Team Saint Robot Builds

[craig_colliass]

Making big wheels

The disc is made from HDPE 20mm thick.
First cut out the blank, Find were the centre for the wheel is going to be. then mark the position with a pen and centre punch the exact point.
I used some steel builders strap as the holes are punched accurately so the dimensions should be good and the wheel round this is screwed one end at the centre punch mark, using a scriber or anything metal and sharp the circle is marked I find with my eyes the line is hard to see so I go over the line with a permanent marker.
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Cutting out the wheel is a long and arduous business but the slower you go the better the final job usually is.
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The tyres for this robot are Motocross motorbike front wheel tyres like Saint first they have to be cut in half radially this means you have half the tyre on each wheel. for the new robot the wheels are so large there are no tyres big enough so the tyres are segmented 12 segments for each wheel. a simple clamp helps, don't forget the bead is steel.
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the tyre is then bolted to the rim the holes for the bolts are measured out first and the holes drilled. The bolts used are stainless steel hex socket domed head (flanged) 8mm machine screws and Nyloc (flanged) nuts to fit.
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more to come

Craig

[craig_colliass]

Just a quick run down on how the robots did at Colchester

But firstly a big thanks to John and all the Robot Wars team for 3 great shows. Looking forward to the next one.

Spiderbot this machine has proved to be quite reliable and didn't miss a beat or a step, the crowed loved it.

Kettlebot ran faultlessly and was a joy to drive.

Tron this robot suffers from a bad driver (me!) in the end I just drove it on the floor flipper because I like to see it fly! the last time it busted a drive motor so that was the end of that the new LiPo batteries are working wonderfully.

Cherub this robot was a complete disappointment for us, as it didn't work properly all weekend, we tried everything to get the lift motor to work but no luck. We have decided to replace the speed controller and radio for the lifter and start again. If you replace the handle and the head you know you fixed the broom!!

Gabriel we decided to get the new robot ready for this event, and carefully test it to see if it would be OK. the robot worked very well I had a drive between shows and I could almost drive it were I wanted it to go!! the handling on this machine is so much better than Saint ever was. also the more powerful motors made the drive so much more responsive it works like a heavyweight Seraph. exactly what I was hoping for.

There were a few problems the major one being the drive on one side was binding somewhere, at the time I thought it was the bearings binding I was concerned some dirt had got on to the bearing tracks on the gearbox. but it turned out to be the motor pinion was tight in one place this has been adjusted and is running much better. A few nuts shaking loose that will need to be looked at but the Wotty didn't break into a sweat and the batteries performed better than expected.

Modifications to the robot I hope to loose a bit of weight on the robot as I expect it to be a little over weight, and adjusting the drive ratio to increase the top speed a little.

all in all a mixed bag for the robots but I hope Gabriel may be one to watch in the future.

[cliveb]

Yes thats the feller Craig. Jonno and Learo have one as well.

[grant_ploughbot]

The 4 channel chargers are very useful for smaller packs, allowing you to charge 4 completely different packs at once. However they're not really powerful enough to use on the larger 6s 5000 packs. If you can find a 100w version they're better but still limit you to less than 1C (4A max charge on 6S).
I tend to have two chargers, a multi charger and a larger more powerful one that will charge a 6s 5000 at 2C easily.

[geeza]

Craig in turbulence I run that same setup as you just posted, optipower brand which I know is what grant will recommend.

[maddox10]

If we're discussing heavier chargers.
Leo has 2*200W and single 400W in his arsenal of chargers.

Of course, if you want to charge real fast... better get a hefty powersupply (One of Grants for example) and this 2*1300W monster.

[craig_colliass]

Thanks for the advice guys most of the bits now ordered.

[craig_colliass]

I thought I would start downloading some pictures of the new Saint build.


Firstly the motors used in this project, the old Saint A used the Bosch 750 units but for an axel robot there has never been enough power , so we are using the Mag motor it has three times the power of the Bosches but the penalty for this is extra weight.

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The wheel hubs are always a cause for concern on the larger wheel robot, as the stresses on these parts are always large. We have decided to stick with the trailer hub design as with Saint A they have never failed in combat and with the taper roller type bearings they are best placed to accept the axial loads expected.

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I always like to have the drive as an assembly that can be removed complete from the robot, here are the drive units complete and ready for the next stage of construction. you can see the gearboxes made by Mike the final drive is 1/2 inch chain similar to Saint A

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Then parts on the garage floor trying to work out the width of the robot and how we are going to squeeze all the bits in, the finned aluminium is the passive heat-sink for the Wotty speed controller.

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Hope you found this intresting

Craig
Team Saint

[craig_colliass]

Gabriel it is then!




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This is not a trick the clearance from the front of the robot to the ground is 14" or 350mm!

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I still have lots to do but I hope to get it going this weekend.

[grant_ploughbot]

I have used two high power chargers very reliably. The Hyperion super Duo and the PowerLab 8 or 6. For these higher power chargers you do need to look at a 24v PSU though. Ideally anything dual channel over 300w per side or parallel charger over 700-700w will do nicely. If you have a cellpro 10s though it might be cheaper to just get a second one of those with the FRA discount through optiPower.