Steve Gunderson (916) Utah State University March 11, 2010

Acknowledgements Dr. YangQuan Chen: Research background and technical instruction Dr. YangQuan Chen: Research background and technical instruction

Agenda Overview Overview Impact of engineering Impact of engineering Principle of operation Principle of operation Types Types Implementation Implementation Application Application Major specifications Major specifications Limitations Limitations Purchasing Purchasing References References Typical Stepper Motor

Overview Stepper motors are brushless electric motors that operate through a radial array of steps Stepper motors are brushless electric motors that operate through a radial array of steps The step sizes vary from motor to motor and can be used in control applications where a defined resolution is helpful with motor manipulation The step sizes vary from motor to motor and can be used in control applications where a defined resolution is helpful with motor manipulation

Overview Stepper motors have become widely implemented in many ways due to their controllability without any form of feedback loop Stepper motors have become widely implemented in many ways due to their controllability without any form of feedback loop Even without feedback, a stepper motor may be controlled to a good degree of precision Even without feedback, a stepper motor may be controlled to a good degree of precision

Impact of Engineering The functionality of stepper motors has been so widely accepted that they have revolutionized the usefulness and ease of implementation of electric motors The functionality of stepper motors has been so widely accepted that they have revolutionized the usefulness and ease of implementation of electric motors They can be used in stable and reliable control system that function with great precision and accuracy They can be used in stable and reliable control system that function with great precision and accuracy

Principle of Operation Voltage applied to the motor causes the rotor to incrementally spin Voltage applied to the motor causes the rotor to incrementally spin More voltage causes more increments to be bypassed around the circle More voltage causes more increments to be bypassed around the circle Typical Stepper Motor

Types Permanent Magnet stepper motors maintain a permanent magnet within the housing Permanent Magnet stepper motors maintain a permanent magnet within the housing Variable Reluctance stepper motors with iron rotors have rotor points attracted to stator magnet poles Variable Reluctance stepper motors with iron rotors have rotor points attracted to stator magnet poles Hybrid Synchronous stepper motors are the combination of the previous two for better performance Hybrid Synchronous stepper motors are the combination of the previous two for better performance

Implementation Stepper motor control varies almost as widely as the stepper motors themselves Stepper motor control varies almost as widely as the stepper motors themselves Control implementation is heavily dependent upon internal configuration and application needs Control implementation is heavily dependent upon internal configuration and application needs Stepper Motor Control inowiring/51

Implementation Drive circuitry for bi-polar stepper motors can be complicated but may be worth the additional torque that the actuator would be able to provide once configured properly Drive circuitry for bi-polar stepper motors can be complicated but may be worth the additional torque that the actuator would be able to provide once configured properly Stepper Motor Control inowiring/51

Implementation Half-stepping and micro- stepping are two implementation modes where the angular resolution may be increased with little change to the control circuitry Half-stepping and micro- stepping are two implementation modes where the angular resolution may be increased with little change to the control circuitry Stepper Motor Control inowiring/51

Application Countless types of stepper motor configurations are in use today all throughout the world Countless types of stepper motor configurations are in use today all throughout the world A wide variety of markets can take advantage of them for precise control actuation A wide variety of markets can take advantage of them for precise control actuation

Application Smaller high precision stepper motors are often used for common actuation tasks Smaller high precision stepper motors are often used for common actuation tasks Their small enclosures are easy to mount to hardware and at low speeds can provide high torque Their small enclosures are easy to mount to hardware and at low speeds can provide high torque Stepper Motors 07/scavenge_materials_to_build_tinker_your_o wn_cnc_machine.html

Application Robotic systems can take advantage of a stepper motor’s quick response and high precision without the constant need of a feedback loop Robotic systems can take advantage of a stepper motor’s quick response and high precision without the constant need of a feedback loop Where needed they can also interface with belts and drive trains Where needed they can also interface with belts and drive trains Stepper Motor geGallery/G4.Handler.stepper.motor.gif

Major Specifications Motors tend to vary widely in response and must be characterized in order to properly control and implement them in a design Motors tend to vary widely in response and must be characterized in order to properly control and implement them in a design Stepper motor characteristic equations are a good start to understanding their behavior, as long as the control circuitry is also taken into account Stepper motor characteristic equations are a good start to understanding their behavior, as long as the control circuitry is also taken into account

Limitations Stepper motor resolution is completely dependent upon the number of teeth on the rotor Stepper motor resolution is completely dependent upon the number of teeth on the rotor As motor velocity increases, there is also a marked decrease in the total torque output which can comprise certain implementations of the actuator As motor velocity increases, there is also a marked decrease in the total torque output which can comprise certain implementations of the actuator

Limitations Different tooth constructions in the motors can lead to varied efficiencies and controllability Different tooth constructions in the motors can lead to varied efficiencies and controllability More complicated motor designs also may require more complicated control electronics with amplifiers and many input lines More complicated motor designs also may require more complicated control electronics with amplifiers and many input lines

Purchasing Stepper motors may be readily purchased from many online retailers Stepper motors may be readily purchased from many online retailers Small electronic stepper motors are found at digikey.com or mouser.com Small electronic stepper motors are found at digikey.com or mouser.com Large-application stepper motors may be obtained from specialty manufacturers and retailers Large-application stepper motors may be obtained from specialty manufacturers and retailers

References Wikipedia.org Wikipedia.org “Mechatronics – An Integrated Approach” by Clarence W. de Silva “Mechatronics – An Integrated Approach” by Clarence W. de Silva

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