Now your talkin You could probably use one of those ThinGaps to power a 50mm dia x 200mm long drum built into the front wedge _________________ https://www.halfdonethings.com/
Fri Mar 03, 2006 5:56 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
I have absolutely no idea how to do it, but Andrew and were looking a Sub today and decided it looked a lot like Dr Inferno Junior without the saw wielding robot on top. There is absolutely no room for a weapon inside, but if I put something on the top...
Meanwhile, I am starting on the final layer; I have to reduce it to around 9mm in the thicknesser, which is famous for chewing up & destroying plastic. Once that part is done, its pretty much down to wiring and screwing everything together. _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Fri Mar 03, 2006 6:26 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
Progress:
With Jolt ready to fight at the next event, I am getting back to Sub. All the frame parts are cut out and very little needs doing to them. I had to make a design change part way through the build to make up for not being able to get the proper length screws: the shoulder screws that hold the wedges on are too long (by about 1mm ) and need a washer uder the nut to tighen down properly. I found I had to grind all the washers down from 16 to 12mm to make them fit - you wouldn't believe how tedious that was!!! I put all the frame pieces, nuts 'n bolts, etc on the scales and everything come to only 6.6 Kg for the frame. That puts the complete bot at a bit over 11Kg - just as well I have those magnet wheels to hold it down
This photo shows the middle layers of the frame with the wedges almost fitted. The large holes around the nuts are to accomodate the washers; in the original design the nuts were a press fit into the plastic with much smaller holes.
I started on the wiring as well. Since I have never fired up the Sidewinder before, it seems like a good idea to try it on the bench before installing it in the bot:
The sidewinder is super easy to wire up with ring terminals and M4 screws. when its in the case its a different story though and I might end up installing the controller bare, with just a plastic shield over the top. As soon as my old radio comes back from Brisbane I will try it all out. _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Thu Apr 06, 2006 5:41 pm
andrew
Joined: 16 Jun 2004
Posts: 3110
Location: Castle Hill, Sydney. N.S.W
Did u leave your transmitter at the event, wouldnt be the first time
what happened? _________________ Andrew Welch, Team Unconventional Robotics
Thu Apr 06, 2006 6:31 pm
dyrodium Experienced Roboteer
Joined: 24 Aug 2004
Posts: 6476
Location: Sydney
nah that's me who does that
And sheets of Ti... and battery packs.. darn i'm so disorganised XD
That's looking pretty darn good so far nick, how are you finding the performance of the sidewinder (if you've tested it yet) ? _________________ ( •_•)
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
I designed Sub specially to combat spinners like Jolt (or Orbit, Kang, reboot etc); who would know better? You could stack a second Subliminal on top of the first one and Jolt would still only just brush the tops of the wheels. vertical spinners have to drive up the long wedges and will probably go right over the top without landing a hit. If Sub does get a hit, its not going to do much to the 10mm of Titanium in the core of the frame.
The only real adversary will be an undercutter with a reasonably long blade and even then I have some upgrades in mind The other thing I like about Sub is that I can put some MDF on the workshop floor and actually learn to drive it - a really new experience for me! _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Thu Apr 06, 2006 8:56 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
I powered everything up today and all the basics work fine - smoke stays in, motors turn etc. There is one strange thing with the controller though; when the motors are turning at less than full speed (with no load other than their gearboxes) , the controller draws around 24A while the motors are only drawing around 2.5 to 3 amps. When the motors are spinning at full speed, the controller's current draw suddenly drops down to 8A, just a bit more than the motors.
The FET heatsinks got quite warm during testing, so the conclusion is that the power is being dissipated in the FETS whenever they are not 100% on. I need to find whether this is a fault of a 'feature' as it could toast both the controller and the batteries. _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Mon Apr 10, 2006 11:53 am
Knightrous Site Admin
Joined: 15 Jun 2004
Posts: 8511
Location: NSW
One thing I was a little worried about the Sidewinder was this little comment:
quote:
- Voltage: 14V to 48V Supply voltage (50V absolute max, down to 6V with external 12V supply)
I'm guessing it doesn't have a switch mode regulator.... Do you have a 12v external pack powering the Sidewinder? _________________ https://www.halfdonethings.com/
Mon Apr 10, 2006 11:58 am
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
I am running it on a 14.4 pack without a seperate ligic supply just for testing. When it's in the bot I will be using a tiny 14.8V LiPo pack and a BEC to give the Sidewinder logic 12V. The Robot Power guys say the logic cirutry draws only a few hundred mA, so I got some tiny 480mAH LiPo cells that weight almost nothing. With a bit of luck, this will also reduce radio interference a little - I am still using a 75MHz tramsmitter on this bot. _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Mon Apr 10, 2006 12:09 pm
Knightrous Site Admin
Joined: 15 Jun 2004
Posts: 8511
Location: NSW
I gather you would be running an external pack later on. I'm no guru at this, but I wonder during your tests if the surges from PWM switching might be causing some voltage problems in the control logic, which might be causing the fet driver to do some funny stuff. But when you boost it to full throttle, the PWM on/off time is like 95% on / 5% off and might be surging the controller less then at half speed where it's surging from 50% on / 50% off duration.
Just bung on a drill pack to the external power tabs and see if that makes a difference, otherwise, wait for Jake/Brett/ffej/RobotPower to come and correct me _________________ https://www.halfdonethings.com/
Mon Apr 10, 2006 12:19 pm
Totaly_Recycled Experienced Roboteer
Joined: 15 Jun 2004
Posts: 1346
It sounds like the fets arent switching properly at the low speeds .I had the ibc set up in Vertex to hold the big solonoide in for failsafeing i found that it also got hot and drew heaaps of current if i didnt run it at full stick but that might have been something to do with the solonoide giveing back emf with the pwm from the controler .
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