Animatics Corp. Publishes New Motion Systems Catalog

Animatics Corporation has published a new 145 page catalog on their expanded line of Motion Systems Products and Peripherals. This comprehensive catalog includes eight product segments fully detailing SmartMotor™ specifications, FieldBus Protocols, Brake Options, Connectivity, Peripherals, Power Supplies, Gear Heads, and Software.

Included is an expanded, dynamic fold out selection chart comparing all the different SmartMotor frame sizes and lengths. Torque curves are now presented at three different input voltages with superimposed, easy-to-read power curves to help optimize use of the increased SmartMotor power for your application.

A new section includes Application Examples illustrating the numerous SmartMotor product features and capabilities. Design guides and conversion charts make the catalog an essential application development tool.

Also featured is information on the Animatics Institute which offers in-depth training programs covering SmartTechnologies™ and Sales and Marketing strategies for Smart products and systems.

Animatics Corporation
www.animatics.com

Electric Vehicles and Electric Motors

A friend of mine finally got delivery of a Tesla Roadster.  This prompted discussion of the drive train and the fact that Tesla has had to go from two speed transmissions which were failing to a transmissionless drive train.  The ultimate mechatronic challenge, the electric car, is also a challenger in terms of the precise  application of electric motor technology.

But it has to be said that the motor and drive solution for the electric car is not where the problem has to be solved.  Any motor can be made to run an electric car.  What is critical is how you apply it.  The starting conditions require high torque at low speed and the running conditions require low torque at high speed.  So, typically, what looks like a small 5 to 15 horsepower running requirement at full speed, becomes a 150 horsepower starting requirement depending on how quickly you would like to start.  If you want to keep up with a Corvette, it uses 450 HP to start.

And this produces a lot of confusion.  Why not use at 2 speed transmission to help the situation.  Fine, but the ones that are available can’t handle the dynamic response of the electric motor.

Can electronics help this situation?  Interestingly, yes.  There is a control algorithm generally called vector control which allows you to manage the rotor torque and stator torque separately.  By varying the phase angle between the two, like advancing and retarding the timing of a mechanical distributor cap on an internal combustion engine, you get different speed torque curves out of the motor.  COOL!  Is there any downside to this?

Yes.  You need more current to produce more torque.  That doesn’t change.  So you have to be able to supply the current, and you have to be able to manage the heat.  The heat is transitory since you only need the high current during starting, but it is best to have sophisticated software running to keep track of the RMS temperature of the motor.  Lower operating temperatures mean longer life and reduced risk of demagnetizing the motor.

So, yes, you can run an electric car with a garden variety AC motor, and with good electronics, you can make it run fairly efficiently.  With higher efficiency motors, the benefit is increased driving range from a given power source.  High efficiency motors are frequently smaller and lighter weigh, but a weight savings in the motor of 50 or even 100 pounds is not that big a factor in the driving range when the curb weight of the vehicle is 3000 pounds.

Basically, its F=ma.  If you can reduce the mass of the vehicle, you reduce the battery payload required to power the car.  Aluminum space frames, like on the Prowler, have been studied by the car industry and can reduce curb weight by 400 pounds and reduce cost by 10% at the same time.  We need to bring all the mechatronic leverage to the situation that we can, if we are going to make electric cars that make sense.  Before its too late for Detroit.

Super Size my Motor?

There is an interesting problem with applying electric motors that is a constant source of difficulty, the nature of peak power versus continuous power.  The problem is that few systems operate at a statistical average power demand.  Frequently, this causes equipment designers to oversize the motor for the application.  At the same time, however, this can put the motor in a very low efficiency operating range.

So what’s the right solution?  Right sizing.  Yes, just like Goldilocks and the Three Bears, not too big, not too small, but just right.

There are some great DOE publications on motor sixing that can be very helpful on the AC motor side, so make sure to give those a look.  But the implications of how to deal with varying loads are complex, each requirement having its own unique conditions that need to be considered.  Is an underpowered application actually safer?  Sometimes, yes.  I recently noticed that a particular orbital sander had been designed so that if the unit became momentarily overloaded, it stalled.  Perfectly safe.  In fact, this design is to be preferred because it prevents accidentally damaging a work piece by burying the sander in the wood and removing too much material.  Who’d have thought of it?  Certainly not Tool Time Tim.  More Power!

In fact, most of us view more as better.  More power means more production.  Or does it.  In an increasingly energy conscious community, more power means more cost.  And that’s really what its all about.  The value of the motor is not just in the purchase price, but also in the operating cost.  Especially if the motor is expected to run for 8 years, 24/7.  (That’s what the life expectancy of large AC motors is)

There’s another trick to the power requirement problem.  How much time is spent at full load and how much time is spent at average power, or, what is the duty cycle?  If the system is starting and stopping frequently it puts different constraints on the motor.  If the system is typically starting only once an hour, then we can consider the thermal duty cycle of the motor.  The momentary peak power requirement is insignificant and the vendor can usually tell from their modeling and testing of their products how much impact the peak current will have on the motor’s average temperature.

After all, its Thermodynamics 101 in the final analysis.  Every energy transformation produces heat as a byproduct.  How much heat a given system can tolerate is the key to its operating life.  In electric motors, the key values are the insulation system’s temperature rating, usually in the range of 150 to 180 C and in the case of steppers, brushless dc and permanent magnet dc motors, the magnet’s ability to resist high temperature and high coercive magnetic fields that can be generated in the motor.  Both sets of limits are generally well considered by suppliers when electrically controller motors are shipped as motor/drive combinations.  This can get a little tricky when pairing motors from one vendor with controls from another vendor.

Top 10 Mechatronic Challenges

I recently wrote on the mechatronic challenge of wind power.  Converting wind into mechanical power that can be harnessed for man’s use has been going on since the 9th Century according to Persian historians.  Certainly wind powered grinding of grains has been around in Europe for several centuries and, lest we forget, wind power pumping of water in the United States.  So there is some irony to the cultural “buzz” about wind power at home and abroad, as if the technology were entirely new.  There’s a lot of history, we’re just updating the technology to produce energy in the age of electricity.

Water has been used for power generation as well.  Following a similar path, we learned during the early part of the industrial revolution how to locate manufacturing plants near waterways so we could convert water flow into mechanical power using the water wheel.  This is, in fact the root of all modern motion control.  All the belts and pulleys, cams, gear reduction systems follow from the work done in mechanical engineering from this period of time.  All of the electronic analogs of the mechanical behaviors found in mechanical systems are the functions which we refer to in mechatronics today.

Wind power and water power gave way in the 1800’s to steam power as the improved steam engine of Watt became the standard of energy efficiency, or should I say “cost effectiveness”.  Because the absolute value of technology is in its cost effectiveness.

Still, wind energy poses a huge technology challenge, as witnessed by the number of vairations that exist and new versions that are emerging.  And hopefully improvements will continue to come from the creativity and  imagination of engineers and inventors all over the world.

But what are the other big mechatronic challenges that come to mind?

Transportation certainly ranks in the top 10.  We have seen hydraulic, pneumatic and electric vehicle solutions touted for a variety of uses, personal transport, delivery vehicles etc.  Ballard Energy and General Motors have both been building hybrid and pure electric buses for city transportation systems for several years with some success.  Interestingly, the electric bus is easier to engineer, which seems unreasonable, but the bus has more interior space to put things like batteries and a methanol converter for generating hydrogen for fuel cells.

But there is a great lesson in what appears to be an almost chaotic string of choices in the transportation arena.  One solution will not work for all requirements.  There are many people for whom a 40 mile per day drive cycle is perfect.  The NEV, Neighborhhod Electric Vehicle, is a golf cart type solution that is rated for street usage, and because of its relatively simple performance requirements, is relatively easy to achieve and lowe cost.  As we categorize cars with greater range, the problems get more difficult, and because of the storage limitations of batteries, have only been achievable as hybrids.  But with some hybrid designs reaching 50 and 60 mpg (estimated), these vehicles may be great solutions for other users.  Although, we must consider their cost effectiveness.  If they cannot be introduced at prices well below $50,000 the absolute value of the technology is not very good.

So forget the 15 second soundbyte that will solve the world’s problems.  It doesn’t presently exist.

I would like to hear from any readers about their picks for the Top Ten Mechatronic Challenge.

A Key to Successful Production-Integrated Measuring – the Encoder

By Reinhard Kuhn
HEIDENHAIN, Traunreut
Product Manager

An encoder’s coefficient of expansion and its tolerances will play a more significant role in future ISO standards for classifying coordinate measuring machines.

A measuring room offers optimum conditions for precise measurements. But it has several disadvantages including high costs for the room, the machine and temperature stabilization, as well as interruption in the flow of production.

Customers continue to push to install more control over the manufacturing process. Part of this push involves placing the measuring machine spatially closer to actual production, a modification known as production-integrated measurement. Through such a modification, measurement results can go “online” into the control of production and thereby affect the precision of the manufacturing process.

However, the harsh nature of a typical manufacturing environment places new requirements on measuring machines. These requirements either did not exist or were less critical in the sheltered surroundings of a measuring room.

Measuring machines on the shop floor are exposed to changing temperatures and more difficult ambient conditions. Shock, vibrations, and contamination occur often. Manufacturers of measuring machines are responding to these requirements with various designs and approaches. However, all are in agreement on one point: Deviations from the 20° C reference temperature specified in DIN 102 change the length and angle on both the work piece and the measuring machine, and these changes must be mathematically compensated.

KNOWN BEHAVIOR
The defined, reproducible thermal behavior of the encoder is indispensible for accounting for such deviations. The encoder’s coefficient of expansion and its tolerances will play a more significant role in future ISO standards for classifying coordinate measuring machines (see ISO TC 213-WG 10).

Thermal expansion = change of length – an unknown quantity

The coefficient of expansion, or deviations from it, influence the use of encoders on measuring machines. Encoders usually feature measuring standards of steel, glass, or glass ceramic.

The relevant literature provides data for the coefficients of expansion; however the data given differ significantly from source to source. Thus, their utility as a basis for length compensation is limited, as becomes visible in the data for steel, for example. A temperature change of even a few degrees can result in deviations of several micrometers in compensation values calculated from an inaccurate coefficient of expansion.

The scanning heads for the LIDA 400 are a standard size, so they meet all requirements for reading the scales of glass and glass ceramic. Also, the identical cross section of the scales allows the graduation carriers to be exchanged.

POSSIBLE METHODS OF ASCERTAINING THE COEFFICIENT OF EXPANSION α
A coefficient of expansion can be measured exactly by a dilatometer, which is a device for measuring thermal expansion. With a well-designed dilatometer it is possible to attain exact data on a material’s coefficient of expansion by measuring a test object and use it to manufacture encoders.  An example is the “alpha measuring station” for measuring the thermal length expansion of bar-shaped bodies. Such a measuring station has been set up at the Physikalisch-Technische Bundesanstalt, Germany’s national metrological institute in Brunswick.

This exactly measured value can then be applied to calculate length compensation. In most cases, companies manage as best they can with data from the literature or the material manufacturer. This makes uncertainty in the result inevitable.

TEMPERATURE AND ACCURACY COMPENSATION
Special care must be taken in setting up a shop-floor measuring machine. Years of experience by the manufacturer result in high reliability and ensure high accuracy in spite of harsh environmental conditions. No compromises in accuracy are made compared with machines in measuring rooms.

Thermal effects must be dealt with through the appropriate know-how, the selection of suitable materials, and providing for thermal requirements. Because temperature increases expand materials to different degrees and these materials take on the surrounding temperature at different speeds, complex calculations are conducted to compensate the effects of temperature and accuracy. A known basis for mathematical compensation is very important—the linear encoder.

Thermally stable encoders are an indispensible prerequisite for basing calculations on accurate measurement data and thereby achieving accurate compensation. The selection of encoder material for shop floor measuring machine is therefore particularly important. While glass or steel scales permit only an approximate value for calculation, the expansion coefficient of 0+/- 0.1 x 10-6K-1 ZERODUR® for glass ceramic scales remains accurate over a large temperature range, and the scales have proven to be durable. The material is used the world over on telescopes, for example, because they place very high requirements on resistance to temperature changes and on distortion-free imaging.

THERMALLY STABLE ENCODERS
The right encoder enhances machine characteristics and contributes significantly to the reliability of the measuring machine. The area of production-integrated measurement is characterized by the following requirements and characteristics:

• Encoders with defined coefficients of expansion
• High accuracy for deviation between compensation points
• Minimal contamination for disturbance-free measurement
• High reliability over a long time period
• Cost-efficient encoders

One type of encoder that meets these requirements is the LIDA 400 exposed incremental encoder. Features include high accuracy and liberal mounting tolerances, high traversing speed, and the small height of the scanning head.

These attributes make it well suited for use on production equipment in automation engineering and the electronics industry as well as for applications on linear drives and in many areas of metrology.

The introduction of new graduation carriers of glass and glass ceramics, such as ZERODUR® and ROBAX®, have expanded the range of applications covered by encoders. They therefore suit applications in shop-floor measuring machines. They are easily installed by the PRECIMET® adhesive film on the back.

The scanning heads for the LIDA 400 are a standard size, so they meet all requirements for reading the scales of glass and glass ceramic (ZERODUR®, ROBAX®). No special scanning heads are needed. Also, the identical cross section of the scales allows the graduation carriers to be exchanged. From the logistical point of view this is a great advantage because the standard LIDA 48 (1 VPP) and LIDA 47 (TTL) scanning heads can be combined with glass ceramic and glass scales as well as with steel scale tapes. The identical carrier cross section of glass ceramic and glass scales make it possible to upgrade existing measuring machines. All designs have the same scanning surface of 14.5 mm², which ensures high tolerance to contamination and generates very clean scanning signals, which can be highly interpolated.

The encoders of the LIDA 400 series have a grating period of 20 µm. They are available in the widely used 1VPP and TTL interfaces and for measuring lengths of up to 30 m (steel) or 3 m (glass and glass ceramic). Traversing velocities up to 480 m/min are possible. The encoders are available with
reference marks as well as integrated magnetic limit switches.

Today’s changing requirements on machines such as measuring machines or production equipment in the electronics industry call for encoders that are also capable of meeting these demands. The problem of thermal expansion can be solved by the proper selection of different graduation carriers that are uniformly capable of using the same model of scanning head.  In conjunction with measuring standards of glass and glass ceramic, the new generation of LIDA 400 exposed linear encoders offer ideal properties for accurate measurement even on shop floor and in production-integrated machines.

HEIDENHAIN
www.heidenhain.com

________________________________________________________________________________________

The METALLUR process

HEIDENHAIN has developed a process—known as the METALLUR process—for manufacturing graduations on glass, glass ceramic, or steel.  The quasi-planar graduation structure provides optimum protection against contamination and thereby greatly enhances encoder reliability. The manufacturing processes are environmentally friendly and do not use chemicals such as those generally needed for etching.

Controllers Help Astronomers Peer into the Universe

In mechatronics applications control is most often paired with motion. The following motion control system works with other components to deliver the required movement precision to research the Universe.

Photo by: Laura Hatch lauriehatch.com

Astronomers working for University of California Observatories (UCO) are creating the first comprehensive survey and map of the distant universe. Called the Deep Extragalactic Evolutionary Probe (DEEP), the team uses twin 10-m W.M. Keck Telescopes located in Hawaii, the Lick Observatory on Mount Hamilton in California, and the orbiting Hubble Space Telescope (HST).

The telescopes collect the light that stars and faint galaxies emitted more than 14 billion years ago. Detecting and analyzing this light requires an approach that includes a complex compliment of mechanical, electronic and optical instruments, along with sensors and software.

One of the key components of the Keck II telescope is the Deep Imaging Multi-Object Spectrograph (DEIMOS). Able to magnify the telescope’s capacity by a factor of seven for faint-galaxy optical spectroscopy, DEIMOS features:
• An optical beam camera with advanced optics and three 13-in. diameter calcium fluoride crystals lenses
• A “slitmask” system that allows observation of 140 galaxies simultaneously
• The largest spectroscopic charge-coupled device (CCD) detector of its type ever made (5-in.2, contains 67 million pixels)
• Sophisticated software for rapid setup and flexure compensation to keep the mirrors stable and aligned to prevent images from moving about on the detector. Conventional spectrographs that suffer from severe flexure make calibration and data reduction difficult.

SYNERGISTIC ENGINEERING
The multiple detectors on each Keck telescope, the DEIMOS spectrograph, and other related instruments require precise motion control of a number of elements, including filter wheels, focusing, apertures and positioning stages. Barry Alcott, development engineer at UCO, has been specifying Galil motion controllers for more than 15 years to handle the motion control tasks.

Alcott used Galil’s RIO Pocket PLC to automate portions of the Hamilton Spectrograph system, the first cross-dispersed spectrograph installed at the Lick Observatory. It operates by having light fed to a grating that sends it in one direction and then immediately feeds it to a prism that disperses it at a 90° angle for very high-resolution spectra.

Alcott configured the multiple I/O points of the controller to automatically control four pneumatic stages used for moving an iodine cell into a beam, opening a light port, moving a mirror into a beam, and opening a mirror cover. The controller’s logic control ensured proper event sequencing. Communication between the controller, the motion system and the I/O points is handled through the built-in Ethernet port.

“I was able to put together this control system in under two weeks. By automating the control of these functions, our astronomers can remotely control the telescope instruments from a home base,” said Alcott. “They no longer need to come to the Mount Hamilton Observatory to adjust the instrumentation.”

Multiple Galil Motion Controllers enable astronomers to precisely control the movement of giant telescopes from a home base.

In addition to the RIO upgrade, the Hamilton Spectrograph was fitted with Galil’s DMC-4080 Accelera Series motion controller.  The dual-loop position mode is used specifically for sub-micron, precise positioning and guidance of the correct light wavelength onto detectors. The dual-loop position data come from a 0.01-m resolution encoder that is placed on the stage and an
auxiliary encoder placed on the motor.

Additional upgrades using Galil controllers are in process at the Mt. Hamilton location.  The 68000 MPU based system of the Kast spectrograph is being replaced with a pair of DMC-4080 controllers. Additionally, a spectrograph is being built for a new remotely operated 2.4 m Automatic Planet Finder (APF) telescope that will be used to search for extraterrestrial planets.  Keck I’s flagship optical spectrograph, the High Resolution Spectrograph (HIRES), uses Galil controllers for precise velocity work in its search for extraterrestrial planets.

PEERING INTO THE DARKNESS
While the Lick Observatory sits atop the summit of 4200-ft Mt. Hamilton in the Diablo Range east of San Jose, CA, the W.M. Keck Observatory is positioned at the 14,000-ft summit of Mauna Kea, a dormant volcano on the Big Island of Hawaii. Its Keck I and Keck II are considered to be the world’s largest optical and near-infrared telescopes, each capable of collecting four times more light than the world-renowned Palomar 200-in. (5-m) telescope located in San Diego, CA.

Astronomers use multiple telescopes from several locations, including the Hubble Telescope, to survey and map the distant universe.
Photo courtesy of University of California Observatory.

Each of the Keck telescopes is equipped with a mirror 33 ft in diameter and composed of 36 hexagonal segments pieced together in a mosaic pattern. Keck I has been in operation since 1993 while the Keck II was commissioned in 1996.

According to a UCO data report, the beginnings of 8- to 10-m astronomical telescope development began at UCO/Lick, with the genesis of what eventually became the Keck telescopes. UCO/Lick faculty member Jerry Nelson designed the unique Keck mirrors, while UC Santa Cruz Professor Steve Vogt is credited for designing and building Keck I’s flagship optical spectrograph, the High Resolution Spectrograph (HIRES).

A second spectrograph at the Keck Observatory, the Eshelette Spectrograph and Imager (ESI), features Galil’s DMC-1500 motion controllers and was recently shipped and commissioned by the UCO/Lick team. DEIMOS, which also features the DMC-1500, represents the third and most advanced optical spectrograph built by UCO/Lick.

In addition to the three spectrographs, Alcott said that the UCO’s Atmospheric Dispersion Corrector (ADC) was built using a Galil DMC-2200 controller for the Keck I telescope. “This essentially helps to improve the differential refraction of the telescope as seen by the existing cassegrain instrument.”

A CLOSER LOOK AT HISTORY
Sandra Faber, a UCO astronomer, UOC professor and a founder of the Keck Observatory, said, “A great telescope like the Keck allows us to explore the River of Time back toward its source. Keck will allow us, like no other telescope in history, to view the evolving universe that gave us birth.”

In fact, UC Irvine scientists recently announced that with the aid of data obtained from the Keck telescope, they have discovered the minimum mass for galaxies in the universe: 10 million times the mass of the sun. “By knowing this minimum galaxy mass, we can better understand how dark matter behaves, which is essential to one day learning how our universe and life as we know it came to be,” said Louis Strigari, lead author of this study and a McCue Postdoctoral Fellow in the Department of Physics and Astronomy at UCI.

Galil
www.galilmotion.com

Link Shaft for Belt Drive Linear Modules

Belt driven linear actuators continue to increase in popularity as designers look to mechatronic systems to move products more quickly, cleanly and efficiently. Larger and faster gantries are being built for an increasing variety of applications in diverse new fields. Pick and place devices, inspection systems, and general material handling continue to take advantage of the speeds and lengths of travel these components offer.
Read more

Tips for the Control Side of Mechatronics

By Leslie Langnau, Managing Editor
Design World

In mechatronic projects, the focus is often on the mechanical and electrical aspects of a system as engineers concentrate on throughput, speeds, accuracy, and so on.  How these system goals affect the desired control selection may not be addressed until too late to make changes. Mechanical engineers do their part, then electrical engineers do their part, then, the controls engineers must make it all work.

In addition to finding ways to improve the communication and interaction of the various engineering disciplines, there are other design aspects that affect controls to keep in mind. Robert Muehlfellner, Director Automation Technology, B&R Industrial Automation Corp., offers a few. Read more

Developing a two-wheeled self-balancing transport platform

Annals of a mechatronic system design project

By Professor Kevin C. Craig and Matthew A. Rosmarin
Rensselaer Polytechnic Institute

Figure 1. The Engineering System Investigation Process.

A senior design team at Rensselaer Polytechnic Institute (RPI) set out to develop an interdisciplinary mechatronic system by designing and prototyping a two-wheeled robotic locomotion platform inspired by (and with the permission of) the Segway Corporation, maker of the Segway Human Transporter. The two-wheeled, self-balancing transport platform utilizes parallel-wheel locomotion to provide precise maneuverability while maintaining system stability. The team tackled both the complexity involved in modeling, analyzing, and controlling the platform, as well as the implementation of two fully operational prototypes in a four-month time period.
Read more

Mechatronics: New answers call for new questions

By Richard Vaughn, Product Engineer
Bosch Rexroth Corporation–Project Management Dept.

In a short time, mechatronics has evolved into a universally accepted engineering concept. It integrates mechanics with electronics – and with engineering itself. The result is expanded technological capabilities and assembly-line successes like the Cartesian multi-axis robot. Because it enables more flexible automated production, users can precisely control parameters such as weight, speed, reach, and work envelope. That is why mechatronics can be the answer to a variety of design challenges.

Mechatronics enables the development of creative designs that extend the capabilities of existing robotics and controls to new levels.

But obtaining the right answers requires asking the right questions – from the very first stage of a design. A mechatronics approach is a 3-stage ongoing process:
—Design – configure the system to accomplish a specific task.
—Integration – determine how components work together.
—Implementation – achieve optimum value in daily operations, and prepare for future changes.

As an example, consider the parameters involved in an application such as pin insertion in automobile underbodies traveling on an assembly line. Proper design begins with the determination of mathematical factors such as payload, travel distance, desired speed, and axes size. Then there are questions of machine control, motor size to deliver proper speed and torque, and even the operator HMI. There is also the key question of how much it all will cost.

The design of a mechatronics system requires a multidisciplinary focus — to root out potential difficulties before they grow into time-consuming, costly and distracting problems.

Here are a few specific mechatronics challenges—and some tips for handling them.

Keep envelope restrictions in mind. Consider work envelope restrictions including walls, supports, and safety barriers to avoid physical interference. The difference between length of a module and length of stroke is also crucial, especially when selecting linear actuators. A rodless actuator’s “dead length” means the actuator’s stroke is shorter than the apparent length of the cylinder. The best approach is to use a 3D simulation, rather than reconfigure system elements later in the project.

Find a proper protocol. Approach the marriage of controls and drives from different sources cautiously – it can lead to problems, especially when using off-the-shelf protocols such as PROFIBUS, DeviceNet or Ethernet. Some off-the-shelf protocols, such as Bosch Rexroth’s IndraControl components, can communicate with many proprietary controllers, but this may not be true of all protocols. Problems may arise if a controller running DeviceNet is added to a platform running PROFIBUS. Similarly, if your plant runs Ethernet, you may not be able to “plug in” a component from any vendor. During the specification phase, you should ensure that compatible off-the-shelf control systems are available for expansion or reconfiguration.

Consider the implications of specifications. Specifications can have powerful, difficult-to-foresee implications for mechatronics. For example, a 480 V 3-phase motor may be ideal for a servo application, but not if your drive amplifier is only capable of 220 V – which may require retrofitting a transformer. A change from Class 1000 to Class 100 semiconductor production clean room conditions may require third party specification.

Build in cable management. Often, this is the last challenge addressed, leading to last-minute scrambles to avoid interference with motion and parts pickup. Rather, cable management for a gantry pick-and-place application should be one of the first factors considered. A program such as Bosch Rexroth’s camoLINE can offer predefined cable management and 3D modeling, letting you “drop in” components to ensure all components work cleanly together.

Cable management is an important and often overlooked consideration during mechatronic system design.

Find the right tool for the job. An application that requires complex interpolative motion, such as cutting or gluing circular seals on catalytic converters, requires an interpolative motion controller and device. Attempts to adapt point-to-point controllers for these applications can be time-intensive and deliver inadequate precision. The best approach is to determine the circular interpolation path and identify the needed controller performance; that in turn will guide the selection of drives, power requirements, I/O and other elements to achieve that performance.

Following some basic tips like these can help avoid common – and costly – problems like either over engineering and over sizing machines (resulting in heavy-duty capabilities that are rarely if ever used) or under sizing machines (not accounting for occasional increases in payload or run speed).

Either situation can unnecessarily increase automation costs, which might discourage implementation of mechatronics – another reason why asking detailed questions is essential.

Integration
Mechatronics is clearly a cross-disciplinary science, requiring expertise in mechanical and electrical engineering as well as electronics and computers. But few have a background in all these disciplines. Those with expertise in one particular area, such as electrical engineering, may end up doing on-the-job training in other aspects of mechatronics, or trying to learn how to incorporate components from an unfamiliar manufacturer.

One effective approach is to use the services of an integrator who specializes in mechatronics and is experienced in blending mechanics and electronics. Cross-disciplinary integrators are becoming more common as mechatronics applications expand, and the trend toward cross-disciplinary integration skill is consistent with the current industry focus on accomplishing more with fewer people.

Integration can act as a “force multiplier,” extending the capabilities of existing technology to create quantum leaps in production efficiency, reduced downtime, and cost savings. For example, an automotive production line can be made many times more productive by substituting different control commands for retooling, and an outboard support axis added to a 3-axis Cartesian robot creates a gantry device. Many similar solutions are possible for designers who adopt a multidisciplinary, full-system approach.

Use of 3D simulation during the design phase of the project can prevent the need for reconfiguring system elements later in the project.

After integration, the final step is implementation. But the final step should be well planned early in the process, or the result can be significant delays and added machine or production line costs. Avoid potential problems by clearly defining the roles and responsibilities of integrator and customer. This task can be a challenge in a process that blends a number of different engineering disciplines to create an integrated solution. The key is communication, right from the beginning — including detailed questions. For example, regarding system adjustments or changes, what is the responsibility of the integrator and what can be done by on-site personnel? The answers should be carefully documented to head off potential problems before they start. Of course, no one can foresee the future. But good implementation envisions the context in which a mechatronics system will operate.

Cross-disciplinary integrators are becoming more common as mechatronics applications expand.

As a cross-disciplinary process, mechatronics demands integrated thinking to go with integrated engineering. Part of this thinking involves the ability to envision the day-to-day operation of assembly line functions, including the working environment and the blending of electronic protocols, to anticipate and head off potential disciplines. Be prepared for the reality of cross-disciplinary requirements that may call for an integration specialist to get all the components working together. Finally, to implement the system, clearly communicate with everyone involved about their roles and responsibilities. For mechatronics to be truly successful, the development process must involve not only mechanical and electronic elements, but process elements as well: the key phases of design, integration, and implementation.

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Software tools speed integration

Proper design begins with determining mathematical factors such as payload, travel distance, desired speed, and sizing of axes. Bosch Rexroth developed “LOSTPED”—a multi-step analysis process to help designers gather information for specifications.

To help answer mechatronic questions, Bosch Rexroth developed “LOSTPED”—a multi-step analysis process for gathering information for specifications. LOSTPED stands for Load (the weight or force applied), Orientation (direction each axis is mounted), Speed (and acceleration), Travel (distance and range of motion), Precision (repeatability or positioning accuracy), Environment (operating conditions), and Duty cycle (duration the machine will run; example: 24 hr/day, 5 days per week). In an automotive assembly application, for example, duty cycle and assembly line speed are crucial to determine insertion arm size, motor size and logic control, along with many other key factors.

Bosch Rexroth
www.boschrexroth-us.com

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