3D Printer with X stepper and Y Odrive D5065 w/AMT encoder using step/dir

1

I need help tuning an Odrive for step/dir control of a D5065.

I’ve built a 3D printer that I’m testing Odrive on. To do this, I’ve swapped out the Y-axis stepper for an odrive3.6 with a D5065 and AMT 102 encoder, same ones as in the Odrive store. My 3D printer control board (duet WiFi) is sending step/dir via its expansion header to the Odrive via a twisted pair. As far as I can tell, this is working fine.

My problem is this: the motor’s responsiveness to step/dir control is too slow. It’s not tracking with the stepper on the X axis. Instead of producing linear trajectories, it’s producing bezier curves. I don’t think this is an issue with lag between the controller and the odrive. Initiation of moves, requiring both the X stepper and the Y Odrive seem to happen at the same instant, as evidenced by 3D prints. I essentially need the Odrive motor to spin up and stop as quickly as possible. As much as I dislike this solution, I need the motor’s velocity/acceleration to be handled by the 3d printer controller.

Any suggestions for how to actually tune the motor’s position control (I’m assuming I need to tune current control) to get it to act more like a stepper?

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You’ll need to increase the position control gains (controller.config.pos_gain) until it behaves how you want. Also, make sure you have your controller.config.counts_per_step set correctly (the default is 2, but you may elect to change your microstepping and your counts_per_step to achieve better pulse rates from the controller)

I forgot to mention, if you really want to reduce the lag you need to send the ODrive the velocity and current feed forward terms. Or use a newer branch like my RazorsEdge branch that generates those terms automatically based on the step rates, via the “input filter”

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@Wetmelon,

Thanks! Is there a location I can read about the meaning/effect of, velocity/current feed forward terms? And where can I read about the position gain? I’ve got the steps configured correctly. I’m going to try these changes out in the next day or so.

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torsenRED, please post updates when you get it to work!
Here is a related post on this topic.