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Nick Fenelli

By Tom Gibson

In spring 2008, Nick Fenelli found himself at a crossroads in his engineering career. He had gone to work for Airtrax in Trenton, NJ as a consultant several years earlier and had become a right-hand person of company founder and owner Peter Amico in running the business. Airtrax pioneered a unique type of wheel that makes forklift trucks more maneuverable and has spawned a new breed of mobility platforms.

But Amico died in 2006, bringing a change in management. “We had established a plan to move forward, but the new management didn’t appreciate that and decided to go down a different road,” Fenelli recalls. “They brought in a group of private investors who saw the company as an opportunity to make some quick money and did that and in the process caused the company to collapse.”

“When we were all handed our pink slips that day, we talked about what we could do,” Fenelli continues. A group of four former employees, nearly the entire technical staff, decided to band together and carry on as equity partners, calling themselves Vehicle Technologies, Inc., Vetex for short. They poured in their personal savings and sweat equity. After about a year, they convinced the directors of Airtrax to give them a limited license to build the Sidewinder, the forklift they had developed using their special omni-directional wheel.

“We were happy doing the work, and we thought it had a potential besides being able to generate a quick buck for some investors. We thought we could actually change the way people do things and improve efficiencies in a whole lot of fields,” Fenelli relates. Today, he finds himself the president of Vetex and leading it into new territory.

The Sidewinder has four unique omni-directional wheels, each consisting of six pairs of polyurethane-covered steel rollers mounted on a hub with tapered roller bearings and angled at 45 degrees to the wheel itself. Each wheel runs on its own AC motor, transmission, brake, and controller.

Despite having no steering mechanism, the Sidewinder can travel in any direction and in any manner a standard vehicle goes, and more – think of a skid-steer that can move straight sideways. Fenelli calls it easy to use. “Wherever you point the joystick, that’s the direction you go, and the more you push the stick, the faster it goes.” If you twist the stick, the vehicle rotates on its own axis. For the vehicle to move laterally to the left, the two left wheels spin toward each other and the two right wheels away from each other.

Playing with a New Toy

Festooned with plastic rollers, the omni-directional
wheel lies at the heart of Vehicle Technologies
and Finelli’s efforts.

As I enter Vetex’ office, Fenelli shows me a prototype demonstration vehicle with the omni-directional wheels, complete with radio control. Here’s my chance to tinker with it. The radio control unit has three joysticks, one for translational movement and two for rotational. He shows me how they can program a vehicle to rotate around any vertical axis you choose.

Fenelli then explains to me how the wheel concept works. “It’s all force vector balancing.” With the roller arrangement, the wheel imparts a force 45 degrees to the axis of the vehicle as it turns. If you spin the front and rear wheels in opposite directions, the fore-and-aft components of the forces will cancel out, but the sideways components will add to each other, making the vehicle go sideways. By varying the speed and direction of all four wheels, you can make the vehicle move any way you want.

I could feel Fenelli’s excitement for this concept. “It is always such a thrill to watch someone’s face when they first see it. Their expressions go through phases of bewilderment, understanding, awe, and joy,” he says. “There is no better feeling than the satisfaction we get sending a vehicle out into a new application for the first time, knowing it is going to dramatically change the way someone works, making their job easier, and enabling them to work smarter and more efficiently than before.”

With the omni-directional wheel on the Sidewinder forklift, warehouses can make more efficient use of their space. “It’s ideal for so many applications where there are space limitations or where just moving back and forth in one direction is inefficient to perform a task,” Fenelli explains.

Paul Hvass, senior research engineer at the Southwest Research Institute (SwRI) has tested the technology on robotic machines and comments, “There’s huge potential for this platform. As the cost comes down, I think we’ll see wide adoption, especially for warehousing where the additional maneuverability is so superior. They’ll get a lot of interest from folks like us and then I think more broadly from other OEMs who want to integrate on top of their platform.”

Peter Amico started Airtrax to market the omni-directional wheel after buying the rights to the technology from the U.S. Navy, which had acquired the patent from a Swedish engineer, Bengt Erland Ilon, who invented the wheel in 1972. After spending millions of dollars and many years developing it, Airtrax sold the first Sidewinder in 2005.

Having come from Ewing, NJ, a suburb just northwest of Trenton, the 57-year-old Fenelli worked with hydraulic presses and process conveying systems earlier in his career. He also designed Yale and Hyster forklifts, working in Lancaster, PA for a while. He started consulting for Airtrax in 1998, designing several prototype vehicles, and came on full-time in 2005 to get U.L. approval for the company’s designs. He also set up a production facility and staffed it.
The first beneficiary of the wheel was the Sidewinder
fork truck, which can maneuver in tighter spaces
than conventional types.

Vetex has an office and lab in an industrial park in Ewing, and when I pull up, the sign outside confuses me at first because it says Alpha Automation. But Fenelli explains that Alpha is their landlord and also a vendor, through a friend. Specializing in electronic component fabrication, they make circuit boards for Vetex. The firm has a machine shop at this facility, one it shares with Alpha Automation. “We do limited production here, mainly subassemblies.” They have a larger manufacturing facility and warehouse in Bristol, PA near Philadelphia. “That plant has a loading dock, so we build bigger stuff there. But this office has air conditioning, so it’s nice for development work. We build the smaller systems here.”

Regional Engineering Workforce
A private employee-owned company, Vetex now has three equity partners, with Fenelli being the only degreed engineer – he has a B.S. in Mechanical Engineering from Lehigh. His wife Mary is a principal and handles financial duties and purchasing; she also worked at Airtrax. Another partner, Bruce McLenegan was an electronic technician at Airtrax and now works as a systems engineer. Robert Cunningham serves as a part-time partner; he worked in quality control at Airtrax. They also have a programmer who was a consultant for Airtrax and an electrical engineer who consults with them. Another consultant develops electronic equipment and circuit boards, and a designer models designs using Autodesk Inventor. The consultants do the software programming using algorithms devised by Fenelli and McLenegan. With all these people spread out in central and southeastern PA and NJ, Fenelli muses, “A high degree of communication takes place via e-mail.”

They assemble the omni-directional wheels from parts supplied by several vendors. They build 21” wheels in their Bristol plant because they get used on Sidewinders there, while 17” wheels and prototypes are built in the Ewing facility. A vendor in California makes the rollers for them. Using a proprietary process, they mold the polyurethane oversize onto a metal bearing housing, and then a machine shop in Ewing machines the polyurethane down to the proper wheel profile.

As Fenelli tells it, “We have 60-plus fork trucks out there doing pretty well. We’re proud of the performance so far. They’re designed to be maintenance free.” He claims the rollers don’t wear out. “We have a bucket of rollers over in the corner that we’re still waiting to send out.” He tells me the idea sells to users, but it’s a hard sell to accountants because it costs three times as much as a standard truck.

This may partially explain why Vetex has put many of its eggs in another basket. They have developed a family of so-called mobility platforms based on the omni-directional wheel. These come into play for installing long or bulky loads, accurately positioning or docking a vehicle or piece of equipment, or simply maneuvering something in tight spaces.
Nick Fenelli shows how a roller is fabricated and assembled on to a wheel.

“One of the most exciting and visible markets we are in is the theatrical market. The technology has been showcased in two major motion pictures and featured in two TV series, but the latest and greatest is the introduction of our equipment into live theater,” Fenelli reports. In theatre applications, they typically build a set on an omni-directional platform. “You can move it about the theatre before, during, or after the performance, and you can set up a scene and have the scenery active in the production.” He explains how in one application, four of their vehicles move boats in a play called Jonah at the Sight and Sound Theatre in Lancaster, one of the biggest theaters in the world. The boats move by remote control via an iGPS navigation system, with the front of one of them extending out over the audience.

Vetex has also seen significant interest in mobility platforms for assembly and maintenance work on aircraft as well as loading weapons and manufacturing applications for missiles. Fenelli adds, “In construction applications, one of the main uses is for plumbers, pipefitters, and HVAC contractors to put plumbing and duct work up into the ceilings of buildings. They can accurately position and easily maneuver long loads where they have to go up in the air.”

Robots No Longer Stationary
Carrying this notion further, Fenelli likes to talk about a concept dubbed RoboMate, which involves putting a robot on a mobile platform. “For 40 years, you’ve had robots working in industrial environments bolted in one location and rotating, doing something over and over again. The next best thing coming down the pike is mobile robotics, having these platforms able to transport the robot and its functionality so it can perform tasks in multiple locations.”

“The robot can move around the manufacturing area and multi-task, bringing flexibility. It can use GPS, lidar, and infrared sensing,” Fenelli adds. A vehicle could use GPS in going outside between buildings and then radio control inside buildings. “There are a tremendous number of applications of this technology we haven’t even scratched the surface on.”

Two examples of mobility platforms that use the wheel.
  SwRI has developed several new robotic systems for industries and processes that aren’t conducive to conventional robotics. Paul Hvass researches robotic applications such as aircraft paint stripping and says they came across Vetex’ technology a few years ago. They have applied it to their MR ROAM system, which uses a Nikon laser metrology system to locate a machine globally no matter where it’s located. “We’re trying to show the feasibility of using mobile-based robots. You can use more off-the-shelf components and reduce cost. Mobile is modular.” And he adds, “The omni-directional platform gives us freedom to optimize how the robot gets in position with respect to the work piece, to give the robot the most range of travel without encountering some kind of collision.”

This leads to what Fenelli describes as possibly the company’s main mission. For the RoboMate, “Almost everybody we come across wants a customized turnkey system. Our primary role is as a systems integrator merging different types of products. Anything people want to be mobile, we’ll put it together.” They use many technologies such as wire guidance and computer control. Besides omni-directional wheels, Vetex provides engineering assistance, drive system components, and compatible accessories to OEMs. Vetex also brings in technologies like MOSFET (metal oxide semiconductor field-effect transistor), sensors, and closed-loop control and can provide a complete 2WD or 4WD CAN (computer area network, like LAN but for vehicles). This bus-based traction system comes with torque or speed control, regenerative braking, automatic parking brake, and onboard diagnostics.

Fenelli rests easier these days knowing that he not only has a stable career but that Vetex is staffed by passionate engineers and technicians who see the full potential of the funky omni-directional wheel and its many possibilities. “It seems like customers are coming to us with new applications every other day,” he says. As their designs play out over time, they should prove that a quick profit isn’t always the answer.

For more information on Vehicle Technologies, visit www.vetexinc.com

For more information on Southwest Research Institute’s robotic research, visit www.mobilemanipulator.swri.org

Victor Li

His Flexible Concrete Bends But Doesn’t Break

If you ask Victor Li about concrete, he will sing its praises. “Concrete is a great construction material, one of the most successful ones man has ever made. That explains its popularity. It is a very good material for constructing bridges, roads, and buildings and many of the things we depend on in our daily life.”

Why, then, has he embarked on a mission to replace the everyday concrete we know? “The main shortcoming of the material is that concrete is brittle, meaning that it cracks, and as a result of cracking, it brings deterioration and damages that require repeated maintenance,” he explains. And he adds, “In situations where a structure experiences severe loading like earthquakes, there can be collapses.”

An engineering professor at the University of Michigan (UM), Li has developed a new type of flexible concrete known as an engineered cement composite (ECC). He hopes it will find widespread use across the country. “We’re trying to create a new generation of concrete that if you put it under excessive bending loads, it bends but doesn’t fracture into pieces like glass.”

Conventional concrete is made by mixing sand, cement, and aggregates such as gravel and then activating it by adding water. It typically has steel or fiberglass reinforcing bars – known in industry slang as rebar – running through it for added tensile strength and to reduce cracking. This results in a material strong in compression but weak in tension or bending.

ECC resembles regular concrete but can weigh up to 40 percent less, consisting mostly of the same ingredients except for the coarse aggregates. It has small polyvinyl alcohol fibers embedded within it, 8-12 millimeters long and about 40 microns in diameter, about half the thickness of a human hair. They have a nanometer-thick surface coating that allows them to slip rather than break under heavy loads. In place of coarse aggregates, it relies on fine sand, as aggregates disturb placement of the fibers and destroy the ductility. In some applications, rebar can be eliminated.

The material has a compressive strength similar to that of regular concrete. But while normal concrete has a strain capacity of .01 percent, ECC has a tensile strength capacity of 3 to 5 percent, or about 300 to 500 times as much, making it far more ductile.
Under strain, bendable concrete behaves more like metal than a ceramic.

In addition, Li says, “Even when ECC gets damaged by excessive loading, the micro cracks are self-controlled, and the crack widths are limited to less than 50 microns. In structures like a bridge deck, we don’t want water or deicing salts to get through the cracks and attack the steel. This kind of deteriorating mechanism is greatly delayed or eliminated.” The net result: “From a long-term standpoint, to improve durability means less maintenance requirements, and that means lower lifecycle costs, particularly for infrastructure like bridges and roadways, where a lot of maintenance is required.”

Li, 55, grew up in Hong Kong and came to the United States to go to college. “The U.S. has strong engineering programs in college. I was hoping to participate in that process of being innovative and creative,” he recalls. First came a B.S. in Engineering Science from Brown University, followed by an M.S. in Mechanical Engineering and a Ph.D.
in solid and structural mechanics, also from Brown.

Following that, Li became a professor of civil engineering at MIT, where he stayed nine years. Then in 1990, he became a professor of civil and environmental engineering
 at the UM, and in 2004, he added the title of professor of materials science and engineering.

About 15 years ago, Li began developing ECC technology at UM. In recalling those early days, he reveals, “A lot of people had the wish for a concrete that doesn’t crack. To make something that actually behaves so requires extensive engineering work. In fact, we spent quite a few years to understand what really makes concrete brittle.”

Working with his colleagues, Li formulated a theory for a new concrete when he taught at MIT and implemented that after he moved to Michigan, extensively testing the material for about six years. Since then, he recalls, “We’ve done a lot of field testing the last 6 to 7 years both in the United States and overseas, particularly in Japan.”
Li heads a lab that develops bendable concrete.

In explaining his motivations for developing bendable concrete, Li reveals, “It was a response to many of the major concerns we face every day in society, things like climate change; our infrastructure is experiencing more and more loads from extreme weather conditions. The concerns about environmental sustainability relating to the high energy and carbon dioxide emissions of producing concrete. The infrastructure in the United States not being in great shape. And of course, the economic crisis we are facing now. States are short of budgets for maintaining their infrastructure. All these are crying out for better materials for construction, concretes that are more damage-tolerant with less burden on the environment and greater durability requiring less repair.”

Actually, the original application of ECC was for seismic structures, particularly in Japan, which lies directly on seismic faults. “The material can deform during the earthquake and absorb the energy without fracturing,” Li reports. “In fact, in Japan, it has gotten beyond field testing and into some full-scale structures.” That work was led by one of his former graduate students. The most recent building to use the technology, a 60-story residential tower was completed about nine months ago in the city of Osaka.

ECC can be used any place where regular concrete is used, though the material is still more expensive. It costs about three times as much, but Li foresees the price dropping in the future. Because they have a longer life than regular concrete, engineered cement composites are expected to cost less in the long run, especially when experience is gained in large-scale production.

But Li points out a number of applications, including the buildings in Japan, where the initial cost of ECC is already low. In such buildings, by using this material in the core of the building, they eliminated other seismic resistance devices used to maintain safety of the building in earthquakes, and those can be extremely expensive.

Another area where ECC can result in savings is on bridge decks, as major problems occur when expansion joints between deck sections jam frequently. In a demonstration project Li’s charges did in Ypsilanti for the Michigan Department of Transportation, the bridge had regular expansion joints replaced by a slab of ECC material 17 feet wide crossing four lanes of traffic. Known as link-slab in this application, the ECC actually expands and contracts as the deck moves with temperature fluctuations. It eliminates many of the common problems associated with conventional expansion joints like joint jamming and leakage, which results in water and deicing salts passing through the joints and corroding the steel supporting the structure. Lifecycle calculations indicate as much as a 40-percent savings in carbon and energy footprints through the use of link-slab on this deck.

ECC can be mixed and placed by the same equipment used for traditional concrete. Li is working with suppliers and Michigan DOT to develop procedures so regular ready-mix trucks can deploy the material. Placement of ECC is actually easier because it is self-consolidating and needs no vibration.

A slab of the new concrete can replace
expansion joints on bridge decks.

Looking back on his career, Li reveals, “This is exactly what I was hoping to do. This type of work is very challenging, but it leads to solutions that help society. It’s very satisfying. By contributing to solving these problems, it makes our work meaningful, problems like climate change and our infrastructure.” He also gets satisfaction from passing on new knowledge to students. “They should be even more clever and innovative than we are. Our students are future innovators.”

In the near future, Li says, “We are conducting research to further improve the material by adding smart functionalities. We’re working on two projects. One is to make the material smarter to know when it has been damaged. Then, it can heal itself when it cracks.” In Li’s lab, self-healed specimens recovered most if not all of their original strength after researchers subjected them to a 3-percent tensile strain, the equivalent of stretching a 100-foot piece three feet. To accomplish this, dry cement in the concrete exposed on the crack surfaces reacts with water and carbon dioxide to heal and form a thin white scar of calcium carbonate. Calcium carbonate is a strong compound found naturally in seashells.
Working with Jerry Lynch, a young colleague at UM, Li is developing a self-sensing version of ECC, meaning if it gets damaged, it knows how much damage it has experienced. It could be used in applications like warning motorists of damage to a bridge structure before they come too close. Or it can help bridge inspectors monitor the condition of bridges and determine when and where to conduct repairs.

“These things are down the road,” Li says. “Our civil infrastructure can be much smarter.” He also thinks ECC “opens the door to potential applications where concrete currently cannot be used.” The future looks bright for concrete as a building material and an agent for improving our infrastructure. Years from now, we’ll probably hear Li extolling its virtues even louder than today.

For more information on bendable concrete, visit www.engin.umich.edu/acemrl/

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