@article{Yong2023,

title = {Thermal Protection of Piezoelectric Actuators Using Complex Electrical Power Measurements and Simplified Thermal Models},

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

doi = {10.1109/TMECH.2023.3277437},

year  = {2023},

date = {2023-06-05},

urldate = {2023-06-05},

journal = {IEEE/ASME Transactions on Mechatronics (Early Access)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Xavier2023,

title = {Modeling of soft fluidic actuators using fluid-structure interaction simulations with underwater applications},

author = {M. S. Xavier and S. Harrison and D. Howard and Y. K. Yong and A. J. Fleming},

url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2023/06/FSI.pdf},

doi = {https://doi.org/10.1016/j.ijmecsci.2023.108437},

year  = {2023},

date = {2023-05-15},

urldate = {2023-05-15},

journal = {International Journal of Mechanical Sciences},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{J22h,

title = {Soft Pneumatic Actuators: A Review of Design, Fabrication, Modeling, Sensing, Control and Applications},

author = {M. S. Xavier and C. D. Tawk and A. Zolfagharian and J. Pinskier and D. Howard and T. Young and J. Lai and S. Harrison and Y. K. Yong and M. Bodaghi and A. J. Fleming},

url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2023/02/J22h-1.pdf},

doi = {10.1109/ACCESS.2022.3179589},

issn = {2169-3536},

year  = {2022},

date = {2022-06-02},

urldate = {2022-06-02},

journal = {IEEE Access},

volume = {10},

pages = {59442-59485},

abstract = {Soft robotics is a rapidly evolving field where robots are fabricated using highly deformable materials and usually follow a bioinspired design. Their high dexterity and safety makes them ideal for applications such as gripping, locomotion, and biomedical devices, where the environment is highly dynamic and sensitive to physical interaction. Pneumatic actuation remains the dominant technology in soft robotics due to its low cost and mass, fast response time, and easy implementation. Given the significant number of publications in soft robotics over recent years, newcomers and even established researchers may have difficulty assessing the state of the art. To address this issue, this article summarizes the development of soft pneumatic actuators and robots up until the date of publication. The scope of this article includes the design, modeling, fabrication, actuation, characterization, sensing, control, and applications of soft robotic devices. In addition to a historical overview, there is a special emphasis on recent advances such as novel designs, differential simulators, analytical and numerical modeling methods, topology optimization, data-driven modeling and control methods, hardware control boards, and nonlinear estimation and control techniques. Finally, the capabilities and limitations of soft pneumatic actuators and robots are discussed and directions for future research are identified.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{J22e,

title = {Nonlinear Estimation and Control of Bending Soft Pneumatic Actuators Using Feedback Linearization and UKF },

author = {M. S. Xavier and A. J. Fleming and Y. K. Yong},

url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2023/02/J22e-1.pdf},

doi = {10.1109/TMECH.2022.3155790},

issn = {1083-4435},

year  = {2022},

date = {2022-06-01},

urldate = {2022-06-01},

journal = {IEEE/ASME Transactions on Mechatronics},

volume = {27},

issue = {4},

pages = {1919-1927},

abstract = {In this article, we combine nonlinear estimation and control methods for precise bending angle control in soft pneumatic actuators driven by a pressure source and single low-cost ON/OFF solenoid valve. First, a complete model for the soft actuator is derived, which includes both the motion and pressure dynamics. An unscented Kalman filter (UKF) is used to estimate the velocity state and filter noisy measurements from a pressure sensor and an embedded resistive flex sensor. Then, a feedback linearization approach is used with pole placement and linear quadratic regulator (LQR) controllers for bending angle control. To compensate for model uncertainties and improve reference tracking, integral action is incorporated to both controllers. The closed-loop performance of the nonlinear estimation and control approach is experimentally evaluated with a soft pneumatic network actuator. The simulation and experimental results show that the UKF provides accurate state estimation from noisy sensor measurements. The results demonstrate the effectiveness and robustness of the proposed observer-based nonlinear controllers for bending angle trajectory tracking.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{J22f,

title = {High Performance Raster Scanning of Atomic Force Microscopy Using Model-free Repetitive Control},

author = {Linlin Li and A. J. Fleming and Y. K. Yong and S. S. Aphale and LiMin Zhu},

url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2022/08/J22f.pdf},

doi = {10.1016/j.ymssp.2022.109027},

issn = {0888-3270},

year  = {2022},

date = {2022-05-01},

urldate = {2022-05-01},

journal = {Mechanical Systems and Signal Processing},

volume = {173},

number = {109027},

abstract = {The image quality of an atomic force microscope depends on the tracking performance of the lateral X and Y axis positioner. To reduce the requirement for accurate system models, this article describes a method based on Model­ free Repetitive Control (MFRC) for high performance control of fast triangular trajectories in the X-axis, and a slow staircase trajectory in the Y-axis, while simultaneously achieving coupling compensation from the X-axis to Y-axis. The design and stability analysis of the MFRC scheme are presented in detail. The tracking results are experimen­ tally evaluated with a range of different load conditions, showing the efficacy of the method with large variations in plant dynamics. To address the coupling from the X-axis to the Y-axis while tracking the non-periodic staircase trajectories, a pre-learning step is used to generate the compensation signals, which is combined in a feedforward manner in real-time implementations. This approach is also applied to address the problem of longer convergence if needed. Experimental tracking control and coupling compensation is demonstrated on a commercially available piezoelectric-actuated scanner. The proposed method reduces the root-mean-square tracking from 191.4 nm in open­ loop or 194.6 nm with PI control, to 2.8 nm with PI+MFRC control at 100 Hz scan rate, which demonstrates the significant improvement achieved by the proposed method.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{J22d,

title = {Model-Based Nonlinear Feedback Controllers for Pressure Control of Soft Pneumatic Actuators Using On/Off Valves},

author = {M. S. Xavier and A. J. Fleming and Y. K. Yong},

url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2022/03/J22d.pdf},

doi = {10.3389/frobt.2022.818187},

issn = {2296-9144},

year  = {2022},

date = {2022-03-17},

urldate = {2022-03-17},

journal = {Frontiers in Robotics and AI},

volume = {9},

abstract = {This article describes the application and comparison of three nonlinear feedback controllers for low-level control of soft actuators driven by a pressure source and single high-speed on/off solenoid valve. First, a mathematical model of the pneumatic system is established and the limitations of the open-loop system are evaluated. Next, a model of the pneumatic system is developed using Simscape Fluids to evaluate the performance of various control strategies. In this article, State-Dependent Riccati Equation control, sliding mode control, and feedback linearization are considered. To improve robustness to model uncertainties, the sliding mode and feedback linearization control strategies are augmented with integral action. The model of the pneumatic system is also used to develop a feedforward component, which is added to a PI controller with anti-windup. The simulation and experimental results demonstrate the effectiveness of the proposed controllers for pressure tracking.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@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}

}

@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}

}

@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}

}

@article{Omidbeike2021,

title = {Five-Axis Bimorph Monolithic Nanopositioning Stage: Design, Modeling, and Characterization},

author = {M. Omidbeike and S. I. Moore and Y. K. Yong and A. J. Fleming},

url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2022/03/J21g.pdf},

doi = {10.1016/j.sna.2021.113125},

issn = {0924-4247},

year  = {2021},

date = {2021-09-16},

urldate = {2021-09-16},

journal = {Sensors and Actuators A: Physical},

volume = {332},

issue = {1},

abstract = {The article describes the design and modeling of a five-axis monolithic nanopositioning stage constructed from a bimorph piezoelectric sheet. Six-axis motion is also possible but requires 16 amplifier channels rather than 8. The nanopositioner is ultra low profile with a thickness of 1 mm. Analytical modeling and finite-element-analysis accurately predict the experimental performance. The stage was conservatively driven with 33% of the maximum voltage, which resulted in an X and Y travel range of 6.22 μm and 5.27 μm respectively; a Z travel range of 26.5 μm; and a rotational motion of 600 μrad and 884 μrad about the X and Y axis respectively. The first resonance frequency occurs at 883 Hz in the Z axis. Experimental atomic force microscopy is performed using the proposed device as a sample scanner.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{J21d,

title = {Design and Control of Pneumatic Systems for Soft Robotics: a Simulation Approach},

author = {M. S. Xavier and A. J. Fleming and Y. K. Yong},

url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2022/03/J21d.pdf},

doi = {10.1109/LRA.2021.3086425},

issn = {2377-3766},

year  = {2021},

date = {2021-06-04},

urldate = {2021-06-04},

journal = {IEEE Robotics and Automation Letters},

volume = {6},

issue = {3},

pages = {5800-5807},

abstract = {Pressure control plays a major role in the overall performance of fluid-driven soft robots. Due to the increasing demand for higher speed actuation and precision, a need exists for a practical design methodology that converts actuator performance specifications to a set of minimum pneumatic specifications, such as receiver volume and pressure, and valve conductance. This article presents a systematic parameter selection approach for pneumatic soft robotic systems by taking into consideration the desired closed-loop pressure responses. The two controllers under evaluation here are the PI controller with anti-windup and the on-off controller with hysteresis. Simulations are developed within Simscape Fluids to evaluate the effect of physical components and controller parameters on the actuator performance. The proposed parameter selection procedures are then applied on three soft actuators and their closed-loop pressure responses are experimentally evaluated. The measured pressure responses are in close agreement with the simulations and satisfy the rise time specifications.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Moore2021,

title = {Serial-kinematic monolithic nanopositioner with in-plane bender actuators},

author = {S. I. Moore and Y. K. Yong and M. Omidbeike and A. J. Fleming},

url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2021/03/J21c.pdf},

doi = {https://doi.org/10.1016/j.mechatronics.2021.102541},

isbn = {0957-4158},

year  = {2021},

date = {2021-03-23},

journal = {Mechatronics},

volume = {75},

number = {102541},

abstract = {This article describes a monolithic nanopositioner constructed from in-plane bending actuators which provide greater deflection than previously reported extension actuators, at the expense of stiffness and resonance frequency. The proposed actuators are demonstrated by constructing an XY nanopositioning stage with a serial kinematic design. Analytical modeling and finite-element-analysis accurately predicts the experimental performance of the nanopositioner. A 10μm range is achieved in the X and Y axes with an applied voltage of +/-200 V. The first resonance mode occurs at 250 Hz in the Z axis. The stage is demonstrated for atomic force microscopy imaging.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{J21b,

title = {Finite Element Modeling of Soft Fluidic Actuators: Overview and Recent Developments},

author = {M. S. Xavier and A. J. Fleming and Y. K. Yong},

url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2021/02/J21b.pdf},

doi = {10.1002/aisy.202000187},

isbn = {2640-4567},

year  = {2021},

date = {2021-02-01},

journal = {Advanced Intelligent Systems},

volume = {3},

number = {2},

pages = {2000187},

abstract = {Many soft robots are composed of soft fluidic actuators that are fabricated from silicone rubbers and use hydraulic or pneumatic actuation. The strong nonlinearities and complex geometries of soft actuators hinder the development of analytical models to describe their motion. Finite element modeling provides an effective solution to this issue and allows the user to predict performance and optimize soft actuator designs. Herein, the literature on a finite element analysis of soft actuators is reviewed. First, the required nonlinear elasticity concepts are introduced with a focus on the relevant models for soft robotics. In particular, the procedure for determining material constants for the hyperelastic models from material testing and curve fitting is explored. Then, a comprehensive review of constitutive model parameters for the most widely used silicone rubbers in the literature is provided. An overview of the procedure is provided for three commercially available software packages (Abaqus, Ansys, and COMSOL). The combination of modeling procedures, material properties, and design guidelines presented in this article can be used as a starting point for soft robotic actuator design.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ruppert2021,

title = {Active atomic force microscope cantilevers with integrated device layer piezoresistive sensors},

author = {M. G. Ruppert and A. J. Fleming and Y. K. Yong},

url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2021/01/J21a.pdf},

doi = {10.1016/j.sna.2020.112519},

issn = {0924-4247},

year  = {2021},

date = {2021-01-19},

urldate = {2021-01-19},

journal = {Sensors & Actuators: A. Physical},

volume = {319},

pages = {112519},

abstract = {Active atomic force microscope cantilevers with on-chip actuation and sensing provide several advantages over

passive cantilevers which rely on piezoacoustic base-excitation and optical beam deflection measurement. Active

microcantilevers exhibit a clean frequency response, provide a path-way to miniturization and parallelization and

avoid the need for optical alignment. However, active microcantilevers are presently limited by the feedthrough

between actuators and sensors, and by the cost associated with custom microfabrication. In this work, we propose

a hybrid cantilever design with integrated piezoelectric actuators and a piezoresistive sensor fabricated from the

silicon device layer without requiring an additional doping step. As a result, the design can be fabricated using a

commercial five-mask microelectromechanical systems fabrication process. The theoretical piezoresistor sensitivity

is compared with finite element simulations and experimental results obtained from a prototype device. The

proposed approach is demonstrated to be a promising alternative to conventional microcantilever actuation and

deflection sensing},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{J20d,

title = {Electrode Configurations for Piezoelectric Tube Actuators With Improved Scan Range and Reduced Cross-Coupling},

author = {D. S. Raghunvanshi and S. I. Moore and A. J. Fleming and Y. K. Yong},

url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2020/09/J20d.pdf},

doi = {10.1109/TMECH.2020.2978241},

issn = {00346748},

year  = {2020},

date = {2020-06-01},

journal = {IEEE/ASME Transactions on Mechatronics},

volume = {25},

number = {3},

pages = {1479-1486},

abstract = {Piezoelectric force and position sensors provide high sensitivity but are limited at low frequencies due to their high-pass response which complicates the direct application of integral control. To overcome this issue, an additional sensor or low-frequency correction method is typically employed. However, these approaches introduce an additional first-order response that must be higher than the high-pass response of the piezo and interface electronics. This article describes a simplified method for low-frequency correction that uses the piezoelectric sensor as an electrical component in a filter circuit. The resulting response is first-order, rather than second-order, with a cut-off frequency equal to that of a buffer circuit with the same input resistance. The proposed method is demonstrated to allow simultaneous damping and tracking control of a high-speed vertical nanopositioning stage.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ruppert2020,

title = {Amplitude Noise Spectrum of a Lock-in Amplifier: Application to Microcantilever Noise Measurements},

author = {M. G. Ruppert and N. J. Bartlett and Y. K. Yong and A. J. Fleming},

url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2020/09/J20f.pdf},

doi = {10.1016/j.sna.2020.112092},

year  = {2020},

date = {2020-05-29},

journal = {Sensors and Actuators A: Physical},

volume = {312},

pages = {112092},

abstract = {The lock-in amplifier is a crucial component in many applications requiring high-resolution displacement sensing; it's purpose is to estimate the amplitude and phase of a periodic signal, potentially corrupted by noise, at a frequency determined by a reference signal. Where the noise can be approximated by a stationary Gaussian process, such as thermal force noise and electronic sensor noise, this article derives the amplitude noise spectral density of the lock-in-amplifier output. The proposed method is demonstrated by predicting the demodulated noise spectrum of a microcantilever for dynamic-mode atomic force microscopy to determine the cantilever on-resonance thermal noise, the cantilever tracking bandwidth and the electronic noise floor. The estimates are shown to closely match experimental results over a wide range of operating conditions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Moore2020,

title = {AFM Cantilever Design for Multimode Q Control: Arbitrary Placement of Higher-Order Modes},

author = {S. I. Moore and M. G. Ruppert and Y. K. Yong},

url = {https://ieeexplore.ieee.org/document/9006926},

doi = {10.1109/TMECH.2020.2975627},

year  = {2020},

date = {2020-02-21},

journal = { IEEE/ASME Transactions on Mechatronics},

pages = {1-6},

abstract = {In the fast growing field of multifrequency atomic force microscopy (AFM), the benefits of using higher-order modes has been extensively reported on. However, higher modes of AFM cantilevers are difficult to instrument and Q control is challenging owing to their high frequency nature. At these high frequencies, the latencies in the computations and analog conversions of digital signal processing platforms become significant and limit the effective bandwidth of digital feedback controller implementations. To address this issue, this article presents a novel cantilever design for which the first five modes are placed within a 200 kHz bandwidth. The proposed cantilever is designed using a structural optimization routine. The close spacing and low mechanical bandwidth of the resulting cantilever allows for the implementation of Q controllers for all five modes using a standard FPGA development board for bimodal AFM and imaging on higher-order modes.},

note = {Early Access},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@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 = {},

pubstate = {published},

tppubtype = {article}

}

@article{Moore2019,

title = {Capacitive Instrumentation and Sensor Fusion for High-Bandwidth Nanopositioning},

author = {S. I. Moore and A. J. Fleming and Y. K. Yong},

url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2019/10/J19c.pdf},

doi = {10.1109/LSENS.2019.2933065},

isbn = {2475-1472},

year  = {2019},

date = {2019-09-09},

journal = {IEEE Sensor Letters},

volume = {3},

number = {8},

pages = {2501503},

abstract = {Precision capacitive sensing methods encode the measurement in a high frequency signal, which requires demodulation. To extract the measurement, the signal is observed over many cycles limiting the bandwidth of the sensor and introducing an undesirable phase lag. To address this limitation, this article outlines a design, which fuses the output of a standard modulated capacitive sensor and a charge amplifier, providing an instantaneous capacitive measurement whose bandwidth is only limited by the speed at which the electronics operate.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Moore2019c,

title = {An optimization framework for the design of piezoelectric AFM cantilevers},

author = {S. I. Moore and M. G. Ruppert and Y. K. Yong},

url = {https://www.sciencedirect.com/science/article/pii/S0141635919302260},

year  = {2019},

date = {2019-08-15},

journal = {Precision Engineering},

volume = {60},

pages = {130-142},

abstract = {To facilitate further miniaturization of atomic force microscopy (AFM) cantilevers and to eliminate the standard optical beam deflection sensor, integrated piezoelectric actuation and sensing on the chip level is a promising option. This article presents a topology optimization method for dynamic mode AFM cantilevers that maximizes the sensitivity of an integrated piezoelectric sensor under stiffness and resonance frequency constraints. Included in the formulation is a new material model C-SIMP (connectivity and solid isotropic material with penalization) that extends the SIMP model to explicitly include the penalization of unconnected structures. Example cantilever designs demonstrate the potential of the topology optimization method. The results show, firstly, the C-SIMP material model significantly reduces connectivity issues and, secondly, arbitrary cantilever topologies can produce increases in sensor sensitivity or resonance frequency compared to a rectangular topology.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Moore2019,

title = {Design and Analysis of Low-Distortion Demodulators for Modulated Sensors},

author = { S. I. Moore and M. G. Ruppert and D. M. Harcombe and A. J. Fleming and Y. K. Yong },

url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2020/05/J19d-reduced.pdf},

doi = {10.1109/TMECH.2019.2928592},

issn = {10834435},

year  = {2019},

date = {2019-07-17},

journal = {IEEE/ASME Transactions on Mechatronics},

volume = {24},

number = {4},

pages = {1861-1870},

abstract = {System-based demodulators in the form of a Kalman and Lyapunov filter have been demonstrated to significantly outperform traditional demodulators, such as the lock-in amplifier, in bandwidth sensitive applications, for example high-speed atomic force microscopy. Building on their closed loop architecture, this article describes a broader class of high-speed closed-loop demodulators. The generic structure provides greater flexibility to independently control the bandwidth and sensitivity to out-of-band frequencies. A linear time-invariant description is derived which allows the utilization of linear control theory to design the demodulator. Experimental results on a nanopositioner with capacitive sensors demonstrate the realization of arbitrary demodulator dynamics while achieving excellent noise rejection.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Wang2019,

title = {Adaptive Scan for Atomic Force Microscopy Based on Online Optimisation: Theory and Experiment},

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

url = {https://ieeexplore.ieee.org/document/8643730},

year  = {2019},

date = {2019-01-31},

journal = {IEEE Transactions on Control System Technology},

abstract = {A major challenge in Atomic Force Microscopy

(AFM) is to reduce the scan duration while retaining the

image quality. Conventionally, the scan rate is restricted to a

sufficiently small value in order to ensure a desirable image

quality as well as a safe tip-sample contact force. This usually

results in a conservative scan rate for samples that have a

large variation in aspect ratio and/or for scan patterns that

have a varying linear velocity. In this paper, an adaptive scan

scheme is proposed to alleviate this problem. A scan line-based

performance metric balancing both imaging speed and accuracy

is proposed, and the scan rate is adapted such that the metric

is optimised online in the presence of aspect ratio and/or linear

velocity variations. The online optimisation is achieved using an

extremum-seeking (ES) approach, and a semi-global practical

asymptotic stability (SGPAS) result is shown for the overall

system. Finally, the proposed scheme is demonstrated via both

simulation and experiment.},

note = {accepted for publication},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ruppert2018b,

title = {Multimodal atomic force microscopy with optimized higher eigenmode sensitivity using on-chip piezoelectric actuation and sensing},

author = {M. G. Ruppert and S. I. Moore and M. Zawierta and A. J. Fleming and G. Putrino and Y. K. Yong},

url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2019/08/Ruppert_2019_Nanotechnology_30_085503.pdf},

doi = {https://doi.org/10.1088/1361-6528/aae40b},

year  = {2019},

date = {2019-01-02},

journal = {Nanotechnology},

volume = {30},

number = {8},

pages = {085503},

abstract = {Atomic force microscope (AFM) cantilevers with integrated actuation and sensing provide several distinct advantages over conventional cantilever instrumentation. These include clean frequency responses, the possibility of down-scaling and parallelization to cantilever arrays as well as the absence of optical interference. While cantilever microfabrication technology has continuously advanced over the years, the overall design has remained largely unchanged; a passive rectangular shaped cantilever design has been adopted as the industry wide standard. In this article, we demonstrate multimode AFM imaging on higher eigenmodes as well as bimodal AFM imaging with cantilevers using fully integrated piezoelectric actuation and sensing. The cantilever design maximizes the higher eigenmode deflection sensitivity by optimizing the transducer layout according to the strain mode shape. Without the need for feedthrough cancellation, the read-out method achieves close to zero actuator/sensor feedthrough and the sensitivity is sufficient to resolve the cantilever Brownian motion.},

keywords = {},

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 = {},

pubstate = {published},

tppubtype = {article}

}

@article{J18e,

title = {Piezoelectric Bimorph Actuator with Integrated Strain Sensing Electrodes},

author = {S. Z. Mansour and R. J. Seethaler and Y. R. Teo and Y. K. Yong and A. J. Fleming},

url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2021/02/J18e.pdf},

doi = {10.1109/JSEN.2018.2842138},

issn = {1530-437X},

year  = {2018},

date = {2018-07-01},

journal = {IEEE Sensors Journal},

volume = {18},

number = {4},

abstract = {This article describes a new method for estimating the tip displacement of piezoelectric benders. Two resistive strain gauges are fabricated within the top and bottom electrodes using an acid etching process. These strain gauges are employed in a half bridge electrical configuration to measure the surface resistance change, and estimate the tip displacement. Experimental validation shows a 1.1 % maximum difference between the strain sensor and a laser triangulation sensor. Using the presented method, a damping-integral control structure is designed to control the tip displacement of the integrated bender},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{J18a,

title = {Monolithic Piezoelectric Insect with Resonance Walking},

author = {S. A. Rios and A. J. Fleming and Y. K. Yong},

url = {https://www.precisionmechatronicslab.com/wp-content/uploads/2021/02/J18a.pdf},

doi = {10.1109/tmech.2018.2792618},

issn = {10834435},

year  = {2018},

date = {2018-02-01},

journal = {IEEE/ASME Transactions on Mechatronics},

volume = {23},

number = {2},

pages = {524-530},

abstract = {This article describes the design, manufacture and performance of an untethered hexapod robot titled MinRAR V2. This robot utilizes a monolithic piezoelectric element, machined to allow for individual activation of bending actuators. The legs were designed so that the first two resonance modes overlap and therefore produce a walking motion at resonance. The monolithic construction significantly improves the matching of resonance modes between legs when compared to previous designs. Miniature control and high voltage driving electronics were designed to drive 24 separate piezoelectric elements powered from a single 3.7 V lithium polymer battery. The robot was driven both tethered and untethered and was able to achieve a maximum forward velocity of 98 mm/s when driven at 190 Hz and 6 mm/s at 5 Hz untethered. The robot is capable of a wide range of movements including banking, on the spot turning and reverse motion.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}