160
5 Optimization Algorithm and RFID System Physical Anti-Collision
The tags are the commercial UHF tags, the readers are Impinj speedway revolution
R420, and the readers’ antennas are Larid A9028. The laser ranging sensor is Wenglor
X1TA101MHT88 with its measuring range of 50 m.
(2) Process of measurement
The process of measurement is described as follows. Firstly, the rotating tray is
mounted on a transportation device. The support frames with tags are placed on the
rotating tray. A reader and some antennas are mounted on the antenna frame. Subsequently, the beam of the laser ranging sensor aims at the support frames. Next, the
cycle number of the rotating tray is set manually. The rotating tray which transports
tags simulates products in and out warehouse at a certain speed. When the rotating
tray with the tags enters the reading area, the antennas receive the RF signal of the
tags, and then send the signal to the laser ranging sensor. Therefore, the reading
range between the tags and antennas can be calculated. Afterwards, the rotating
tray returns to the initial point and the above operations are repeated until the cycle
number reaches the set value. Finally, the average value is used as the reading range
between the tags and the antennas [21, 22].
The reading range is measured indirectly. Adjust the optical lift platform so that
the laser beam can be aimed at the box; the intersection of laser beam and the antenna
frame plane is defined as the reference points. The range from the tags to the reference
point is
R = S − L
(5.1)
where S is the range of laser ranging sensor to tags and L is the range of laser ranging
sensor to reference point.
The range between tag and i th RFID antenna is
R i = (R
2
+ H
2
i )
1/2
(5.2)
where H i is the distance between i th RFID antenna and reference point. When the
antennas are fixed on the antenna frame, the range between reference point and
i th RFID antenna is measured manually and then inputted to the program. In the
measurement, the tags are distributed randomly in space.
5.1.2 Establishment of 3D Tag Network Based on Template
Matching and Edge Detection
The tag network consists of multiple nodes, where each node represents a specific
location for the corresponding tag. In this experiment, the location of the tag is
distributed in space randomly, as shown in Fig. 5.3.
5 Optimization Algorithm and RFID System Physical Anti-Collision
The tags are the commercial UHF tags, the readers are Impinj speedway revolution
R420, and the readers’ antennas are Larid A9028. The laser ranging sensor is Wenglor
X1TA101MHT88 with its measuring range of 50 m.
(2) Process of measurement
The process of measurement is described as follows. Firstly, the rotating tray is
mounted on a transportation device. The support frames with tags are placed on the
rotating tray. A reader and some antennas are mounted on the antenna frame. Subsequently, the beam of the laser ranging sensor aims at the support frames. Next, the
cycle number of the rotating tray is set manually. The rotating tray which transports
tags simulates products in and out warehouse at a certain speed. When the rotating
tray with the tags enters the reading area, the antennas receive the RF signal of the
tags, and then send the signal to the laser ranging sensor. Therefore, the reading
range between the tags and antennas can be calculated. Afterwards, the rotating
tray returns to the initial point and the above operations are repeated until the cycle
number reaches the set value. Finally, the average value is used as the reading range
between the tags and the antennas [21, 22].
The reading range is measured indirectly. Adjust the optical lift platform so that
the laser beam can be aimed at the box; the intersection of laser beam and the antenna
frame plane is defined as the reference points. The range from the tags to the reference
point is
R = S − L
(5.1)
where S is the range of laser ranging sensor to tags and L is the range of laser ranging
sensor to reference point.
The range between tag and i th RFID antenna is
R i = (R
2
+ H
2
i )
1/2
(5.2)
where H i is the distance between i th RFID antenna and reference point. When the
antennas are fixed on the antenna frame, the range between reference point and
i th RFID antenna is measured manually and then inputted to the program. In the
measurement, the tags are distributed randomly in space.
5.1.2 Establishment of 3D Tag Network Based on Template
Matching and Edge Detection
The tag network consists of multiple nodes, where each node represents a specific
location for the corresponding tag. In this experiment, the location of the tag is
distributed in space randomly, as shown in Fig. 5.3.