Sync Two stepper motor

Using Arduino Project Guidance
1

I have a project i my mind like this https://www.youtube.com/watch?v=OIFk4JHc1VY

Following major component i can use.
1 x arduino mega
3 x A4988 driver
3 x nema 17 ( 1 x master, 1 x slave 1 x for sliding)
2 x optical encoder https://robu.in/product/incremental-optical-rotary-encoder-400-pulse-400-ppr/?gclid=EAIaIQobChMImqDsr6HY3gIVmh0rCh06pQk3EAQYASABEgL1vPD_BwE

What I am going to do..

  1. Before powering the electronics I manually aligned the shaft of both master & slave motor.
  2. Master stepper motor will start first its speed is set through a pot.
  3. After some seconds I press a button to start second stepper motor (slave)
  4. Now the speed and position of the slave motor will control through a PID logic so that it get sync with the master.
  5. PID Setpoint is the encoder value of master motor.
  6. PID Process value is the encoder value of slave motor.
  7. PID output is the speed control of slave motor.
  8. Encoder value of both motors get reset to zero after each revolution.
  9. As soon as both motor get sync, we can tell this through the encoder value of both motor, when both encoder gives same value means they are in sych.
  10. As sync is done both motors are in equilibrium now slider motor moves the slave motro towrds the master motor upto predefined length.
  11. And we can see a perfect performance of stepper in sync, shaft attachemt of both motor get into each other in precise way

My question is

Can PID works with continuously changing set point ??

I can manage to get the speed sync of both stepper its easy.
But for position sync i have to used PID control in which encoder value of master is used as setpoint which is continuously changing. and PID generate output to change the speed of slave motor this both encoder value get same.

so my question is
Can PID works with continuously changing set point ??

I would highly appreciate any kind of your input on this ..

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2

Seems to me you are thinking of a very complex solution.

Stepper motors move in steps so you will know how many steps the first motor moves from the home position. And you will know the speed from the interval between steps. Just make the second motor do the same thing?

...R

PS. I can't see the purpose of the device in the video