카메라를 이용한 축계 비틀림 계측장치 개발에 관한 연구

Abstract

In this paper, a method to measure shaft twisting angle is suggested. In traditional techniques to measure twisting angle, a strain gauge has been widely used although it has some considerable disadvantages. Many papers concerned about it but there were few limits. In case of using a strain gauge, a variety of parts is equipped with a shaft. Also the install work on the shaft and acquiring a correct signal for analysis are too difficult. Furthermore it is very expensive and complicate and it is impassible that the twisting angel can be concurrently measured in operating states. So we try to develop an alternative approach to solve the problem and propose the new method for measuring twisting angle by using vision measurement system. In a different field, Mitsubishi Heavy Industries industrialized synchronous control of multi rolls using vision measurement system on printing press. In this way, because shafts or gears for coupling the parts of printing press are eliminated; controllability, maintainability, installation and power consumption are enhanced. In this study, templates for image processing are attached at the both ends of a shaft and CCD cameras equipped with micro lens are installed. In order to synchronously capture the images by each camera, a trigger mark and a optical sensor are used. Then the central coordinates of templates between the first and the second image captured by each camera are compared to calculate the twisting angle. To find central coordinates of templates, the pattern matching method is applied. And a torque transducer is used to confirm the reliability. Because cameras are used in place of human's eyes, this proposed measurement system does not need to contact with a shaft and twisting angle is intuitively measured. So it can be installed and calibrated easier than traditional measurement system and suitable for any shafts. On the top of this, it is possible to measure the twisting angle in the operating state of the ship.