A Vision-Based Fuzzy Control to Adjust Compression Speed for a Semi-Dieless Bellows-Forming
Department of Mechanical Engineering, Universitas Indonesia, Jakarta 16424, Indonesia
Department Mechanical and Bio-functional Systems, Tokyo University, Tokyo 153-8505, Japan
Department of Mechanical Systems Engineering, Tokyo Metropolitan University, Tokyo 192-0397, Japan
Author to whom correspondence should be addressed.
Metals 2020, 10(6), 720; https://doi.org/10.3390/met10060720
Received: 9 April 2020 / Revised: 19 April 2020 / Accepted: 29 April 2020 / Published: 28 May 2020
(This article belongs to the Special Issue Latest Hydroforming Technology of Metallic Tubes and Sheets)
A novel semi-dieless bellows forming process with a local heating technique and axial compression has been initiated for the past years. However, this technique requires a high difficulty in maintaining the output quality due to its sensitivity to the processing conditions. The product quality mainly depends on not only the temperature distribution in the radial and axial direction but also the compression ratio during the semi-dieless bellows process. A finite element model has clarified that a variety of temperature produced by unstable heating or cooling will promote an unstable bellows formation. An adjustment to the compression speed is adequate to compensate for the effect of the variety of temperatures in the bellows formation. Therefore, it is necessary to apply a real-time process for this process to obtain accurate and precise bellows. In this paper, we are proposing a vision-based fuzzy control to control bellows formation. Since semi-dieless bellows forming is an unsteady and complex deformation process, the application of image processing technology is suitable for sensing the process because of the possible wide analysis area afforded by applying the multi-sectional measuring. A vision sensing algorithm is developed to monitor the bellows height from the captured images. An adaptive fuzzy has been verified to control bellows formation from 5 mm stainless steel tube in to bellows profile up to 7 mm bellows height, processing speed up to 0.66 mm/s. The adaptive fuzzy control system is capable of appropriately adjusting the compression speed by evaluating the bellows formation progress. Appropriate compression speed paths guide bellows formation following deformation references. The results show that the bellows shape accuracy between target and experiment increase become 99.5% under given processing ranges.