I am new to the electronics hobby so any hep is appreciated. For my application I need a quiet motor that can provide high torque at low speed. I purchased a NEMA 17 stepper motor (model is 17HS4401s) and I am using the DRV8825 driver chip and PIC microcontroller to drive it. I've connected the circuit like as the diagram below with a 12 volts 2 Amps motor power supply.

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Now, after getting the motor to work, mounting it using screws and attaching the load, the motor itself is stable, yet the shaft vibrates and causes the causing the load to vibrate with it. I've tried the following:

  1. Microstepping the motor to 1/32 steps -> Reduced the vibrations a lot but the load still vibrates
  2. Limiting the current to 1.4 Amps -> Did not make a difference
  3. Limiting the current to 1 Amp -> Again reduced the vibration a bit but the load still vibrates
  4. Different step frequency values (0.5 ms, 1 ms and 2 ms) but no significant change happened

Is there a way to get a smooth stable motion from the motor and stop the shaft from vibrating? Would switching to a different driver the TMC2100 SilentStepStick make a difference?

  • \$\begingroup\$ What is the motor part number (or if you don't have it, how many degrees per step), and how fast is the shaft rotating when it is vibrating objectionably? \$\endgroup\$ – TimWescott Jan 9 at 22:35
  • \$\begingroup\$ The motor is 200 steps (1.8 degree) stepper with 1/32 microstepping so so 6400 steps per rotation. and I send a new step signal every 0.5 ms \$\endgroup\$ – moaz Samy Jan 9 at 23:03
  • \$\begingroup\$ Can you post a picture of the mechanical setup? My stepper vibrates when not mounted solidly. \$\endgroup\$ – Mattman944 Jan 10 at 0:15
  • \$\begingroup\$ if you have a scope and a cheap current sense transformer, stick it on one of the motor wires, you can learn a lot. there are many potential reasons \$\endgroup\$ – Pete W Jan 10 at 2:22
  • \$\begingroup\$ one clue to look for: remove load, and/or damp shaft with finger, see if it gets better. another thing to try that can be a clue: temporarily plug in a larger stiffer power supply. another one: try a different driver with same mech. setup. another: motor gets extremely hot. \$\endgroup\$ – Pete W Jan 10 at 2:25
  1. Only use full steps for max torque. Use appropriate pulley ratios on belt to increase torque as required.
  2. motor noise while moving is due to mechanical resonance, which is dependent on lack of stiffness and lack of damping and bearing slop exciting frame resonance.
  3. Motor noise while idle should not occur but if you hear a squeal noise , it is because of electrical resonance , which depends on supply noise and cable characteristics which transfers motor inductance to the driver.
  4. Ensure at if 2A=24W that the motor has a miniature fan for cooling and same for electronics.
  5. Your motor coil specs are 1.7A and 1.5 Ohms.
  • \$\begingroup\$ I would think it is perfectly possible for torque variations to cause vibration. Stepper motors are not known for smooth torque. Do you think it is impossible that the vibration is caused by torque variations during rotation? \$\endgroup\$ – mkeith Jan 9 at 22:54
  • \$\begingroup\$ @Tony I don't mind the noise as much I mind the vibration. and I don't know the reason r the fix for that vibration \$\endgroup\$ – moaz Samy Jan 9 at 23:04
  • \$\begingroup\$ @mkeith I have considered that, but I found people on videos and the internet using stepper motor and never complaining about vibration so maybe it is something wrong with my config? I need to drive the load from the motor directly and avoid belts or gears or something similar \$\endgroup\$ – moaz Samy Jan 9 at 23:06
  • \$\begingroup\$ I was talking to Tony. He seems to be dismissing the idea that the steps are causing the vibration. I note you say that microstepping helped, so I wonder if torque pulses are causing vibration. In my experience, vibration usually IS caused by mechanical issues. But I would think that with a stepper motor it could also be caused by torque vibrations. \$\endgroup\$ – mkeith Jan 9 at 23:18

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