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Tibob
08-25-2006, 01:47 PM
Greetings to all, My first post ever in forums> usually i enjoy reading the stuff vs posting them. I had this endeavor for a very long time, and wanted to share with more capable brains than mine. I have been in R/C Helicopters for the past 20 or so years, modelling in general. However newer technology and design, Can be applied to the priciples of motion platform building. In recent model helis, flight controls are direct linkages to the swash positioned in either 90 or 120 degrees utilizing 3 sevros working all at the same time. Its a priciple called CCPM standing for Cyclic Collective Pitch Mixing. That can provide with bank, pitch, Heave. as would other systems. From other browsings and most of you have done. Open cockpits had this USB board that can be adapted .
Generally 3 wires. positive, negative, signal. Now usb only provide 5 volts, but we dont care about that as we would get power from alternate source. I was looking at powering more powerfull servos from lathes and mills with enough KG/f to sustain the weight and speed desired for our platform. All priciples remaining the same, i can venture in saying $600 a reasonable price for such a design priciple or still too expansive? Any toughts. Debate your take on this as it appaears to be a relatively simple principle. The tough part is the software part i guess that would come from the usb card programming.
Whats nice about it is that its scalabe, another servo can be added for sway as well.

AndyT
08-25-2006, 10:49 PM
Welcome to the forum!

Sounds great! Where do you get the sevos for that? Let me make sure we are talking the same thing here. $600.00 /US for everything?

Tibob
08-25-2006, 11:21 PM
Thanks for welcoming me. That is a rough estimate that i am predicting. I have scoured ebay and servos can be had for as little as $100 per unless you want to get fancier. My theory is relatively simple to build. and i also applaud the rack and pinion principle as well. But with the CCPM principle, i easy to adapt. when time permits i will post examples. BUt let us assume a triangular platform , can be 90 degrees or 120 degrees. Ball links at each end. Servos directly mounted underneath with arms that the connectings rods will be attached to. All servos moving at the same speed up and down will provide heave. any of all servos can still be actuated independently. That is were the software comes into play. the usb board i beleive someone else on the forum did mention about from opencockpits, has its own controller. but it can only provide enough voltage for a small servo. My reasoning was to get and external power source for the larger type servos while retaining the signal from the usb board. The software would get the feedback from FS . framing the platform is a matter of choice on hardware. In essence the initila investment cost is not that steep. Its more labor and brain power then anything else.Check out this link then you can see the promise
http://www.iroquois.free-online.co.uk/ccpm.htm
Sorry made a boo boo in psating the link.
http://www.iroquois.free-online.co.uk/ccpm.htm

AndyT
08-26-2006, 01:14 AM
Tibob,

THANKS! A number of years ago I was taking helicopter lessons and I had designed a simplified swashplate system. I'd forgotten about that and now your link reminds me about it and that it would be the perfect mount for the motion platform.

It will do 3 DOF with no problem! Now I just have to build a small scale version to test. Thanks again!