On 10/24/2016 11:16 PM, Marius Liebenberg wrote: > Hi All > I have a problem with a machine using servos. It is a 4 axis machine > with the 4th axis being rotary. The linear servos are tuned and working > very well but the rotary axis is not behaving well. It has a severe > oscillation and I cannot seem to get the PID trimmed to stabilize the > servo.
This sounds similar to a setup with a linear scale used as feedback as opposed to a rotary encoder on the motor. This configuration usually has a lot of backlash between the motor position (command input) and the scale (feedback). When a command is invoked it can take quite a while for the feedback to show up. This makes the control loop unstable because corrections always come too late. I would connect HALscope to check the delay between the loop command and feedback. Ideally, feedback should start coming in on the next servo period after a command. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/ ------------------------------------------------------------------------------ The Command Line: Reinvented for Modern Developers Did the resurgence of CLI tooling catch you by surprise? Reconnect with the command line and become more productive. Learn the new .NET and ASP.NET CLI. Get your free copy! http://sdm.link/telerik _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
