chrispeng [ad_1]
After Hurricane Katrina hit New Orleans in August 2005, rescue teams quickly moved into the area to help. During rescues they frequently write codes on buildings to convey important information to rescue teams arriving later, or to help those who are disoriented in the rubble realize that they have reached a special area, for example, codes It will reflect whether the building is dangerous or safe and whether there is gravel in the building.
Researchers in the Black Forest region of Germany have developed the decoding system using radio frequency identification technology. Their RFID-enabled urban search-and-rescue concept features robots and humans working together in disaster zones to delineate affected areas and transmit information to command centers.
The rescue team used robots equipped with radio-frequency reading antennas to map the area. The antenna is mounted parallel to the ground to read embedded tags.
“He works like an ant,” says Alexander Kleiner, a researcher at the Albert-Ludwigs-Universität Freiburg company in Breisgau, who has written a paper on the use of radio frequency identification to map search and rescue efforts for robots and humans. “Ants leave trails so that their companions can tell by smell that they have detected a specific area.” The project, sponsored by the University and the German Research Foundation, aims to create a system that uses human and robotics to efficiently delineate disaster areas in order to speed up the rescue process and save lives.
For example, after a disaster, rescuers and robots can join forces to attach radio frequency tags to buildings that have been inspected and write key messages on the tags. That way, other rescue groups can identify the condition of a particular building or get advice on what to do next, just by reading the tags on a computer. Additionally, as multiple rescue teams and robots reach and read the tags via different roads, the data they produce can be combined to calculate the tag’s location and draw a comprehensive map for headquarters to use. This is important, for example, if adjacent buildings are covered with reinforced concrete, it will hinder the reading of satellite positioning system signals.
Last year, Kleiner and his colleagues tested the robotic and human-powered system on a university campus using passive radio frequency tags. In early 2008, the researchers did just one test with the robot, this time using active tags.
Passive RF Mapping Test
The first trial used Tagsys’ Ario 13.56 MHz passive RFID tag and Medio S002 reader. The trial was carried out by a six-person research team in Freiburg in April 2007. Each member is equipped with an electronic compass, an electronic pedometer and a pair of gloves. The gear was developed by TZI Bremen and utilizes a built-in radio frequency reader.
The devices are all connected to a small laptop computer carried by each rescue team member. During the experiment, the crew was tasked with exploring a nine-kilometer (5.6-mile) urban area. The urban area is mainly composed of residential buildings up to six storeys. They use the dead reckoning method in basic navigation techniques to make guesses about the current position based on the previously determined position and estimate the upcoming position based on the travel speed, time and route. There is only about 70 meters of error between the location calculated by this method and the actual location. By reading the 20 radio frequency tags they had previously placed on the building at the intersection, embedded within the stickable tags, and combining that information with information gathered through dead reckoning, the rescue team was able to calculate their current location , and the error is only 10 meters (33 feet). But, Kleiner said, producing high-quality maps is difficult because of errors in the estimates. People climb ladders, walk slopes or run throughout the rescue.
During one test, participants wore gloves fitted with radio frequency readers
“If you use passive tags, you can only collect information from very close to the tag,” Kleiner said. “So passive tags can only help rescuers know if they have reached a specific location. Dead position. Guessing can give an initial guess about the trajectory of the walk. But the longer you walk, the more error it produces. By using RFID technology to identify when a walker is walking in a circle, the system can The tracking process is mapped. Mathematically speaking, it is difficult to achieve a second reading of the RFID tag. The algorithm reorganizes the trajectory so that it applies to all the sites that are visited again.” He said the process was It is called Simultaneous Localization Mapping (SLAM). The program implements the combination of RFID data and position estimation.
In addition to this, participants also possessed global positioning devices. Maps are detected through location data collected by GPS.
In another trial, conducted in August 2007, rescuers and robots used RFID technology to jointly create maps to enhance dead reckoning estimates. A compass, wheelbase odometer and radio frequency reader are installed on the robot. The antenna of the radio frequency reader is parallel to the ground, so that the reader can read the tags on the ground while traveling. Both the robot and the crew explore an area of about 900 square meters (2,953 square feet) and read 10 passive radio frequency tags previously embedded in the ground. They were able to reduce dead reckoning estimates from 150 meters (492 feet) for humans and 50 meters (164 feet) for robots to 5 meters (16 feet) for both humans and machines. In addition to this, the researchers also tested the device’s ability to read randomly distributed radio frequency tags in the basement.
Applied Active RF Sensors
The Microsystems Engineering Department of the University of Freiburg developed a wireless sensor node according to the specifications required by ZigBee, so that it can experiment with active radio frequency identification technology. This sensor measures air pressure, temperature and antenna orientation. “There are two accelerators in the sensor node to measure gravity in order to orient the antenna,” Kleiner said. “This allows the sensor to detect when the antenna is not oriented correctly — for example, if the antenna tipped over.”
In the experiment, nine active radio frequency tags with sensors were installed on outdoor traffic signs, and the orientation of the tags was fixed. The four robots that drive into the area, one by one, read the tags and leave the readings for the other robots. All these data are collected and processed for mapping.
Kleiner’s rescue team utilizes passive high-frequency tags placed on buildings or embedded in the ground.
By leveraging information from other robots, Kleiner said the individual robots were able to improve mapping accuracy by a margin of error of 2 meters (6.6 feet) compared to exploring on their own. “You can imagine a situation where the first robot drives by and does computer mapping using dead reckoning and radio frequency detection,” he explained. A map is stored in each nearby radio frequency tag. A second robot then travels through the area and repeats what the first robot did. However, it also reads information from the previous robot and draws more for an accurate map.”
The robot detected an active RF signal at a distance of 30 meters (98 feet) from the tag and created a map with an error of 1 meter (3.3 feet). “Accuracy then depends primarily on the accuracy of the estimate of the distance between the robot and the RFID tag, which is determined by the strength of the signal,” Kleiner said.
“We learned from our experiments that the environment and arrangement of the tags greatly affect the decay of the signaling pathway. Therefore, in order to estimate a reliable distance based on the strength of the signal, these parameters must be predicted in advance.” “It would be more difficult to apply the technique to an indoor environment, because the signal would be reflected off objects or walls and cause the signal to travel along different paths,” Kleiner said. This situation is known as the ‘multipath propagation’ problem. “. But he also pointed out that if the three-dimensional structure of the indoor environment can be known in advance, then the RFID system can also be applied indoors. The robot can realize the positioning of people in the building on the basis of predicting the structure of the building model.
Companies are now interested in the concept, Kleiner said, and he hopes to get sponsorship from the European Union, as his mapping system could also play a role in ensuring safety by inspecting nuclear devices by robotic teams.
“I’m sure everyone who studies synchronous location mapping methods will recognize that RFID technology, from a practical standpoint, is the most promising solution,” he said, “because most of the ideas for synchronous location mapping methods are currently Not used in disasters. Cameras don’t help rescue teams because they can’t penetrate smoke. GPS is completely useless when satellite signals are blocked by reinforced concrete buildings. And current 3D laser measurement technology is too expensive.
[ad_2]
