Dynamic object following is an essential ability for mobile robots in various application scenarios such as auxiliary cargo transportation, disabled assistant caring, and multirobot formation. A dynamic object following method for a mobile robot based on ultrahigh-frequency (UHF) radio frequency identification (RFID), which uses a phase difference information-based dynamic following model, is presented in this article. Through this method, a mobile robot equipped with an RFID reader can follow a dynamic target object attached with a passive RFID tag. A cost function is constructed to indicate the changes in relative distance and bearing between the target object and the following robot, allowing the real-time calculation of the translational and rotational velocities of the following robot using an algorithm base on proportional integral differential (PID)-based controllers. Compared with the existing RFID-based following methods, the proposed method can achieve a satisfactory distance and bearing following accuracy by using RFID phase difference information without any tedious and time-consuming phase drift or antenna installation calibration. Real experiments were conducted using commercial off-the-shelf (COTS) UHF RFID, and results show that the proposed method is effective and robust, the respective average distance and bearing following errors were approximately 1.65 cm and 4.94° during the robot-following tests and 4.45 cm and 6.03° during the human-following tests. The proposed method has promising applications in mobile robot following of dynamic object to provide service or assistance in large storage and manufacturing industries.

中文翻译：

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基于UHF RFID的移动机器人基于相位差信息的动态对象跟随方法

动态对象跟随是移动机器人在各种应用场景中的基本能力，例如辅助货物运输，残疾人辅助护理和多机器人编队。本文提出了一种基于超高频（UHF）射频识别（RFID）的移动机器人动态目标跟踪方法，该方法使用基于相差信息的动态跟踪模型。通过这种方法，配备有RFID阅读器的移动机器人可以跟随附着有无源RFID标签的动态目标对象。构造了一个成本函数来指示目标对象与后续机器人之间的相对距离和方位的变化，允许使用基于比例积分微分（PID）控制器的算法实时计算后续机器人的平移和旋转速度。与现有的基于RFID的跟随方法相比，该方法通过使用RFID相位差信息可以实现令人满意的距离和承载跟随精度，而无需任何繁琐且费时的相位漂移或天线安装校准。使用商用现货（COTS）UHF RFID进行了真实的实验，结果表明，该方法是有效且鲁棒的，在机器人跟随测试期间，各自的平均距离和轴承跟随误差分别约为1.65 cm和4.94°在人体追踪测试中为4.45厘米和6.03°。