- Title
- Design, characterization and control of serial-kinematic X-Y-Z nanopositioner for high-speed Atomic Force Microscopy
- Creator
- Wadikhaye, Sachin
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2014
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Design of instruments that are capable of visualising matter at nano-meter scale is a highly challenging task. Atomic Force Microscopy (AFM) is one such tool that has enabled researchers from multiple disciplines to explore samples with high resolution nanoscale imaging. However, the throughput of the conventional AFM has been limited by the scanning bandwidth of its nanopositioner. This dissertation addresses challenges with mechanical design of serial-kinematic nanopositioners and control techniques to enhance the performance of this family of nanopositioners. Serial-kinematic configuration is appealing to designers since they differentiate the positioning systems along the three axes, X,Y and Z into three stages. However, design and control of such nanopositioners is a major concern because of interlacing of stages. In this thesis, flexure geometries are analysed, sensor positioning is studied and controllers are designed to make the nanopositioners compact, fast and accurate. Two designs of high-speed nanopositioners are presented which are integrated with commercial AFMs to achieve high-speed imaging. A compact serial-kinematic nanopositioner is designed to replace a piezoelectric tube nanopositioner in a commercially available NT-MDT NTEGRA AFM. Mechanical design involves selection of compact high stiffness flexures using analytical stiffness calculation. Vibration, hysteresis and time delay compensation involving design of Integral Resonant Control (IRC), integral action and feedforward control is presented to overcome the impediments to fast scan. The design of IRC accommodates for the time-delay, and thereby ensuring robust stability. Scanning results with line rates up to 200 Hz demonstrate the applicability of the nanopositioner for high-speed imaging in AFM. The second nanopositioner is designed to integrate with another commercially available Nanosurf easyScan-2 scan-by-probe AFM. A novel tapered flexure geometry is introduced to reduce mass of the fast stage to increase its natural frequency. Evaluation of the sensor positioning in serial-kinematic nanopositioner is furnished. The best sensor configuration is incorporated in the design which not only provides the exact position of the sample but also gives the cross coupling as seen by the sample. A feedforward controller is designed to overcome the dynamics and hysteretic effects to improve the imaging and tracking performance of the nanopositioner. The nanopositioner is integrated with AFM and scan results for line rates up to 640 Hz are reported. The two nanopositioner designs and associated control techniques were analysed and positives and limitations are discussed. Finally, the future work is described in brief.
- Subject
- nanopositioning; Atomic Force Microscopy; flexure design; control design
- Identifier
- http://hdl.handle.net/1959.13/1048139
- Identifier
- uon:14878
- Rights
- Copyright 2014 Sachin Wadikhaye
- Language
- eng
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| Thumbnail | File | Description | Size | Format | |||
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| View Details Download | ATTACHMENT01 | Abstract | 133 KB | Adobe Acrobat PDF | View Details Download | ||
| View Details Download | ATTACHMENT02 | Thesis | 20 MB | Adobe Acrobat PDF | View Details Download |