Developing a patient guidance module for hospital robots
Authors: Muhammad Kamrul Hasan, Tamas Szecsi
Abstract
In this paper the development of a patient guidance module for an Intelligent Robot Swarm for Attendance, Recognition, Cleaning and Delivery (IWARD) hospital robot is described. The proposed prototype module features an Active RFID reader and active Tags. While a patient is guided to the X-ray room, or a visitor to a patient’s ward, the speed of the robot can be adjusted automatically according to the pace of the person using the system. The reader is to be installed on a Pioneer 3DX base robot and active tags can be worn by the follower. Furthermore, a device driver will be developed for the reader in the Player work environment, which is a language and platform independent network server for robot control [1].
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Dear authors
I’m interested in RFID used for distance measurement. In p.3 of your paper 3 ranges of distance from robot to patient are considered and 3 different robot’s speeds.
But from four graphs in p.6 I can see that reliability of that measurements is very poor due to RFID characteristic. How do you intend to resolve this problem because patients could be confused if robot start to change its speed after every distance reading when some disturbances arise.
Tadeusz
P.S. The last sentence of p.6.1.1.1.Task1 is not completed.
Dear Authors,
I am also interested in the performace of the RFID devices. What is the effective range of this device? I wonder if an isolation shield from one side of the RFID reader would help identifying the direction of the follower. With a shield from one side, signals from this side will be weakened if possible. In this case, the robot will be able to tell roughly where the follower is relatively. Do you think this will help in your application and be feasible?
Thanks.
Dear Tadeusz,
First thank you for corrections.I have re uploaded my paper.
Active RFID systems seem applicable only to detect whether the tags are in its range and are not reliable to calculate the exact distance using RSSI value.
so alternative idea is describe in P5 and in fig 4. The idea is based on having two different range tags added together and worn by the follower.
Dear Ze Ji
Typical read ranges of Wavetrend Tags with
various antennas are shown in Table 1 in P4.
Practically the range varies on the battery power of the Tags.In experiment,TG-801 series tag has maximum 6m and LTG-100 & 800 has maximum 14m range.
While the robot is guiding the patient the distance is more important than direction of the patient.If we use an isolation shield it will confuse the system because in this case-
-either the patient could be far away(less RSSI)
-or patience could be on that side of reader where the isolation shield is placed.(less RSSI value again)
Now how robot will know which is the case?
Thanks.
Dear Muhammad
Thanks for answer, but I wasn't clear in my question.
I'm afraid that nominal range values are not always
reliable in practical applications and robot can be in some situation misleaded.
You write:
Test1: While the majority of the tags RSSI values decrease over the distance, tag 475689 was only detected at 1 and 2 meters, the reader could not detect them at any further distance.
Test2: Tag 475689 again appeared to be unreliable as this time at 4m it could not be detected, while at 5m it could.
Test3: Two of the tags 508433 and 508408 had higher RSSI values at 5m then they did at 1m.
Test4: ... tags have similar values at 1 m, but then take on their own characteristic curves as the distance increases.
Looking at this – are You sure that do not occur situations when:
- tag5 with nominal range 5m will not be detected at distance of 4m
- and tag2 with nominal range 2m will be detected at the same time at the same distance of 4m (look for increasing characteristics in Tests 3 and 4)
- and few second later readings will change to opposite
What will robot do than ?
;)
Tadeusz
Dear Tadeusz,
Its true the reading is quite un reliable.
But during testing the tags where hold stationary.But in our guidance scenario when the patient are moving with the tags
for shaking or rotating the data can be detected.
Now taking it exactly 3 m and 2 meter is not quite possible but I've tried to prof a concept of using two different range tags.
while the RFID pro gramme is running to detect the tag within few seconds(as Tag transmitting data contentiously)the pro gramme gets outputs of several data.Now as i am not going to instruct the robot every second depends on my readings.I can store the data in a database and use some filtering i can discard the unreliable data and based on the result periodically i can instruct the robot to synchronize its speed.
Thank You Muhammad for this explanation. I wish You success
in the project. I hope that on IPROMS 2009 I could read about results and methods used for resolving the problem.
;)
Tadeusz
Dear authors and all other conference participants,
Welcome to the robotics session of this IPROMS 2008 conference.
My name is Ze Ji, and I am the co-chair of this session.
If you need any assist regarding this session, please feel free to contact me via email: JiZ1 (at) cf.ac.uk.
First, I would thank the authors for contributing to IPROMS 2008.
For this paper, I have realised that the video has not been uploaded. Could the authors please prepare a video presentation and upload it? This will be helpful for others understanding your paper better. Here is the instructions on how to create a video presentation
In order to access the full text papers and video presentations and other functionalities, all conference participants are encouraged to register on the IRPOMS website online for free.
You are very welcome to post questions after reading the papers, and I believe the authors will be there very happy to answer you.
I hope you will enjoy this session.
Kind regards,
Ze Ji
Robotics Session Co-Chair
IPROMS 2008