Upload
electromate
View
145
Download
0
Tags:
Embed Size (px)
Citation preview
Improving SmoothnessSmoothness and AccuracyAccuracy
in Stepper Systems
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
High PerformanceHigh Performance Stepper DrivesStepper Drives
from Applied Motion ProductsApplied Motion Products
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
About Applied Motion
Founded in 1978Privately OwnedHeadquarters in Watsonville, CA30 Employees
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
About Applied Motion
Visit us on the web at http://www.applied-motion.com
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
About Applied Motion
Motors from AsiaWe partner with motor manufacturers in Japan, China, and Taiwan.Our oldest partner, Tamagawa Seiki in Japan, has been our partner for almost 30 years.
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
About Applied Motion
Drives from the U.S.A.We research, develop, and design all of our drive electronics.We recently formed a joint venture with Shanghai Moons’ Motor Co. to develop new motor & drive products.
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Products
We offer a wide range of Step Motors, Servo Motors, and Drives
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Today’s Discussion
Applied Motion steppers drives improve upon two aspects of step motor system performance
Smoothness – by eliminating resonance
Accuracy – by closing the position loop
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Inherent Problem
ResonanceStep motors are resonant because in short their rotors behave much like a classic “mass on a spring”.
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Inherent Problem
ResonanceWhen a step motor takes a step, the rotor reacts to the changing stator field in the same way a mass on a spring reacts to a change in position.
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Inherent Problem
ResonanceJust like the mass on a spring, the motion of the rotor settles into position after each step.This settling can last as long as a second or more in worst cases!
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Inherent Problem
ResonanceIf the settling doesn’t occur rapidly, or the ringing of the rotor gets worse, the motor can become unstable and lose position (stall).
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Inherent Problem
ResonanceThere are two major, negative side effects of resonance.
Rough motion
Loss of torque, which can lead to loss of position
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Inherent Problem
ResonanceRough motion
When step motors resonate they generally vibrate excessively.This can be bad for sensitive equipment.
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Inherent Problem
ResonanceLoss of torque
When step motors resonate much of the torque available in the motor is used up in keeping the rotor synchronized with the stator field, and in worst cases the motor will not have enough torque to move the load.Loss of torque often leads to stalling.
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Solution
ResonanceThere are three main remedies for resonance.
MicrosteppingTorque Ripple SmoothingElectronic Damping
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Solution
MicrosteppingMicrostepping does not eliminate the natural resonant frequency of a step motor, but it does diminish the level of excitation.In other words, smaller steps mean smaller responses.
coarse steps microsteps
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Solution
MicrosteppingStepper drives from Applied Motion can microstep even when the control signal is low resolution.This is called Microstep Emulation.
coarse stepsfrom externalindexer
microstep emulationperformed by drive
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Solution
Torque Ripple SmoothingTorque ripple smoothing reduces the inherent torque ripple that all step motors display at low speeds (typically well under 5 rps).Torque ripple smoothing works by applying a “negative” current to the motor which offsets the torque ripple.
torque ripple
negative current
result = smoother motionELECTROMATE
Toll Free Phone (877) SERVO98Toll Free Fax (877) SERV099
Sold & Serviced By:
Solution
Electronic DampingElectronic damping remedies two aspects of the motor’s resonance.
Inherent resonant frequencies of the motor.A complex interaction between drive and motor that happens at higher speeds, often called “mid-band resonance”.
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Solution
Electronic DampingThe end result of electronic damping is to minimize and even eliminate the resonant response of the step motor over a wide range of speeds.
withoutelectronic dampingwithelectronic damping
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Solution
High performance stepper drives from Applied Motion offer…
Microstep EmulationTorque Ripple SmoothingElectronic Damping
All of which contribute to…Smoother motion from your step motor
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Inherent Problem
Accuracy – Open Loop SystemsWhen properly sized an open loop step motor system can be adequately accurate for most applications.Keys to proper sizing are knowing the load and knowing the move parameters ahead of time.However, the nature of an open loop system is such that no built-in mechanism exists for indicating a motor mis-position or stall.
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Solution
Accuracy – Open LoopIn situations where an extra layer of accuracy is required, step motors from Applied Motion can be fitted with high resolution, incremental encoders.The encoder is mounted to the rear shaft of the step motor (order “D”option).
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Solution
Accuracy – Open LoopThe encoder is then connected to the drive via a feedback cable.
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Solution
Accuracy – Open LoopApplied Motion stepper drives can perform two main functions when an encoder is added to the system.
fool-proof Stall DetectionStall Prevention w/ Position Maintenance
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Solution
Fool-proof Stall DetectionStall detection works when the stepper drive monitors encoder position relative to commanded motor position.As soon as a mis-position occurs the drive stops motion and sets a fault to notify the user.This method is fool-proof because it works under all conditions, regardless of motor speed or load conditions.
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Solution
Stall PreventionLike stall detection, Stall Prevention works when the stepper drive monitors encoder position relative to commanded motor position.As soon as a lag between the encoder position and the commanded motor position occurs the stepper drive starts to slow the motor speed.
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Solution
Stall PreventionSlowing down the motor allows the motor to operate in a speed range where its torque output is higher, and therefore have a better chance of finishing the move.
Target Move Profile
Target Time
Target Move ProfileActual Move Profilewith Stall Prevention
Target Time
Actual Time
Point at which torquedemand increases
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Solution
Position MaintenanceWith Stall Prevention turned on the drive automatically corrects errors in motor position from external forces when the motor is at rest.In other words, if the motor is “bumped” out of position it automatically corrects itself.
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Solution
High performance stepper drives from Applied Motion offer…
Encoder feedback options
Which contribute to…A more accurate motion control system
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Hardware
High Performance Stepper Drives from Applied Motion
ST Series
STAC6 Series
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Hardware
ST Series: Two power ranges
ST55 A/phase (peak)24-48 VDC input
ST1010 A/phase (peak)24-80 VDC input
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Hardware
ST Series: Three levels of control-S
Step & DirectionOscillatorHost command execution (SCL)SiNet Hub compatible
-QDrive with built-in motion controller
-SiDrive with built-in indexer
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Hardware
ST Series: -S modelsST5-SST10-S
Microstep EmulationTorque Ripple SmoothingElectronic DampingSmall size
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Hardware
ST Series: -Q modelsST5-QST10-Q
Microstep EmulationTorque Ripple SmoothingElectronic DampingEncoder feedback option
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Hardware
ST Series: -Si modelsST5-SiST10-Si
Microstep EmulationTorque Ripple SmoothingElectronic DampingEncoder feedback option
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Hardware
STAC6 Series: High power drive6 A/phase (peak)160 VDC bus110 or 220 VAC inputUL recognized (110 VAC)
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Hardware
STAC6 Series: Three levels of control-S
Step & DirectionOscillatorHost command execution (SCL)SiNet Hub compatible
-QDrive with built-in motion controller
-SiDrive with built-in indexer
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Hardware
STAC6 Series: Model NumbersSTAC6-SSTAC6-QSTAC6-QE (expanded I/O)STAC6-SiSTAC6-220-SSTAC6-220-QSTAC6-220-QE (expanded I/O)STAC6-220-Si
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Hardware
STAC6 Series: All ModelsMicrostep EmulationTorque Ripple SmoothingElectronic DampingEncoder feedback optionUL recognized (110 VAC units)
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By:
Visit
www.appliedwww.applied--motion.commotion.com
for more information
ELECTROMATEToll Free Phone (877) SERVO98
Toll Free Fax (877) SERV099www.electromate.com
Sold & Serviced By: