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Articles from 2005 In March


Robots Enable Non-Invasive Surgery

Patients with inoperable tumors too young to immobilize for frame-based radiosurgery, or patients in danger of radiation overdose, now have hope. Robot technology is combining with precise diagnostic X-Ray beams to allow a stereotactic radiosurgery system from Accuray (www.accuray.com) to match CT images with live images to accurately target tumors with cancer-destroying radiation beams.

The CyberKnife© system requires no incisions, draws no blood, requires no anesthetic and is performed in an outpatient setting.  An option to the system compensates for patient breathing using a new respiratory tracking system.  These tight targeting tolerances allow treatment close to critical organs and treatment of some tumors not treatable by traditional forms of radiotherapy, and treatment for patients who have already received the maximum allowed dose of radiation to certain organs.

How it Works
A Kuka robot (www.kukacontrols.com) is used to precisely position the radiation beams during the surgical procedure. The robot’s control software uses VxWorks to control real-time operation, but also co-exists on the same machine with Windows XP which provides the operator interface.

John Patchkin, an applications specialist for Kuka, says the system utilizes a six-axis robot with a 200 kilogram payload capability.  The robot controller uses VxWin® software to provide a software extension to VxWorks, and eliminate the need for additional control hardware or intelligent co-processor boards.  The user interface is Windows XP embedded written in C#.  All of the system’s control system is handled by VxWorks including I/O, trajectory generation and motion control.

The VxWin® software extension offers the stability and real-time performance that enabled the Accuray CyberKnife system to gain FDA approval. Patchkin says that positioning accuracies for the system are sub-millimeter during dynamic motion operations.  Plus, the openness of the VxWin software allows easy integration of DeviceNet I/O with the robot and Ethernet-based communication with an external Silicon Graphics workstation.

System Operation
Traditional stereotaxy is a method used in neurosurgery for locating points within the brain using an external frame.  Until recently, this type of surgery used an external frame to locate and treat tumors and lesions with radiation.  Its advantage is that it focuses the radiation tightly on the treatment site while limiting radiation exposure in adjacent tissue and eliminates the rigid stereotactic frame.

The Accuray system relies on the cranium or small metallic markers implanted in the tumor to serve as the frame of reference.  X-Ray cameras are mounted underneath and on both sides of the patient, and a moveable table is used to position the patient during the treatment.  The system continuously updates the target position of the miniaturized linear accelerator by comparing real-time diagnostic X-Ray images with previously generated CT scans.  The updated target position is continually fed to the robot control system that re-positions the linear accelerator attached to the robot.

The linear accelerator shoots hundreds of tightly focused high energy radiation beams during the course of the treatment.  This enables the rigid stereotactic frame used by traditional methods of radiotherapy to be discarded in favor of a non-invasive flexible mask for intracranial tumors.  The non-invasive mask eliminates the need for anesthesia, is more comfortable for the patient and provides greater flexibility for breaking-up the treatment.

“Of necessity, we set very high standards for the reliability and accuracy of the robot controlling the linear accelerator positioning,” notes Dr. Euan Thomson, President and CEO of Accuray. “We were impressed by the performance of the system and Kuka’s commitment to assist in the systems integration of the CyberKnife system.”

Thomson says the system is unique because it uses a robot to position the linear accelerator, which offers increased maneuverability for more complete coverage of complex target volumes while minimizing effects on surrounding healthy tissue and organs.  He says the six-axis robot arm also makes previously unreachable tumors accessible for treatment.

The diagnostic X-Ray cameras are used to snap real-time pictures of the target volume.  A workstation compares these pictures against previously generated CT scans and locates the spatial position of the target volume.  This information is fed to the robot, which continually updates the position of the linear accelerator.  Whenever movement of the tumor is measured, the position of the robot is updated within milliseconds.

System Operation:  X-Ray cameras are located under and on both sides of the patient, and a moveable table positions the patient during treatment.  The system updates target position of the linear accelerator by comparing X-Ray images with previously generated CT scans.  Updated target position is fed to the robot control system which re-positions the linear accelerator attached to the robot.

Designing for Moldability

The goal is to design and produce a pair of mating connectors for a handheld scanning device that can withstand 100,000 mating cycles without performance degradation … and the challenging environment a postal carrier will encounter.  The project team has three months to produce customer-approved, mating pair connector assemblies.

That’s the situation that Amphenol engineers (www.amphenol-aerospace.com) found themselves in last September.  Complete the product design, review material specifications, line-up testing and collaborate with an injection molding house on moving the design from 3D models to approved, precision molded parts by December 15th.

“The project required completing the design in a few weeks and parts within a couple months,” says Jeremy Ruff, a design engineer at Amphenol.  “We were looking for a mold house to produce molds very rapidly, manufacture parts to our print first-shot and complete the project in five weeks.”

Concurrent Design & Engineering
To jumpstart the project, Amphenol relied on an ongoing relationship with Genesee Precision (www.genprec.com) and reserved a spot in its manufacturing capacity to build parts as the design team worked to complete both the mating connector and mold designs.

Amphenol utilizes Pro-Engineer from PTC for CAD design, while Genesee Precision operates with Unigraphics from UG Solutions.  Although these CAD platforms differ, file translation allowed for immediate sharing of 3D models of the mating pair connector design rather than waiting for final drawings.  Matt Schiavi, a program engineer at Genesee Precision, began to interrogate the design and evaluate it for manufacturability. 

Concurrent Design

Mating connector pair achieves 100,000 mating cycles, critical for handheld devices frequently connecting to a docking station, by maintaining accuracy of injection molded housings.

Amphenol relied on Genesee Precision to make design recommendations and provide feedback on gate locations and any gate vestige on the part from the mold since the product tolerances were so tight.

“We didn’t know exactly how they would mold the part,” says Ruff, “so we specified general areas where we would like features to be and surfaces where we couldn’t have any marks from the molding process.  We documented those requirements in our drawings and sent it with the 3D model.”

Since the diameter on the core holes for the connector pins has a feature tolerance of +.001 inch and a true position tolerance of .001 inch, the design team altered the original 3D model to create uniform wall thicknesses throughout the part.  Genesee Precision conducted a preliminary design review with Basilio Sosa, a process engineer at Amphenol, to ensure proper mold function and part fill.

The team determined that extending the connector pin configuration even though some locations wouldn’t be used, would help control the shrink of the part and produce a higher tolerance molded part by maintaining uniform wall thicknesses.  “The true position tolerance of .001 inch for the hole location means you can only be off less than .0004 inch in both the X and Y directions,” says Schiavi.  “You can fabricate the steel for the mold to be within .001 inch true position but if you get abnormal shrink, the steel can be correct but shrink can pull the part out of tolerance.”

Precision Mold Design
By week four of the project, Genesee Precision had molded preliminary parts for internal review with a “steel safe” factor built into the mold design.  This approach guarantees the accuracy of critical dimensions in building the mold since it’s always easier to tweak the mold by removing steel in the mold rather than adding it.

Using this approach, the mold designers identify critical dimensions that are high tolerance.  A CAD file incorporating the revised 3D model, produced 100% to scale, was used to transfer every detail of the mold assembly to manufacturing personnel.  First-shot parts are measured to determine how much more steel needs to be removed from the mold to achieve the mean of a tolerance that may be +.001 inch using high precision machining or EDM operations.

    
CAD file released for production incorporates 3D model produced 100% to scale, and shows design of completed mold assembly.

Achieving the Goal
By week five in the project, Genesee Precision worked through final tweaks to the mold and produced 200 first article parts for inspection and review.  Later that week after gaining approval, Genesee Precision delivered 5,000 parts and Amphenol started building connectors for the handheld devices.

Gordon Collins, program manager for Amphenol says that the new connector design is particularly well suited to hand held devices which are frequently mated to an electrical docking station.  He says the connector uses patented Amphenol BrushTM contacts which have low engaging forces while achieving high durability exceeding the 100,000 mating cycles.

Robot-Assisted Surgery

Patients with inoperable tumors too young to immobilize for frame-based radiosurgery, or patients in danger of radiation overdose, now have hope. Robot technology is combining with precise diagnostic X-Ray beams to allow a stereotactic radiosurgery system from Accuray (www.accuray.com) to match CT images with live images to accurately target tumors with cancer-destroying radiation beams.

The CyberKnife© system requires no incisions, draws no blood, requires no anesthetic and is performed in an outpatient setting.  An option to the system compensates for patient breathing using a new respiratory tracking system.  These tight targeting tolerances allow treatment close to critical organs and treatment of some tumors not treatable by traditional forms of radiotherapy, and treatment for patients who have already received the maximum allowed dose of radiation to certain organs.

How it Works
A Kuka robot (www.kukacontrols.com) is used to precisely position the radiation beams during the surgical procedure. The robot’s control software uses VxWorks to control real-time operation, but also co-exists on the same machine with Windows XP which provides the operator interface.

John Patchkin, an applications specialist for Kuka, says the system utilizes a six-axis robot with a 200 kilogram payload capability.  The robot controller uses VxWin® software to provide a software extension to VxWorks, and eliminate the need for additional control hardware or intelligent co-processor boards.  The user interface is Windows XP embedded written in C#.  All of the system’s control system is handled by VxWorks including I/O, trajectory generation and motion control.

The VxWin® software extension offers the stability and real-time performance that enabled the Accuray CyberKnife system to gain FDA approval. Patchkin says that positioning accuracies for the system are sub-millimeter during dynamic motion operations.  Plus, the openness of the VxWin software allows easy integration of DeviceNet I/O with the robot and Ethernet-based communication with an external Silicon Graphics workstation.

System Operation
Traditional stereotaxy is a method used in neurosurgery for locating points within the brain using an external frame.  Until recently, this type of surgery used an external frame to locate and treat tumors and lesions with radiation.  Its advantage is that it focuses the radiation tightly on the treatment site while limiting radiation exposure in adjacent tissue and eliminates the rigid stereotactic frame.

The Accuray system relies on the cranium or small metallic markers implanted in the tumor to serve as the frame of reference.  X-Ray cameras are mounted underneath and on both sides of the patient, and a moveable table is used to position the patient during the treatment.  The system continuously updates the target position of the miniaturized linear accelerator by comparing real-time diagnostic X-Ray images with previously generated CT scans.  The updated target position is continually fed to the robot control system that re-positions the linear accelerator attached to the robot.  

The linear accelerator shoots hundreds of tightly focused high energy radiation beams during the course of the treatment.  This enables the rigid stereotactic frame used by traditional methods of radiotherapy to be discarded in favor of a non-invasive flexible mask for intracranial tumors.  The non-invasive mask eliminates the need for anesthesia, is more comfortable for the patient and provides greater flexibility for breaking-up the treatment.

“Of necessity, we set very high standards for the reliability and accuracy of the robot controlling the linear accelerator positioning,” notes Dr. Euan Thomson, President and CEO of Accuray. “We were impressed by the performance of the system and Kuka’s commitment to assist in the systems integration of the CyberKnife system.”

Thomson says the system is unique because it uses a robot to position the linear accelerator, which offers increased maneuverability for more complete coverage of complex target volumes while minimizing effects on surrounding healthy tissue and organs.  He says the six-axis robot arm also makes previously unreachable tumors accessible for treatment.

The diagnostic X-Ray cameras are used to snap real-time pictures of the target volume.  A workstation compares these pictures against previously generated CT scans and locates the spatial position of the target volume.  This information is fed to the robot, which continually updates the position of the linear accelerator.  Whenever movement of the tumor is measured, the position of the robot is updated within milliseconds.

System Operation:  X-Ray cameras are located under and on both sides of the patient, and a moveable table positions the patient during treatment.  The system updates target position of the linear accelerator by comparing X-Ray images with previously generated CT scans.  Updated target position is fed to the robot control system which re-positions the linear accelerator attached to the robot.

Components Answer Networking’s Call

Networking is expanding rapidly throughout the off-highway equipment field, impacting the many components that are used throughout this broad marketplace. Sensors, gateways, and other modules are beginning to feature CAN interfaces.

ITT’s foot pedal marks another step forward for digital controls.

“Everyone is looking for some variation of CAN,” says Michael Sewick, product manager at ifm efector Inc. of Exton, PA. The company debuted its controller gateway system at IFPE, controlling special purpose applications on a vehicle and tying that data to the equipment’s power train.

Networking is also making it easier to move to electronic throttle controls. ITT Industries Inc. of White Plains, NY, is rolling out single and double foot pedals designed for rough off-highway applications. The output characteristics, operating force, and deflection angle can all be customized.

Other component and subsystem suppliers are also broadening lines that employ J1939, the heavy equipment version of CAN. For example, Siemens VDO is broadening its CAN Cockpit offerings, supplying more gauges and instrument cluster displays that are network compatible.

Equipment makers are also bullish on the trend towards increasing communications between subsystems throughout the vehicle. “We’re moving to CAN in all our new products as we go forward,” says a spokesman for Ingersoll-Rand.

Web Links
ITT Cannon
Ifm efector

Belts, Rollers Help Boost Equipment Reliability

The largest, most complex equipment on the Conexpo show floor can be brought down when a small but critical part breaks. That’s prompting manufacturers of belts, rollers and other equipment to continue pushing technology forward.

Equipment makers are striving to improve quality both long term and right out of the factory. John Deere Construction Equipment vice president Bob Brock notes that warranty complaints and warranty costs were substantially reduced during 2004, helping improve profits while adding to the company’s reputation.

Gates Corp. of Denver, CO, rolled out the Predator, a V-belt designed for shock loaded applications such as chippers, crushers and oilfield equipment. Chloroppene rubber compounds provide heat and oil resistance, while aramid fiber tensile cords provide durability. A wear-resistant cover withstands debris punctures and shear forces.

Nexen Group Inc. of Vadnais Hts., MN, is unveiling a profile rail brake that improves efficiency, holding components firmly in critical safety-off conditions. The brake is kept disengaged with air pressure, clamping down when air is exhausted.

Inductive proximity sensors from ifm efector Inc. of Exton, PA, have been upgraded to protect against liquid ingress.

Sensor Use Rising in Off-Highway Applications

The off highway market’s growing adoption of electronic technologies is opening up a strong market for sensor makers. Solid state sensors are seeing substantial growth in many different aspects of the construction and agricultural markets.

Electronic controls are taking over in a number of areas in off highway applications, from engines to cabs to hydraulics, much like they have replaced mechanical systems in autos. The adoption of these microprocessor-based systems opens the market for sensors, which provide real-world information to the digital controllers.

Subsystem designers are devising techniques for steering by wire, using network connections to replace hydraulics and mechanical steering systems. As the technology moves closer to production in the conservative off-highway market, engineers are changing technologies to improve performance. SKF USA Inc. recently switched from Hall Effect sensors. “We’re using absolute position sensors that have high resolution, 12 bits, that are non-contact so there’s no wear and tear on the components,” says Tim Ruiz, applications engineer at SKF of Kulpsville, PA.

Eaton Corp. Hydraulic Operations in Eden Prairie, MN (www.eaton.com), is employing sensors in its VersaSteer electrohydraulic technology, which includes programmable valves. Sensors make it possible to adjust steering sensitivity so operators driving down the road at high speed and those doing fine moves in tight areas move the wheel in increments tied to those tasks.

Though sensors are seeing far more acceptance in off-highway products, designers note that the harsh environment requires special packaging. For example, tire pressure monitoring sensors are being put inside a number of tires for autos.

But in off-highway markets, the programs are still in development. “The difference from cars is mostly to scale for off-road applications. Size is one factor, but mainly mining and other off highway applications have shock and vibration requirements that are a lot more dramatic,” says Barry Rexroad, senior engineering manager at Bridgestone/Firestone’s Off Road Tire Group in Nashville, TN (www.bfor.com).

Laser, GPS Help Construction Companies Level Worksites

Construction companies are beginning to adopt new electronic systems to simplify grading and leveling of building sites. Laser and GPS technologies are finding new applications in construction, improving quality while making it possible for less-experienced operators to finish worksites.

CST/berger has trimmed the price of its Lasermark electronic self leveling system to $1,500, roughly half the price of previous generation systems. The dual-grade includes improved head positioning techniques to improve alignment (www.cstsurvey.com).

Trimble’s laser system helps operators quickly set up grading levels.

Trimble Navigation Ltd. of Sunnyvale, CA, yesterday rolled out the Trimble Site Positioning System, which includes two new Global Positioning System (GPS) receivers, and construction-centric software for heavy and highway construction applications.  The station incorporates advanced hardware features such as long-range reflectorless measurement of stockpiles, rock faces, cuttings, embankments, hard-to-reach and/or dangerous locations.

The software is designed for easy stakeout right in the field and easy computation of cut and fill values. A “light bar” display shows elevation, design elevation and the cut / fill values so operators don’t need high skill levels to set up the systems.

Caterpillar Inc. of Peoria, IL, is using laser-based technology in its AccuGrade system, which controls bulldozer blades so they can level a large building site within a few millimeters. The AccuGrade system lasers also let less skilled operators perform final grading, which requires much more precision than preliminary grading of a site.

Telematics Takes Off

Telematics has not found much success in the automotive field, but off-highway equipment makers are adopting the technology. Heavy equipment providers are offering a variety of telematic systems that send data from equipment to maintenance personnel or dealers, providing far more information that can be used to keep equipment operating without breakdowns.

Telematic technologies are taking advantage of the growing use of CAN networking, which makes operational data available. Telematic system can transmit data to pre-selected sites, providing data on the operating conditions, as well as the location of equipment.

Data can be sent at intervals set by users, ranging from hourly to daily connections. “We can provide location information, workload an hours of operation, any error codes that have occurred, and trend information on operating temperatures,” says Peter Robson, product marketing manager at Komatsu America Corp. of Vernon Hills, IL.

Other vendors are bullish on existing systems. “Telematics has been extremely well received by early adopters,” says a spokesman for Caterpillar Inc. of Peoria, IL. John Deere is also optimistic about its Greenstar program, as well as its other telematic offerings.

Engines Reduce Emissions

Engine manufacturers are pushing forward with techniques for reducing emissions, complying with the EPA’s Tier 3 regulations. Technologies developed for use in off highway equipment are being used to power pumps, compressors, and irrigation systems.

Tier 3 regulations call for dramatic reductions in the emission of particulates and oxides of nitrous. Though those regulations don’t phase in for many of these fixed location applications, engine makers are marketing the new engines into these applications.

John Deere Power Systems of Waterloo, IA, is targeting pumps, compressors, and irrigation systems as part of its strategy to sell half its engines outside the company. “Right now, we sell about 45% of our engines outside the company. We’d like to increase that percentage,” says Jim Payton, engine sales manager at Deere (www.johndeere.com/jdpower).

Deere’s PowerTech line has been approved by the EPA. The line ranges from 174-750 hp. Electronic controls are a key technology used to reduce emissions without driving up fuel consumption or reducing hp levels of the engines.

Another factor that helps in these applications is quiet operation. “We’ve put the fuel injectors inside the engine, which really reduces noise,” Payton says.

Cummins Inc. of Columbus, IN, is also moving forward with the Tier 3 QSB engine unveiled in Las Vegas. The line delivers from 135-275 HP. Electronic controls and high pressure common rail fuel systems are key elements of the engines. Its Tier 3 engines are designed to quickly upgrade for Tier 4 regulations that will be phased in in coming years.

Deere’s Tier 3 compliant engine is targeted at pumps and compressors.

Win a New Pickup

Attendees aren’t likely to buy much of the heavy equipment seen at IFPE/ CONEXPO-CON/AGG for their home use, but they will have an opportunity to put a close relative in their garage. International Truck and Engine has teamed up with Irwin Industrial Tools to hand over the keys for the world’s largest pickup, the CXT.

At the show, the two companies will divulge the first details of a contest that starts on April 1. The grand prize of the "Rule the Road Giveaway" is a one-year lease of an International CXT for one dollar. Other top prizes include NASCAR race weekend packages, a large selection of Irwin toolkits and miniature remote-controlled CXT replicas. More info is at www.ruletheroadgiveaway.com.

International Truck will also be rolling out the 7700, its latest line of severe service vehicles specifically targeted at bridge formula mixer, super dump and block hauler applications. Additional applications include severe service tanks and logger trucks.

The frame system of the International 7700 includes a single 12.25-inch frame that is 400 pounds lighter than many double 10-inch frames. Two models offer a front bumper to axle setting of 29.1 inches and frame system that optimizes payload weights for states that follow bridge formula limits.

The line also has chassis packaging options that create a faster and less expensive model for mounting truck bodies such as mixers and multiple lift axle trucks.

The standard engine is a 305-horsepower Cummins ISM with an 1150-pound-foot torque rating. It’s coupled with an Eaton Fuller 10-speed overdrive transmission.

Drivers have not been neglected. The "Fit and Finish" door features a cab exhauster to let the air out so that the door is tight and noise is reduced. The cab’s storage space exceeds competitive cab with two overhead compartments and side-door storage areas. The steering wheel houses buttons for cruise control and other functions.
http://www.internationaldelivers.com/site_layout/news/printversion.asp?id=609&group=severe&name=Severe

Details on the contest to win an International CXT for a year will be divulged this week.