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What to build?
CIMs sound like a good option. But your arguments for Bosches also ring particularly true.
I think you are right to go with the heavy, having read your reasoning above. And I certainly think that flippers need powerful drive trains. Your objective as a robot builder is to deliver your weapon to your opponent. And the better drive you have, the better you will be able to do that. Id be very much inclined to go for 36V if you can. Bosches on 36V are a fantastic drive (as Tornado demonstrates so eloquently (in as far as fighting robots can be considered eloquent
). Geared down reasonably for something like 12mph (a very good speed for most live event arenas). If you get some decent current limiting speedos, then youre laughing.
As for orders of magnitude, well, yes conceivably, but there is absolutely no reason why (apart from money obviously) you shouldnt have a 36V LEM powered drive train- LEMs weigh as much as Bosches, and whilst you need a slightly more resilient drive train to cope with them, that is made up for by having considerably lower RPMs, so not so much reduction required.
That brings me on to Speedos. You can build them, yes, but they will probably end up being more expensive, but certainly a fantastic learning curve, and when they do blow up, youll be able to fix them. The low power side is basically a PIC, which, being a software person) you should have no problems with. Im not a software person, but I can cope with PICs, and that is the more fun side of the current speedos Im building. The high power side is more difficult for me- I can cope with MOSFETs, their drivers, high and low side, charge pumps and so on, but current limiting is giving me enormous headaches, to the point that Im tempted to get some logic level MOSFETs with built in current limiting. While their on resistence is fractionally higher, we can get round that problem by paralleling them. The choice between H-Bridge and Relays is largely a software one. H-Bridges are harder to program for, but are nicer in terms of control. I would go for a relay controller however, as it uses fewer MOSFETs (cheaper and considerably less bulk when you consider how banks of MOSFETs in an H-bridge need to be arranged, plus you dont need a complex system of copper buss bars), is easier to program for, you dont have to worry about high and low side driving, and a number of other reasons which are randomly entangling themselves in my head. If you wont to get something on the arena, and having fun, buy some 4qds or similar (or perhaps a roboteq- though that€™s probably a little on the expensive side) then you can build speedos on the side, and incorporate features into them as you begin to get an idea of what you want in a speedo. As I said, theyre fun, satisfying projects, but not really enormously practical for a first robot.
Ground clearance- the likes of Cassius and firestorm produce rather elegant wood shavings as their fronts plane across the floor. Storm 2 has more ground clearance than I expected, however it still seems to get under everything because its front is so bloody hard, so delivers its KE more effectively into the opposing robot such that the opposing robot jumps up perpendicular to storms wedge, and so storm gets under it. At least that€™s what seems to be happening last time I saw it.
No need to apologise for long ramblings, theyre well punctuated and readable, which makes a refreshing change. Although far too much time spent on MSN has done no favours for my typed English, Im still very much from the €˜Babeth€™ school of thought when it comes to forum postings, as the way you/one writes speaks volumes.
CIMs sound like a good option. But your arguments for Bosches also ring particularly true.
I think you are right to go with the heavy, having read your reasoning above. And I certainly think that flippers need powerful drive trains. Your objective as a robot builder is to deliver your weapon to your opponent. And the better drive you have, the better you will be able to do that. Id be very much inclined to go for 36V if you can. Bosches on 36V are a fantastic drive (as Tornado demonstrates so eloquently (in as far as fighting robots can be considered eloquent
). Geared down reasonably for something like 12mph (a very good speed for most live event arenas). If you get some decent current limiting speedos, then youre laughing. As for orders of magnitude, well, yes conceivably, but there is absolutely no reason why (apart from money obviously) you shouldnt have a 36V LEM powered drive train- LEMs weigh as much as Bosches, and whilst you need a slightly more resilient drive train to cope with them, that is made up for by having considerably lower RPMs, so not so much reduction required.
That brings me on to Speedos. You can build them, yes, but they will probably end up being more expensive, but certainly a fantastic learning curve, and when they do blow up, youll be able to fix them. The low power side is basically a PIC, which, being a software person
) you should have no problems with. Im not a software person, but I can cope with PICs, and that is the more fun side of the current speedos Im building. The high power side is more difficult for me- I can cope with MOSFETs, their drivers, high and low side, charge pumps and so on, but current limiting is giving me enormous headaches, to the point that Im tempted to get some logic level MOSFETs with built in current limiting. While their on resistence is fractionally higher, we can get round that problem by paralleling them. The choice between H-Bridge and Relays is largely a software one. H-Bridges are harder to program for, but are nicer in terms of control. I would go for a relay controller however, as it uses fewer MOSFETs (cheaper and considerably less bulk when you consider how banks of MOSFETs in an H-bridge need to be arranged, plus you dont need a complex system of copper buss bars), is easier to program for, you dont have to worry about high and low side driving, and a number of other reasons which are randomly entangling themselves in my head. If you wont to get something on the arena, and having fun, buy some 4qds or similar (or perhaps a roboteq- though that€™s probably a little on the expensive side) then you can build speedos on the side, and incorporate features into them as you begin to get an idea of what you want in a speedo. As I said, theyre fun, satisfying projects, but not really enormously practical for a first robot. Ground clearance- the likes of Cassius and firestorm produce rather elegant wood shavings as their fronts plane across the floor. Storm 2 has more ground clearance than I expected, however it still seems to get under everything because its front is so bloody hard, so delivers its KE more effectively into the opposing robot such that the opposing robot jumps up perpendicular to storms wedge, and so storm gets under it. At least that€™s what seems to be happening last time I saw it.
No need to apologise for long ramblings, theyre well punctuated and readable, which makes a refreshing change. Although far too much time spent on MSN has done no favours for my typed English, Im still very much from the €˜Babeth€™ school of thought when it comes to forum postings, as the way you/one writes speaks volumes.
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