• A review of demodulation techniques for amplitude-modulation atomic force microscopy 

      Ruppert, Michael G.; Harcombe, David M.; Ragazzon, Michael Remo Palmén; Moheimani, S.O. Reza; Fleming, Andrew J. (Journal article; Peer reviewed, 2017)
      In this review paper, traditional and novel demodulation methods applicable to amplitude-modulation atomic force microscopy are implemented on a widely used digital processing system. As a crucial bandwidth-limiting component ...
    • Analysis of PI-Control for Atomic Force Microscopy in Contact Mode 

      Messineo, Saverio; Ragazzon, Michael Remo Palmén; Busnelli, Fabio; Gravdahl, Jan Tommy (Peer reviewed; Journal article, 2021)
      This article investigates the properties, from a nonlinear control system standpoint, of atomic force microscope (AFM) systems, whenever operated in contact mode and controlled in the vertical direction by proportional-integral ...
    • Control in Atomic Force Microscopy: A Fractional Order Approach 

      Moltumyr, Andreas Hanssen (Master thesis, 2019)
      Denne avhandlingen er viet til undersøkelsen av fraksjonell-ordens kontroll innen nanoposisjonering. Hovedmålet har vært å teste og finne ut om teorien bak fraksjonell kalkulus kan bli brukt til å forbedre følging av ...
    • Exponential Convergence Bounds in Least Squares Estimation: Identification of Viscoelastic Properties in Atomic Force Microscopy 

      Ragazzon, Michael Remo Palmén; Gravdahl, Jan Tommy; Pettersen, Kristin Ytterstad (Journal article; Peer reviewed, 2017)
      Using atomic force microscopy (AFM) for studying soft, biological material has become increasingly popular in recent years. New approaches allow the use of recursive least squares estimation to identify the viscoelastic ...
    • Fractional-order Control: Nyquist Constrained Optimization 

      Moltumyr, Andreas Hanssen; Ragazzon, Michael Remo Palmén; Gravdahl, Jan Tommy (Peer reviewed; Journal article, 2020)
      The adoption of fractional calculus in control systems has enabled the synthesis of new controllers with fractional-order derivatives and integrals. Several optimization-based methods for tuning of linear fractional-order ...
    • Frequency domain analysis of robust demodulators for high-speed atomic force microscopy 

      Ruppert, Michael G.; Harcombe, David M.; Ragazzon, Michael Remo Palmén; Moheimani, S.O. Reza; Fleming, Andrew J. (Journal article; Peer reviewed, 2017)
      A fundamental but often overlooked component in the z-axis feedback loop of the atomic force microscope (AFM) operated in dynamic mode is the demodulator. Its purpose is to obtain a preferably fast and low-noise estimate ...
    • Generalized Lyapunov Demodulator for Amplitude and Phase Estimation by the Internal Model Principle 

      Ragazzon, Michael Remo Palmén; Messineo, Saverio; Gravdahl, Jan Tommy; Harcombe, David M.; Ruppert, Michael G. (Journal article; Peer reviewed, 2019)
      Effective demodulation of amplitude and phase is a requirement in a wide array of applications. Recent efforts have increased the demodulation performance, in particular, the Lyapunov demodulator allows bandwidths up to ...
    • H_inf Reduced Order Control for Nanopositioning: Numerical Implementability 

      Ragazzon, Michael Remo Palmén; Eielsen, Arnfinn Aas; Gravdahl, Jan Tommy (IFAC Proceedings series;, Journal article; Peer reviewed, 2014)
      In this paper we discuss how model reduction affects the stability and computational complexity of controllers for nanopositioning systems. A robust H∞ multiple-input multiple-output controller is designed and implemented ...
    • Higher-Harmonic AFM Imaging with a High-Bandwidth Multifrequency Lyapunov Filter 

      Harcombe, David M.; Ruppert, Michael G.; Ragazzon, Michael Remo Palmén; Fleming, Andrew J. (Journal article; Peer reviewed, 2017)
      A major difficulty in multifrequency atomic force microscopy (MF-AFM) is the accurate estimation of amplitude and phase at multiple frequencies for both z-axis feedback and material contrast imaging. A lock-in amplifier ...
    • Lyapunov estimation for high-speed demodulation in multifrequency atomic force microscopy 

      Harcombe, David M.; Ruppert, Michael G.; Ragazzon, Michael Remo Palmén; Fleming, Andrew J. (Journal article; Peer reviewed, 2018)
      An important issue in the emerging field of multifrequency atomic force microscopy (MF-AFM) is the accurate and fast demodulation of the cantilever-tip deflection signal. As this signal consists of multiple frequency ...
    • Lyapunov Estimator for High-Speed Demodulation in Dynamic Mode Atomic Force Microscopy 

      Ragazzon, Michael Remo Palmén; Ruppert, Michael G.; Harcombe, David M.; Fleming, Andrew J.; Gravdahl, Jan Tommy (Journal article; Peer reviewed, 2017)
      In dynamic mode atomic force microscopy (AFM), the imaging bandwidth is governed by the slowest component in the open-loop chain consisting of the vertical actuator, cantilever, and demodulator. While the common demodulation ...
    • Model-Based Identification of Nanomechanical Properties in Atomic Force Microscopy: Theory and Experiments 

      Ragazzon, Michael Remo Palmén; Gravdahl, Jan Tommy; Pettersen, Kristin Ytterstad (Journal article; Peer reviewed, 2018)
      The ability of the atomic force microscope (AFM) to resolve highly accurate interaction forces has made it an increasingly popular tool for determining nanomechanical properties of soft samples. Traditionally, elasticity ...
    • Nanopositioning in Atomic Force Microscopes: Robust Control Design, Order Reduction and Numerical Implementability 

      Ragazzon, Michael Remo Palmén (Master thesis, 2013)
      This thesis can be divided into two overall topics. The first concerns control design for nanopositioning devices, and specifically an Atomic Force Microscope (AFM). The second topic concerns the implementability issues ...
    • On implementation of the Preisach model identification and inversion for hysteresis compensation 

      Stakvik, Jon Åge; Ragazzon, Michael Remo Palmén; Eielsen, Arnfinn Aas; Gravdahl, Jan Tommy (Peer reviewed; Journal article, 2015)
      A challenge for precise positioning in nanopositioning using smart materials is hysteresis, limiting posi-tioning accuracy. The Preisach model, based on the delayed relay operator for hysteresis modelling, isintroduced. ...
    • Topography and force imaging in atomic force microscopy by state and parameter estimation 

      Ragazzon, Michael Remo Palmén; Gravdahl, Jan Tommy; Pettersen, Kristin Ytterstad; Eielsen, Arnfinn Aas (Journal article; Peer reviewed, 2015)
      A novel imaging method for atomic force microscopy based on estimation of state and parameters is presented. The cantilever dynamics is modeled as a linear system augmented by the tip-sample interaction force. The states ...
    • Viscoelastic Properties of Cells: Modeling and Identification by Atomic Force Microscopy 

      Ragazzon, Michael Remo Palmén; Gravdahl, Jan Tommy; Vagia, Marialena (Journal article; Peer reviewed, 2017)
      Identification of mechanical properties of cells has previously been shown to have a great potential and effectiveness on medical diagnosis. As a result, it has gathered increasing interest of researchers over the recent ...