kkeerroo
Experienced Roboteer
Joined: 17 Jun 2004
Posts: 1459
Location: Brisbane
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A bit of a story there:
Ever since I started designing combat robots I wanted a linear actuator for a claw or lifter. But for our first robot we went for something simple, Hellbringer, which then got a simple, cheap weapon, the saw. That was more fun then I first realised so I needed a bigger one, The Aggressor. But I realised I lost half my fights due to being flipped so I wanted a robot that could run inverted, so I built Adversary. When I was kicking the idea of Adversary around (literally) I got way too many great ideas (don't we all) and one was modular weapons like on Hellbringer. One of the ideas was the Claw which need a linear actuator.
So I went looking on the net for a linear actuator. I sent a few e-mails to Linak and got a few back, but I was busy with work and that idea stopped. I then stumbled across a electical surplus web-site that had these really cheap, powerful linear actuators for about $90 american. But they wouldn't ship them to Australia, which was annoying. I was looking at the battlebots forum one lunch time and found a thread to a surplus web-site selling cheap linear actuators for $80. At first I thought it was the same web-site, but I had a look anyway. It was a different web-site and after more looking I found 2 more surplus web-site with the same package. I tired buying a linear actuator from all the sites and all of them turned me down for being Australian (they didn't want to ship overseas).
I then turned to the greatest man in the world, Jim Smentowski, and asked him if he could buy one and then I could buy it off him. It turns out he was also looking at these linear actuators too sell on the robot market place and turned them down as being cheap, slow and heavy and no good for robots. He said I should keep looking for something better. I then went against him and posted a post on the battlebots forum and asked for help there (sorry Jim). I got about 3 post from builders saying the same thing Jim did, but I then got another one from Brian Foote that was more helpful.
Brian used to compete in Battlebots with his light weight robot Fang. But when battlebots stopped he stopped building due to other comitments and hobbies. So he had these "spare" actuators lying around that wern't currently being used and he wanted to know if I wanted one since I sounded so desperate. Well bloody oath I did.
After several e-mail and picture exchanges I paypaled him $50 for the actuator and $59 for the postage (about $150 dollers australian in the end) and then it arrived a week later. At this stage I was running out of time before then annihilator and literally got Adversary running with the weapon 10pm the night before the compitition. Thats the main reason I didn't know how heavy the robot would end up with the weapon.
But recently I've been scribbling down where the weight went. Without a weapon attached to the cross bar and the electronics bays empty Adversary was 6kg, with the claw and electronics 14.5kg. We pulled 1kg of wire out of it at the annihilator, but I still can't remove much more to keep the claw on there, so I'll have to build a light weight just for it.
More designing, Yay. _________________ Get Some!!!
Secretary of the Queensland Robotics Sports Club inc.
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