TitleInversion-based iterative feedforward-feedback control
NameZhang, Yan (author), Zou, Qingze (chair), Yi, Jingang (internal member), Baruh, Haim (internal member), Benaroya, Haym (internal member), Rutgers University, Graduate School - New Brunswick,
SubjectMechanical and Aerospace Engineering,
DescriptionThis thesis presents the development of inversion-based iterative feedforward-feedback (II-FF/FB) approach and its application to achieve high-speed force load in nanomechanical property measurement of soft materials in liquid, and high-speed nanopositioning control using piezoelectric actuators. High-speed nanopositioning is needed in various applications. For example, high-speed precision tracking of the force load is needed to measure the rate-dependent viscoelasticity of a wide range of soft materials in liquid, including live cells. In these applications, however, various adverse effects exist that challenge the precision tracking of the desired trajectory. For instance, during the nanomechanical measurement in liquid, the tracking precision is limited by the thermal drift effect, the reduction of the signal to noise ratio, and the hysteresis and the vibrational dynamics effects of the piezoelectric actuators (used to position the probe relative to the sample), particularly during high-speed measurements. These adverse effects limit the positioning precision not only during quasi-static operation (i.e., low-speed), but also in high-speed tracking. This research is focused on the development the II-FF/FB technique to tackle these critical issues in practical applications. Motivated by the challenges in high-speed nanomechanical measurement of soft materials in liquid, the II-FF/FB is developed by inverting the closed-loop system dynamics, and then updating and correcting the inversion-based input through iterations (called the closed-loop injection II-FF/FB, CIII-FF/FB technique). A proportional-integral (PI) feedback controller along with a notch-filter is utilized to improve the robustness of the entire system against dynamics uncertainties and the gain margin of the closed-loop system. The proposed CIII-FF/FB technique is implemented in experiments to the nanomechanical property measurement of a poly (dimethylsiloxane) (PDMS) sample in liquid. The experimental results show that by using the CIII-FF/FB technique, precision tracking of the desired force load profile can be achieved in high speed nanomechanical measurement of soft materials in liquid. We also study an alternative approach to the II-FF/FB approach by inverting the plant dynamics to generate the feedforward input, and injecting the feedforward input into the feedback loop by augmenting it to the feedback one (called the plant-injection II-FF/FB, PIII-FF/FB technique). These two II-FF/FB techniques, the CIII-FF/FB and PIII-FF/FB techniques, are compared through two experimental implementations: (1) the nanopositioning tracking of a piezo-bimorph actuator, and (2) the force-load profile tracking in nanomechanical measurements in liquid. The experimental results are analyzed and discussed to compare the performance of these two approaches under various conditions.
NoteIncludes bibliographical references
Noteby Yan Zhang
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.