# Linear Encoders on CoreXY motion system

Hello,

I just received my O-Drive and am very excited to start tinkering around with it and learning all it can do. One thing I had thought about doing was using it to drive a CoreXY type motion system using linear encoders.

I haven’t been able to find any information on whether linear encoders would work considering each motor moves the tool head at 45deg to the axes (ie if motor A spins and motor B is stationary, the tool head will move at a 45deg angle from both X and Y). Is there a way to integrate linear motors to work with this type of kinematic system?

I realize this may be more advanced but I thought I’d ask because it’s something I’m thinking of doing for a capstone next year.

Cheers!

Linear encoders are usually used on the motion controller(the one that does the coreXY kinematics and tells the motors how to move) to close the outer control loop. Not the motor controller(this is the odrive) that drives the motors.

I’m about to purchase a odrive to run a linear tubular motor with linear encoder incremental.
How do you go about calibrating the magnet set and winding.
I have 45 magnets and 9 coils.

Does the forcer(the part with the coils) have 9 wires coming out? It usually has 3. These are the phases. I belive the number of pole pairs is the number of magnets on the rail.

3 wire in star.
3 coils per phase, 9 coils all up.
6-pole,
450 mm long tube with 45 magnets.
This can all change.
I’m making it myself.
Im also using a 1um resolution magnetic incremental encoder.
I was worried about the odrive not being able to read that amount of pulses.

It’s not the amount of pulses but the frequency they come. I think odrive can do about 4MHz reading, which isn’t all that much for a linear encoder. The count frequency and and number of pulses is the limit how fast the encoder can count, otherwise pulses will be missed.

ODrive can do better than 4MHz, especially if you have push pull drivers. Filtering as it is is good for about 10MHz iirc

I was thinking of using a teensy 4.0 to read the pulses.
Would that work

You can. It has hardware counters in it. Not sure it’s strictly necessary for that purpose only(unless you need some other custom things too). Maybe try the odrive inputs first and see where that takes you.

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Hi there can you recommend push pull drivers or a link on DIY