This paper presents wireless sensing systems to increase safety and robustness in industrial process control, particularly in industrial machines for marble slab working. The process is performed by abrasive or cutting heads activated independently by the machine controller when the slab, transported on a conveyer belt, is under them. Current slab detection systems are based on electromechanical or optical devices at the machine entrance stage, suffering from deterioration and from the harsh environment. Slab displacement or break inside the machine due to the working stress may result in safety issues and damages to the conveyer belt due to incorrect driving of the working tools. The experimented contactless sensing techniques are based on four RFID and two capacitive sensing technologies and on customized hardware/software. The proposed solutions aim at overcoming some limitations of current state-of-the-art detection systems, allowing for reliable slab detection, outside and/or inside the machine, while maintaining low complexity and at the same time robustness to industrial harsh conditions. The proposed sensing devices may implement a wireless or wired sensor network feeding detection data to the machine controller. Data integrity check and process control algorithms have to be implemented for the safety and reliability of the overall industrial process. 1. Introduction The transformation of stone blocks coming from quarries into finished products, for example, tiles, sculptures, building materials, stone powder, and so forth, is performed through several different industrial processes. In the case of slab-shaped products (e.g., tiles), marble blocks coming from quarries are firstly sawn by a gangsaw [1] into marble slabs with a resulting irregular contour and with rough surfaces. Slabs are afterwards polished in a polishing machine [2], cut into smaller and regular slabs by means of cutting machines, and finally become end products. The process control of marble slab working is nowadays mainly based on a feed-forward control scheme: the marble slab is transported inside the machine by a conveyer belt; at the entrance of the machine, contact or optical sensing technologies are used to derive information on the presence and shape of the slab which are then used by the machine controlling system to drive the working heads on the slab when it is passing under them. Due to unforeseen events that may occur to the slab inside the machine, mainly slab displacement and cracks, the controlling system may drive the working heads on the base of not up-to-date
D. Miorandi, E. Uhlemann, S. Vitturi, et al., “Guest editorial: special section on wireless technologies in factory and industrial automation,” IEEE Transactions on Industrial Informatics, vol. 3, no. 2, pp. 95–98, 2007.
M. Bramanti, et al., “A procedure to detect flaws inside large sized marble blocks by ultrasound,” Subsurface Sensing Technologies and Applications, vol. 2, no. 1, pp. 1–13, 2001.
[6]
M. A. Selver, O. Akay, E. Ardali, B. A. Yavuz, O. ？nal, and G. ？zden, “Cascaded and hierarchical neural networks for classifying surface images of marble slabs,” IEEE Transactions on Systems, Man and Cybernetics Part C, vol. 39, no. 4, pp. 426–439, 2009.
[7]
J. D. Luis-Delgado, J. Martínez-Alajarín, and L. M. Tomás-Balibrea, “Classification of marble surfaces using wavelets,” Electronics Letters, vol. 39, no. 9, pp. 714–715, 2003.
[8]
S. A. Coker and Y. C. Shin, “In-process control of surface roughness due to tool wear using a new ultrasonic system,” International Journal of Machine Tools and Manufacture, vol. 36, no. 3, pp. 411–422, 1996.
[9]
E. Bozzi and M. Bramanti, “A planar applicator for measuring surface dielectric constant of materials,” IEEE Transactions on Instrumentation and Measurement, vol. 49, no. 4, pp. 773–775, 2000.
[10]
D. Vaccaneo, L. Sambuelli, P. Marini, R. Tascone, and R. Orta, “Measurement system of complex permittivity of ornamental rocks in L frequency band,” IEEE Transactions on Geoscience and Remote Sensing, vol. 42, no. 11, pp. 2490–2498, 2004.
[11]
S. Saponara, F. Iacopetti, A. Carrafiello, E. Valentini, L. Fanucci, and B. Neri, “Capacitive sensors for process control in industrial marble machines,” in Proceedings of the 5th IEEE International Workshop on Intelligent Data Acquisition and Advanced Computing Systems: Technology and Applications (IDAACS '09), pp. 142–147, Rende, Italy, September 2009.
[12]
B. Osoincah, “Proximity capacitive sensor technology for touch sensing applications,” Freescale White Paper, 2007.
[13]
S. Saponara, F. Iacopetti, A. Carrafiello, L. Fanucci, B. Neri, and R. Massini, “Experimental analysis towards the application of RFID technologies in industrial marble machines,” in Proceedings of the 5th IEEE International Workshop on Intelligent Data Acquisition and Advanced Computing Systems: Technology and Applications (IDAACS '09), pp. 67–71, Rende, Italy, September 2009.
[14]
I. Ar and Y. S. Akgul, “A generic system for the classification of marble tiles using Gabor filters,” in Proceedings of the 23rd International Symposium on Computer and Information Sciences (ISCIS '08), pp. 1–6, October 2008.
[15]
J. Martínez-Alajarín, J. D. Luis-Delgado, and L. M. Tomás-Balibrea, “Automatic system for quality-based classification of marble textures,” IEEE Transactions on Systems, Man and Cybernetics Part C, vol. 35, no. 4, pp. 488–497, 2005.
[16]
K. Finkenzeller, RFID Handbook: Fundamentals and Applications in Contactless Smart Cards, Radio Frequency Identification and Near-Field Communication, John Wiley & Sons, 3rd edition, 2010.
[17]
RFIDline, “RFid project: special technology on marble and granite,” 2007, http://www.rfidstone.com.
[18]
R. Wessel, “Italian stone supplier uses RFID to track marble, granite,” RFIDJournal, 2007.
[19]
K. Kwon, J. Ryu, J. Sohn, and I. Chung, “Intelligent process control system with RFID cuboid,” in Proceedings of the 11th International Conference on Electronic Commerce (ICEC '09), pp. 1–8, Taipei, Taiwan, 2009.
[20]
G. Fenu and P. Garau, “RFID- based supply chain traceability system,” in Proceedings of the 35th Annual Conference of the IEEE Industrial Electronics Society (IECON '09), pp. 2672–2677, November 2009.
[21]
B. S. Choi, J. W. Lee, and J. J. Lee, “An improved localization system with RFID technology for a mobile robot,” in Proceedings of the 34th Annual Conference of the IEEE Industrial Electronics Society (IECON '08), pp. 3409–3413, November 2008.
[22]
EM Microelectronic, “EM4102 Read only contact less identification device,” 2005.
[23]
PSION Teklogic, “Workabout Pro guide,” 2004.
[24]
CAEN SpA, “A928 long range UHF reader data sheet,” 2007, http://www.caen.it/rfid.
[25]
Open 2.4？GHz RFID Sputnik, http://www.openbeacon.org.
[26]
Y.-C. Choi, M.-W. Seo, Y.-H. Kim, and H.-J. Yoo, “A multi standard 13.56？MHz RFID reader system,” in Proceedings of the International Technical Conference on Circuit/System, Computers and Communications (ITC-CSCC '08), pp. 1073–1076, 2008.
[27]
N. Choi, et al., “Design of a 13.56？MHz RFID system,” in Proceedings of the 14th International Conference on Advanced Communication Technology (ICACT '12), pp. 840–843, 2006.
[28]
Beijing Hongchangtag Tech-Sci Development Inc, “HCT-HFR-80507,” 2012, http://www.hongchangtag.com/product.asp?id=15&f1id=1&f2id=19&f1=3.
[29]
M. Chaplin, “Water structure and science; water and microwaves,” http://www.lsbu.ac.uk/water.
[30]
M. Kollar, “Measurement of capacitances based on a flip-flop sensor,” Sensors & Transducers Magazine, vol. 35, no. 8-9, pp. 1–7, 2003.
[31]
G. Brasseur, “Design rules for robust capacitive sensors,” IEEE Transactions on Instrumentation and Measurement, vol. 52, no. 4, pp. 1261–1265, 2003.
[32]
L. Fanucci, S. Saponara, and A. Morello, “Power optimization of an 8051-compliant IP microcontroller,” IEICE Transactions on Electronics, vol. 88, no. 4, pp. 597–600, 2005.
[33]
D. Dugdale, Essentials of Electromagnetism, The Macmillan Press, London, UK, 1993.
[34]
F. Marco, System and method for a plant for working natural stones. European Patent Application 10425405.7, 2010.
