Future Power 2010

Just visited the Renewable Energy World Conference.  Lots of really interesting topics to consider.  Lots of companies making progress in so many areas, it’s hard to sort everything out. Solar Power, tracking systems, Wind Power, engineering companies, geothermal systems.  All trying to define their role in the new energy economy.

Several companies, notably including Honeywell, are offering small wind packages.  These are systems with varying sizes of equipment that will generate electricity from wind.  Small wind can be defined as sized for operation of a single family home.  In the case of the Honeywell system it is designed to eliminate 18% of annual electrical power required.  With a target selling price around $4500 it will take a while for this unit to pay for itself.  And that is the difficult part about small wind.  There are many systems out there, from 2500 watts to 10,000 watts maximum output.  But the wind blows when it wants to, so it’s hard to tell what the payback will be for a small residential system.

A really “hot” topic is energy storage.  The demand for power does not follow the ability to produce power when wind or solar sources are being used.  So there has to be an intermediate storage capability to help the system manage the difference.  Anybody got a storage cell?

Well, as a matter of fact, A123 batteries who has been leading the lithium storage race, does have a storage cell.  They have a lot of them.  Some 2 Megawatt storage systems that fit inside a semi trailer.  Pretty impressive stuff.  They call it an APU, Auxilliary Power Unit.  Just like a diesel generator, only no smoke, no noise and no moving parts at all.  Pretty impressive.  And there’s more.

A123 has a technology migration path that they believe will create significant improvements over the currently available product.  The current wave of nanoscale processes applied to lithium battery chemistry will lead to decreasing costs and increasing energy density even further.  Both critical aspects of the business since competition for high energy density battery technology is coming from all over the world, including China and North Korea.  So if we want to hold onto this product technology and all the markets it applies to, we need to keep pushing the cost and performance envelope.

One interesting aspect of all this technology development is that we may see choices as consumers of power.  The current model of energy delivery being a highly centralized industry is going through a transformation of sorts.  This change may come quickly, and may have huge repercussions in our economy as the current group  of utility companies are forced to change their operating model.  What if everyone went off the grid?  What would the role of utility companies be? They might cease to exist, or become maintenance and operations experts keeping everything running.

What will the future of the power industry be?

B&L Designs Shaftless Press Which Cuts Time In Half

Located in Effingham, Ill., B&L Machine & Design specializes in the remanufacturing of various printing presses and ancillary equipment. Its particular expertise is on the Harris M-1000 and M-110 series presses, as well as splicers, infeeds, chillers and folders. By redesigning all the electrical and mechanical components and subsystems, B&L exceeds customer expectations for the increased set-up, changeover and print speeds demanded by today’s publishing industry, while saving substantial capital for commercial printing companies.

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

More on Motor & Drive integration

The motor and drive combination is a basic building block of motion control.  Each component is useless without the other.  So it’s pretty important to come up with a good definition for what the “system” performance needs are to make sure that you end up where you need to be in your design.

Generally, we go to single source suppliers whose motors and controls are designed to operate together.  This approach guarantees minimum performance levels which the supplier can be held accountable for, and that’s a great thing.  But it usually comes with a huge list of features that will not be used in the application, but which you must pay for anyway.

In the industrial user community this is a great benefit because common environmental conditions such as dust, dirt, oil, or washdown conditions are more difficult to deal with and many products are built to these environmental standatds.  No special precautions are needed to make the equipment work.  And the suppliers warranty their equipment for continuous operation at stated speed, torque and environmental conditions.

But as we migrate into other businesses, machinery builders and equipment manufacturers have to apply the same motors and controls in larger numbers, and the overhead costs of motors and controls designed for industrial use become very expensive and make the cost of machinery less competitive.

In the machinery world, much of the electrical components will be built into control cabinets.  So if the packaging is going to be provided, is an enclosed controller somewhat redundant? Or can the motor speed control be integrated into the motor physically to reduce cost?  This is especially attractive if the cost of cabling a single motor can run 10-20% of the total cost of the motor and control.

There are performance elements that need to be considered in the applications as well.  How should the motor behave at zero speed?  What kind of torque regulation is needed?  What is the exact duty cycle of the application (on time versus off time)?   In these areas of motor and control operation the relationship of the motor to the drive is critical.  The drive electronics must have the ability to regulate current going through the motor without casusing overheating.  Some type of sensor on the motor must provide information about the position of the rotor at fairly high resolution, certainly more than every 120 degrees of rotation as with the common Hall effect sensors.

So as much as we may look at the purchase of a motor and controller as a system, there are a lot of nuances involved in the search process for the right hardware for any given application.  And that is probably one of the more difficult parts of doing motion control applications.

Hexapod Robot Gives 10lbs Of Force For Medical Applications

The miniature hexapod system provides more than 10 lbs of force and motion in all six degrees of freedom.
It can be used for manufacturing and placing of parts requiring very high precision, for microscopy applications or laser and optical alignment

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

Tips for Improving Mechatronic Collaboration

By Leslie Langnau, Managing Editor

The use of mechatronics principles should make new product/device design faster, easier, and deliver fabulous and inexpensive products. But many engineering groups grapple with this design approach. Why do some groups work while others struggle?

We’ve heard about the promise of mechatronics for many years. Off-the-record, we hear comments about the “problems with mechatronics.” Some engineering groups get it and apply it with great success. Others don’t even want to hear the term. But there is no denying that whatever you call it, this approach to design is necessary in today’s world of multifunction, multitasking equipment and systems.

You don’t have to refer to this approach as mechatronics. Said Kevin C. Craig, Ph.D., Professor of Mechanical Engineering, Marquette University, “I define mechatronics as multidisciplinary engineering system design.” This definition is much more descriptive.

A number of engineers and managers are looking into why this approach appears to either not deliver on its promises or why it only works for some. Their research so far indicates that there are three main problems: Education, corporate structure, and the lack of truly collaborative design tools.

Education should break down the walls, but …
Years ago, the wall between manufacturing and engineering had to come down before industry realized measureable improvements in productivity. A similar situation faces those who wish to implement mechatronics, only this time the walls that must come down are those between engineering disciplines.

Education has played a role in building those walls, partly in response to demands of last century’s corporations and labor unions who segregated engineering manpower into separate functions; mechanical, electrical, and others. Today, inertia maintains the status quo with many universities and colleges continuing to segregate engineering disciplines. Even the professors don’t collaborate with each other! The result is mono-functional engineers (a new term that you may hear more of soon).

This singular focus has created engineers who speak a different engineering language from each other. Noted John Pritchard, global product manager, Kinetix Motion Control, Rockwell Automation, “At a recent workshop with 50 engineers pulled from all areas of a company, the language discrepancies were clear. We were discussing how to take a mechatronic approach to robot design. In the conversation, the mechanical engineers spoke about their struggles with reverse dynamics. The control guys said their biggest challenge was Cartesian to joint transforms. This conversation went on for ten minutes before they realized they were talking about the same thing, just using different words. The control guys were thinking about math while the mechanical guys were thinking about links, angles, and so on. For this group, the solution was to speak mathematics.”

A few educators are aware of this issue and are initiating a profound change, which we will go into shortly.

Another educationally based problem involves awareness; the decisions any engineer makes can affect other engineers’ choices for a design. “Lack of such awareness trips up many projects,” agreed Pritchard. “The choice of material is a fairly common decision that causes problems. For example, in the design of a reciprocating mechanism controlled by a servo system, a mechanical engineer may choose steel over aluminum. The steel may be more readily available, less expensive, standard practice, and so on. The control engineer, however, is now confronted by several constraints because of this choice. The servo motor must have three times the peak torque to accelerate at the same rate it would have needed had the mechanical engineer gone with aluminum. In addition, the design will need a bigger motor, bigger drive and circuit breaker, heavier wiring, bigger amp supply, bigger everything.

“The mechanical engineer may have no idea how the design of one part impacts the overall machine. A 10¢ per part saving may really result in up to $10,000 additional cost in order for the control engineer to deal with the larger inertia. And there are many choices like this; couplings, compliance, gearbos backlash, and so on,” continued Pritchard. “And the control engineers and the electrical engineers do the same thing; trapezoidal acceleration, for example, can excite resonances which can frustrate the mechanical engineers. Another example is the common practice of putting acceleration at 100% rather than a lower percentage, which can impact wear.”

“And control systems is one of the more important disciplines for mechanical and electrical engineers to have some knowledge of,” added Razvan Panaitescu, manager of Engineering for Mechatronics, Siemens. “It stands in between mechanical and electrical. You don’t need to know electronics deeply, just enough to model.”

A few professors have witnessed this lack of awareness and are developing programs that will not only solve it, but that will create shifts in the traditional engineering labor pool.

A change is coming
Ken Ryan, Director of the Center for Applied Mechatronics at Alexandria Technical College in Minn., spoke about what educational institutions can do to resolve these issues. He sees the engineering role shifting into two main categories: the specialist engineer (which is probably most of you) and the cross functional engineer.

The Specialist or mono-functional engineer is the traditional Mechanical Engineer (ME), Electrical Engineer (EE), Controls Engineer (CE) and so on. These individuals are experts in their chosen field. “Industry will always need these individuals,” said Ryan, “but not in the numbers that they have hired previously. I see a day when a company’s engineering labor force will consist of about 20% of these specialists.”

The Cross-Functional engineer is essentially the mechatronics engineer. This individual has more of a breadth of training, learning much about multiple engineering disciplines but typically not to the depth of the specialist engineer. These are the people corporations need to make mechatronics programs successful. Noted Ryan, “I think these people will make up about 40% of the engineering labor pool in a typical corporation.”

The cross-functional engineer can be further divided into two categories:

The Technologist: This individual is meant to be the functional extension of the traditional engineer; they implement the designs of the specialist. She/he is a member of a mechatronics team and will often function as a liaison among the specialists. This individual’s role is coordinative and integrative, both vertically and horizontally.

The Technician: This individual does what an engineer tells him/her to do. They are responsible for installation, service, and maintenance of mechatronically designed equipment. The remaining 40% of a corporation’s engineering pool will likely consist of these skills.

Mechatronics requires that either you master more than one or two engineering disciplines, or you develop a group of generalists to support the specialists. The cross-functional engineer will never replace the specialist engineer because they do not have a comparable depth of knowledge.

At Alexandria Technical College, the program is very successful. The college is in the middle of a huge packaging machinery area. By developing a cross-functional engineering program, graduate students find placement in all kinds of industry including transportation, mining, marine, automation, and other areas. “Once we took ourselves out of the packaging box,” said Ryan, “then we started finding lots of people interested in our students because these fields are all trans-functional fields.”

Corporate structure needs to nurture collaboration, not impede it
Global locations and engineers grouped by discipline do more to create miss-communications than solve it. “The biggest problem is interaction among disciplines,” noted Panaitescu. “Many corporations still physically group engineering disciplines so that engineers either work only with other engineers of their discipline, or they work in isolation.” The most successful companies have an open culture and nurture it.

Then there is the issue of cooperation, which can be sidetracked by corporate structure. “Engineers are naturally competitive,” said Panaitescu.

“But companies with more successful mechatronic design programs leverage the competitiveness between project-focused cross-functional engineering groups rather than having individual engineers competing against each other,” noted Pritchard. “The strategy of ‘which group will produce the best machine’ works well.”

Successful users of mechatronics also use a common design process that everyone sticks to. “One goal of a common design process is to ensure engineers check with each other throughout, ensuring that one decision does not impede future decisions from other engineers involved in the design,” said Panaitescu. “Corporations do not need to mandate that engineers attend communication classes; that is not the issue.”

Part of this common process involves the creation of a requirements document. It lays out in the beginning, what the design must do. Noted Panaitescu, “it is not often used because its not very interesting paperwork. But it can help speed product development.”

“The first step is to sit with the customer and decide what the device must do,” continued Panaitescu. “It will not significantly differ among projects. But if you define soundly, thoroughly, then everyone thrives. Naturally, the requirements will include performance, precision, timing, vibration and so on. But the requirements should also include how a system performs and how it will be designed; did you optimize that machine, reduce its carbon footprint? How much material did you put into the machine? These factors should be part of the mechatronics concept. The requirements change as we change. If you have such a process that incorporates physical mechatronics concepts with requirements concepts, then you have everyone in the team looking at the same goal, a common perspective.”

Proctor & Gamble, for example, has resolved many of these issues. Said Craig, “P&G has developed internal programs that have broken down the silos, embraced mechatronics, developed integrated design, and offer in-house courses that look at the mechanical, electrical, and controls. It’s doable.”

The need for truly interoperable software tools
The biggest issue with the various CAD and other product-development tools is that they do not offer the required level of interoperability that lets a controls engineer interact with the design of an electrical engineer.

“At first glimpse,” said Craig Therrien, product manager, Dassault Systèmes SolidWorks Corp., “it might appear that a simple movie of a machine in operation is all that is necessary for a collaborative mechatronics approach.

However, although a 3D-based mechanical CAD animation of intended machine function is a huge improvement over 2D drawings – and can help pinpoint potential collisions – it does not convey important engineering information that electronics and controls engineers need to select, size, and program the appropriate system. Nor can an animation alone help engineers factor the effect of their decisions into the mechanical design.”

Something more than moving pictures is needed to take advantage of mechatronics. Programs should provide control engineers access to mechanical engineering information, such as mass, material properties, moments of inertia, and force/torque requirements, to choose the most suitable electronic control mechanism. Mechanical engineers need to combine the loads created by specific electronic controls with the output of dynamics analyses to validate a system’s structural integrity. Controls programmers need to be sure the system functions as intended without any mechanical or electronics systems issues. In short, everyone involved needs an integrated mechatronics design environment that moves mechanical and controls design information in both directions. This helps the team to make important decisions and design modifications during the design cycle rather than as a result of costly prototyping.

Two soon-to-be-released examples of such a mechatronics environment are the integration between SolidWorks® Motion kinematics and dynamics analysis software and controls automation packages LabVIEW® from National Instruments and Motion Analyzer® from Rockwell Automation.

“With these integrated tools,” continued Therrien, “the mechanical engineer can model a machine in SolidWorks 3D CAD software and conduct kinematics and dynamics analyses in SolidWorks Motion software. Then, electronic systems engineers and control programmers can access the entire motion simulation from either LabVIEW or Motion Analyzer, including pertinent engineering data such as force, torque, and friction requirements, to design and program the control system. Finally, the mechanical engineer can access detailed controls information, such as the type of device or the size of the motor, to conduct additional stress and vibration analyses.

Noted Marc Monaghan, engineering systems manager at Hartness International, a manufacturer of packaging systems, “We are constantly looking for ways to reuse our design data, and the merging of mechatronic control simulation with mechanical design is an excellent approach. This integration extends the benefits of kinematic simulation into the arena of control programming, allowing the initial concepts of control logic to be designed and tested simultaneously with the mechanical function that it needs to control.

“Project timelines are more aggressive than ever, giving us much less time to develop designs with iterations of physical prototyping,” Monaghan added. “The integration of 3D modeling, analysis, and control development allows us to identify potential issues and opportunities for innovation long before the first part is produced. It is another step towards getting more problems solved during the design phase of a project, when cost savings and efficiency improvements deliver the most benefit.”

Engineers at NCR Ltd., a leading manufacturer of ATM machines, also desire and require better product design tools. According to Dr. John White, chief engineer at NCR, “We use mechatronics to optimize performance. An interoperable program, such as the SolidWorks and LabVIEW connection, gives our R&D teams the ability to develop a digital prototype in advance of a physical build. LabVIEW controls the motion trajectories while SolidWorks is used to calculate the driving forces, power requirements, and stresses. Connecting the control software to the mechanical assembly provides our engineers with the data needed for full design analysis and optimization. For us, it’s all about reliability through optimization.”

Dassault Systèmes SolidWorks Corp.
www.solidworks.com

National Instruments
www.ni.com

Rockwell Automation
www.rockwellautomation.com

Custom Transfer System Adds Value by the Millisecond

Services and products from hydraulics, pneumatics, electrics, and linear technology were linked by Rexroth engineers to produce a custom engineering concept for Swiss company Mikron Machining Technology. “The fact that Rexroth offers coordinated components from pneumatic, hydraulic and electric drive technology right through to high speed control enabled us to select the most suitable characteristics for specific functions,” said Rolf Held, design manager, Mikron. The result was a machine tool that makes real added value out of milliseconds.

In a production environment, fractions of a second count and can accumulate to the extent that they affect cycle times. Automated transfer systems play a key role in many industries, particularly when metal parts must be processed using a number of different machining sequences. Suppliers to the automotive industry, for example, machine a number of items considerably more economically using intelligent transfer units. The machines pick up workpieces in clamping devices and transfer them automatically to the individual machining stations where they are drilled, milled, turned, chamfered or de-burred. Threads are cut and knurled profiles applied. Even peripheral processes such as installation operations or checks can be integrated into these transfer operations. With the transfer concept, all parts can be machined simultaneously.

The Multistep™ XT-200 is setting new standards for transfer systems – especially for the control speeds and the drives used for the various functions. The system makes precision manufacturing possible in non-stop operation. At the same time, the individual stations work practically hand in hand.

Extremely short chip-to-chip times ensure nearly continuous machining, and the system can even be used for high speed cutting. A key advantage is that it combines the productivity of a linear transfer machine with the flexible re-tooling capability of a machining center.

The concept is based on individual interlinked dual spindle modules, which can be used on a stand alone basis, or spread over up to four modules. Five interpolating CNC axes and up to 144 tools machine complex small and medium series parts on five and a half sides without remounting. If the parts are automatically re-mounted in-process, it is possible to machine six sides. The Multistep™ can be adapted to the production volume at any time. In addition, a loading and unloading station can assume the component feed function.

Without a break
While the main advantage of this machine is precision manufacturing almost without a break, further advantages come from the short chip-to-chip time of less than a second and the unusual dynamics. Accelerating the Rexroth CKK linear systems up to 1.4 g to 52 m per minute and spindles with speeds up to 40,000 rpm make for short machining cycles. This is where drive technology from Rexroth comes in: rodless pneumatic cylinders from the BRP Rexmover Series with a diameter of 50 mm and a stroke of 400 mm, as well as a linear axis Type CKK20-145 for strokes of up to 1,100 mm. The maximum force on this axis is around 72 kN in the direction of movement.

“At the end of the day it’s the number of milliseconds that we gain from a number of different points that is the decisive factor,” said Held.

In the standard version, the Multistep™ is fitted with a high-speed CNC Rexroth IndraMotion MTX. Up to 64 axes can be operated in twelve CNC channels independently of one another. The maximum extended version features 54 axes that are required to work in parallel. “Using any other approach would mean that we would need at least two controls and we would have to combine these with each other,” said Held.

The PLC can process 1,000 instructions in 60 ms. At the same time the CNC offers, when controlling eight axes, an interpolation cycle time of 1 ms maximum. The Rexroth IndraDrive servo drives have integrated safety functions for secure hold and safe movement. “Also of interest is the so-called feedback capability, with which the generator capacity of the motors is fed back into the network during the braking operation,” noted Held. Mikron uses the force of hydraulic components for clamping the direct drive B/C axes. The tool clamping mechanisms in the motor spindles that close by means of spring assemblies are opened hydraulically. Here the valve blocks are the same for all spindle variations.

When it comes to workpiece handling in the loading and unloading station as well as workpiece transfer, it is pneumatics that takes care of speed and safety. With the HF03-LG “light generation,” Mikron uses a light and compact variant of the HF valve series. It has a narrow valve width, yet can flow up to 700 standard liters. By using plastic plates, the weight can be reduced even further. The pneumatic and electric controls are located towards the front and arranged in one direction, thus offering increased installation potential, compactness and the possibility of adapting to the space available. By way of an alternative to the traditional multi-pole connection, a field bus connection is used.

From a single source
When it comes to compressed air treatment, Series AS2 maintenance units feature a modular structure. The individual air treatment processes are brought together in maintenance units made from high quality plastic. Filtering, closed-loop control, lubricating and draining – the configuration is geared to user requirements. With the patented oil-fill system, the oil is directly extracted from the storage tank by suction using a hose. This means that the maintenance unit is protected against fouling by oil.

The maintenance units for the pneumatics are located, like the hydraulic power unit and the master control, in a separate control cabinet. The cabinet also houses the central lubrication, power connection and the fire extinguishing system. This arrangement corresponds to the modular structure of the Multistep™ and, by ensuring simple and rapid access to central components, guarantees that the unit is maintenance friendly.

Bosch Rexroth Group
www.boschrexroth-us.com

Motor and Drive Combinations

There is a subtle premise that often escapes us as we talk about motors and the controls that run them.  It is that the motor and controller operate as a package.  In most situations, a customer specification is for input voltage and output torque and speed.  That’s all that is important.  How you get there doesn’t matter a great deal.

But ironically, most motor manufacturers are predominately mechanical engineering centered.  And most drive electronics companies are electronics centered.  And they have very little in common with each other.  Except that their products must work together.  And oftentimes, that’s where the trouble starts.

The drive manufacturer warrants that his drive will produce current and voltage.  But the the motor can have very complex constraints to deal with in response to the excitation of the electronics.  How accurately a 6 step approximation of the sine wave performs, for example, can result in overheating in the motor depending on the loading of the system.  And as the motor winding heats up, the resistance in the motor can change dramatically, especially in the low inductance windings that are common in many specialty motors available today.

Then there are the cabling issues for connecting the motor and drive electronics.  The ac drive industry found out quickly that long wire runs can result in stored energy in the wires themselves.  Standing wave phenomena could cause higher voltages than expected and blow holes in the winding insulation in the motor.

Power semiconductor prices have fallen considerably in the last few years creating situations where it is sometimes cheaper and more reliable to put in parallel devices than to attached single power devices to large heat sinks.  This leads to some serious new options for packaging the electronics.  How about drive circuits in the end bell or junction box attached to the motor?  Actually, some models of the GE ECM motor (now owned by Beloit) are ac fan motors with variable frequency drives and intelligent controls built directly into the motor end bell.  You may have one in your main air handler in the air conditioning system of your home.  I was surprised to find out that I did.

I used to think that thermodynamics of these systems would be impossible to manage.  But the fact is that the drive efficiencies are getting really good.  One team I worked with was producing a 500 Watt brush drive that only shed about 20 Watts of loss at full load.  That’s some incredible efficiency.  So the notion of integrating motors and drive electronics is much more reasonable than it used to be.  And there are stepping motor packages that have been doing it for years.

So where is this all heading?

The fact is that the motor and drive electronics must work together as a package.  There is an increasing need, and an opportunity to create further performance enhancements, by the two technologies working more closely together.  More innovation will lead to better energy efficiency and new design opportunities and a chance to recharge (pun intended) an industry that has been losing share to offshore competition in the last few years.

Maxon Announces Strategic Collaboration with National Instruments

Maxon Precision Motors is pleased to announce a strategic collaboration with National Instruments (Austin, TX). The initiative will look to highlight mutual areas of interest in the field of robotics. An informal relationship between the two companies was initiated as early as 2006, with the inclusion of NI LabVIEW VIs in Maxon’s EPOS family of digital position and speed controllers. Most recently the two companies collaborated on the design and development of ViNI , an all inclusive robotics platform created by engineers at National Instruments. ViNI is driven exclusively by Maxon motors, gearheads and encoders and NI CompactRIO embedded controls.

“NI and Maxon have worked together to integrate the high productivity of NI LabVIEW graphical software and the high-precision drive systems of Maxon Motors so roboticists don’t have to assume the integration workload,” said Shelley Gretlein, Senior Group Manager of LabVIEW Real-Time & Embedded at National Instruments. “Also, with the release of LabVIEW Robotics software, design engineers now can access native Maxon Motor interfaces ready-to-run on their next autonomous system.”

Other notable robotic applications driven by Maxon motion control products include the Mars “Rover” by Jet Propulsion Laboratory, “Da Vinci” surgical robot by Intuitive Surgical and “DARwin” the humanoid robot developed at RoMeLa, the Robotics & Mechanisms Laboratory at Virginia Tech University.

Both Maxon and National Instruments recognize that advancements in each respective area of expertise are complementary and look to provide designers with state-of-the-art hardware and software solutions for developing new robotic products and applications. Several joint marketing efforts are slated for 2010. Maxon will continue to focus its R&D efforts on electric motors, sensors and motion controllers while National Instruments will leverage its LabVIEW platform, NI LabVIEW NI SoftMotion Module, and CompactRIO.

“It is an exciting time to be involved in the robotics industry. Over the years Maxon has directed a significant portion of our engineering efforts toward the development of specialized products for robotic applications, and we are just beginning to realize the benefits of our investment. We are pleased to be working with NI and their talented group of engineers”, states Kirk Barker, Electronics Product Manager.

CompactRIO, LabVIEW, National Instruments, NI, ni.com and SoftMotion are trademarks of National Instruments. Other product and company names are trademarks or trade names of their respective companies.

National Instruments
www.ni.com

maxon motor
www.maxonmotorusa.com

NASA Reveals Robot Astronaut: Robonaut 2

NASA is turning to robotics to help their astronauts while in space.  NASA scientists have developed a new dexterous humanoid robot which can work side by side with humans

Robonaut2, or R2, is the next generation dexterous robot that uses the same tools as humans, allowing it to work safely along with people, a necessity both on earth and in space. The machines are faster and can use their hands to do work beyond the scope of prior humanoid machines.

R2, the next iteration of Robonaut, could assist astronauts during hazardous space missions using leading edge control, sensor and vision technologies.

Working side by side with humans, or going where the risks are too great for people, machines like Robonaut will expand our capability for construction and discovery.

According to NASA, the robots were developed with General Motors through a Space Act Agreement to accelerate development of the next generation of robots and related technologies.

Wind Energy Equipment Testing

Some friends were discussing the recent visit of Department of Energy Secretary Steven Chiu to Clemson University to deliver a check for $45 million to start a test facility for horizontal wind turbine gearboxes.  It seems that there have been a number of gearbox failures in recent years that suggest a wider problem that will need to be solved in order for wind energy to become as reliable and cost effective as promised.  Gear boxes are failing in the range of 10 years of operation, and occasionally, sooner than that.

This is not difficult to understand.  The forces acting on the gearbox are huge.  On the input side you have 3 blade propeller with blades that are now approaching 200 feet in length.  I don’t care how light weight they are, carbon fiber epoxy or Kevlar or whatever, the forces are tremendous.  In addition the blades have to rotate to take them out of the wind when the wind is too fast for the system to operate.  So there are actuators at the base of the blades adding to the weight and mechanical complexity.

Then there is the intermittency of the wind itself.  This can manifest itself as bursts of wind or winds of different speeds hitting the same rotor.  Which can lead to all kinds of impulse loads on the gearbox.  Gear teeth becoming momentarily unloaded and loaded in response to the wind.  This is actually one of my favorite “Stump the Band” questions for mechanical engineers; what is the formula for the shock load of gear tooth reversal?  It’s big, whatever it is.  And the shock load of the propellers is driving the gearbox against a high inertia load, the generator.  So there is a lot of resistance to overcome.

But the really scary part is that the gear systems are often in the range of 30,000 pounds in weight.  And they are mounted on metal masts at heights of 1.5 times the blade length.  So that would be 300 feet up in the air in the case of a system with a 200 foot blade.  Making the replacement of a failed gearbox a bit more complex than dropping the transmission out of a car, for example.  Especially since most wind farms are in very remote locations where the land is cheap and the wind blows some of the time.

This lead the Department of Energy to put out requests for proposals to address the technical question of providing the industry with a resource to help in the design of gearbox systems with much higher reliability than the current designs.  Total cost of this effort, approximately $100 million dollars.  The proposed test facility is targeting 20 megawatt power handling capability, or approximatley 27,000 horsepower depending on the exact rpm of the system.  This is an incredibly big piece of machinery.

Clearly, gearbox technology has to get better for the wind industry to continue to prosper.   I wonder if we are putting a band aid on a technology that is fundamentally flawed.  Maybe we need to be concentrating on the next generation of the technology and improving the cost performance by an order of magnitude.  Surely we can do better.

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