On Thursday 11 July 2013 15:04:57 Viesturs Lācis did opine: > 2013/7/11 Jon Elson <[email protected]> > > > A potential LinuxCNC project is to build a CNC bender. > > The only thing I don't know how to do is the bend angle. > > What would be desirable is to set the bend angle in the > > G-code, and have it passed to a HAL module such as > > comp.comp, to decide when to turn the bend motor off. > > The bending is done by a motor/gearbox, and you just > > > shut off the motor when the right angle is reached. So, > > it can't be dealt with like a typical axis. I'm pretty sure there > > is a way to do this, but I can't remember how. > > Could you, please, explain, why can't it be treated like a typical axis? > How about this kind of modification: > 1) use A or whatever other axis word to set the bend angle; > 2) use axis.n.motor-pos-cmd pin to read the requested value and link > that to your HAL component. > > I understand that HAL component is the place to compare actual bend > angle with requested to turn the motor off, once requested value is > reached. Just like John, I am interested in how do you intend to track > actual bend angle?
As I see it, the bend angle achieved must be encoded, and since the elasticity of the material varies with the bend angle, I don't see any way but to bend to the desired angle, relax the pressure and measure apply for another .25 degrees, measure, and basically just keep hammering it till the correct angle has been reached. I believe linuxcnc can be made to do that. Perhaps even it could be made to learn by comparing the achieved angle with the desired angle, and then bending an additional 95% of the difference, repeat till its within the tolerance window. Convergence should be achieved in 2 or 3 pushes I'd think. Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> is up! My views <http://www.armchairpatriot.com/What%20Has%20America%20Become.shtml> BOFH excuse #255: Standing room only on the bus. A pen in the hand of this president is far more dangerous than 200 million guns in the hands of law-abiding citizens. ------------------------------------------------------------------------------ See everything from the browser to the database with AppDynamics Get end-to-end visibility with application monitoring from AppDynamics Isolate bottlenecks and diagnose root cause in seconds. Start your free trial of AppDynamics Pro today! http://pubads.g.doubleclick.net/gampad/clk?id=48808831&iu=/4140/ostg.clktrk _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
