In manufacturing environments, mobile radio frequency identification (RFID) robots need to quickly identify and collect various types of passive tag and active tag sensor data. The purpose of this paper is to design a robot system compatible with ultra high frequency (UHF) band passive and active RFID applications and to propose a new anti-collision protocol to improve identification efficiency for active tag data collection.
A new UHF RFID robot system based on a cloud platform is designed and verified. For the active RFID system, a grouping reservation–based anti-collision algorithm is proposed in which an inventory round is divided into reservation period and polling period. The reservation period is divided into multiple sub-slots. Grouped tags complete sub-slot by randomly transmitting a short reservation frame. Then, in the polling period, the reader accesses each tag by polling. When tags’ reply collision occurs, the reader tries to re-query collided tags once, and the pre-reply tags avoid collisions through random back-off and channel activity detection.
The proposed algorithm achieves a maximum theoretical system throughput of about 0.94, and very few tag data frame transmissions overhead. The capture effect and channel activity detection in physical layer can effectively improve system throughput and reduce tag data transmission.
In this paper, the authors design and verify the UHF band passive and active hybrid RFID robot architecture based on cloud collaboration. And, the proposed anti-collision algorithm would improve active tag data collection speed and reduce tag transmission overhead in complex manufacturing environments.
This work was supported in part by the Natural Science Foundation of Education Department of Shaanxi Province (2018JK0704), the Science and technology plan project of Xi'an(201805040YD18CG24-3,2019GXYD17.3), the key Research and Development plan of Shaanxi Province (2018ZDXM-GY-041, 2018GY-150), the Science and Technology Research Plan Project of Xianyang (2017k01-25–14), Foshan entrepreneurship and innovation team project (2017IT100032) and the National Key R&D Program of China (2018YFC0810100).
Wang, H., Yu, R., Pan, R., Liu, M., Huang, Q. and Yang, J. (2021), "Fast tag identification for mobile RFID robots in manufacturing environments", Assembly Automation, Vol. 41 No. 3, pp. 292-301. https://doi.org/10.1108/AA-11-2020-0182
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