Running stepper motors with encoders with RAMPS

Is it possible to control stepper motors with encoders in closed loop with RAMPS 1.4?

For closedd loop you need a processor with enough power to run the various loops. The Mega256 just doesn't cut the cake here, you would need an ARM based 32 Bit board and of course a firmware and shield that supports the encoders and loops.
I am not aware of any commonly available 3D printer electronics that offers this.

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[www.bonkers.de]
[merlin-hotend.de]
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The Mod-T printer uses DC motors with encoders, this was mentioned in the ServoLolu thread, but I don't know what electronics is used.

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I basically want to make an automation equipment (not 3D printer) using 5 encoded stepper motors. I was thinking if I can use RAMPS plus MEGA with writing my own little code. Any clues if possible with RAMPS?

The mega is to small and the ramps has no options to connect the encodrs, so no

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[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

... I've done this for a test with an ArduinoDUE, soldering a plug for the encoder on a prototyping shield.

The standard arduino servo-libraries aren't very fast - IIRC I've got below 200kHz 'reaction' time ... needed more than 300

So if oyu want a 5-axis encoding/controlling software, you'll have to write it from scratch to get usefull speeds even with the Due ...

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Viktor
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Teensy 3.2 with SPI controlled encoders may be fast enough.

Running stepper motors closed-loop is more complicated than simply adding more steps if you get out of position. This is because when moving at higher speeds, simply adding more steps will just cause the motor to keep skipping steps. Instead, most closed-loop stepper controllers commutate the steppers like you would a brushless DC servo motor, and then run a PID servo control loop that modulates the drive current to the motor to control the position. This is what the Leadshine and Quicksilver closed-loop stepper systems do. The commutation process is a lot more demanding, computationally, than just doing PID servo control.

You might also be interested in this closed-loop stepper controller that I worked on for a bit, but abandoned for lack of interest.

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bobc
The Mod-T printer uses DC motors with encoders, this was mentioned in the ServoLolu thread, but I don't know what electronics is used.

The MOD-t uses conventional DC motors and encoders rather than closed-loop steppers, and it uses a proprietary controller board and firmware. In the Servolulu thread, I replaced the MOD-t controller board with a Teensylu board and 4 of my Servolulu drivers.

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LoboCNC

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bobc
The Mod-T printer uses DC motors with encoders, this was mentioned in the ServoLolu thread, but I don't know what electronics is used.

The MOD-t uses conventional DC motors and encoders rather than closed-loop steppers, and it uses a proprietary controller board and firmware. In the Servolulu thread, I replaced the MOD-t controller board with a Teensylu board and 4 of my Servolulu drivers.

Right. Can you tell what CPU/DSP is used on the original board, or have they scrubbed the markings?

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Quote
bobc
Right. Can you tell what CPU/DSP is used on the original board, or have they scrubbed the markings?

The board has an STM32F103 processor.