On 7/8/14 09:05 , John Kasunich wrote: > > I believe Jeff Epler wrote a HAL component years ago to > do just this. I'm not at a Linux box right now, but I think it > might be called "offset". It adds a value to the outgoing > position command, and subtracts the same value from the > incoming position feedback. It is intended to be installed > between motion and either the PID loop (servo) or the > stepgen (stepper). > > The other half of the equation, accel and velocity limiting, > also has a ready-made HAL component, limit3. The offset > from the THC goes into limit3, and even if it instantly steps, > the output of limit3 obeys acceleration and velocity limits. > That output would then go to the offset block.
This sounds perfectly reasonable to me. (Disclaimer: i dont know how a torch height controller should work.) Here's an ascii-art pseudo-code hal diagram describing how i'd try to do it: thc.voltage -> pid -------\ axis.N.motor-pos-cmd -> offset -> limit3 -> (actual joint cmd) axis.N.motor-pos-fb <---/ ^---------------(actual joint fb) The pid component would maintain the thc voltage by adding or subtracting an offset to/from the commanded Z position as needed, based on torch voltage (and some statically controlled setpoint). Maybe some extra circuitry to toggle the pid enable pin when the corner-lock condition kicks in. The limit3 component limits would be setp to the joint position, velocity, and acceleration limits from the ini file. -- Sebastian Kuzminsky ------------------------------------------------------------------------------ Open source business process management suite built on Java and Eclipse Turn processes into business applications with Bonita BPM Community Edition Quickly connect people, data, and systems into organized workflows Winner of BOSSIE, CODIE, OW2 and Gartner awards http://p.sf.net/sfu/Bonitasoft _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
