Applied Mechanics and Materials Vols. 530-531

Abstract: Speed tolerance between handrail and the steps, pallets or belt of the escalator or moving walk is important to the passengers safety. This thesis proposes a novel design of ARM Cotex-M4 based double-channeled testing instrument for speed tolerance test which adopts two independent optical encoders to acquire the speed of handrail and the steps. The design handles parameter information obtained through two independent optical encoders by ARM Cotex-M4, then calculates and displays the result by LCD. The experiment shows that the measuring error and resolution ratio agree well with the standard. It can quickly detect the speed tolerance between handrail and the steps and the function of intelligent indication is convenient to the inspector. The field test shows that it can meet the requirements of test and the efficiency is also greatly improved.

Abstract: In light of the shortcomings present in the measuring devices of shaft lining surface deformation, a shaft lining surface deformation measuring device was proposed. With a protective cap to reduce the influence of external environment, the measuring device can reflect the deformation of shaft lining according to the tautness of a strain steel string. Featuring by its simple structure, operational convenience, and low cost as well, the device has been applied to the auxiliary shaft of Maiduoshan mine, Ningxia, China. The upper part of Maiduoshan auxiliary shaft had been constructed using mine tunneling method, before the bottom part of large water inflow section been constructed using freezing method. The deformation of the completed shaft lining was measured during the freezing method construction, to provide important references for technical personnel taking reasonable protective actions.

Abstract: Measurement process is a specific process to support product quality, and export measurement requirements is the beginning of the measurement process control, it is important to achieve the goals of product quality and manage risk of incorrect measurement results. Measurement requirements, including the requirements for the measurement process and the requirements for measuring equipment, measuring requirements, measuring staff, measurement method, ambient conditions and the measured object as a system, use Measurement Capability Index, quantitatively export measurement requirements of measurement processes and measuring equipment to ensure that measurement processes and measuring equipment satisfy the intended use, make the process of measurement requirement derived more scientific and more standard.

Abstract: The conventional phase difference measuring methods in the phase shift laser range finder are usually implemented with complex hardware circuits and phase discrimination algorithm. In this paper an FFT phase difference measuring method is designed and implemented based on STM32F407VG microcontroller. This method takes the advantage of the pre-set and fixed frequency of the beat signal by setting the analog-to-digital conversion rate precisely and making the input data length of FFT integral multiples of the beat signal period. In this way spectrum correction is no need. The hardware circuits and phase discrimination algorithm is simplified. The test results show that the phase difference measuring accuracy of 1/12000 is achieved.

Abstract: A phase unwrapping algorithm for 3D shape measurement of discontinous surface is presented. The proposed phase unwrapping algorithm can overcome the phase discontinuous problem.Three channel values in HSV space are completely employed to calculate the pattern color information intensity, the relative position relationship between adjacent pixels hue channel value is used to decide absolute phase fringe order. The proposed unwrapping algorithm can be applied to the measurement for 3d object with large height steps and/or spatially isolated surfaces. The correctness of the proposed algorithm is validated by our simulated experiment.

Abstract: Detecting the location offset of laser spot center method to monitor roadbed settlement is a kind of portable, easy to layout method. Detection laser spot center offset, we can use gravity, circle fitting, ellipse fitting and Gaussian curve fitting, etc method. Gravity algorithm is only involves basic arithmetic and low precise, and ellipse fitting is higher precise. Because of the angle between the optical axis and the target, the laser spot is more approximate as a ellipse. Using the ellipse fitting algorithm, Sub-pixel precise threshold segmentation and Canny edge extraction we obtained an ideal monitoring precise of the roadbed settlement.

Abstract: Based on the requirement of small errors in measuring roundness (cylindricity) error, a leveling methodology which using a dual-point vertical layout has been put forward and analyzed. According to the direction cosine of the axis of workpiece, the amount of leveling has been defined and calculated, which overcomes the problem brought by manual adjustment technology and forms theoretical bases of fast, accurate leveling and high precise measurement. The assessment of roundness (cylindricity) error is to search for a center (cylinder axis) which satisfies the minimum condition. Due to the reliance of initial solutions and relative slowness in terms of convergence precision and convergence rate when using Nelder-Mead simplex method, a combinative method of Quasi-Newton and N-M simplex method has been proposed which achieves a fast, accurate search for global optimums. With the proof of the simulation of classical testing functions using Matlab and the measured data, the convergence rate and precision will be enhanced effectively has been certified with the combination of both methods mentioned above which ensuring and improving the measuring precision of workpiece.

Abstract: Based on WAMS technology and the demand of real projects, a method of mixed measurement of zero-sequence parameters for two parallel coupled transmission lines is proposed. The principles and specific methods of mixed measurement mainly based on the incremental method are explained in details.The mathematical model is given and a digital simulation of coupled transmission lines with different zero-sequence parameters is conducted to verify the method.

Abstract: White light measurement is increasingly applied in automotive sheet metal parts measurement nowadays. Although white light measurement has substantially improved the measuring efficiency, this method has a low precision and poor reproducibility at present stage. This paper firstly analyses the process of white light measurement, then uses DMAIC Method to establish a unified measuring standard for white light measurement, in order to improve the precision and reproducibility of this method and promote the equipment utilization.

Abstract: It designed a simple system device which can detect the concentration of melamine in pure milk in this paper. Using the visible-near infrared light source to irradiate melamine-contained milk solution, the reflection spectra would have obvious change at the wavelength of 500 nm with the increasing concentration of melamine in pure milk, and the reflection spectra are nearly overlapped at the wavelength of 1000 nm. Based on this principle, combined with the photoelectric technology and computer technology, collecting light at 500nm is used to determine the concentration of melamine, and collecting light at 1000nm is used to eliminate the Interference of other ingredients in milk. The experimental result shows that, when the concentration of melamine is not less than 3 , the relative error produced by the device is less than 1%. And the device can quickly detect whether the milk containing melamine in real-time and accurately show the concentration of melamine, which make the device have strong practicability.