Parameter uncertainty is a key challenge in the real-time control of nanopositioners employed in scanning probe microscopy. Changes in the sample to be scanned introduces changes in system resonances, requiring instantaneous online tuning of controller parameters to ensure stable, optimal scanning performance. This paper presents a method based on the frequency-domain algebraic derivative approach for the accurate online identification of the nanopositioner's parameters. The parameter estimates are produced within a fraction of one period of the resonant mode frequency, allowing almost instantaneous tuning of controller parameters. Experimental results show that the proposed method can be utilized to automatically tune an integral resonant control scheme that combines both damping and tracking actions, and consequently deliver positioning performance far superior to that achieved solely due to the scheme's inherent robustness properties. It is further shown that the achieved performance compares favorably with an optimally designed control scheme of the same type.
#1Changbae Hyun(UNIST: Ulsan National Institute of Science and Technology)H-Index: 8
#2Harpreet Kaur(UA: University of Arkansas)H-Index: 37
Last. Jiali Li(UA: University of Arkansas)H-Index: 22
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In this work, we demonstrate that a tuning fork can be used as a force detecting sensor for manipulating DNA molecules and for controlling the DNA translocation rate through a nanopore. One prong of a tuning fork is glued with a probe tip which DNA molecules can be attached to. To control the motion and position of the tip, the tuning fork is fixed to a nanopositioning system which has sub-nanometer position control. A fluidic chamber is designed to fulfill many requirements for the experiment: ...
Last. Xiaohui Xiao(WHU: Wuhan University)H-Index: 12
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Cross-coupling effect severely hinder fast and accurate tracking for parallel piezo nanopositioning stages. In this paper, a data-driven feedforward decoupling filter (DDFDF) is proposed to reduce the cross-coupling caused errors. Traditional control methods for coupled system could achieve good performance on the premise that the dynamic model is accurate and no non-minimum phase zeros exist. The proposed method is totally data-driven with the advantage of no need for accurate identified model ...
#1Duyoung Min(UCLA: University of California, Los Angeles)H-Index: 9
#2Mark A. Arbing(UCLA: University of California, Los Angeles)H-Index: 16
Last. James U. Bowie(UCLA: University of California, Los Angeles)H-Index: 70
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Manipulating single molecules and systems of molecules with mechanical force is a powerful technique to examine their physical properties. Applying force requires attachment of the target molecule to larger objects using some sort of molecular tether, such as a strand of DNA. DNA handle attachment often requires difficult manipulations of the target molecule, which can preclude attachment to unstable, hard to obtain, and/or large, complex targets. Here we describe a method for covalent DNA handl...
High-speed atomic force microscopy (HS-AFM) has been established and used, which can visualize biomolecules in dynamic action at high spatiotemporal resolution without disturbing their function. Various studies conducted in the past few years have demonstrated that the dynamic structure and action of biomolecules revealed with HS-AFM can provide greater insights than ever before into how the molecules function. However, this microscopy has still limitations in some regards. Recently, efforts hav...
Last. Sumeet S. Aphale(Aberd.: University of Aberdeen)H-Index: 14
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Positive Velocity and Position Feedback (PVPF) is a widely used control scheme in lightly damped resonant systems with collocated sensor actuator pairs. The popularity of PVPF is due to the ability to achieve a chosen damping ratio by repositioning the poles of the system. The addition of a necessary tracking controller causes the poles to deviate from the intended location and can be a detriment to the damping achieved. By designing the PVPF and tracking controllers simultaneously, the optimal ...
We deal with the online identification of the payload mass carried by a single-link flexible arm that moves on a vertical plane and therefore is affected by the gravity force. Specifically, we follow a frequency domain design methodology to develop an algebraic identifier. This identifier is capable of achieving robust and efficient mass estimates even in the presence of sensor noise. In order to highlight its performance, the proposed estimator is experimentally tested and compared with other c...
#1Sajal K. Das(UNSW: University of New South Wales)H-Index: 93
#2Hemanshu R. Pota(UNSW: University of New South Wales)H-Index: 48
Last. Ian R. Petersen(UNSW: University of New South Wales)H-Index: 74
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This paper presents the design and experimental implementation of a novel multi-input multi-output (MIMO) control structure using two negative-imaginary damping controllers to damp the first resonant mode and attenuate cross coupling effects between the axes of a piezoelectric tube scanner. The dynamics of the scanner in the lateral and longitudinal axes are identified from measured data and the design of the controller using a MIMO framework is done based on a reference model matching approach....
#1Masih Mahmoodi(U of T: University of Toronto)H-Index: 5
#2James K. Mills(U of T: University of Toronto)H-Index: 39
Last. Beno Benhabib(U of T: University of Toronto)H-Index: 34
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A new modified integral resonant control (IRC) scheme is demonstrated herein for vibration suppression of the flexible links of parallel kinematic mechanisms (PKMs). Typically, the resonance frequencies and response amplitudes of the PKM links experience configuration–dependent variation within the workspace. To address these variations, a robust quantitative feedback theory (QFT) approach is utilised herein on a cantilever beam, with a variable tip mass as a proof of concept. The proposed IRC s...
#1Andres San-Millan(UCLM: University of Castilla–La Mancha)H-Index: 7
#2Vicente Feliu(UCLM: University of Castilla–La Mancha)H-Index: 32
Vibrations are present in many mechanical structures and machines, and are often associated with their elastic parts. Characterizing these vibrations, i.e., obtaining their frequencies, amplitudes and phases, is of most interest in many applications ranging from the maintenance of civil structures to motion control. This paper presents a method for the online and reliable identification of the defining parameters of two unknown sinusoidal signals through the use of their measured sum in the pres...
In this paper, we present a high-speed pick-and-place method for cell-assembly applications. In addition to the range of motion and accuracy, the agility of a manipulation system is an important parameter, but it has been so far underrated in the literature. To begin high-speed micromanipulation, obtaining 3-D positions of both the target microobject and the end effector rapidly is necessary. Controlling the residual vibration of the end effector, which is greater at high speed, is another arduo...
#1Wenchong Chen(College of Management and Economics)H-Index: 1
#2Hongwei Liu(College of Management and Economics)H-Index: 1
Last. Ershi Qi(College of Management and Economics)H-Index: 1
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Abstract Advanced technologies (e.g., distributed sensors, RFID, and auto-identification) can gather processing information (e.g., system status, uncertain machine breakdown, and uncertain job demand) accurately and in real-time. By combining this transparent, detailed, and real-time production information with production system physical properties, an intelligent event-driven feedback control can be designed to reschedule the release plan of jobs in real-time without work-in-process (WIP) explo...
