A micromouse builders blog
Here we are with ten days to go before the UK micromouse competition and Decimus is still far from ready. All the basic software is there but there are still issues with the basic motion control. I have all the turns calculated and the parameters have been tuned to a good first approximation. This takes hours of tedious repetitive work as the parameters are altered…
Having half a mind on the challenge of half-size micromouse, I was looking at some information on the megabitty controller. As supplied, it may well have enough features to make a micromouse controller but that wasn’t what caught my eye. On the board are two full-bridge motor drivers. While looking for data on these, I came across the slightly more flexible Si9986, also by Vishay…
Going through some old notes, I came across reference to the micromouse maze solving methods described some time ago by Adachi in Japan. While these are apparently quite well known in Japan, they are, as far as I can tell, almost completely unknown in the West. At least, I can’t find any description of them in English anywhere on the web. After a lot of hard work with the Google translator and some assistance from Lem Fugitt, I think I have them pieced together…
I have just returned form the Rise of the Robots event at the National Space Centre in Leicester. Just one of many specially themed weekends they hold, this proved a great success for exhibitors and guests alike. Visitors were able to experience a variety of robotic experiences from the mayhem of Robot Wars to the more genteel charm of a range of walking robots made by David Buckley. Naturally, there was room for micromouse. The space tie-in was provided by the presence of a particularly scary set of Daleks…
The MINOS 2008 conference ended, as usual, with a couple of semi-formal competitions. The maze solver final is always interesting as we get to see some of the potential for the summer competition. So far it seems I will still be holding firmly on to a runner-up place. The image on the left is the maze configuration for the finals at MINOS. The blue path is the shortest at 31 cells and would be chosen by a simple solver or one that liked to run diagonals The green path would be taken by a mouse that preferred straights.
We often tell beginners that they can learn a lot by building a non-contact wall following micromouse. If it can keep track of where it is and knows when it is in the centre of the maze, most of the hard problems have been solved. To get to that stage, you need working sensors, reliable motor control and good information about the maze and the mouse’s position in the maze…
As set up for the last post, my micromouse Decimus is performing reasonably well on the ground. So far. The data plots show some features that are a little bit curious. However, my concerns over the apparent error in the endpoint were a little misleading. The recorded error is derived from the integral of the set speed and the total count from the wheel encoders. Thus, it does not represent an actual error on the ground…
With new tyres and a tweak to the acceleration profilers it is time to grab some data from Decimus again. The tyre seem to give me reliable grip up to 4m/s/s. They will probably manage more but I seem to have other control issues then. In any case, a dusty maze will soon put paid to that. For this trial, the mouse was commanded to move forward 4 squares with no limit on its top speed…
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