Joined: 01 Jun 2005
Posts: 220
Location: Melbourne, Victoria
Puncturer - Team AJW - VIC
Robot Stats
Robot name : Puncturer
Location: Melbourne VIC
Robot weight: Feather 13.6 kg
Type of Robot: Wedge + Spikes
Drive system: 2 x 100W Scooter Motors
Type/size of wheels: 5" (127mm) Scooter wheels
Weapon/s: Spikes
Speed/motor control: Scorpion XL and RCE200 R/C Solid State D-Switch Ver A
Power: 2 x 12V 3A Panasonic SLA
Type of radio controller: Spektrum
Last edited by Andrew W on Fri Jan 05, 2007 6:39 pm; edited 6 times in total
Mon Oct 09, 2006 3:44 pm
Andrew W
Joined: 01 Jun 2005
Posts: 220
Location: Melbourne, Victoria
The controller is going to be a modified PRC. I am looking at using the 150W scooter motors controllers from Oatley to provide the variable speed and using a 30A DPDT relay to provide the direction control.
I'm using a ULN-2803 darlington driver instead of the ULN-2003, so I can use all 8 outputs from the 18X instead of only 7.
Andrew W
Mon Oct 09, 2006 3:49 pm
dyrodium Experienced Roboteer
Joined: 24 Aug 2004
Posts: 6476
Location: Sydney
Hey mate, those coin hopper motors and gearboxes on oatley seem to have a fairly slow output (only a few rpms i believe).You'd be better off getting a car can motor or other high power motor and gearing it down a little (such as 2:1) to get the KE up. Good luck with it! _________________ ( •_•)
The coin hopper's speed it quite low but I was thinking of replacing the motor with another motor (perhaps a drill motor or the 100W jaycar motor). I was thinking of chain or belt driving the weapon from one of the 8mm D shafts.
Tue Oct 10, 2006 8:31 pm
Glen Experienced Roboteer
Joined: 16 Jun 2004
Posts: 9481
Location: Where you least expect
getting a good start youll need some pretty remarkable gear up off the gearbox if your using that. only about 150rpm or so at 18-24v which is nothing. not sure what size the motor is but it could be okay i guess if you belt drive it from the motor alone. (which would be alot smarter then using the whole gearbox) _________________ www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz
Tue Oct 10, 2006 9:00 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
From the Oatley web site:
quote:
Some approx. voltage/current & RPM figures of the motor/gearbox.
2V 80mA 7RPM,
6V 100mA 30RPM,
12V 120mA 60RPM,
18V 140mA 110RPM,
The speed is around 50 X too slow and the current draw is around 100 X too low as well - this motor isn't going to spin up anything bigger than an antweight weapon. Rather than mess about with gearing down a motor then gearing it back up with belts, just use a direct belt drive as Angus suggested; it's likely the gearbox isn't built to take impacts and will break quickly.
A 100W scooter motor would do, but the fan motor setup that Angus is using is cheaper, more powerful and is also easier to mount a pulley to IMHO. _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Tue Oct 10, 2006 9:03 pm
Andrew W
Joined: 01 Jun 2005
Posts: 220
Location: Melbourne, Victoria
Been looking at the controller, and found the 18X has got only one pwm out . I've looked at the 28X and it has 2 pwm outputs - perfect to connect to the 150W Oatley motor controller. The 28X outputs line up perfectly with the ULN2803 driver chips inputs when you put the chips side by side, makes wiring up the bit of veroboard heaps easier .
I've found that the 24V DPDT relays from Jaycar a perfect match with the 100W scooter motors, I've stalled the motors and then reversed the polarity using the relay and I didn't do any damage to the relay
Figured out how I'm going to build the frame out of the bits of steel from the old bikes. Old bikes + angle grinder -> cheap source of good quality steel
Still not sure about the weapon motor, but will probably go with a car fan motor, probably like the one Neweyn uses on his robot (I think it comes out of a TR Magna).
Mon Oct 16, 2006 8:43 pm
Andrew W
Joined: 01 Jun 2005
Posts: 220
Location: Melbourne, Victoria
Found it will be too difficult to cut the 8mm steel (I don't have access to an oxy torch), so I'll use a stainless steel blade instead. I think the blade is around 16mm wide.
I've also weighed the nicad batteries that I was going to use to replace the SLAs and found that there will only be a few hundred grams difference between them . The Nicads are Sanyo N3000CR and 20 of them in a box weighs about 2.1KG, 400gm lighter than the 2 12V 3.2A SLAs.
Sat Oct 21, 2006 8:30 pm
Philip Experienced Roboteer
Joined: 18 Jun 2004
Posts: 3842
Location: Queensland near Brisbane
Do you need the battery box? The 24 v pack of N-3000CRs should only be 1.7 kg by themselves. _________________ So even the rain that falls isn't actually going to fill our dams and our river systems
Sun Oct 22, 2006 5:58 am
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
The Magna motors are great for bots; light yet quite powerful @ 24V. Just don't mount the blade directly on the motor shaft - it will bend after just a few hits. _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Sun Oct 22, 2006 8:55 am
Andrew W
Joined: 01 Jun 2005
Posts: 220
Location: Melbourne, Victoria
Tried to weld the old bike steel at TAFE last Friday. The teacher said I couldn't arc it because the wall thickness was too small, so he suggested I oxy it. I tried using the oxy but I was finding that I could get one piece molten but not the other due to the different thicknesses of the metals . When I took it home and stress tested it I found that the majority of the welds didn't work at all . So there goes the idea of using old bike frames.
Anyway I've been able to get some 6mm Aluminium flat so it looks like I'll be using that for the frame, along with 3mm gal for the corner mounting points.
Thu Nov 09, 2006 8:19 pm
Spockie-Tech Site Admin
Joined: 31 May 2004
Posts: 3160
Location: Melbourne, Australia
Take it to a Pro bike shop or Fabrication/welding shop with a TIG. Chances are they will be able to weld it properly.
Being to be able to produce battle worthy welds with your first time on a metal glue gun is pretty unlikely. Its something much better off left to someone who drives a welder for a living.
To hold the frame together while you mock up the design, drill some small holes in it, and use Twisted wire and Gaffa tape.
Internal non-structural brackets to hold access panels, and mounting things can be done with angle-aluminium, a drill, hacksaw and pop rivets at home after the main structural elements have been welded.
If you do the setup and jigging it in place properly so the welder can just go "zap zap zap" and stick it all together it should work out fairly cheap as well _________________ Great minds discuss ideas. Average minds discuss events. Small minds discuss people
Thu Nov 09, 2006 11:37 pm
Rotwang Experienced Roboteer
Joined: 15 Jun 2004
Posts: 1589
Location: Vic
I would be happy to weld up your frame Andrew, just tack it or tape it best you can and we can work out how to get it to me.
Fri Nov 10, 2006 4:57 pm
Valen Experienced Roboteer
Joined: 07 Jul 2004
Posts: 4436
Location: Sydney
I've used the PIC16F877A for driving of PWM's $12 or so from Jaycar. Seems pretty reliable in terms of handling nasty EMI, some people have had problems with latchup in their chips before. _________________ Mechanical engineers build weapons, civil engineers build targets
Fri Nov 10, 2006 6:15 pm
Andrew W
Joined: 01 Jun 2005
Posts: 220
Location: Melbourne, Victoria
Thanks for the offer Gary, but I've decided to go for an aluminium frame, mainly because the steel had too small a wall dia and overall dia.
Here are some pictures of the parts I'm using.
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