Engineering News 7956

Street smarts: sensors relieve gridlock Innovative new technologies are helping monitor traffic, maintain roads, and keep drivers informed of snarl conditions By Jean Young Gonzalez,
Western Technical Editor

Long Beach, CA--It's 6:28 a.m. and your morning commute has already become a nightmare. A jackknifed big rig caused a freeway pile-up and overflow traffic has made the surface streets look like a parking lot. Goodbye 8:00 meeting.

No matter where you drive, from New York's Tappen Zee Bridge to San Francisco's Golden Gate, traffic congestion is an increasing problem, with few new roadways under construction and more vehicles pouring onto already overcrowded streets and highways. Last year alone, Americans lost 2 billion hours idling in traffic.

Looking to the latest high-tech gadgets in their quest for answers to America's mobility and safety problems, Congress has appropriated $95 million per year for intelligent transportation systems through 2004.

Although smart highway projects, such as a futuristic demonstration of driver-less cars piloted by magnetic "nails" embedded in the car-pool lanes to steer them down a stretch of San Diego's I-15 are still decades away, intelligent ramp meters, automated incident reporting, vehicle classification, speed detection, electronic toll roads, and traveler information systems are in operation today. Sales of these infrastructure products alone will reach $2.6 billion by 2002, says the Freedonia Group, a Cleveland-based industrial market research firm.

Now sensor companies are jockeying to become anchor tenants in the business of helping state transportation departments monitor traffic, maintain roads, and keep drivers informed of snarl conditions.

Finding the road less traveled. Southern California drivers, for example, can avoid bottlenecks in some of the nation's worst traffic conditions, with the help of 750 miles of freeway sensors that feed data on vehicle density and speed into a Caltrans traffic management center and onto easy-to-read, web-based traffic conditions maps.

But roadway sensors have traveled a long way from the relatively unsophisticated electromagnetic inductive loop detectors first embedded in concrete more than 30 years ago to passively count cars and determine speed.

Now, new sensor breeds mix advanced processing, magnetics, infrared, video, radar, and sonar with traditional loop technologies to help city planners manage traffic minute-to-minute.

"With live data from new sensors, we can obtain highly accurate snapshots of how roads are being used to sequence signals or study roadway capacity," says John Duve, intelligent vehicle manager with the San Diego Association of Governments.

Making dumb loops smart. Orincon produces a magnetic vehicle sensor used to make the millions of existing standard-size inductive loops in roadways into smart systems. The young San Diego-based firm, which cut its teeth solving signal and image processing problems for ARPA, has applied advanced signal processing techniques and neural network algorithms to a vehicle's inductive loop signal to determine 13 different vehicle types with 85% accuracy.

In the IVS-2000 system, the signature or "fingerprint" obtained from the inductive loop is sampled and processed by a neural net, which is trained to distinguish between a 16-wheeler and a Honda Civic. A roadway information computer processes vehicle fingerprints from one loop station to the next by matching frequencies. In this way travel times are measured over distances between loop stations, typically 1.252 to 1 mile apart.

"The IVS-2000 enables transportation planners to glean new information from existing infrastructure," says Don Owen, Orincon product manager. The sensor also performs vehicle origin/destination tracking, incident detection and automatic traffic control.

"By uniquely identifying a vehicle at some point along the road and picking it up again at another point, we can log travel time and speed with a 6 to 10% error rate--valuable stuff for cities mapping out traffic control strategies," says Owen.

Taking on tough environments. There are a million loops in the asphalt at more than 300,000 intersections in the U.S., but they are not widely loved in states with harsh climates says Pete Mills, a senior electrical engineer with the Federal Highway Administration. Severe cold snaps and heat waves make wireless detectors an important option to eliminate equipment failures due to expanding and contracting pavement joints.

A new, battery-powered vehicle detector dubbed the Road Runner and developed by Midian Electronics (Tucson, AZ) uses a wireless sensor with a low-powered, dual-axis magnetometer to detect vehicles. By using two magnetometers in parallel and a timer to measure speed between pulses, the unit can calculate vehicle speed. "Older magnetometers are single axis with manual calibration, but we've incorporated the horizontal axis with auto self-calibration to eliminate problems endemic to old single axis magnetometers," says Michael Soulliard, marketing director.

When a car drives over the detector, its magnetic signature causes a slight change in the earth's magnetic field. The detector recognizes this change and an arrival pulse is transmitted to a road-side receiver, which forwards the data on to a traffic control system. The system operates below 100 mW and in the range of 47 MHz. Another data packet or pulse is sent to the receiver when the car departs the detect area. The system, which has just been patented, is now under evaluation in several states.

Piezos in a pizza box. Measurement Specialties Sensor Products Div., spun off from parent AMP in 1998, produces a coaxial piezoelectric polymer cable that is positioned into a 3.254-inch-wide slot cut into the roadway. The sensor system, compact and flexible enough to ship in a pizza-sized box, senses a vehicle axle passing over it. The piezo sensor is embedded into a hard epoxy or resin in the slot, and it converts the strain imposed on it into a small (250 mV for a car; 2.5V for a truck) analog electrical pulse. Roadside electronics convert this signal into a digital timing pulse.

By using two sensors spaced a predetermined distance apart, the speed of the vehicle can be determined very accurately--so much so that they are used throughout Europe within speed-enforcement cameras. Once the speed is determined, the sensors are able to count the number of axles on a vehicle, determine the time between the axles, and calculate the distance between each of the axles.

More advanced electronics will integrate the signal from the sensor and make a determination on the vehicle's weight.

The sensors are in force on some of the busiest roads in America, from I-95 in Connecticut to I-5 in California for real-time traffic management and pavement performance studies.

Some transportation departments, especially those in areas with extreme weather conditions, have turned to non-intrusive traffic detection technologies such as above-ground microwave and video-detection devices.

Schwartz Electro-Optics (Orlando, FL) integrates lasers, optics and optical detectors into active laser radar for vehicle detection and classification. The Schwartz Autosense, with its two laser-beam detection zones, enables overhead imaging of vehicles for classification and size measurements. Applications include toll collection and bridge/tunnel clearance verification, traffic flow, routing, and monitoring.

A line-scanned laser rangefinder develops a vehicle profile. Using vehicle motion in the direction of travel allows a range image of the vehicle to be formed. The sensors provide absolute vehicle dimensions and speed. "The detection accuracy of this system has been quantified at 99.99% in 10,000 vehicles tested, with a classification accuracy at 98.7%," according to Norm Abramson, director of business development.

Sick Optic-Electronics has also just introduced a class of sensors for toll booth applications. Called the DS 60, it uses the principle of light-transit time to sense the distance to an approaching car. The time between transmission and reception of the pulse is directly proportional to the distance between the scanner and the object. A major advantage over conventional proximity sensors, which are located in the vicinity of moving traffic, is the fact that the DS 60 can be mounted up high or at a distance away from approaching cars.

In the end, John Duve, ITS Manager with the San Diego Association of Governments, sums it up best. "We are not building new roads in this country, so we have to make most of what we have. New sensor technologies will allow us to manage a 3-fold increase in traffic."

What this means to you:

Pothole police investigate truck damage

San Marcos, California--A new technology first developed for the U.S. Army Corp of Engineers can test the impact that moving vehicles, particularly heavy trucks, have on the highway below. Using rolling wheel deflectometer technology, the PPS-2000 produced by Phoenix Scientific computes the shape of the deflection basin--a tear-shaped depression--formed in the pavement by heavy truck wheels. A test truck rolling along with traffic processes successive pavement surface profiles that extend from the wheel out to beyond the deflection basin. The profiles are measured by laser ranging scanners as a replacement for its older "falling weight" cousin, which requires lane closures and causes traffic problems.

The Pavement Profile Scanner 2000 is a laser radar employing a high-power, 2W infrared laser (diode) modulated at 1.5 GHz to generate high-resolution, high-speed profiles.

"Our roads are one of the biggest investments taxpayers make ," says Bill Herr, president of Phoenix Scientific. "This system gives infrastructure managers more complete and timely information which they can use to determine the strength and remaining service life of roads. It helps them plan and prioritize for road repair and replacement."

The PPS-2000 scans the deflection basin in one sweep, 1,000 times a second to collect 1,000 data points per scan or 1 million samples per sec. Operating 7 ft from the roadway surface with a plus or minus 45 degrees view, a 14-ft-long profile is produced with an accuracy of a few thousandths of an inch. Civil engineers employ mathematical modeling software, using predicted future traffic loads in combination with current pavement strength to calculate remaining service life.

After enduring rigorous evaluation tests on a truck developed by Applied Research Assoc. of Vicksburg, MI for the Federal Highway Administration, the PPS-2000 will undergo demonstration testing this month in Ohio. The system is under test for measurement of other pavement conditions, including joint rutting, load transfer, faulting, slab curl, and potholes.

With its combination of data rate and precision developed to accomplish rolling wheel deflection measurement, this core technology has potential for use in many other applications, including airport runway testing, high-speed-rail testing, and robotics sensing for navigation.

Design with precision before prototyping

Gayden, Warwickshire--Project managers dream of catching mistakes early in the design cycle when revisions can be made at minimal cost and without jeopardizing the project timing. By implementing a process known as Electronic-build in the development of Rover's new executive car, the Rover 75, engineers at Rover Large Car Projects made this a reality. Computer-Aided Production Engineering (CAPE) tools from software developer Tecnomatix (Herzliya, Israel) were key.

Beginning in 1998, Rover increased its number of CAPE terminals from six to 43. The company used Tecnomatix's DYNAMO to package components in assemblies, define insertion and extraction paths for parts, and check service and maintenance procedures long before the first prototype was built. Engineers studied the assembly process and assessed critical areas using VALISYS tolerance analysis. They used ROBCAD to design, simulate, and optimize critical manufacturing processes and ergonomics.

Engineers took part in more than 500 design reviews during the Rover 75 development. As a result, more than 750 problems were caught. For example, E-build showed that a problem in the assembly of the rear suspension could be solved by changing the part assembly order.

"The main purpose of the Electronic-build process is to address the quality issues," says Paul Towers, information technology manager for Rover. "By building the prototypes virtually with CAPE tools, in advance of the actual hardware, we can focus on the engineering performance as opposed to the fit or assemble ability of individual components. The use of visualization and multi-functional design reviews are now standard procedures at Rover."

Tecnomatix CAPE tools are fully integrated into Rover's information technology environment so engineers can access the data directly from multiple CAD systems.

High-speed industrial network cuts operating costs

Appleton, WI--Are new Windows NT-based industrial PCs and industrial networks about to shelve standard PLC control for good? At least one forward-thinking Midwestern OEM thinks so. RapidPak has scaled the power of a Profibus network to its line of compact, stand-alone horizontal vacuum packaging machinery for food and medical markets.

While the concept of a high-speed industrial network evokes images of immense, multi-node manufacturing plants, RapidPak's strategy may herald a paradigm shift in machine control that resonates all the way down to even the most basic machinery.

"To the uninitiated, an industrial network on a single machine probably seems like overkill," says Ed Schultz, divisional sales manager for Rapid-Pak and a key influence in the PC-control decision. "But PC control and a high-speed Profibus network have helped us leapfrog our competitors technologically, yet remain cost-competitive when you factor in the considerable reductions in installation time and field service." Customers report that annual operating costs are typically an astounding 85% less than the competition's rollstock machines.

RapidPak President Ray Buchko concurs that PC control is the future of this industry for a number of reasons. Not the least of which is the company's ability to attain Wisconsin's Dairy 3A food equipment sanitation approval--the only company in its industry to achieve this rating, which is stricter than USDA standards. With machine production expected to double in the coming year, RapidPak's strategy is clearly not going unnoticed, either by customers or the press. The 10-year-old firm recently landed on the "Inc. 500'' list of America's fastest growing companies.

The decision to integrate an industrial network with PC control evolved not out of a leading-edge mentality, but--as is often the case--out of necessity. In this instance, the need was for sterilization. In food packaging machinery, especially for meat and produce, complete access to all components and invulnerability to high-pressure, high-temperature washdown are critical to avoiding the risk of bacterial contamination.

"Obviously, these requirements have a major impact on design," says Buchko. RapidPak began redesigning its machinery from the ground up two years ago, starting with easily removable guards, a stainless steel frame, and solid rollers that were impervious to washdowns and cleaning chemicals. The decision to switch to touchscreen PCs for control and totally potted electronics followed shortly thereafter, replacing hard-to-sanitize push-button controls and moisture-vulnerable electronics.

Amazingly, RapidPak completed controls redesign in just over six months, using Profibus-capable components and bus hardware from companies such as Beckhoff, InterlinkBT, and TURCK. The RapidPak systems use "soft PLC" software running within Windows NT. The processor is a 133-MHz industrialized PC with an integrated modem, CD-ROM drive, and industrial touchscreen interface. Moisture-sensitive electronics are isolated in a remote electrical panel. But instead of placing I/O boards in a PLC rack, RapidPak uses machine-mounted, watertight I/O modules from TURCK, greatly reducing wiring and panel size.

The company sought to use unmodified, standard products from best-of-class providers, a move designed to "future proof" the machines and ensure a stable supply of stock replacement components. With its new strategy, RapidPak claims to have lowered its manufacturing and installation costs by simplifying wiring demands both on the factory floor and in the field.

Because of the need to withstand high-pressure washdowns, RapidPak selected NEMA 4 quick-disconnect cordsets and busstop^(R) stations from InterlinkBT, along with TURCK sensors and sensor cables. In doing so, RapidPak was able to replace more than 90 point-to-point wires with a bus topology--a watertight fieldbus network that considerably reduces the complexity and physical footprint of the controls. Schultz says RapidPak software engineers were also able to integrate many previously hardwired functions into the control software itself.

"A major benefit of the network is the ability to isolate and diagnose I/O errors," says Bruce Gilles, RapidPak electrical engineering manager. "While clearing faults once required a long shutdown as an electrical engineer hunted through wiring diagrams, the LED diagnostic functions of the I/O devices on the network are quickly isolated, and troubleshooting can be performed easily by floor operators with a minimum of training. If there's a problem, we can usually work through it over the phone in a matter of minutes. Barring that, we can actually dial into the machine through an on-board modem and perform remote maintenance at a device level."

While reductions in field service costs are a huge bonus for RapidPak, elimination of downtime offers the customer an incentive that's difficult to ignore. Schultz says RapidPak's arsenal of high-tech tools doesn't end there. "Currently, we're producing an on-board CD-ROM that provides all machine documentation, a backup copy of the operating system, and an interactive manual that takes the operator through diagnostic and maintenance procedures step-by-step with visual images of the components in different operational states."

Schultz says the Internet-capable, browser-based application will further reduce customer downtime and lessen customer service demands on RapidPak, lowering the company's overall costs. "It's truly a 'smart' machine," says Schultz. "It can not only visually drill down diagnostics for an operator, but anticipate problems and even ensure adherence to maintenance intervals."

As one might expect, customers are enthusiastic about the benefits. Schultz says the industrial network methodology provides a solid foundation to support sweeping changes that are already be-ginning to alter the face of the food and medical packaging industries. With the network's ability to enable real-time monitoring, product ID, and statistical and validation feedback to MIS systems, RapidPak will be among the first to offer unit-level product verification data and tracking capabilities.

Plastics hold key to slimmer notebook computers

Pittsfield, MA--Just how thin can notebook computers become and yet perform even better at an affordable price? GE Plastics experts tackled that question in an 18-month review of 15 commercially available notebooks from a materials and manufacturing perspective. They present their findings in an 40-page report entitled "The Fulcrum Notebook."

"Our concept delivers innovative systems and creative ideas that can provide manufacturers with productivity improvements to meet intensifying global competition," explains Marilyn Lye, GE Plastics market development manager. "The concept combines outstanding thermal and shielding systems with engineering thermoplastics design advancements to develop a better-performing and more cost-competitive notebook."

To establish proper design guidelines, the concept focused on a prototypical multimedia notebook. The computer included a floppy drive, CD-ROM/DVD drive, hard drive, and one battery. It also incorporated sound and video with options for a ZIP^(R) drive, an extra battery, a JAZ^(R) drive, a second hard drive or other possible upgrade modules.

A carbon-filled engineering thermoplastic from GE Plastics' Custom Engineered Products served as the enclosure material for EMI/RFI shielding. The design also embodied thin-wall molding and enhanced boss and rib design for weight and cost savings. Thin-wall technology combines advances in processing machines and plastic materials with sophisticated tooling designs for injection molding.

The project also studied creative solutions suggested by PolymerSolutions, a joint venture of GE Plastics and the industrial design firm Fitch, Inc. Some key findings:

In general, most notebook computers may be over-shielded, resulting in added parts and cost. Most require less than 20dB of shielding to meet regulatory requirements.

The modular Fulcrum Concept envisions that all notebook parts be "hot-swapped," allowing the user to configure the notebook to suit the application. This can simplify assembly processes and allow for just-in-time assembly, the study reports.

To produce the thinnest notebook, while retaining modular bays, the GE concept moves components inside the computer as close together as possible, yet leaves airflow space for cooling.

"The knowledge derived from the Fulcrum Concept can help customers with requirement analyses, material selection, conceptual evaluation, and performance characterization," Lye concludes.

Functional FDM parts aid in artificial lung experiment

Ann Arbor, MI--Michigan Critical Care Consultants Inc. (MC3) used FDM rapid prototyping technology from Stratasys Inc. (Eden Prairie, MN) to build a functional prototype of an artificial lung implant. Engineers used the prototype in animal testing to determine how the heart would react to the implanted device. Rapid prototyping technology allowed the design team to make changes and adapt to requirements as the design process progressed, while reducing overall design time and costs.

"One key consideration is the housing, which must be highly adaptable," says Patrick Montoya, MC3's president. "It needs to be adapted for implantation. Every time we do an experiment, the design may have to be changed to improve performance."

MC3 designed the artificial lung using SolidWorks CAD software and then exported design data to Stratasys' QuickSlice software to build the prototype part. In one instance, "We decided to rotate the part and as a result had to move pressure ports from one position to another," says Montoya. "Using the FDM rapid prototyping technology and SolidWorks software allowed us to quickly incorporate these changes in the next design iteration."

Stratasys' ABSi material provides the functionality MC3 needs for experimentation and the translucency required to see fluid inside the artificial lung. For example, the design team could determine if the artificial lung contained bubbles, which must be removed during implantation.

Once engineers built the prototype, they dipped it in a solvent to ensure good surface seal and excellent fluid flow the company says. For this application, engineers heat-sterilized the parts because the material is susceptible to the traditional method, ethylene oxide gas. However, ABSi parts can also be sterilized using gamma radiation. Montoya says that without the strength, stability, and translucency of ABSi, MC3 would not have been able to perform functional tests on a first-generation prototype.

Before this method, machining a prototype took at least a few days. Now, engineers can produce several prototypes in a matter of hours with a single RP step. MC3 also saved up to 80% in costs using FDM instead of machining techniques. "We used to pay $100 to $400 for a small machined prototype," notes Montoya. "Using FDM, the same prototype costs us $80 in materials and overhead."

To this date engineers have conducted many tests that resulted in design iterations. And for now, Montoya says the MC3 design team wants to fine-tune the design while it has the ability to make changes quickly.

He comments, "It simply wouldn't have been possible to take on this project if we didn't have the FDM system."

Small manufacturing facility features big-company support

Rocky Hill, CT--Large companies can provide large resources, but sometimes their giant size can get in the way, slowing down production speed.

Loctite Corp.'s 43,000 ft² Rapid Response Small Scale (R2S2) manufacturing facility keeps response time under a month and a half, the company says. The facility opened in August 1998, and is located 11.252 miles from Loctite's North American headquarters.

The new facility promises customers adhesive solutions in 45 days or less. "It's like a small company with large-company resources," says Jim Heaton, director of electronics marketing for Loctite. Previous large-company turnaround could be as long as 12 to 18 months, he adds.

Indeed, electronic manufacturing is an area where speed is crucial. "When you're supplying for the cutting edge of technology, you have to formulate quicker," Heaton says.

The new facility's promise of speed also comes from its proximity to Loctite's North American headquarters. "If there is a problem, we can just come over, rather than have to video conference," says Jerry Perkins, director of general industrial marketing. Loctite has R&D offices in Dublin, Ireland and Yokohama, Japan, as well as manufacturing facilities in Puerto Rico.

Loctite chemists and engineers can synthesize small chemistry in smaller reactors. They can then move to larger machines when the chemistry is right. "Our ability to create new chemistry really sets us apart," Heaton says. "We develop our resin technology with the goal of solving a distinct need that commercial resins cannot provide, with no regard toward selling that resin as a finished good."

The R2S2 facility also features a 1,000- ft² Class 10,000 clean room for the manufacture of microelectronics adhesive manufacturing and packaging. Loctite manufactures and packages its underfills, dam and fills, glob top encapsulants in the room. This ensures adhesives with filler particles smaller than 13 microns are pure, the company says.

The clean room, which Loctite says is the first one in the adhesives industry, is comprised of cells with movable walls that engineers can pull in or drop out for bigger mixes. While currently used for electronic-application adhesives, Perkins says that medical adhesives may be a future possibility.

The R2S2 facility is the first of three planned sites. The Dublin, Ireland and Yokohama, Japan R&D sites will have adjoining similar R2S2 facilities by mid-1999, the company says.

Ford kicks off ARS

Detroit, MI--Ford is making available its Advanced Restraints System (ARS) to enhance front-occupant safety in head-on collisions. Proprietary-at-press-time sensors and microprocessor/sensor modules will take into account seat position relative to an airbag, occupant weight, safety-belt engagement, as well as impact severity. These will trigger an appropriate response by belt pretensioners and dual-stage, variable inflation-rate airbags. The ARS system also includes energy management retractors in the center of safety-belt spools. These deform under the high peak loads produced by the most severe impacts, reducing force-related injuries from belts. The company plans on introducing ARS this year on new and significantly revised models, until its entire line is so equipped.