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—In this study, the actuator load force of a nanopo-sitioning stage is utilized as a feedback variable to achieve both tracking and damping. The transfer function from the applied actuator voltage to the measured load force exhibits a zero-pole ordering that greatly simplifies the design and implementation of a tracking and damping controller. Exceptional(More)
—In this paper, a piezoelectric tube of the type typically used in scanning tunneling microscopes (STMs) and atomic force microscopes (AFMs) is considered. Actuation of this piezoelectric tube is hampered by the presence of a lightly damped low-frequency resonant mode. The resonant mode is identified and damped using a positive velocity and position(More)
This paper introduces integral resonant control, IRC, a simple, robust and well-performing technique for vibration control in smart structures with collocated sensors and actuators. By adding a direct feed-through to a collocated system, the transfer function can be modified from containing resonant poles followed by interlaced zeros, to zeros followed by(More)
—Piezoelectric transducer (PZT) patches can be attached to a structure in order to reduce vibration. The PZT patches essentially convert vibrational mechanical energy into electrical energy. The electrical energy can be dissipated via an electrical impedance. Currently, impedance designs require experimental tuning of resistive circuit elements to provide(More)
Many popular modes of scanning probe microscopy require a vertical feedback system to regulate the tip-sample interaction. Unfortunately the vertical feedback controller imposes a severe limit on the scan-speed of scanning probe microscopes. In this paper, the foremost bandwidth limitation is identified to be the low-frequency mechanical resonances of the(More)
AUXIN BINDING PROTEIN1 (ABP1) has long been characterized as a potentially important mediator of auxin action in plants. Analysis of the functional requirement for ABP1 during development was hampered because of embryo lethality of the null mutant in Arabidopsis thaliana. Here, we used conditional repression of ABP1 to investigate its function during(More)
— Piezoelectric tube scanners are employed in high-resolution positioning applications such as scanning probe microscopy and nano-fabrication. Much research has proceeded with the aim of reducing hysteresis and vibration, the foremost problems associated with piezoelectric tube scanners. In this paper, two simple techniques are proposed for simultaneously(More)
Whether morphogenesis is cell division-driven or organismal-based has been a long-running debate in plant biology. This article is a summary of a series of experiments aimed at distinguishing these alternate views by local manipulation of parameters of cell division frequency, orientation, and growth within the shoot apical meristem. These data, put in the(More)
This paper studies the feedback structure associated with piezoelectric shunt damping systems and introduces a new impedance structure for multi-mode piezoelectric shunt damping. The impedance is shown to be realizable using passive circuit components and digital implementation of the associated admittance transfer function is discussed.
In this work the measurement quality of capacitive displacement sensors is augmented with the high dynamic sensitivity of piezoelectric transducers. By combining the low-frequency performance and stability of capacitive sensors with the high sensitivity and bandwidth of piezoelectric transducers, a displacement RMS noise of 1 nm and range of 100 mum is(More)