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The article reports on a portable robotic arm developed by National Aeronautics & Space Administration. The experimental robot arm matches the strength, flexibility, and weight of a human arm. Since conventional electrical and electro hydraulic arms are too heavy, the actuator is powered by compressed air, constrained by hydraulic pressure, and instructed by digital commands. Bill Birchard, president of Andronics and the actuator's inventor, explains that hydraulic fluid totally blocks actuator motion except for controlled flow through a set of pulsed valves. INSETS: AIR OVER HYDRAULIC ACTUATOR WITH DIGITAL RETARD;PNEUMATIC ACTUATOR WITH HYDRAULIC INTENSIFICATION;Not just air;PNEUMATIC ACTUATOR WITH PNEUMO-MECHANICAL BRAKING

The article reports that air actuators normally are neither linear nor stiff, and the equations that describe them are complex. Conditions required for fast, stable actuator response are different at mid-stroke than at either end of the stroke. Engineers eliminated bounce from a new pneumatic system with a nonlinear electronic controller based on a dedicated microprocessor. Three new elements help solve the problem. Position control begins with a permanently magnetized, multiplelayer tape applied along one side of the system's rodless cylinder.

The article provides an in-depth analysis of the configuration of a web-fed envelope machine developed by engineers at ASCO Joucomatic in the U.S. The engineers eliminated the cam and replaced it with an electropneumatic system based on the company's Sentronic™ proportional valve. Other applications of the system include speed control, load balancing systems, cable laying by helicopter, and pinch force control on welding robots.

The article provides a solution to problems faced by engineers in applying pneumatic insertion and extraction cylinders to quickly load tote boxed onto conveyors. Engineers at Norgren Automotive Inc. suggested that a rodless cylinder that has a low profile must be specified. They have decided to use Murray Equipment Co.'s carousel. The carousel has many advanced features including its capacity to choose the parts needed for a particular tote load from a list of barcodes.

This article presents information related to functioning associated with a vacuum lifter. According to Peter Mangano, president of Nu-Vac Devices Inc. the vacuum holds the strip, and the actuator moves down until the strip is in position on the edge of the folder. Then the vacuum is released. The lifter picks up and delivers strips of any material. Actually, it wasn't as easy as it sounds. The strips travel rapidly from tracks located on both sides of the conveyor into vertical feeders. At rates of 200 strips a minute, vacuum pick-and-place devices, one on each side of the conveyor, grab each strip and firmly force it onto the glued edge of the folder. INSET: Vacuum Lifter.