low mining rate, the mine seismograph measurement new technology is applied to measure the coal seam washout zone with long distance and high resolution. Based on the analyzing geophysics characteristic of the coal seam washout zone, this paper investigates the characteristics of time-distance curve of the measurement technology, and studies the application example of detecting the development and boundary scope of the old river-seam coal seam washout zone long-distance ahead of tunnel. The result shows that the measurement of the development and the boundary scope of the coal seam washout zone by using the mine multi-wave seismograph meet the practical requirement with small error and being consistent with the actual conditions during the process of mining.
Abstract: Multisine signal is often employed as an appropriate excitation to represent the complex modulated RF signals for accurate measurement of modern wireless communication system. This paper presents a novel way of designing a multisine signal by using Discrete Fourier Transformation coefficients to represent the digital modulation signals. Investigations of the approach on the IS-95 reverse-link signal as original signal is demonstrated the designed multisine signal can approximate represent original signal.
Abstract: The roundness error is an important index of mechanical part and its interchangeability, it is the key to quality of product. A new method for calculating the roundness error based on artificial bee colony algorithm has been proposed in this paper. Artificial bee colony algorithm is an evolutionary computation. It has the character of simple technique, easy digital realization and few controlling parameters. Firstly, the basic principle of artificial bee colony algorithm is concisely introduced in this paper. The detailed steps for calculating the roundness error based on artificial bee colony algorithm have been described. Finally experiment results are given. These results have shown that the proposed method can correctly and effectively evaluate roundness error. The proposed method can overcome the local convergence in evaluation of roundness error based on least square method (LSM).
Abstract: Nano-Grating measurement technology has been made great development in our country, for its unique advantage which isn’t available in laser interferometer. This paper presents a Nano-grating interferometer displacement measuring system based on double diffraction grating and Semiconductor laser light source, analyzes the error origin of the system in detail and uses error correction and compensation method to improve the measurement accuracy. The experimental result indicated that the system does have stable interferometer, high signal contrast, and easy adjusted optical path, further more the system with a strong environmental adaptability and compact structure. Under 20mm range and 50mm/sec measurement speed, the system’s measuring repeatability is below 30nm.
Abstract: The influence of the frame structure’s deformation of the automatic hydraulic tile press on energy consumption has long been neglected. In this paper, a case study in two common beam-column types hydraulic automatic tile press, get the deformations of the columns produced by the tensile by using the finite element method, and then calculate their energy consumption due to deformations. Through analysis and comparison, provide a reference for future design and selection of the hydraulic automatic tile press.
Abstract: Based on the principle of tracking inversion points method for north-finding, the tracking inversion points method without torque is presented with a tracking and controlling system. According to the gyroscope’s cursor signal captured in real time, the theodolite can be turned round by the electric turntable to follow the swing of the main axis of gyroscope. After simple calculating, the coarse north can be obtained. The influence of changed torque of hang spring is reduced and the measurement precision is improved. It has been proved through experiments that the coarse north can be obtained in a large range by the tracking inversion points method without torque. The experiment shows that the measurement precision is superior to 30′ and it costs no more than 7minutes to obtain the coarse north-finding.