You don't need precise control over position so a stepper would probably be overkill. The easiest way might be a hobby servo. It's geared down to provide high torque and has a built-in motor driver and position feedback so you don't need a separate motor controller.If you can measure the torque needed to turn the knob you can use that information to get a strong-enough servo. I'd start by doubling the required torque for plenty of margin.
Please enter a valid email to subscribe
We need to confirm your email address.
To complete the subscription, please click the link in the
email we just sent you.
Thank you for subscribing!
via Egeo 16