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Sin/Cos Encoders and Sinusoidal Drives help Galil Controllers Achieve Ultra-Precise Motion May 18, 2013

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Introduction

The use of linear motors for precision motion applications has increased as technology has improved.

Galil DMC-31012 Motion Controller

Galil DMC-31012 Motion Controller

A linear motor typically uses a servo drive with sinusoidal commutation to minimize torque ripple and provide quiet smooth motion. It is also becoming more common for linear motor manufacturers to provide position feedback in the form of an analog sin/cos encoder as this method uses the signals from the motor magnets and is more cost-effective.  Galil motion controllers now provide options for sinusoidal drives and interpolation of sin/cos analog feedback for smooth control of ultra-high performance applications.

Galil controllers use an intelligent interpolation algorithm allowing inexpensive sin/cos signals to be used successfully in high-precision applications.   The AF command is used to set the analog feedback resolution at 2n counts/period. Galil drives perform sinusoidal commutation and are easily programmed using a choice of three different commutation methods.  An example showing how to configure Galil controllers and sine drives for use with linear motors with sin/cos encoders is below.

An example of a Galil Controller used with a Copley ServoTube Linear Motor

Galil’s DMC-31012 motion controller with an internal 800W sinusoidal drive and sin/cos feedback interpolation option was used  in an application with a Copley ServoTube linear motor with  sin/cos encoder. The goal was to move a stage and maintain a position accuracy of .04mm.   The stage manufacturer specified a 25.6 mm/sin feedback period for the encoder signals which is equivalent to the motor’s magnetic cycle.

The AF command was used to interpolate the analog feedback at 2n counts/period. N= 10 was used for this application.  AF 10 provided an interpolation of 1024 counts/period.  The system position resolution can be calculated using the equation below:

Resolution = 25.6mm /1024 counts = .025mm/count

.025mm/count resolution is within our target accuracy of .04mm.

It’s important to note that sin/cos feedback sensors are analog and more prone to noise compared to a digital signal. The DMC-31012 allows an AF of 12 but AF 10 was chosen because it met the accuracy specifications while minimizing the affect of noise.

There are three methods to initialize sinusoidal commutation with Galil sinusoidal drives, BI, BZ and BX.  For this application, the BZ command method was selected because it was better for high static friction. The BI command, which uses halls to initially commutate, is ideal in most cases but the Copley motor did not provide Hall sensors.

Another parameter used for commutation was the BM command.  BM is the brushless modulus of the system or the length for which one magnetic cycle completes. For the Copley ServoTube, the motor’s sin/cos period is the same length as the motors magnetic cycle.  For AF 10, the setting for BM is 1024.

Once AF, BZ and BM were configured during initialization, the controller system was tuned for optimum performance using the GalilSuite tuning software.

Galil controllers with the sin/cos feedback option and sinusoidal drives provide a good solution for controlling linear motors with a high degree of accuracy and extremely smooth commutation. Sinusoidal drives and sin/cos feedback options are available on Galil’s DMC40x0 multi-axis controller and the DMC-31012 single-axis controller.

For more detailed information, see application note #5523 “Connecting to a Linear Motor with Sinusoidal Commutation and Sin/Cos Feedback.” http://www.galilmc.com/support/appnotes/miscellaneous/note5523.pdf

For additional information on the DMC-31012 from Galil can be found at-

http://www.servo2go.com/product.php?ID=105334&cat=

For more information, please contact:

Editorial Contact:

Warren Osak
sales@servo2go.com
Toll Free Phone:  877-378-0240
Toll Free Fax:   877-378-0249
www.servo2go.com

Galil DMC-40×0 Accelera Series Now Available with 2 Ethernet Ports May 2, 2013

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Galil has just released the latest model in the DMC-40×0 Accelera Motion Controller Series. There is now a -C022 option that provides two Ethernet ports for easy-daisy chaining of multiple controllers. The -C022 option is available for 1- through 8-axis versions of the DMC-40×0 motion controller. For example, DMC-4060-C022 specifies a 6-axis model with dual Ethernet ports.

Galil DMC-4000 Motion Controller

The DMC-40×0 is part of Galil’s latest generation Accelera series. Based on a powerful RISC processor Accelera controllers provide ultra high-speed with 40 microsecond command processing,  up to 32kHz servo update rates, and acceptance of encoder inputs up to 22MHz. Other features include optically isolated inputs and outputs, high power outputs for driving brakes and relays, uncommitted analog inputs, dual encoder inputs for each axis, and plenty of program memory for storing application programs.

The DMC-40×0 provides precise control of a variety of motors including brush servos, brushless servos, steppers and piezo ceramic motors. It can be easily connected to external drives of any size or to internal multi-axis drives contained within the DMC-40×0 controller.  The DMC-40×0 controllers with internal drives reduce space, cost and wiring. Table 1 shows the  multi-axis drive options available for the DMC-40×0 series.

Internal multi-axis drive options

As a combined controller and drive unit, the DMC-40×0 is compact and measures 8.1” x 7.25” x 1.72” for the 4-axis model and 11.5” x 7.25” x 1.72” for the 8-axis model. The unit accepts power from a single DC supply between 20-80VDC.

For additional information on the DMC-40×0 Accelera Series and new -C022 dual Ethernet port option, see

http://www.servo2go.com/product.php?ID=101658&cat=

For more information, please contact:

Editorial Contact:

Warren Osak
sales@servo2go.com
Toll Free Phone:  877-378-0240
Toll Free Fax:   877-378-0249
www.servo2go.com

RIO-47300 Pocket PLC Has 48 Digital and 16 Analog I/O, and Two Ethernet Ports January 25, 2013

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On the heels of the recently released RIO-47142 comes the new RIO-47300 which is an expanded model that includes two Ethernet ports, more I/O, and screw terminals.  The RIO-47300′s Ethernet ports allow an unlimited number of RIOs to be daisy-chained together without an external Ethernet switch. The RIO-47300′s memory allows 400 program lines, 254 variables, 1000 array elements, 6 PID control loops and 5 Ethernet handles.   Digital inputs and outputs on the RIO-47300 are increased from 16  to 24 each for a total of 48 optically isolated digital I/O. All the digital outputs are high-power 500mA outputs. The 16 analog inputs and outputs are user-configurable for +/-10V, +/-5V, 0-10V or 0-5V.

Galil RIO-47300 Pocket PLC

Galil RIO-47300 Pocket PLC

The RIO-47300 uses screw terminals for quick and easy prototyping.   Dimensions of the RIO-47300 are 10.8” x 4.7” with DIN tray.   The RIO-47300  is $495 US in single quantity and $360 US/ea in quantities of 100.

Galil’s RIO Pocket PLC series provides a cost-effective, compact and intelligent solution for programmable I/O control.  Standard features of the RIO series include a RISC processor for fast handling of I/O and logic, multitasking, PID process control loops, timers, counters, web interface, email alerts, datalogging, Ethernet and RS232 ports, LED indicators for all digital I/O ports, and an option to interface to position sensors, thermocouples and RTD temperature sensors.   The RIO is easy to program using Galil’s intuitive command language or Galil’s Ladder Interface Software.   The complete list of RIO-47300 features is listed in Table 1.   Table 2 shows currently available RIO models.

More information on RIO-47300 Series from Galil can be found at the link below-

http://www.servo2go.com/product.php?ID=102190&cat=

For more information, please contact:

Editorial Contact:

Warren Osak
sales@servo2go.com
Toll Free Phone:  877-378-0240
Toll Free Fax:   877-378-0249
www.servo2go.com

Galil DMC-4080 Helps Guide Remote Controlled Vehicle Used in Hyper-Realistic Military Training September 26, 2012

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There’s a big lump in the throat of the infantryman as he sees the dented, dirty sedan quickly approaching the checkpoint after exiting the bomb-riddled village and well-known terrorist stronghold.  With his M-16 poised and adrenaline rushing, he peers in to identify the driver behind the dusty windshield.  Is this the enemy?  Are these civilians?

A warning shot is fired, but the car speeds up, and shots to flatten the tires are not slowing this maniac down.  The soldier fires again.  This time, the windshield bursts and blood splatters from the driver’s forehead as the sedan screeches to a halt.

For the infantryman, he can breathe a sigh of relief.  Not only for a job well done, but because he also knows that the village and enemy combatant isn’t real—no matter how real it all seemed at the time.

The sedan is primarily made of hardened foam.  The enemy is a dummy—literally.  Even the blood isn’t real

They’re all props set up by Strategic Operations, Inc. (STOPS), a San Diego-based company specializing in creating Hyper-Realistic™ training environments for military, law enforcement and homeland security operations.  Since 2002, the company has provided such training to over 450,000 Marines, soldiers, sailors and Coast Guard personnel to prepare them for the battlefields of Iraq, Afghanistan and other hostile places.

“Our company uses movie-industry special effects along with actual military tactics, and provides everything you can think of to re-create wartime environments with hyper-realistic scenarios.  This includes props ranging from full-out villages, buildings and vehicles to live actors and realistic dummies with all the fake blood, guts and weaponry.  The purpose is to train the military by placing them in action-packed, real-life combat situations so they can respond quickly and without panic, and be prepared and sensitized for any battlefield situation,” said Kit Lavell, Executive Vice-President of STOPS.

There appears to be no limits when it comes to the level of “hyper” realism.  For example, to simulate the horror of combat wounds, the company has employed amputee actors who will wear prosthetic limbs designed to fly off with “blood” spurting when they are shot or blown-up.

“Participants (trainees) so willingly suspend disbelief that they become totally immersed and, eventually, stress inoculated,” Lavell adds.

Adding to this realism is STOPS’ Ballistic Unmanned Ground Vehicle (BUGV) used for preparing soldiers for live-fire vehicle check point/entry control point scenarios, for sniper training, and for dealing with vehicles that have been converted into mobile bombs.  It features an expendable lightweight foam body that can be designed and formed to simulate a sedan, taxi, bongo or pickup truck and more.  It rests on a ballistic steel frame capable of holding up against a barrage of real .50 caliber bullets.

Of course, no live driver sits in the BUGV; just hyper realistic foam mannequins of all nationalities.  Real people, of course, are employed to operate the vehicle via a sophisticated remote control device, with key driving functions managed by a DMC-4080 8-axis Ethernet motion controller from Galil Motion Control, Rocklin, CA.  The controller also incorporates two Galil D3040 4-axis, 500W drives with each capable of operating at voltages between 20V and 80V.

Three of the axes of the Galil controller control the steering, shifting and throttle actions, while a fourth axis is used for additional steering requirements. Another axis is used for controlling a machine gun mounted inside the vehicle and which fires blanks at the trainees.  The remaining three axes are reserved for testing and other features. STOPS uses some of the controller input/output (I/O) to operate relays that energize such functions as the ignition or turn signals.

A key factor why STOPS specified the Galil controller is its ability to function with utmost reliability inside a vehicle subject to extremely harsh conditions, like wide-ranging temperatures of -10°C to 65°C; dusty, loose and uneven terrain; real ammunition and explosives; and chemicals.

For STOPS, failure is not an option with the controller.

“The overall robustness of the Galil controller is impressive,” said Lavell, who liked how the Tell Torque feature of the DMC-4080 takes readings from the motor of the BUG-V to determine the harshness of the terrain it is on, and then delivers its findings to the remote control “driver” so he can either ease down or rev up the engine accordingly.

Other Galil features play significant roles in operating the BUGV, such as the Homing Routine and Limits feature which allows for safe power-up of the vehicle and re-centering of the wheels for each training session.

“We also use Galil’s Position Tracking Mode to send position data streams from the host to the four axes used for driving the BUGV.  The data throughput is excellent, with no issues, no latency,” said Lavell.

STOPS engineers found the native Galil programming language easy-to-use, which helped enable them to incorporate several safety routines into the operating system.  For example, whenever the controller does not receive a data stream, it goes into a fail-safe routine that brings the vehicle to a stop.

The BUGV is proving to be an effective way to prepare soldiers for combat in urban environments.  Officially referred to as “Military Operations on Urbanized Terrain” or MOUT, these are military actions planned and conducted on a terrain complex where man-made construction such as residences and buildings, along with increased population (as opposed to rural areas), affects the tactical options available to the commander.

“A checkpoint in Afghanistan is a typical MOUT scenario,” explained Lavell.  “When a vehicle approaches, the Rules of Engagement go into effect.  If the vehicle doesn’t respond to a warning shot within a certain number of meters, then there is an escalation of the response: first, fire a warning, then shoot the tires, then shoot the engine block, and then shoot the occupant.  This is quite challenging to train for because in the field the aspect ratio of the approaching vehicle is difficult to judge.  The Hyper-Realistic training simulation using the BUGV helps the training solder see what the approaching vehicle looks like at 300 meters, then 200 meters, then 100 meters and closer.”

It turns out that having the increased use of a training vehicle like the BUGV doesn’t just train soldiers to become more effective fighters, it also helps to increase their own survivability.  According to the Defense Science Board, the probability of being a casualty decreases significantly after the first few “decisive combats.”

Typically, STOPS takes a week’s time to customize a MOUT training system, including re-creating enemy villages.  “We can create real environments that look like any place in the world, such as in Afghanistan or Iraq.  The buildings and villages are not only realistic, they are modular so they can quickly be built and re-built after they’ve been shot or blown up,” said Lavell.

For more information on the Galil DMC-4080 Controller, click on the link below-

http://www.servo2go.com/product.php?ID=101658

For more information, please contact:

Editorial Contact:

Warren Osak
sales@servo2go.com
Toll Free Phone:  877-378-0240
Toll Free Fax:       877-378-0249
www.servo2go.com

Galil Controller Used to Help Paraplegic Surgeon Perform Operations Again July 24, 2012

Posted by Servo2Go.com in News & Events.
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Every so often, Galil is given the opportunity to support an application that can truly change the life of others. This last spring, Galil was contacted by a group of students from the University of Wisconsin asking for us to help them create SPOT. SPOT, which stands for “Standing Paraplegic Omni-directional Transport” is a project aimed to help Dr. Garret Cuppels, a 37-year-old orthopedic surgeon, return to the emergency room after a tragic fall in 2010 that damaged the thoracic region of his spine and left him paralyzed from the waist down. Since the SPOT device is to be used in the emergency room it had a specific set of requirements that other standard wheel chairs could not satisfy:

  • That it could comfortably place Dr. Cupples in a standing position leaving his arms free to perform surgical tasks.
  • That the design was small and extremely mobile; specifically, that the device could “side-step” or move left or right.
  • That the system be easily controlled via joystick.
  • Lastly, that brakes on each of the four wheels be automatically turned on when the device is not in use

These requirements drove the University of Wisconsin team to utilize the unique properties of Mecanum wheels1 and to seek out Galil’s small, easy-to-use, and flexible DMC-4143 four-axis motion controller. The operator of SPOT will control the vehicle using a simple joystick. The joystick outputs two 0-5V analog signals proportional to how far the user is pushing the joystick either left-and-right and up-and-down. The analog signals are connected into two of the 8 available 12-bit analog inputs on the DMC motion controller. The DMC-4143 is programed to jog each of the four Mecanum wheels motors different directions and speeds depending on this simple operator input.

The multithreaded capabilities of Galil’s products allow both analog signals to be read simultaneously allowing the jog speeds for each motor to be updated in ultra-tight loops. The team also utilized four of the 8 opto-isolated digital outputs to control the brakes. A single command, the BW (brake wait) command, is issued which automatically enables the brakes when the motors are turned off—an important safety requirement for the application.

The team’s use of engineering to assist another in need has beckoned industry wide support and national attention. The SPOT project was recently featured on WGN news which can be viewed at  http://youtu.be/ipNWTfnqVV0. As the team continues to move forward on their application they continue to receive both help from Galil Support Team and from other industry leaders. To follow the team’s progress or to make a contribution, go to the SPOT’s website at http://bmedesign.engr.wisc.edu/websites/project.php?id=464

or their sponsorship page here  http://www.fundly.com/uwbiomedicalengineeringdesign.

Galil owes a special thanks to the University of Wisconsin Team for allowing us to be involved with their project to help get Dr. Cupples back in the ER. Thank you Professor Amit Nimunkar, Michael Konrath, Bret Olson, Justin Cacciatore, Blake Marzella, and James Madsen.

For more information on the motion controls from Galil Motion Control, click on the link below:

http://www.servo2go.com/supplier.php?id=1031080104

For more information, please contact:

Editorial Contact:

Warren Osak
sales@servo2go.com
Toll Free Phone:  877-378-0240
Toll Free Fax:       877-378-0249
www.servo2go.com