November 2003
Table of Contents
Application snapshots that show how handy a sensor can be.
Donna Pellerin George

App Snaps Straighten Up and Fly Right

jet engineTo optimize jet engine performance and ensure safety, operators of small aircraft rely on overhaul facilities to inspect, replace, or regrind the hundreds of small stainless steel and Inconel blades that generate thrust power in their jet engines. Erosion and foreign objects can cause the blades to bend and degrade over time, adversely affecting the engine’s performance.

In the past, overhaul facilities manually inspected the blades to indicate the length and position of each within the rotary intake. The problem is that jet engines can contain hundreds of blades—the Rolls Royce AE3007, a typical engine used in many individual operator and passenger aircraft, can contain more than 900! So the technicians had to perform a slow and labor-intensive process on each blade to determine if it needed to be replaced.

LMI Technologies (USA), Inc., and Oryx Systems have developed a system that can accurately inspect blades on the fly (ahem) at high speeds. LMI provided the system’s noncontact laser twin sensor (LTS); Oryx contributed the sensor software package and signal processing hardware.

To automate the inspection process, Oryx positions the LTS diagonally below the rotor. As the rotor spins, the sensor measures the length of each blade tip from the centerline of each wheel and sends the data to Oryx’s PC-based controller. Measurements are made in 200 ms with a tolerance of ±0.005 in. and resolution of ±0.0001 in. Software then provides a report of the average, high, and low readings for every blade, identifying those that need replacement or repositioning. The system also ensures that new blades are positioned properly within each intake and ground down to meet specifications.

Contact Mike Snow, LMI Technologies (USA), Inc., Southfield, MI; 248-359-2409, Or David Lacey, Oryx Systems, Inc., Charlotte, NC; 704-846-1866,

App Snaps Deep Space Mine

CCD arrayThe science of astronomy serves as both our window on the past and our doorway to the future. Yet scientists, cosmologists, and astronomers can uncover only as much of our history and our destiny as their tools allow.

To aid this quest, the Imaging Technology and Products business unit of Sarnoff Corp. has developed an array of 112 high-sensitivity CCD imagers that will allow astronomers to reach farther into space and further back in time.

Custom-designed imagers form the focal plane of the QUEST (Quasar Equatorial Survey Team) camera, one of the world’s largest astronomical CCD cameras. It was installed on a 48 in. Oschin telescope at California’s Palomar Observatory, where it will help search for objects in deep space, including quasars, asteroids, and supernovas, to give scientists deeper insights into the origins of the universe.

“QUEST required imagers that would respond to even the faintest light from outer space and capture the full 48 in. image from the telescope,” said Charles Baltay, Eugene Higgins Professor of Physics at Yale. Baltay headed the team that constructed the camera hardware. “There are no standard CCDs that meet these objectives,” he said. “Sarnoff not only created a more sensitive imager in an unconventional format as required for this telescope, but it delivered all the devices we needed on its first production run.”

The new imagers use back-illumination technology to boost QE (quantum efficiency, a measure of sensitivity) in the visible light spectrum. They are buttable on two sides to minimize gaps between devices when assembled in the camera’s focal plane.

An unconventional format and time-delay integration capability allows the Sarnoff CCDs to let QUEST operate in “drift scanning mode,” in which the telescope doesn’t move to counteract the Earth’s rotation. Instead, objects are allowed to drift across the field of view at the same rate as the computer records their images. The result is clear, unstreaked photographs of long strips of sky, ideal for high-resolution sky surveys.

Contact Tom Lento, Sarnoff Corp., Princeton, NJ; 609-734-3178,

App Snaps Get Your Dogs in a Row

Hot dog eaters grill them, boil them, steam them, but rarely approach the sphinx-like riddle that accompanies them: Why do wieners come eight to a pack when their buns come in tens?

But let’s stick with mysteries we can solve. Sutter GmbH, located in Worrstadt, Germany, produces 18–20 tons—that’s up to 40,000 pounds—of franks a day. If it weren’t for modern high-tech automation, that sum would drop precipitously, limiting cookouts to burgers and cole slaw.

hot dogsKnowledge-based robot technology and robots equipped especially for use in the food processing industry make it possible to automatically sort and package products that are difficult to handle, such as hot dogs (or tofu pups, for the more adventurous). “About 850 kg of hot dogs pass through the robot-equipped packaging system per hour,” said Harry Schmitt, vice president of Sutter, “and directly next to the robot line, we also package 850 kg of hot dogs, but this is done by 10 or 11 workers.”

Placing hot dogs in plastic packaging shells is not a simple pick-and-place task; that’s where Rexroth Turboscara SR8 robots come in. Because the robots move along a course parallel to the belt, synchronization is key. The sausages leave the smoke house in random orientation and are directed to the system by a conveyor belt, traveling at 13 meters/s. Their variations in curvature is a mark of quality in this particular product. Image processing registers their position on the belt, and the IMT software calculates how they can be optimally repositioned by means of suction with the fewest motions. Neural networks and fuzzy logic, which can carry out these simulations in fractions of a second, assist with the task. The software then coordinates the robots based on the simulation results.

The temperature in the three-shift operation is kept at 55°F, day and night. The standard dustproof configuration of the Turboscara SR8 was modified to satisfy requirements for use in the food processing industry. The gears, bearings, and motor cover—needed because the entire system is disinfected and cleaned once a day—are stainless steel, and the motor has been treated with a food lacquer.

Advanced networking technology supports the user’s staff with remote maintenance and diagnosis via ISDN. The two Turboscara SR8s are equipped with PC-based robot control from Rexroth, enabling IMT to intervene quickly via TCP/IP for maintenance and minor program corrections. A standard network provides internal and external communication of the robot control.

Contact Udo Schwarze, Bosch Rexroth AG, Stuttgart, Germany; +49 (711) 811 228 94,

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