Hi.
I am searching for a matching motor, that i can manage with my Arduino board.
The Motor should move 1 meter long approximately 1 kg hard metal rod. The motor will be connect in the middle of this rod.
The movement need to be slowly and smoothly.
The motor should move the rod exactly 180 degree, and than back.
I tried first of all servo motors, but the most of them can move 175 degree.
Than i tried dc motors, in this case they can not move exact 180 degree. After some iterations i had a big error rate.
I'll be very glad if someone can suggest appropriate motor type or some links and instructions.
Best regards
Andy
First of all i tried typical servo motors. The problem was with exact 180 degrees. I tried may be 6 different steppers. They all can move 175-178 degrees. If i remove plug, then i can't control the exact degree.
Than i tried Nema 17 motor, in this case it is difficult to control the exact degree and if i set slowly motor movement, it moves gradually and not smoothly. All same motors have error rate +-1.8 degree.
A 200 steps-per-revolution stepper motor should move exactly 180deg with 100 steps.
I am not clear if the problem with the servos was that they would not position themselves with sufficient accuracy or if their total travel was less than 180 deg. Some servos do have limited travel and other can travle a bit more than 180 deg. A sail-winch servo can do 3 revolutions with position control (some can do 6).
It would help if you can post a diagram of what you are trying to do. I can't conceive of how a motor can be attached to the middle of a rod without a belt or gears.
You'll likely have big problems with low frequency resonance if using a stepper motor on such high
inertia load - microstepping x 32 or better is probably worth trying to smooth out vibrations. Stepper is
probably the best approach if there's no other torque than the moment of inertia. Mechanical damping is
also worth experimenting with, but you'll require microstepping to get smooth motion.
Having reduction gearing is also worth looking at - this also gives you more torque, but you'll have
some backlash as well...
anbuki:
Than i tried dc motors, in this case they can not move exact 180 degree. After some iterations i had a big error rate.
anbuki:
All same motors have error rate +-1.8 degree.
What kind of precision do you need?
I'd think a servo, a stepper or a DC motor could be made to work.
The servo could be made to work by using an external pot instead of the one inside the servo.
A properly sized stepper should work with a proper control algorithm (and drive circuit). You need to make sure and accelerate and decelerate the stepper properly.
A DC motor could also do the job with a good encoder and a good control algorithm.