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Batch, multiproduct chemical processing facilities present special challenges for conducting thorough hazard assessments. New or improved methods are needed to perform quality hazard analyses while reducing time and resource demands on facility personnel. A technique has been developed to expand traditional hazard and operability (HAZOP) methodology to include additional parameters for process operational...
Similar to combustion engines comprising multiple cylinders engaged with a crankshaft, multiple piezoelectric stack actuators (PSA) engaged with a common output rod can produce smooth, long stroke motion with desired properties. In particular, when equally spaced multiple units are arranged to push sinusoidal gear teeth on the output rod, the system exhibits unique collective behaviors thanks to “harmonic”...
Piezoelectric stack actuators have many advantageous characteristics including power density, backdrivability, and their ability to efficiently hold a force for long periods of time. The stack actuator was integrated into a high-gain amplification mechanism which in turn was integrated into a poly-actuator, an actuator made up of several units. A proportional controller was used to close the loop...
Capacitive actuators, such as piezoelectric stack actuators, provide an efficient solution for robotic and mecha-tronic systems that typically require large forces and minimal velocities over long periods of time. To overcome the stack actuator's limitations, particularly their limited stroke, a harmonic poly-actuator design is presented. This design utilizes a multitude of intermediate buckling amplification...
A novel design concept of piezoelectric actuators producing large displacement while transmitting a significant amount of energy is presented. A rolling-contact buckling mechanism with a novel preload mechanism can amplify the PZT stack’s displacement on the order of 100 times while transmitting several times larger work output than conventional flexure-type displacement amplification mechanisms....
A novel design concept is presented for amplifying the displacement of a PZT stack over 50-fold while transmitting a significant amount of work per cycle. Piezoelectric devices, such as PZT stack actuators, have a competitive power density, while consuming virtually no energy for generating a force at a constant position. Despite the salient features, the actual work usable for activating a load is...
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