Control methods for stepper motors
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Traditional stepper motors move when they receive a command to advance a certain number of pulses, which correlate to a distance. Steppers are considered open-loop systems because they lack a feedback mechanism to verify that the target position has been reached.
In stepper motor systems, if the available motor torque is not adequate to overcome the load, the motor will stall or skip over one or more pulses, creating a difference between the desired position and the actual position reached.
The most straightforward way to operate a stepper motor in closed-loop mode is to compare the theoretical position which should have been reached based on the number of steps, with the actual position reached based on the encoder feedback. If there is a difference between the target and actual positions, the controller initiates a correction move.
A third method for operating stepper motors in closed-loop mode employs sinusoidal commutation. If the rotor and stator magnetic fields are not properly aligned, the encoder adjusts the motor current to exactly match the torque needed to move or hold the load. Because the feedback is used to control torque by manipulating the motor current, this mode is sometimes referred to as servo control.
Closed loop stepper motor eliminate many of the disadvantages of traditional open-loop stepper systems, making them similar in performance to servo motors. But servo motors outperform even closed-loop steppers in applications that require high speed, high torque at high speed, or the ability to handle changing loads.
See more:
https://www.oyostepper.com/category-30-b0-Closed-Loop-Stepper-Motors.html
https://www.oyostepper.com/goods-345-Closed-Loop-Stepper-Driver-0-82A-24-80VDC-for-Nema-34-Stepper-Motor.html
In stepper motor systems, if the available motor torque is not adequate to overcome the load, the motor will stall or skip over one or more pulses, creating a difference between the desired position and the actual position reached.
The most straightforward way to operate a stepper motor in closed-loop mode is to compare the theoretical position which should have been reached based on the number of steps, with the actual position reached based on the encoder feedback. If there is a difference between the target and actual positions, the controller initiates a correction move.
A third method for operating stepper motors in closed-loop mode employs sinusoidal commutation. If the rotor and stator magnetic fields are not properly aligned, the encoder adjusts the motor current to exactly match the torque needed to move or hold the load. Because the feedback is used to control torque by manipulating the motor current, this mode is sometimes referred to as servo control.
Closed loop stepper motor eliminate many of the disadvantages of traditional open-loop stepper systems, making them similar in performance to servo motors. But servo motors outperform even closed-loop steppers in applications that require high speed, high torque at high speed, or the ability to handle changing loads.
See more:
https://www.oyostepper.com/category-30-b0-Closed-Loop-Stepper-Motors.html
https://www.oyostepper.com/goods-345-Closed-Loop-Stepper-Driver-0-82A-24-80VDC-for-Nema-34-Stepper-Motor.html
