1. Building Your Robot.
Rescue Robots generally include one computer brick, two motors, and one, two or three light sensors. Premier Rescue Robots generally add another motor and either a touch or ultrasonic sensor. Sometimes, Rescue Robots also use an ultrasonic sensor.
To start experimenting with a Rescue task, either Robot2 (DomaBot) or Robot3 (ClareBot) would be suitable as the base for a first attempt while you check out how to follow a line using light sensors.
However almost all competition Rescue & Premier Rescue Robots are built specially for this task, because Rescue Robots have to fit inside a cylinder 18 cm diameter and 18 cm high. Premier Rescue Robots can be bigger, having to fit into a cylinder 27 cm diameter and 27 cm high. To get an idea of what some of them look like, click here for Premier Rescue Robots, click here and/or click here for Rescue Robots. A video of some of the Rescue Robots from the 2008 Perth National RoboCup event can be seen by clicking here.
2. Teaching your Robot how to follow a light/dark edge using one light sensor.
There are some hints about this in DrGraeme's Challenge 24 (click here) - work through this Challenge. Note the "Reminder" after Challenge 24 regarding calibrating your Robot's light sensor.
The Tasmanian Rescue Mat (see DrGraeme's Challenge Arenas/Challenge 102, click here) is different from the Arena used in Challenge 24. In Challenge 24 you taught the Robot to follow a silver border around a dark arena. In the Tasmanian Rescue mat, your robot has to follow the edge of a dark line on a white arena. This may seem different, but the same principles apply - in both cases your Robot is following a light/dark edge.
Build a Robot that can follow a light/dark edge, and demonstrate this to your mentor/teacher. If you have access to a Tasmanian Rescue Mat, see if your Robot can go from one end of the mat to the other. Adjust your Robot and its instructions so that it can handle the corners and curves, and go as far around the course as your Teacher/Mentor thinks reasonable.
3. Thinking about the Green squares.
As well as dark lines on a white background, the Tasmanian rescue mat has green squares. Each green square occurs at a junction where several dark lines meet. The green square is meant to be a hint - if your Robot recognises the green square, and turns in that direction, it gets an extra two bonus points to add to add it's score.
How could you teach your Robot to recognise that it has found a green square? Think about this, and discuss it with your team. Choose the best solution that your team suggests, change that suggestion into a computer program, and download that program into your Robot.
Are the instructions you have given your Robot sufficient for it to recognise green squares and turn in the right direction? - If so, congratulations! If not, you have to realise that your Robot has no common sense, and you have to give it very exact instructions to teach it to do something that is so easy for you, but seems to be so difficult for your Robot. Try again!
4. Using multiple Light Sensors
Some of the Robots you looked at in the web pages referred to in “1. Building Your Robot” used more than one light sensor. There are several reasons that they have more than one light sensor.
Firstly, a Robot using more than one light sensor can generally go around the Rescue Course faster than a one-light-sensor Robot.
Secondly, a Robot using more than one light sensor can generally go in the direction indicated by the green squares more reliably than a one-light-sensor Robot.
Thirdly, a Robot using more than one light sensor is marginally easier to program when it is necessary to push the imitation person out of the green swamp.
It is not necessary to use a Rescue Robot with more than one light sensor to compete in RoboCup Tasmania, but with the high standard shown in recent years, many students think it is probably necessary to use more than one light sensor if they want to finish up in the top three results for their class.
If you want to explore having more than one light sensor on your Rescue Robot, Challenge 102 (click here) may be of interest. Read through this Challenge.
Challenge 102 will not give you exact instructions about how to set up your Robot to follow a line, but it will give you a general direction in which to focus your work. Don’t worry about green squares just yet. See if you can get your Robot to use multiple light sensors to follow a line. Concentrate on getting your Robot to go as quickly as possible around the portions of the Rescue mat that have no green patches, without leaving the line.
When you think you have managed to get your Robot going as fast as you think it can, while still being reliable in following the line, demonstrate your Robot to your teacher/mentor.
5. Taking Notice of the Green Squares
Having completed “4. Using Multiple Light Sensors” to the best of your ability, you should carefully save that program, and then start to see if the program can be modified to reliably recognise green squares. To achieve this, you will have to be able to teach your Robot to recognise the difference between white, green and black.
Recognising the difference between green, white and black will be necessary if your multiple-light-sensor Robot is to get to the end of the Rescue Course, ready to push the “Person” out of the “Green Swamp”. There will be no more help on this, as this is a big part of the RoboCup Rescue tournament challenge. You will need to talk ideas over between your team members, and try out a lot of ideas to get the best one working. But is there a best way to do this? Think about this carefully, try out your ideas, and record your runs (including timings each run). Write the results of your runs down, so that you have a record of which ideas are better than your other ideas – these records can save a lot of arguments later on!
When you are satisfied, demonstrate your runs to your mentor/teacher.
6. Rescuing the “Person” from the “Swamp”.
When your team has completed “5. Taking Notice of the Green Squares” to your team’s satisfaction, and your Robot is finishing the Tasmanian Rescue Course at least some of the time, it is time to think about rescuing the "person" from the "dangerous swamp" caused by the (imaginary) "chemical spill".
The entrance to the swamp is marked by a patch of silver paper. Next you have to teach your Robot to recognise not only the difference between black, green and white, but also the difference between black, green, white and silver.
When your Robot can detect the silver paper (and still run reasonably reliably around the Rescue Course), your next task is to find the person.
Again, there will be no more help on this, as this is also a big part of the RoboCup Rescue tournament challenge. You will need to talk ideas over between your team members, and try out a lot of ideas to get the best one working. But is there a best way to do this? Think about this carefully, try out your ideas, and record the success/failure of your runs.
For Rescue tournaments your Robot’s task is to get the person out of the swamp somehow.
For Premier Rescue tournaments, your Robot’s task is to avoid an obstacle, get through the gridlock, and lift the “person” out of the swamp onto a platform.
Write the results of your runs down, so that you have a record of which ideas are better than your other ideas – these records can save a lot of arguments later on!
When you are satisfied, demonstrate your runs to your mentor/teacher.
You are now ready to test your Robot’s abilities against the course that the RoboCup officials lay out to test your Robot. The real purpose of the RoboCup is to demonstrate to the people at the tournament your team’s ability to teach your Robot how to handle these tough tasks. If your Robot can pass even one square, that is an achievement to be proud of – think how many other students in Tasmania could not do that – every team that gets a score is a winner! Some get higher scores and that is nice, but if you can get your Robot to complete even part of the course at a Tasmanian RoboCup tournament, that that is an achievement to be really proud of! –Good luck!
8. Important Extra Resource
Since the general hints above were written, some relevant and quite advanced NXT-G programming examples that are vital to RoboCup Rescue and Premier Rescue have been provided on the National RoboCup web site; to go to the appropriate web page click here.
www.DrGraeme.net - Tasmanian RoboCup Junior Rescue preparations for 2009