Tag Archives: catching

NXT-Spy – First successful implementation of the ball finding / catching.

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Today is a big day for this project, the robot now manages to find balls and to catch them on its own.
In fact, all last week problems are solved: A ball of Blu-Tack solved the balancing problem and the solution I thought about last week to solve the lag problem worked quite well, in fact, apart the fact that the robot is moving very slowly, it manages to find balls quite efficiently.
So here is the video that shows the success of the experiment (I accelerated the video of 200% because the robot is operating very slowly):

[yframe url=’http://www.youtube.com/watch?v=arTqjEFSyMQ’]

Today, I also did some testing in the white environment and figured out that Data Matrix 2D barcodes worked way better than the QR code as they are way less complex. I am even wandering why I chose QR codes the first time… maybe because it is more beautiful 🙂

Supervisor’s comment:

Well done; how about finding the Blue and Red corners?  They work most of the time but because the flag goes out of view it makes it hard to know when you have reached the corner.
Has also written up the report so far as he is not here next week.  So he has done two week’s work in one!!!!

NXT-Spy – First tests of the ball finding / lifting part of the experiment

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Today, I have been able to test for the first time the robot’s controller in an ideal environment. This experiment cannot really be called as a success as I have faced a very disturbing issue: even when we are working in the best conditions (for this experiment, I worked with a Wi-Fi ad-hoc connection between the phone and the PC instead of using a router between the two), the images rate is still too low to be able to easily control the robot.

To solve this problem with the current configuration, I think that the best way is either to try to predict the position of the ball based on the speed of the robot or to simply slow down the speed of the robot to a minimum.

A second minor problem is that as predicted, the robot is too heavy on the phone’s side, the solution is obviously to put a weight on the other side of it to counterbalance.

But there are not only bad news: automatic control of the robotic arm works like a charm: as soon as the ball is touching the arm, it lifts it.