Brushless servo motors – more control for valves with linear actuators

Reprint of blog posted by Ryan Klemetson of Tolomatic on Tue, Mar 24, 2015 @ 08:03 AM

Many process industry control engineers are looking to more sophisticated motion control solutions for valve automation. That’s because there’s an ever-growing need to improve productivity, increase efficiency and minimize downtime. It’s essential that engineers be able to control the valves that regulate the flow of materials throughout a facility. Continue reading ‘Brushless servo motors – more control for valves with linear actuators’

Service robots use flat motors

maxon

Service robots for the disabled must be reliable, safe and easy to use.  The right motion system components are essential for these highly specific applications.

Unlike industrial robots for manufacturing, service robots come with their own specification requirements aimed specifically at the end user, and the most discriminating user at that—a human being.  That’s why designing and manufacturing service robots takes a particular set of skills and engineering expertise.  For example, when Canada-based Kinova Robotics creates designs for this market, the design team brings years of experience in the field.  And although they’ve modified the robots over the years, as new products and systems become readily available, they can produce higher quality and more useable products.  Using the latest technologies allows the designers to continue to advance offerings to the public.

The company’s Jaco2 Robotic Arm provides a lightweight, quiet and easily controlled device to the service industry.  The robotic arm moves around 6° of freedom through the use of six flat motors designed and manufactured by maxon precision motors.

The arm was designed using six joints from a shoulder-type joint through to a functional wrist joint.  The robot can manipulate a maximum payload of 1.5 kg at full extension, as well as a 2.5 kg payload at a mid-range extension.  Both of these payloads are adequate for the needs of most disabled people in the process of living a normal life.  The robotic arm device itself weighs only 5.3 kg, which was an important specification for it to mount to a wheelchair without tipping it over.

Because the first three joints must handle the highest torque for movement of the extended arm as well as for lifting items a user needs, the design team chose to use maxon’s EC 45 flat brushless dc motors.  These motors deliver a maximum continuous torque to 134 mNm (19 oz-in.) in a small, compact 70 W package. And since the Jaco2 needed to fit inside the robotic arm itself, there had to be less heat generated through motor operation—a huge benefit of the flat motors.  Although the motors can operate at very high speeds, that was not a necessary requirement for the application.  For the robotic arm to be manipulated efficiently, the device only needed to move at a speed of 20 cm per second, which translates to about 8 rpm maximum for the actuators’ outputs (about 1100 rpm for the motors).

The second three joints in the Jaco2 arm are also EC 45 flat motors, but are 30 W versions.  Again, they were chosen to help keep heat dissipation at a minimum, since the motors were mounted inside the arm itself.  Further, the flat motors were necessary because of the compact space allocated to the robot joints. The motor efficiencies were a critical point in selecting the EC series for the application.  Plus, according to one member of the engineering team, maxon was open to slight customizations, which allowed the team to fit the motors to the application perfectly.  Through the use of slip rings that were designed and manufactured in-house, each axis on the arm has infinite rotational capability.

Gearing for the arm incorporates harmonic drives translating to a 1:136 ratio for the large actuators in joints one and three, a 1:160 ratio for the large actuator in joint two, and 1:110 ratio for the small actuators located in joints four, five and six.

maxon2

The Jaco2 Service Robot uses three EC 32, 15 W motors to operate the finger of the robot.  Kinova engineers provided an in-house design for the lead screw mechanisms incorporated inside the fingers. The linear actuators had to be small due to the limited space available.  The actuators were designed in-house because the company’s engineering team found that it was less expensive to design the lead screws they needed than to buy them off the shelf from another vendor.  Although the flat motors have some minor degree of cogging, that did not affect the accuracy or other operations of the robot that would be critical to the user.  Quiet operation of the motors only added to their overall appeal for the application, especially because of the human-robot interaction. The company wanted the device to be as transparent as possible to a user.

All the motors in the arm are daisy chained using a single cable that runs through the system.  The tight form factor dictated the size and type of motor the design team could use.  The Jaco2 uses 18 to 29 Vdc for operation at 25 W nominal power (100 W peak power).  Control of the arm is performed through an RS485 (internal) and CANBUS (external) protocol. The system comes with two expansion card connectors for future use.

The controller features redundant security on each actuator/finger, redundant error check in actuators and control system, position and error calculation performed every 0.01 seconds, Cartesian and angular trajectory control, and force and torque control options.

maxon3

Each Jaco2 Robotic arm is controlled easily through the user’s wheelchair control or through a user friendly joystick, which provides the precision necessary for the human-robot interaction needed for the disabled person.  All the software required for the system was written by the Kinova Robotics engineering team so that the operation of the Jaco2 met all their in-house specifications and goals.  The software runs on Windows, Linux Ubuntu and ROS, and was written using C# and C++.

maxon precision motors, inc.
www.maxonmotorusa.com

Tags:  Maxon, Maxon Motor, flat motor, pancake motor, service robot, Kinova, Jaco, Jaco Arm, BLDC motor, Kinova Robotics

Motors deliver higher power density for compact robots

Kuka’s compact robots in the KR Agilus series are precise, agile and fast.  As agile systems, these five-axis and six-axis handling units feature short cycle times and high repeatability, particularly for pick-and-place tasks.

Synchronous servomotors from Kollmorgen’s AKM series play a major role in achieving this precision. Using collaborative co-engineering, the two companies reduced the installation volume of the motors compared to standard models.  The performance of the robots within their rated load range sets new standards for speed, cycle times and energy supply.  They can even handle unusual tasks in base and cover installation positions. Kollmorgen developed the custom motors by adapting motors from the standard AKM servomotor series.

As fast all-rounders, the robots are suitable for general industrial applications.  With a dead weight of 51 kg, the basic model can support loads up to 6 kg.  The compact robots are suitable for process automation in the packaging, electronics, food and pharmaceutical industries.

“We made a significant contribution to short cycle times and high precision by adapting our servomotors from the AKM series to Kuka’s specific needs,” said Theo Loy, sales manager at Kollmorgen.

The co-engineering partner adapted the design of the synchronous servomotors to make them fit perfectly in the joints of the robots.  That also enabled the engineers to increase the already high power density.

The objective was to find ways to implement custom performance improvements and structural assembly adaptations without sacrificing the advantages of industrial series production.  The aim was to optimize standard motors by making controlled modifications.  With custom adaptations, such as cable strain reliefs, modified bearing shells, Kuka-specific connector configurations or special drilled holes in the output shaft, the motor manufacturer could reliably maintain the majority of its standardization.  But is that still possible when the entire design geometry is fundamentally changed?

Using the smallest servomotor in the AKM series, it had to be made even thinner to fit compactly into the wrist joint of the robot.  The co-engineering process started off with 3D models and outside contours, and in the end it involved working with detailed design data.

To make things easier for the customer in the Kuka project, Kollmorgen also incorporated the engineering expertise of its own suppliers, such as a specially adapted motor brake.

“It acts as both a holding brake and an emergency brake,” said Loy. The KR Agilus is the only robot in its class that features Kuka’s Safe Operation function, which drastically simplifies human-robot interaction.

The AKM series of high-acceleration, permanent-magnet servomotors are available in 28 housing and mounting combinations.  They also feature reduced energy consumption, high control accuracy and high availability, and they are compatible with all commonly used supply voltages thanks to specifically adapted stator windings.

Information on the AKM Brushless Servo Motors can be viewed at the following webpage-

AKM Series Product Information

For more information, please contact:

EDITORIAL CONTACT:
Warren Osak
sales@electromate.com
Toll Free Phone:   877-737-8698
Toll Free Fax:       877-737-8699
www.electromate.com

 

Tags:  Kollmorgen, AKM, Servo Motor, BLDC Motor, Electromate, AKM Servomotor

Stepper Motor Primer

Stepper Motors from Electromate

Stepper Motors from Electromate

There are three basic types of step motors: variable reluctance, permanent magnet and hybrid.  A hybrid step motor is a simple low cost means of providing good motion performance.  Step motors are electromechanical devices that work by dividing shaft rotation into discrete distances called steps. Basically, they are brushless motors which include permanent magnet variable reluctance and hybrid types.  Most step motors are hybrids and feature 200 steps per revolution (1.8 degrees). The magnetic structure of the motor is designed to be incremental in nature i.e one pulse to the motor causes the armature to move one complete step.  At power up, a hybrid step motor could rotate up to ±3.6 degrees in either direction due to the rotor having 200 natural detent positions….

Click on the link below to download this complete white paper.

http://www.electromate.com/db_support/downloads/StepperMotorPrimerv2.pdf

For more information, please contact:

EDITORIAL CONTACT:

Warren Osak
sales@electromate.com
Toll Free Phone:   877-737-8698
Toll Free Fax:       877-737-8699
www.electromate.com

 

Tags:  Step Motor, DC Step Motor, Stepper Motor, BLDC Motor, Automation, Motion Control

Pre-recorded Webinar. EtherCAT as a Master Machine Control Tool

YouTube 50minute Video by Galil Motion Control

Topics include an overview of the communication scheme, physical layout and applications where EtherCAT is the right solution.

There is an increasing demand in the automation and motion control industries for a localized motion control solution that can coordinate motion between multiple remote components. Previously, field bus protocols such as Modbus or Ethernet/IP have been implemented to address remote I/O connectivity. Although successful in moving data across automation networks, these protocols lacked the real time performance necessary for a distributed motion control system.

The EtherCAT communication protocol provides a high speed, low overhead communication scheme that allows efficient, deterministic communication between motion controller and remote components. Based on CANOpen and streamlined specifically for point to point transmission of real time data, the EtherCAT standard is quickly becoming the preferred choice for centralized control of tightly coupled motion between remote components. This presentation is aimed at designers of automation and motion control systems with a basic understanding of Ethernet/IP and EtherCAT communications. Topics will include an overview of the communication scheme, physical layout and applications where EtherCAT is the right solution.

Webinar Presenter: Matt Klint, Galil Motion Control

To watch this pre-recorded Webinar, click on the link below.
https://www.youtube.com/watch?v=NNh-dA3LH-o

 

Tags:  EtherCAT, Machine Control, Motion Control, Electromate, Galil, Galil Motion Control, Webinar

Evolution of Ethernet in Control Systems

A new white paper by Galil Motion Control

Ethernet was developed in the 1970’s and was started being used commercially in the 1980’s.  By the end of the 1980’s it was the dominant network technology.  It was initially used to connect computer systems and peripherals in a Local Area Network (LAN) and quickly evolved to be the protocol used for Wide Area Networks (WAN).  Then came the world-wide web and the incorporation of the internet into every aspect of communication.

In the mid to late 1990’s, Ethernet’s popularity spread to control systems.  The engineering team here at Galil Motion Control determined Ethernet was a viable protocol in 1999 and introduced its first Ethernet Motion Controller.  Even today, Ethernet is the most popular method of network communication in control systems….

Click on the link below to read this complete white paper article-

http://www.mydigitalpublication.com/publication/?utm_source=MAN-eblast&i=228662&utm_campaign=141016G&utm_medium=email#{“issue_id”:228662,”page”:10}

Power Supply Selection for Servo Amplifiers

White Paper reprint: by Rene Ymzon, Advanced Motion Controls

 

There are several factors to consider when selecting a power supply for servo amplifiers.

1. Power requirements

2. Isolation

3. Regeneration

4. Voltage ripple

Power requirements refers to how much voltage and current will be required by the amplifier(s) in the system.  Isolation refers to whether the power supply needs an isolation transformer.  Regeneration is the energy the power supply needs to absorb during deceleration.  Voltage ripple is the voltage fluctuation inherent in unregulated supplies.

Each consideration is discussed in detail in the following pages [click on the link below…]

http://www.electromate.com/db_support/downloads/ApplicationNote-PowerSupplySelection.pdf

EDITORIAL CONTACT:
Warren Osak
sales@electromate.com
Toll Free Phone:   877-737-8698
Toll Free Fax:       877-737-8699
www.electromate.com

 

Tags:  servo amplifier, power supply, power supply selection, isolation, voltage ripple, regeneration

 


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