Sheng-Chung Tzeng

Simple three-dimensional laser angle sensor for three-dimensional small-angle measurement.

A simple three-dimensional (3D) laser angle sensor for 3D measurement of small angles based on the diffraction theorem and on ray optics analysis is presented. The possibility of using position-sensitive detectors and a reflective diffraction grating to develop a 3D angle sensor was investigated and a prototype 3D laser angle sensor was designed and built. The system is composed of a laser diode, two position-sensitive detectors, and a reflective diffraction grating. The diffraction grating, mounted upon the rotational center of a 3D rotational stage, divides an incident laser beam into several diffracted rays, and two position-sensitive detectors are set up for detecting the positions of +/-1st-order diffracted rays. According to the optical path relationship between the three angular motions and the output coordinates of the two position-sensitive detectors, the 3D angles can be obtained through kinematic analysis. The experimental results show the feasibility of the proposed 3D laser angular sensor. Use of this system as an instrument for high-resolution measurement of small-angle rotation is proposed.

Development of a novel optical measurement system for the error verification of a rotating spindle

A new spindle error measurement system is described. It employs a specially designed rotational fixture with a corner cube to replace the precision reference master ball used in the traditional method. A two-dimensional position-sensitive detector (PSD) is used to replace the noncontact sensor for measuring the motion error of the rotating spindle. The rotational fixture is held on the tool holder, and the PSD is mounted on an adjustable holder to detect the position of an incident laser beam reflected from the corner cube. When the spindle rotates, the spindle error changes the direction of the reflective beam and also the positions of the spots on the PSD. Thus, the radial runout of the spindle can be obtained via the PSD outputs. The theoretical analysis to eliminate the setup error and eccentricity-induced error, as well as the error analysis, is given. This system is proposed as a new instrument and method for spindle metrology.

Flow Structure in an Inner Rotating Annular Channel with Ribbed Wall Cylinder

In this investigation, we explore the flow field of an annular channel between two horizontal concentric rotating cylinders, i.e., between a rotating inner cylinder and a stationary outer cylinder. Resulting from interactions between centrifugal force, viscous force and different boundary conditions, flow fields in an annular channel probably develop groups of opposite Taylor vortices when the Taylor number is higher than a critical value. Geometrical parameters of rotating cylinder channels, such as the channel widths and circumferential ribs are also affected by the flow field. Four types of rotating inner cylinder are available in this experiment: smooth walled (Model A), and circumferential ribs of three different sizes (Models B–D). The aspect ratios for circumferential ribs are 5/3, 5/2, and 10/3, which generate periodically embedded cavities of 10, 15, and 20 mm. The radius ratios between the inner and outer cylinders were ηs=0.89, and ηrib=0.94, respectively. Taylor numbers ranged between (8.565–1312.943)×103, and centrifugal force arising from the rotation of Model A was Fs=0.22–3.3 N. The centrifugal forces arising from the inner cylinders with embedded circumferential ribs were Frib=0.23–3.49 Nt. Because the wavelength of the Taylor vortices was subjected to the influence of different geometrical conditions, the flow field structure of Model A was different at both ends of the cylinder. Conversely, various forms of Taylor vortices occurred between annular channels with circumferential ribs in the case of Models B–D, and the vortex evolved from the edge of the circumferential ribs in a more stable manner than in Model A. The wavelengths of the Taylor vortices were λA=30 mm, λB and λD=20 mm, and λC=15 mm. Experimental results of flow visualization demonstrated it to be well suited for benchmarking engineering designs for heat transfer, cooling, and tribology of rotating machinery.

The design and fabrication of a temperature diagnosis system for the intelligent rotating spindle of industry 4.0

Abstract Nearly all machinery depends on high-speed rotation to convert kinetic energy into output power. However, high-speed rotation generates heat which needs to be removed to prevent operational anomaly. Prolonged overheating will result in decreased accuracy and reliability of the machine and may even cause serious damage. It is therefore valuable to monitor the heat generation in each and every part of a rotating shaft while it is operating. Internal sensors can be installed to determine temperature distribution and measures can be taken to remove heat from places which reach high temperature to prolong the life of the shaft and its precision. However, to measure temperatures in a high-speed rotating body, it is necessary to provide a means of transferring the signal from the sensors to the measuring device because leads cannot be used. This paper describes a temperature measuring device that uses a slip ring to transfer temperature sensor signals from a rotating spindle to the measuring instruments. Successful measurement of the internal temperatures of a rotating component is very useful. In event of a temperature anomaly, an alarm can be given which allows action to be taken to avert both damage to the machine itself and the output of defective production.

Development of a Measuring System for the Measurement of Motions Errors of a Linear Stage

A high precision six-degree-of-freedom measuring system is developed in this paper for the motion measurement of a linear stage. It integrates a miniature dual-beam fiber coupled laser interferometer with the multiple optical paths and quadrant detectors to be capable of measuring six-degree-of-freedom motion errors. The proposed measuring method provides rapid performance, simplicity of setup, and pre-process verification of a linear positioning stage. The experimental setup and algorithm for the error verification are presented in the paper. The measuring range of the proposed measuring system is ±40μm for straightness and 40 arc sec for pitch, roll and yaw. Within the range of ±40μm and 40 arc sec, it has been found that the system’s resolution and accuracy of measuring straightness error components are about 0.04 μm and ±0.06 μm, respectively. The resolution and accuracy of measuring pitch and yaw angular error components are about 0.06 arc sec and ±0.8 arc sec, respectively. The resolution and accuracy of measuring roll angular error are about 0.05 arc sec and ±0.07 arc sec, respectively.Copyright