Controling steppermotor with raspberry pi

Question

For a school project, I need to control a stepper motor with a raspberry pi or Arduino. I was thinking about a NEMA 17 or NEMA 23 motor. I study mechanical engineering so I don't have much experience with programming Arduino or a raspberry pi.

The motor has to move a carriage 450mm linearly with a variable speed between 50 and 250mm/s. I will use a leadscrew with a lead of 25mm/rev. torque is not a big problem. I calculated the max motor speed to be 600rpm for 250mm/s.

• my questions are:

what motor should I use?

can I program the speed to be adjustable?

is this even possible?

how should I start to program this?

Is 600rpm posible with a nema 23 or 17? on google i find anywere from 400 to 1500rpm max

I hope some of you can help me with some of the questions. if you think you have something you can help me with, please respond.

Answer 1

25 mm/rev lead screw is probably a little big to drive with a NEMA17. Go with the NEMA23.

A typical motor driver will allow you to send direction and step commands over the GPIO. This is the easiest way to control the motor in open loop mode. Your program will tell the controller to take 200 steps to move your linear slide by 25 mm each step being about .125 mm.

The speed is going to be determined by how fast you send step commands. If you send 1 step every millisecond, you will get a linear velocity of 125 mm/s. If you send a step command every 5 milliseconds, you'll get a linear velocity of 25 mm/s.

Starting a stepper motor at high velocity often doesn't work very well, so you'll likely need to include a ramp-up and ramp-down in your program to prevent the motor from skipping steps. If you are running in open loop mode, you have to make sure this never happens or you won't be able to keep track of the position.