Publications

@article{Wang2019b,

title = {Scan Rate Adaptation for AFM Imaging Based on Performance Metric Optimisation},

author = {K. Wang and M. G. Ruppert and C. Manzie and D. Nesic and Y. K. Yong },

url = {https://ieeexplore.ieee.org/document/8867937},

doi = {10.1109/TMECH.2019.2947203},

year  = {2019},

date = {2019-10-14},

journal = { IEEE/ASME Transactions on Mechatronics},

abstract = {Constant-force contact-mode atomic force microscopy (AFM) relies on a feedback control system to regulate the tip-sample interaction during imaging. Due to limitations in actuators and control, the bandwidth of the regulation system is typically small. Therefore, the scan rate is usually limited in order to guarantee a desirable image quality for a constant-rate scan. By adapting the scan rate online, further performance improvement is possible, and the conditions to this improvement has been explored qualitatively in a previous study for a wide class of possible scan patterns. In this paper, a quantitative assessment of the previously proposed adaptive scan scheme is investigated through experiments that explore the impact of various degrees of freedom in the algorithm. Further modifications to the existing scheme are proposed and shown to improve the closed-loop performance. The flexibility of the proposed approach is further demonstrated by applying the algorithm to tapping-mode AFM.},

note = {early access},

keywords = {AFM, Nanopositioning, Scan Pattern, SPM, Tracking Control},

pubstate = {published},

tppubtype = {article}

}

@article{J18f,

title = {A Comparison Of Scanning Methods And The Vertical Control Implications For Scanning Probe Microscopy},

author = {Y. R. Teo and Y. K. Yong and A. J. Fleming},

url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2021/02/J18f.pdf},

doi = {10.1002/asjc.1422},

year  = {2018},

date = {2018-07-01},

journal = {Asian Journal of Control},

volume = {30},

number = {4},

pages = {1-15},

abstract = {This article compares the imaging performance of non-traditional scanning patterns for scanning probe microscopy including sinusoidal raster, spiral, and Lissajous patterns. The metrics under consideration include the probe velocity, scanning frequency, and required sampling rate. The probe velocity is investigated in detail as this quantity is proportional to the required bandwidth of the vertical feedback loop and has a major impact on image quality. By considering a sample with an impulsive Fourier transform, the effect of scanning trajectories on imaging quality can be observed and quantified. The non-linear trajectories are found to spread the topography signal bandwidth which has important implications for both low and high-speed imaging. These effects are studied analytically and demonstrated experimentally with a periodic calibration grating. },

keywords = {Scan Pattern, SPM},

pubstate = {published},

tppubtype = {article}

}

@article{Bazaei2017,

title = {Combining Spiral Scanning and Internal Model Control for Sequential AFM Imaging at Video Rate},

author = {A. Bazaei and Y. K. Yong and S. O. R. Moheimani },

url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2017/05/07482697.pdf},

year  = {2017},

date = {2017-02-01},

journal = {IEEE Transactions on Mechatronics},

volume = {22},

number = {1},

pages = {371-380},

abstract = {We report on the application of internal model control for accurate tracking of a spiral trajectory for atomic force microscopy (AFM). With a closed-loop bandwidth of only 300 Hz, we achieved tracking errors as low as 0.31% of the scan diameter and an ultravideo frame rate for a high pitch (30 nm) spiral trajectory generated by amplitude modulation of 3 kHz sinusoids. Design and synthesis procedures are proposed for a smooth modulating waveform to minimize the steady-state tracking error during sequential imaging. To obtain AFM images under the constant force condition, a high bandwidth analogue proportional integral controller is applied to the damped z-axis of a flexure nanopositioner. Efficacy of the proposed method was  demonstrated by artifact-free images at a rate of 37.5 frames/s.},

keywords = {Scan Pattern, SPM},

pubstate = {published},

tppubtype = {article}

}