Stepper or servo for positioning accuracy (Urgent)
Stepper or servo for positioning accuracy (Urgent)
(OP)
I am looking for a motor in order to position in the space vertically precisely a small load.
I am sorry I don't know much about motors.
So I am hesitating between stepper motor and servo motor.
Do you have any idea how could I chose the best one?
Stepper motor :
I have heard that the stepper motor is not good because that it can miss some steps. And I need to be precise in position (rotation angle)
However maybe it wouldn't happen to me because I need a low speed and low couple.
Servo motor :
Which kind of motor would be the best?
I will certainly add with it a absolute encoder.
Torque = 1.45Nm
Speed = 100U/min
So could you give me any advises where I could get more information?
I am sorry I don't know much about motors.
So I am hesitating between stepper motor and servo motor.
Do you have any idea how could I chose the best one?
Stepper motor :
I have heard that the stepper motor is not good because that it can miss some steps. And I need to be precise in position (rotation angle)
However maybe it wouldn't happen to me because I need a low speed and low couple.
Servo motor :
Which kind of motor would be the best?
I will certainly add with it a absolute encoder.
Torque = 1.45Nm
Speed = 100U/min
So could you give me any advises where I could get more information?





RE: Stepper or servo for positioning accuracy (Urgent)
For a mundane application I'd probably reach for stepper. For a dynamic application like machining I'd reach for servos.
Can you say what exactly you are driving?
Keith Cress
kcress - http://www.flaminsystems.com
RE: Stepper or servo for positioning accuracy (Urgent)
"If you properly size a stepper it will never skip."?
I would use the motor to move a linear system (with a belt and a carriage : see linked files)
RE: Stepper or servo for positioning accuracy (Urgent)
Look for a "micro stepping" motor with a "stepper indexer" (stepper controller), from companies such as Oriental Motors or Parker-Compumotor. If you don't know much about motors, then it's time you learned. Most of the manufacturers produce catalogs and engineering manuals with the required selection + sizing methods in them. Steppers were originally about 200 steps/revolution, but there were a few problems with those. Modern steppers have achieved resolutions of 1000's of steps/revolution. Even further, if you gear down this motion through a planetary gearhead, you may achieve extremely precise rotary motion. Your rotational speed, however, will be reduced accordingly.
TygerDawg
Blue Technik LLC
Virtuoso Robotics Engineering
www.bluetechnik.com
RE: Stepper or servo for positioning accuracy (Urgent)
I have been looking to drivers, controllers and stepper motors all day.
I have found some more explanation about my problem :
http://www
So I would like to purchase a stepper motor.
But a problem remain not totally fixed.
How could I know my stepper motor won't go too fast and would miss some steps? How could I know the limit value of load and speed for each of these stepper motor so it doesn't miss some steps?
RE: Stepper or servo for positioning accuracy (Urgent)
Do not concentrate on an almost non-existing problem. Concentrate on the task.
Missing steps are a problem when you either have resonances in your mechanical system or if you accelerate/decelarate too fast. Or if your load is more than the motor can handle. All these things can easily be designed out of the system.
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Stepper or servo for positioning accuracy (Urgent)
Thank you Skogsgurra.
RE: Stepper or servo for positioning accuracy (Urgent)
IMO, one of the key (underappreciated) advantages of servos is they give you greater confidence that you can accomplish anything within your performance envelope -- that is, anything up to maximum speed and maximum torque. You don't have to worry about "no-go" zones within that envelope.
You don't have that blanket assurance with steppers (although good microstepping drives go a long way to alleviating that problem). Good stepper users will carefully evaluate their system at the particularly speeds and torques they will be using to ensure proper operation, and will not automatically assume they can do anything up to maximum speed and torque levels without proper characterization.
If your application is fairly simple, with well-known speeds and loads, this should not be a significant problem.
Curt Wilson
Delta Tau Data Systems
RE: Stepper or servo for positioning accuracy (Urgent)
Keith Cress
kcress - http://www.flaminsystems.com
RE: Stepper or servo for positioning accuracy (Urgent)
ps. let me know if I shouldn't be using Manufacturer's names on the forum...I'm not intending to promote any particular brand, just trying to pass on experience.
RE: Stepper or servo for positioning accuracy (Urgent)
Keith Cress
kcress - http://www.flaminsystems.com