Many of the constraints of the work are environmental.  If work is being done outdoors, then temperature and humidity are a factor.  Felling trees and in the forest requires extremely high forces due to the work needed to cut through a tree and drag it to a truck to be hauled off for processing.  Processing trees, even in a plant environment, requires some serious hardware, 125 horsepower band saws are not unusual.

Doing work on a ship or oil rig has additional constraints because of the presence of explosive fumes and fuels.  Often the need to avoid any possibility of igniting a combustible atmosphere causes engineers to apply pneumatic control systems.  Yes, there is still a compressor somewhere to generate the compressed air supply, but that is usually remote or contained to avoid exposure to the volatile atmosphere.

Environmental constraints come in many forms.  Extremely high temperatures push the limits of what is possible.  Making glass, semiconductors, and primary metal processing are all high temperature environments where engineers have developed whole technologies in order to bring us the materials we use in everyday life.

The simplest action of rolling or sliding becomes a real challenge when environmental constraints are added to the work statement.  Sawdust becomes a potential abrasive in woodworking environments that can introduce severe wear in moving parts.  Corrosive and explosion proof atmospheres as well as food industry applications introduce all sorts of chemical compatibility problems that require special materials and processes in order to meet strict guidelines for safety.

As always, resourceful engineers have worked out solutions for all of these difficult applications.  One family of solutions to rolling applications is the use of all ceramic bearings.  No steel, no lubrication.  None is needed because the ceramics are extremely high purity to start with and have extremely high precision surfaces eliminating the need for lubrication.  No outgassing or contamination to worry about.

Other solutions take the form of air bearings and non-contact material handling devices.  Air bearings have become more readily available for conventional applications, but are particularly compelling in large machinery applications where precision is required.  Large flat screen display glass  presents unique challenges that successfully addressed using a combination of air bearing regions and vacuum regions to move the glass without actual contact and with overall flatness measured in millionths of an inch.

A unique solution in pneumatic material handling takes compressed air driven into a funnel shaped recess and creates a vacuum in the center and an air cushion at the edges where the air is exiting.  This creates a vacuum pickup that never quite comes in contact with the part, leaving no marks.  Perfect for solar cell and some food and beverage applications.

Engineers continue to meet the unique challenges of industry and create commerce at the same time.  And that’s what it should be about.

Mechatronic Tips

The new sizes 300 and 500 meet the highest requirements concerning torque, compactness and dynamics. Features include high rigidity, extreme precision and excellent performance, making the TPM+ 300/500 actuators a fundamental contribution to increase the productivity of any machine.

Technical specifications at a glance:

- Torque up to 10,000 Nm

- Compact design coupling the alpha TP+ 300/500 gearbox and 220 series motors

- Optional strengthened output bearing (special gear housing)

www.wittenstein-us.com

Mechatronic Tips

Ovid Bell Press in Fulton, Mo. specializes in print runs from 5,000 to 125,000 copies and works for a variety of multi-color magazine and journal publishers. Recently, B&L needed to help this customer perform shorter-run production work as well as meet the critical make-ready time reductions. Make-ready, in this case, is defined as the period from deceleration after a print run through the time required to remove components as well as the set-up configuration from the previous job. It also covers the installation of new components and set-up on the next job and, finally, the time needed to accelerate the press back up to adequate speed and production of the new forms, all with comparable print quality. A productive press under these short-run conditions must have faster changeover times than traditional presses in the commercial sector, where the runs are considerably longer.

According to Jim Strange, manufacturing manager and electrical engineering supervisor at B&L, “I would say that the shaftless printing implementation on this particular Harris M-1000 press was the biggest part of our challenge. We had determined a shaftless design was the best solution to provide the flexibility of options needed for our core base of printing equipment, in order to compete in this new short run arena.” Strange explained that the press infeed system was converted to a belt drive, eliminating the need for gear trains and oil baths. All the web tension controls were moved to the servo motion processor, thereby further reducing component count.

B&L redesigned the entire gear train, from a standard line shafted unit, to accept dual motor servo control. By doing this, over 60 components were eliminated by a circumferential register control for all new motor mounts, plate and blanket gearing and servo positioning. The engineers, both mechanical and electrical, at B&L also produced an accurate and reliable plate loading system that enabled plate changes in a fraction of the time required on shafted presses, while leaving the web stationary on the press. This was made possible by the accuracy and flexibility of the servo drive system, according to Strange.

Finally, the folder section of the press was rotated, creating a smaller footprint and improving the folder use, which enabled this customer to install another similar press that can feed either the existing folder or new one. This solution created a more flexible pressroom for better response to market conditions and job flow.

To help with this conversion, B&L contacted three of the largest suppliers of servo control systems for its industry. Each candidate was supplied a press layout, specifics on each piece of required equipment and print quality goals needed to achieve a successful project. A 30-day window was allotted for proposals. When all the proposals had been received and reviewed, the project was awarded to Siemens. Larry Hines, president and owner of B&L, attributed this decision to the vendor’s design assistance, technical competence, service support and current installed base on similar equipment.

The Siemens solution included a Simotion D445 motion controller, Sinamics S120 drives and 1PH7 servo motors. B&L utilized the Simotion Shaftless Standard, a pre-configured application that implements the basic operations for a coordinated motion system and includes rudimentary HMI screens. This software is provided at no charge and saves a great number system engineering hours.

An all-servo design enabled B&L to eliminate drive lines and gave this remanufacturer considerable flexibility in the reconfiguration of existing equipment. Rod Davidson, senior mechanical engineer for B&L, said, “The servo drives enabled us to redesign the entire infeed, and we integrated an absolute encoder to control web tension for smoother operation. Furthermore, the servo drives in the print units let us remove a large number of existing components. Being able to access all the motor position information and scale it to our needs made it easy to build intelligent HMI screens for setting up the phasing, plate positioning and register control.” Finally, he noted the servo drive in the chill unit facilitated further reduction of component count and simplified belt drive configurations. All the mechanical and electrical reconfiguration was accomplished without the need for costly clutch components, according to Davidson.

“The make-ready time was the area most affected by the servo system. It was cut by at least 50 percent,” said Jim Strange. “The servo system provides the accuracy we required to make the overall process work with dependable, repeatable results.” He also commented that the servo-controlled circumferential register control increased the press accuracy and provided savable print more quickly. Scrap reduction savings have been in the 20 percent range, as well as a corresponding time savings achieved by a faster time-to-good print output.

Overall install time on the press was cut by over 25 percent, due to less drive line construction required, while manufacturing time was reduced by 20 percent, thereby benefiting B&L and its customer alike.

MECHATRONICS IDENTIFIES PROBLEM DURING COMMISSIONING, HELPING CUSTOMER COMPLETE PROJECT

During the commissioning process on this Ovid Bell printing press rebuild at B&L, a mechatronics analysis and optimization protocol was conducted by Razvan Panaitescu, engineering manager for mechatronics standards and regulations at Siemens, working in tandem with his Siemens counterparts in application engineering and installation. Mechatronics is the integration of electronics and mechanical engineering, relating to the performance or the design of equipment and machinery. Razvan Panaitescu is a leading authority in this discipline for Siemens.

A problem had surfaced during the test runs on the rebuilt shaftless Harris M-1000 offset press, involving an out of tolerance registration issue. The registration points were visibly oscillating, and the cause was initially thought to lie with the controllers or drives installed as part of the new Siemens product suite onboard.

However, Panaitescu and his team determined the problem resulted from gaps between both the plate and blanket cylinders on the press. When the controllers were finely tuned in a damping optimal setting of higher integrator times and lower proportional gains, the print quality was significantly improved and the registration problems seemed to subside. Not convinced the goal had yet been met, Panaitescu did further vibration testing. A thorough vibration and modal analysis was conducted, using the sophisticated instruments of the Siemens Mechatronics department. The problem was still evident, though to a lesser degree. As he explained, “A resonant frequency remained detectable and that led us to believe there were further mechanical problems in the gear train on two print units, as both continued to reflect unacceptable vibration conditions.” The suggestion was made to check the mechanical accuracy of the gear train and possibly the gear teeth dimensions.

As Panaitescu mused, “Just as a doctor uses the stethoscope on patients, we listen to the drives and press cylinders. From our analysis, we determined the mesh frequency was indicating a sprocket/gear problem.”

In the end, it was determined by B&L and its supplier that an off-normal angle bore on a gear and sprocket assembly was indeed the root cause of the registration problems. Replacements were installed and the press is running well, the result of the mechatronics applied here.

www.blmachinedesign.com

Mechatronic Tips

After two decades of experience with the design and production of hexapod robots, PI’s electro-mechanical / piezoelectric six-axis positioners are among the most advanced multiaxis precision motion control systems in the world.

Features and Advantages of the M-810 Miniature Hexapod

• Operation in Any Orientation
• High-Stiffness 6-Axis Hexapod with 5 kg Load Capacity
• Very Compact: 10 cm Diameter, 11.8 cm Height
• 0.2 Micron Minimum Incremental Motion (40 nm Resolution)
• Long Travel Ranges to 40 mm (linear) and 60° (rotation)
• Powerful Controller with Freely Definable Virtual Pivot Point
• High Velocity of 10 mm/s
• Linear and Rotary Multi-Axis Scans

Parallel Kinematics Advantages
Parallel-kinematic motion systems have a number of advantages over standard serial kinematic (stacked) positioning systems:

Virtual Pivot Point: Rotation Around any Point, not unlike the Human Hand
Only one Moving Platform, No Accumulation of Guiding and Lever-Arm Errors
No Moving Cables for Improved Reliability and Precision
Smaller Package Size
Increased Stiffness, Reduced Inertia, Better Dynamics

Smaller Motors and Encoders, Controller & Software Included. The limited space necessitated the usage of new  technologies for encoders, motors and other integrated electronic components.  The M-810 is compatible with PI’s tried and proven hexapod controllers that are supported by windows software and a library of drivers and programming examples for applications such as optical alignment etc.  PI also provides simulation tools for hexapod integration.

PI Hexapods come with load ranges from 2 kg to >1000 kg.

Applications

Precision manufacturing, high precision placement of parts; alignment of optical components & lasers, microscopy applications, neuroscience.

www.physikinstrumente.com

Mechatronic Tips

The Pumplon wheel, which resembles the shape of a pumpkin, or even a melon depending on its shape (hence the name Pumplon), is designed to change shape to whatever the road conditions call for through a rotary mechanism.

Living in a climate where you get to experience the four seasons to their extreme, you can get wet & rainy springs, 100-plus degree summers, chilly and colorful falls, and blistering cold winters.  If you were to install the Pumplon on your car, according to Pumplon, you would not need to change them for any weather reason or road condition.  Say for instance it was spring-time and there was a heavy rainstorm, by switching the Pumplons to the skinnier shape, it would increase contact pressure, cutting through the water on the road, allowing you to more safely arrive at your destination.  Or if the road is flooded, switch the tires to the widest setting to make the car amphibious.  In the summer, one may just want to hit the highway and cruise with the top down and feel the find in their hair, and for that they would change the Pumplon to the normal, or “ball”-look setting.  For the fall and winter, when you may be trudging through mud or snow (intentionally or not), you will need as much surface area out of my tires as possible.  You would consequently set the tire to its “melon” shape to get as much grip and surface area as possible, hopefully getting yourself unstuck in the mountain, or get you through the snow-packed roads to grandma’s house for Christmas.

With the world “going green”, it has brought about some rather interesting, very innovative ideas and concepts, and this one is no exception. The green benefits can be very numerous, from reducing travel times to increasing fuel efficiency.

The Pumplon wheel is the creation of Osmar Vicente Rodriguez, a native of Brazil, also a professor of industrial design at RCA Innovation.  His intention for creating the Pumplon was primarily for solving transportation problems for farmers in developing countries where the majority of roads are either unkempt and in very bad condition.

How does it work, you may ask?  The secret to the Pumplon is a steel shaft that can expand and retract by means of a rotary mechanism, pneumatic or hydraulic, adjusting rings which makes the wheel deformation wider or narrower.

The material of the tires has been the subject of special consideration. According to Rodriguez, “initially they were steel, but we replaced it with a thermoplastic material, which is easier to produce, lighter and cheaper, and is recyclable. The cover is of vulcanized rubber, similar to that used in tires conventionally, but more flexible to allow changes in size.”

Mechatronic Tips

So  our first reaction to energy storage as a mechatronic challenge  might be that it’s really just a chemistry problem and not mechatronic at all.  But energy storage comes in many forms and applications.  Energy storage is a requirement of almost every form of energy and control systems.  Hydraulic and Pneumatic systems require accumulators to store energy so that short term loads don’t use up enough power to make the system unable to respond to demands placed on them.  Energy rate over time is a governing principle in all these systems.

The initial linkage in my thinking was the electric car.  As someone who worked in the electric car field many years ago, it was that the battery that killed the electric car.  Carrying 2200 pounds of lead acid batteries to make a car go from here to there simply didn’t make sense.

There has been a lot of debate on that subject and a LOT of incomplete information offered which clouds our understanding of the social or political problem.  But the cost and energy density of the battery pack is making sufficient progress to insure that quite a few new vehicle options will be available in 2010 and 2011.

In normal batteries energy densities of 30 Watt hours per kilogram of weight are common.  Nickel metal hydride doubled the energy density to about 80Wh/kg.  But the real improvements are coming from the lithium chemistries at 130+Wh/kg.  There are more dense chemistries around, but they are typically very high temperature or otherwise very expensive, and so not practical for widespread use.

But the energy storage problem is not limited to chemistry.  The flywheel energy storage system has been a topic of engineering development for decades.  Energy density in these systems is in the range of 100 to 130 Kilowatt hours per kilogram, a thousand times more power.

So why aren’t we working on that for cars?  It’s been done several times and never quite works out.  Chrysler had a prototype K type car with a Garrett flywheel system.  Couldn’t make it small enough to be cost effective.  And there were issues of life expectancy and failure modes due to the fact that flywheel was operating on magnetic bearings in a vacuum housing.

The national power grid has exactly the same problem at orders of magnitude more power.  If there is to be any hope of an intelligent national power grid, storage systems of this kind are needed to act as a buffer between demand and supply..   Solar power is only available when it is daylight and there are no clouds.  Wind power only happens when the wind is blowing.  This means that supply is intermittent over time.  So if there are big fleets of electric cars charging overnight, there have to be storage systems that can manage the energy storage requirement.

So mechtronic challenge #4 – Energy storage. Large and small, high efficiency and long term.

Mechatronic Tips

But mechatronics includes pneumatic and hydraulic systems, and basically anything that moves. And what moves Americans more than our cars? So I return to an earlier comment that the electric car is the Ultimate Mechatronic Challenge.

But it doesn’t have to be electric. Hydraulic systems have traditionally been the highest energy density for application of pure power. Anyone who has seen a back hoe in action realizes how well hydraulics work for high power. The EPA is partnering with Eaton and Peterbuilt to make a clean diesel-hydraulic hybrid that may end up as the fleet vehicle for UPS delivery. Double the mileage and drastically reduced emissions are just part of the package.

Even pneumatic cars have been built with some success. Check out Guy Negre’s MDI company in Luxembourg. Its a controversial solution, but the fact that the demo vehicle is built and running means they have reached a certain level of success. The 5 seater minivan runs 60 miles a day before air is needed, with a forecast selling price of $16,500.

The Th!nk electric is in test in Norway and the new model is expected sell for $30K with lithium batteries from A123 and 120 mile driving range. This would be a fabulous entry into the market if everything works as planned.

The latest effort by the X Prize Foundation is a $10M prize for the best car design that reaches 100mpg or equivalent. There are currently 60 companies with letters of intent to compete. This is where real innovation takes place.

So there are some interesting lessons to be considered;

The vehicle fleet in the US was evenly divided between electric, steam and fuel solution in the teens and twenties. This is because no single technology solution is the right answer for every situation. When Ford’s assembly line process brought the cost of the car down dramatically so that many people could afford it, Rockefeller made a deal to deliver low cost gasoline as the fuel. That’s part of how we got to where we are today. But the real point is we should have a lot of technology choices as consumers.

Mechatronics is never more challenging than when we look at the car as a portable system and try to figure out the best overall solution, balancing the power source, manufacturing cost and overall system efficiency.

Big companies rarely innovate. Ford and GM have lost major ground in the low emission race, putting America’s industry at risk. When you think of all the steel, glass and fabric that goes into a car, there is a lot more at stake that the assembly worker in Detroit.

Government continues to spend hundreds of millions of dollars on R&D that should be the responsibility of the private companies that stand to gain from these efforts. Given the track record of the last 30 years, its hard to argue that Government needs to be involved. I just hope our tax dollars are being spent wisely.

And lastly, the energy question which is a two-part; shouldn’t government’s regulatory role be to insure that oil and natural gas are readily available from domestic sources instead of finding every excuse why we can’t? And how many of our petro-dollars find their way to funding violent anti-American organizations?

Just some things to think about.

Mechatronic Tips