colinleer Posted October 19, 2022 Share Posted October 19, 2022 Does Power PMAC have any built-in input shaping capability? e.g. I have a significant mechanical resonance in my system that I'd like to compensate for. or, is there a mechanism for computing my own trajectory and using that in the servo command loop, versus the in-built move mode trajectory interpolation Quote Link to comment Share on other sites More sharing options...
Eric Hotchkiss Posted October 19, 2022 Share Posted October 19, 2022 We have a tool to remove vibration called a Trajectory Pre-Filter, sometimes referred to as vibration suppression. We used to have a demo where a linear motor had a block and spring on top. When vibration suppression was enabled, the block did not vibrate. Typically either a Low-pass or notch filter would be used. I would recommend to start with a Low-pass. The concept is discussed in the Power PMAC Users Manual and the tool to implement the filter in interactive position loop tuning. There is also a way to use MATLAB to generate a trajectory, but it's much more complicated and I don't know if it would have input shaping functionality. Quote Link to comment Share on other sites More sharing options...
colinleer Posted October 19, 2022 Author Share Posted October 19, 2022 Hi Eric, Thank you for the feedback, I will definitely look into the pre-filter tool. To follow up on the trajectory calculation, suppose I had computed my own trajectory offline and had an array of position targets per servo cycle...is it possible to send this to PMAC to execute? Quote Link to comment Share on other sites More sharing options...
Eric Hotchkiss Posted October 27, 2022 Share Posted October 27, 2022 This is possible. You could servo the motor to a position of zero and then write a position to Motor[1].MasterPos every servo cycle. There will be a delay of one servo cycle. I am including training slides on position following. Not everything applies when just writing to MasterPos directly. Offset/normal following mode applies, as well as the speed and acceleration limit features on the last slide. It would be best to do this from a custom servo routine attached to Motor 0 (written in C, pshm->Motor[x].MasterPos=Value;). 1 Quote Link to comment Share on other sites More sharing options...
steve.milici Posted October 27, 2022 Share Posted October 27, 2022 You can also send “live” position targets in G-code format to a PMAC Rotary Buffer: F100 X10 Y25.6 Z18.01 X11.55 Y21.7 Z15.67 . . . See the sections “Rotary Motion Programs” in the “Power PMAC User’s Manual” starting on pages 602, 614 and 629 for further details. Quote Link to comment Share on other sites More sharing options...
colinleer Posted October 31, 2022 Author Share Posted October 31, 2022 Thanks Eric and Steve, Eric, would you mind reposting the training slides you mentioned? not seeing an attachment in your post. thanks! Quote Link to comment Share on other sites More sharing options...
Eric Hotchkiss Posted October 31, 2022 Share Posted October 31, 2022 Here they are. Position Following.pdf Quote Link to comment Share on other sites More sharing options...
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