Scanning Probe Microscopy
Probe Based Lithography
Probe based lithography involves creating nanometer sized features from photoresist and metal on conducting and semiconducting substrates. Near field optical, electrical and thermal fields are employed in combination with evaporation, etching and electroplating to provide high-speed alternatives for mask-less nanofabrication.
Nanopositioning
A nanopositioner is a electromechanical device for moving objects in three dimensions with atomic, or sub-atomic resolution. Nanopositioners are employed in applications such as imaging, fabrication and optics. This field encompasses mechanical design, sensor design, and control theory. More details.
Electroactive Optics
Piezoelectric actuators can be combined with mirrors, lenses and objectives to actively control the path and properties of an optical field or laser beam. High speed electro-optics are required for precision lasers, maskless lithography, and microscopy.
Precision Sensors
This project aims to study the fundamental limitations of capacitive, optical and magnetic position sensors. New techniques are under development to provide sub-atomic resolution over extremely wide bandwidth.
Biomedical Devices
An endoscopic pill robot is being developed for noninvasive imaging and intervention. The robot can be swallowed and includes power transmission, 6-Dimensional localization, and locomotion.
Piezo Actuators and Amplifiers

Piezo bender actuator with integrated 200V power electronics
Piezo Robotics
Due to their compact size and high efficiency, piezoelectric actuators are ideal for micro-actuation in bio-inspired robotics. This project is developing actuators and mechanics for a piezoelectric dragon-fly robot.
de Bem, N. F. S.; Ruppert, M. G.; Fleming, A. J.; Yong, Y. K.
In: Sensors and Actuators A: Physical, vol. 338, pp. 113496, 2022, ISSN: 0924-4247.
@article{J22a,
title = {Simultaneous tip force and displacement sensing for AFM cantilevers with on-chip actuation: Design and characterization for off-resonance tapping mode},
author = {N. F. S. de Bem and M. G. Ruppert and A. J. Fleming and Y. K. Yong},
url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2022/03/J22a.pdf},
doi = {10.1016/j.sna.2022.113496},
issn = {0924-4247},
year = {2022},
date = {2022-03-08},
urldate = {2022-03-08},
journal = {Sensors and Actuators A: Physical},
volume = {338},
pages = {113496},
abstract = {The use of integrated on-chip actuation simplifies the identification of a cantilever resonance, can improve imaging speed, and enables the use of smaller cantilevers, which is required for low-force imaging at high speed. This article describes a cantilever with on-chip actuation and novel dual-sensing capabilities for AFM. The dual-sensing configuration allows for tip displacement and tip force to be measured simultaneously. A mathematical model is developed and validated with finite element analysis. A physical prototype is presented, and its calibration and validation are presented. The cantilever is optimized for use in off-resonance tapping modes. Experimental results demonstrate an agreement between the on-chip sensors and external force and displacement measurements.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Ruppert, M. G.; Martin-Jimenez, D.; Yong, Y. K.; Ihle, A.; Schirmeisen, A.; Fleming, A. J.; Ebeling, D.
Experimental Analysis of Tip Vibrations at Higher Eigenmodes of QPlus Sensors for Atomic Force Microscopy Journal Article
In: Nanotechnology, vol. 33, iss. 18, pp. 185503, 2022, ISSN: 1361-6528.
@article{Ruppert2022,
title = {Experimental Analysis of Tip Vibrations at Higher Eigenmodes of QPlus Sensors for Atomic Force Microscopy},
author = {M. G. Ruppert and D. Martin-Jimenez and Y. K. Yong and A. Ihle and A. Schirmeisen and A. J. Fleming and D. Ebeling},
url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2022/03/J22c.pdf},
doi = {10.1088/1361-6528/ac4759},
issn = {1361-6528},
year = {2022},
date = {2022-02-10},
urldate = {2022-02-10},
journal = {Nanotechnology},
volume = {33},
issue = {18},
pages = {185503},
abstract = {QPlus sensors are non-contact atomic force microscope probes constructed from a quartz tuning fork and a tungsten wire with an electrochemically etched tip. These probes are self-sensing and offer an atomic-scale spatial resolution. Therefore, qPlus sensors are routinely used to visualize the chemical structure of adsorbed organic molecules via the so-called bond imaging technique. This is achieved by functionalizing the AFM tip with a single CO molecule and exciting the sensor at the first vertical cantilever resonance mode. Recent work using higher-order resonance modes has also resolved the chemical structure of single organic molecules. However, in these experiments, the image contrast can differ significantly from the conventional bond imaging contrast, which was suspected to be caused by unknown vibrations of the tip. This work investigates the source of these artefacts by using a combination of mechanical simulation and laser vibrometry to characterize a range of sensors with different tip wire geometries. The results show that increased tip mass and length cause increased torsional rotation of the tuning fork beam due to the off-center mounting of the tip wire, and increased flexural vibration of the tip. These undesirable motions cause lateral deflection of the probe tip as it approaches the sample, which is rationalized to be the cause of the different image contrast. The results also provide a guide for future probe development to reduce these issues.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Seethaler, R.; Mansour, S. Z.; Ruppert, M. G.; Fleming, A. J.
Piezoelectric Benders with Strain Sensing Electrodes: Sensor Design for Position Control and Force Estimation Journal Article
In: Sensors and Actuators A: Physical, vol. 335, pp. 113384, 2022, ISSN: 0924-4247.
@article{Fleming2022,
title = {Piezoelectric Benders with Strain Sensing Electrodes: Sensor Design for Position Control and Force Estimation},
author = {R. Seethaler and S. Z. Mansour and M. G. Ruppert and A. J. Fleming},
url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2022/03/J22b.pdf},
doi = {https://doi.org/10.1016/j.sna.2022.113384},
issn = {0924-4247},
year = {2022},
date = {2022-01-22},
urldate = {2022-01-22},
journal = {Sensors and Actuators A: Physical},
volume = {335},
pages = {113384},
abstract = {Piezoelectric benders are widely used in industrial applications due to their low-cost and compact size. However, due to the large relative size and cost of displacement sensors, bender actuators are often operated in open-loop or with feed-forward control, which can limit positioning accuracy to 20% of full-scale. To improve the positioning accuracy of piezoelectric benders, this article proposes integrating resistive strain gauges into the electrode surface by chemical etching or laser ablation. These strain sensors are then used to measure and control the tip displacement. The proposed sensors are shown to suffer from significant cross-coupling between the actuator voltage and measured signal; however, this can be mitigated by judicious choice of the sensor location and actuator driving scheme. In addition to position sensing, a method is also presented for simultaneous estimation of the contact force between the actuator tip and load. The proposed methods are validated experimentally by controlling the tip position of a piezoelectric bender while simultaneously estimating the force applied to a reference load cell.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Xavier, M. S.; Tawk, C. D.; Yong, Y. K.; Fleming, A. J.
3D-printed omnidirectional soft pneumatic actuators: Design, modeling and characterization Journal Article
In: Sensors and Actuators: A. Physical , vol. 332, iss. 2, pp. 113199, 2021, ISSN: 0924-4247.
@article{Xavier2021,
title = {3D-printed omnidirectional soft pneumatic actuators: Design, modeling and characterization},
author = {M. S. Xavier and C. D. Tawk and Y. K. Yong and A. J. Fleming},
url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2022/03/J21f.pdf},
doi = {10.1016/j.sna.2021.113199},
issn = {0924-4247},
year = {2021},
date = {2021-12-25},
urldate = {2021-12-25},
journal = {Sensors and Actuators: A. Physical },
volume = {332},
issue = {2},
pages = {113199},
abstract = {Soft pneumatic actuators are usually fabricated using molding and casting techniques with silicone rubbers, which requires intensive manual labor and limits repeatability and design flexibility for complex geometries. This article presents the design and direct 3D-printing of novel omnidirectional soft pneumatic actuators using stereolithography (SLA) with an elastic resin and fused deposition modeling (FDM) with a thermoplastic polyurethane (TPU). The actuator is modeled and optimized for bending performance using the finite element method along with a hyperelastic material model that is based on experimental uniaxial tensile data. The designs inspired by fast pneumatic network actuators (PneuNets) allow for multimodal actuation including bending, extension and contraction motions under positive, negative or differential pressures. The predicted results from the finite element method are compared with the experimental results for a range of actuation configurations. These novel omnidirectional actuators have significant potential in applications such as pipe inspection and biomedical devices.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Young, T. R.; Xavier, M. S.; Yong, Y. K.; Fleming, A. J.
A Control and Drive System for Pneumatic Soft Robots: PneuSoRD Inproceedings
In: International Conference on Intelligent Robots and Systems, Prague, Czech Republic , 2021, ISSN: 2153-0866.
@inproceedings{Young2021,
title = {A Control and Drive System for Pneumatic Soft Robots: PneuSoRD},
author = {T. R. Young and M. S. Xavier and Y. K. Yong and A. J. Fleming },
url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2022/03/C21b.pdf},
doi = {10.1109/IROS51168.2021.9635874},
issn = {2153-0866},
year = {2021},
date = {2021-09-27},
urldate = {2021-09-27},
booktitle = {International Conference on Intelligent Robots and Systems},
address = {Prague, Czech Republic },
abstract = {This article describes an open-source hardware platform for controlling pneumatic soft robotic systems and presents the comparison of control schemes with on-off and proportional valves. The Pneumatic Soft Robotics Driver (PneuSoRD) can be used with up to one pump and pressure accumulator, 26 on-off valves, and 5 proportional valves, any of which can be operated in open or closed-loop control using up to 12 sensor inputs, which allows for the simultaneous control of a large number of soft actuators. The electronic driver connects to a National Instruments myRIO controller or an Arduino Due with the use of an adapter shield. A library of pressure control algorithms in both LabVIEW and Simulink is provided that includes bang-bang control, hysteresis control and PID control using on-off or proportional valves. LabVIEW and Simulink provide user-friendly interfaces for rapid prototyping of control algorithms and real-time evaluation of pressure dynamics. The characteristics and performance of these control methods and pneumatic setups are evaluated to simplify the choice of valves and control algorithm for a given application. },
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}