Appliance Design - October 2008 - (Page 29)

MOTORS To get around this, both companies use AC voltage. Nanomotion uses two AC sine waves to generate the ultrasonic standing wave. Similarly, New Scale’s motor uses AC sine waves to generate ultrasonic standing waves. Stoianovici led a group of researchers in the development of a non-magnetic, pneumatic motor that does not require high voltage and electrical frequencies to operate. In fact, it doesn’t require any voltage or electrical frequency at the motor. Their pneumatic motor, dubbed the PneuStep, uses compressed air generated by standard air compressors to drive the motor. The electric compressors are located away from imagers to avoid any interference. The pressure per square required to move the piston is about 10 psi. The PneuStep is based on the premise that end-to-end motion within a cylinder is almost exact. The motor is made up of three cylinders, which are spaced 120 Deg around a motor gear head, and within each cylinder a piston moves linearly. Propelled by air, the pistons slide back and forth almost the exact amount with each stroke. When pressurized sequentially, they generate motion and each stroke moves the gear assemblage a precise amount. If the sequence is cylinder 1, cylinder 2, cylinder 3, the gear head moves forward in a clockwise rotation. If the sequence is reversed, the gear head moves backwards in a counter-clockwise rotation. It becomes in effect, a stepper motor, or what Stoianovici calls the world’s first pneumatic stepper motor. The steps can be made in minute amounts; the robot in his laboratory has a one linear step of about 50 micrometers (0.05 mm). An electrooptical interface is used to verify positioning. Currently, the motors are being used in-house to move the robots that control medical probes and other devices used for urological testing. Researchers in Belgium, are using the technology to study the brains of lab rats. New versions of the motor are in development, and licensing of the technology is available, he says. All of the part’s motors are plastic and can be made through injection molding. The basic motor is rotary, but the gear head can also be configured for linear motion and in various step sizes. Like the piezo electric motors, the PneuStep can be used in applications other than those that require non-magnetic motors, as long as it can be air-operated. A household appliance is an unlikely use for the technology, he says, but air-operated power tools might work. While these pneumatic and piezo motors will never replace traditional magnet-based motors, those devices that are made from non-ferrous materials and are non-magnetic will continue to have their place. In fact, much like the piezo crystal that grows when an external force is applied, these nontraditional motors may find new uses as electronics become smaller and their uses become more diverse. < For more information, email: Johns Hopkins University, dss@jhu.edu New Scale Technologies, dviggiano@newscaletech.com Nanomotion, afeinstein@nanomotion.com www.applianceDESIGN.com AD07084WELL.indd 1 applianceDESIGN October 2008 29 6/4/08 9:19:37 AM http://www.wdtl.com http://www.wdtl.com http://www.applianceDESIGN.com

Table of Contents Feed for the Digital Edition of Appliance Design - October 2008

Appliance Design - October 2008 Contents Editorial Shipments/Forecasts News Watch Prototyping - Materials Play the Part Prototyping - Mix & Match Motors Electronics Coatings Design Marts Association Report: AHRI Advertiser's Index

Appliance Design - October 2008

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