Need design help for a robot to essentially follow a line and pick up a ball
dark_skye
Posts: 1
Hello, i've just registered
My brother wants to design a robot with BASIC stamp's to follow a line and pick up a ball, as part of a Search and Rescue competition that Robocup in Western·Australia puts on for school students. He has entered for the last two years in other areas of the competition, however has found that the lego mindstorm RCX is a little unreceptive to his needs.
We are wondering what software and hardware needs to be purchased in order to do this. As far as a chassis and things not directly related to the microcontroller go we are pretty much fine, but we need to know what we need to purchase in terms of sensors and motors to achieve this goal.
The robot itself needs to be battery powered.
It will need motors to move itself, movement coming from two wheels that in all likelihood my brother will mount to the rear. Plus, it needs another one or two motors to operate some sort of scoop or claw or suction that hold the object into place.
Firstly, the track that the robot has to follow has plenty of twists and turns, and thus either it has to have a fairly slow and steady speed, or the light sensors have to be fairly sensitive and relay readings fast, something that conventional lego sensors do not do. As for what the sensors are actually sensing, it is the·difference between the colours green, yellow, and black. The light sensors are generally mounted facing directly downwards· probably no more than 5 or 6 centimetres from the ground, hence range isn't a particularly large issue.
It also needs to be able to sense an object that it needs to pick up. he has usually done this with just a lego light sensor with mixed, inconsistant results. If the robot could find exactly where there object is by scanning for it with some kind of sensor, align itself to the object, judge the distance, and then accurately grab and pick up the object, it would make our day.
My brother will be new to programming in the BASIC language, something far different from lego's programming format, thus any books and such on the subject would also be of great help.
Cheers for the help in advance.
·
My brother wants to design a robot with BASIC stamp's to follow a line and pick up a ball, as part of a Search and Rescue competition that Robocup in Western·Australia puts on for school students. He has entered for the last two years in other areas of the competition, however has found that the lego mindstorm RCX is a little unreceptive to his needs.
We are wondering what software and hardware needs to be purchased in order to do this. As far as a chassis and things not directly related to the microcontroller go we are pretty much fine, but we need to know what we need to purchase in terms of sensors and motors to achieve this goal.
The robot itself needs to be battery powered.
It will need motors to move itself, movement coming from two wheels that in all likelihood my brother will mount to the rear. Plus, it needs another one or two motors to operate some sort of scoop or claw or suction that hold the object into place.
Firstly, the track that the robot has to follow has plenty of twists and turns, and thus either it has to have a fairly slow and steady speed, or the light sensors have to be fairly sensitive and relay readings fast, something that conventional lego sensors do not do. As for what the sensors are actually sensing, it is the·difference between the colours green, yellow, and black. The light sensors are generally mounted facing directly downwards· probably no more than 5 or 6 centimetres from the ground, hence range isn't a particularly large issue.
It also needs to be able to sense an object that it needs to pick up. he has usually done this with just a lego light sensor with mixed, inconsistant results. If the robot could find exactly where there object is by scanning for it with some kind of sensor, align itself to the object, judge the distance, and then accurately grab and pick up the object, it would make our day.
My brother will be new to programming in the BASIC language, something far different from lego's programming format, thus any books and such on the subject would also be of great help.
Cheers for the help in advance.
·
Comments
As noted above the BOEbot would be a good choice of platform for this project. Parallax also makes a gripper that will mount on the front of the BOE. I just got one, but I haven't had time to play with it yet. It's how I'm going to relax over the Christmas break
As for motors, the BOE comes with modified hobby motors which are very easy to use. As you already know, detecting and picking up the object reliably is the trick. What is the shape, size, weight and color of the obejecy you need to pick up? This may affect your choice of sensors etc.
As to object detection, the two most common forms are infrared or ultrasonic. Assuming the object is somewhere around the size of a soda can, you could try a combination of ultasonic and IR. One possible set up would be a US sensor in the center of the robot, with two IR sensors, one mounted on either side of the bot. The US sensors are better at long range detection. So, the bot finds the object, gets close to it, and then used the IR sensors to home in on it. If they IR sensors are set the correct distance apart for your object, you should be able to home in on it.
Another possibility is a pan/tilt sensor array. I made one for our hydrogen powered robot, which you can see here:
http://madlabs.info/h2fcrp/h2fcrp_sensors.shtml
As for learning PBASIC, download a copy of "What's a microcontroller". I use this text to teach basic stamp programming, and it really has all you'll need to get started and finish this project.
HTH,
Jonathan
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