2024
7.
Fangzhou Xia*; Ivo W Rangelow; Kamal Youcef-Toumi
Active Probe Atomic Force Microscopy: A Practical Guide on Precision Instrumentation Book
Springer, 2024, ISBN: 978-3-031-44232-2.
Abstract | Links | BibTeX | Tags: Actuator, Atomic Force Microscopy, Design, Education, Experimentation, Instrumentation, Mechatronics, MEMS, Modeling & Simulation, Motion Control, Nanorobotics, Piezoelectricity, Review, Sensor, Signal Processing, Theory
@book{2023AFMbook,
title = {Active Probe Atomic Force Microscopy: A Practical Guide on Precision Instrumentation},
author = {Fangzhou Xia* and Ivo W Rangelow and Kamal Youcef-Toumi},
url = {https://link.springer.com/book/10.1007/978-3-031-44233-9},
doi = {https://doi.org/10.1007/978-3-031-44233-9},
isbn = {978-3-031-44232-2},
year = {2024},
date = {2024-02-06},
urldate = {2023-10-01},
publisher = {Springer},
abstract = {From a perspective of precision instrumentation, this book provides a guided tour to readers on exploring the inner workings of atomic force microscopy (AFM). Centered around AFM, a broad range of mechatronic system topics are covered including mechanics, sensors, actuators, transmission design, system identification, signal processing, dynamic system modeling, controller. With a solid theoretical foundation, practical examples are provided for AFM subsystem level design on nano-positioning system, cantilever probe, control system and system integration. This book emphasizes novel development of active cantilever probes with embedded transducers, which enables new AFM capabilities for advanced applications. Full design details of a low-cost educational AFM and a Scale Model Interactive Learning Extended Reality (SMILER) toolkit are provided, which helps instructors to make use of this book for curriculum development. This book aims to empower AFM users with deeper understanding of the instrument to extend AFM functionalities for advanced state-of-the-art research studies. Going beyond AFM, materials presented in this book are widely applicable to precision mechatronic system design covered in many upper-level graduate courses in mechanical and electrical engineering to cultivate next generation instrumentalists.},
keywords = {Actuator, Atomic Force Microscopy, Design, Education, Experimentation, Instrumentation, Mechatronics, MEMS, Modeling & Simulation, Motion Control, Nanorobotics, Piezoelectricity, Review, Sensor, Signal Processing, Theory},
pubstate = {published},
tppubtype = {book}
}
From a perspective of precision instrumentation, this book provides a guided tour to readers on exploring the inner workings of atomic force microscopy (AFM). Centered around AFM, a broad range of mechatronic system topics are covered including mechanics, sensors, actuators, transmission design, system identification, signal processing, dynamic system modeling, controller. With a solid theoretical foundation, practical examples are provided for AFM subsystem level design on nano-positioning system, cantilever probe, control system and system integration. This book emphasizes novel development of active cantilever probes with embedded transducers, which enables new AFM capabilities for advanced applications. Full design details of a low-cost educational AFM and a Scale Model Interactive Learning Extended Reality (SMILER) toolkit are provided, which helps instructors to make use of this book for curriculum development. This book aims to empower AFM users with deeper understanding of the instrument to extend AFM functionalities for advanced state-of-the-art research studies. Going beyond AFM, materials presented in this book are widely applicable to precision mechatronic system design covered in many upper-level graduate courses in mechanical and electrical engineering to cultivate next generation instrumentalists.
2022
6.
Chen Yang*; Fangzhou Xia; Yi Wang; Kamal Youcef-Toumi
Comprehensive study of charge-based motion control for piezoelectric nanopositioners: Modeling, instrumentation and controller design Journal Article
In: Mechanical Systems and Signal Processing, vol. 166, pp. 108477, 2022, ISSN: 0888-3270.
Abstract | Links | BibTeX | Tags: Actuator, Experimentation, Instrumentation, Mechatronics, Modeling & Simulation, Motion Control, Piezoelectricity, Theory
@article{2021_MSSP,
title = {Comprehensive study of charge-based motion control for piezoelectric nanopositioners: Modeling, instrumentation and controller design},
author = {Chen Yang* and Fangzhou Xia and Yi Wang and Kamal Youcef-Toumi},
url = {https://www.sciencedirect.com/science/article/pii/S0888327021008219},
doi = {https://doi.org/10.1016/j.ymssp.2021.108477},
issn = {0888-3270},
year = {2022},
date = {2022-01-01},
urldate = {2022-01-01},
journal = {Mechanical Systems and Signal Processing},
volume = {166},
pages = {108477},
abstract = {High performance motion control of piezoelectric nanopositioners is crucial for a wide range of applications. The primary challenges stem from several aspects, including hysteresis and creep effects, along with the lightly damped mechanical resonance. In view of these issues, this paper proposes a comprehensive charge-based motion control solution, including a generalized electromechanical model, a charge controller with non-resistive DC stabilization and a robust charge control (RCC) strategy. The advantages of charge-based control in system identification and controller design are clearly indicated. Towards this solution, a generalized model of piezoelectric nanopositioner is first proposed, showing the effectiveness of charge control approach in the presence of arbitrarily complicated mechanical dynamics. Furthermore, we present a charge controller with a simple configuration, which eliminates the frequency-dependent performance of classical controller design. This guarantees consistently high control performance over the full operating bandwidth. Finally, to deal with the mechanical resonance and remaining nonlinearities and uncertainties, we propose a control strategy that combines charge control and robust feedback control into a single framework. Superior tracking and damping control performance of the proposed solution is confirmed by extensive experimental validations.},
keywords = {Actuator, Experimentation, Instrumentation, Mechatronics, Modeling & Simulation, Motion Control, Piezoelectricity, Theory},
pubstate = {published},
tppubtype = {article}
}
High performance motion control of piezoelectric nanopositioners is crucial for a wide range of applications. The primary challenges stem from several aspects, including hysteresis and creep effects, along with the lightly damped mechanical resonance. In view of these issues, this paper proposes a comprehensive charge-based motion control solution, including a generalized electromechanical model, a charge controller with non-resistive DC stabilization and a robust charge control (RCC) strategy. The advantages of charge-based control in system identification and controller design are clearly indicated. Towards this solution, a generalized model of piezoelectric nanopositioner is first proposed, showing the effectiveness of charge control approach in the presence of arbitrarily complicated mechanical dynamics. Furthermore, we present a charge controller with a simple configuration, which eliminates the frequency-dependent performance of classical controller design. This guarantees consistently high control performance over the full operating bandwidth. Finally, to deal with the mechanical resonance and remaining nonlinearities and uncertainties, we propose a control strategy that combines charge control and robust feedback control into a single framework. Superior tracking and damping control performance of the proposed solution is confirmed by extensive experimental validations.
2021
5.
Chen Yang*; Nicolas Verbeek; Fangzhou Xia; Yi Wang; Kamal Youcef-Toumi
Statically Stable Charge Sensing Method for Precise Displacement Estimation of Piezoelectric Stack-Based Nanopositioning Journal Article
In: IEEE Transactions on Industrial Electronics, vol. 68, no. 9, pp. 8550-8560, 2021.
Abstract | Links | BibTeX | Tags: Actuator, Experimentation, Instrumentation, Mechatronics, Modeling & Simulation, Motion Control, Piezoelectricity, Theory
@article{2020IEEETIE_2,
title = {Statically Stable Charge Sensing Method for Precise Displacement Estimation of Piezoelectric Stack-Based Nanopositioning},
author = {Chen Yang* and Nicolas Verbeek and Fangzhou Xia and Yi Wang and Kamal Youcef-Toumi},
url = {https://ieeexplore.ieee.org/abstract/document/9177358},
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
journal = {IEEE Transactions on Industrial Electronics},
volume = {68},
number = {9},
pages = {8550-8560},
publisher = {IEEE},
abstract = {Piezoelectric self-sensing is a promising displacement estimation technique that has captured a broad range of attention since its origin. However, one long-standing and critical issue associated with this technique is its unstable static performance. This issue significantly undermines the sensing accuracy and the long-term reliability, which are primary concerns in industrial applications. In this article, we show that this challenging issue can be finally solved. The proposed solution consists of two steps. First, we develop a novel charge sensing circuit that provides an explicit access to observe any disturbance that might impact the static sensing. Second, by introducing cascaded observers, a self-improvement sensing scheme is developed. High accuracy displacement estimate can, thus, be reconstructed by fusing the reference signal, the observed disturbance, and the original sensing signal together. Experimental validations demonstrate the expected stable performance. The root-mean-square sensing errors are well below 1%. The developed self-sensing technique is a competitive solution for nanopositioning applications, also due to its self-contained, immunity to environmental disturbance, and plug-and-play features.},
keywords = {Actuator, Experimentation, Instrumentation, Mechatronics, Modeling & Simulation, Motion Control, Piezoelectricity, Theory},
pubstate = {published},
tppubtype = {article}
}
Piezoelectric self-sensing is a promising displacement estimation technique that has captured a broad range of attention since its origin. However, one long-standing and critical issue associated with this technique is its unstable static performance. This issue significantly undermines the sensing accuracy and the long-term reliability, which are primary concerns in industrial applications. In this article, we show that this challenging issue can be finally solved. The proposed solution consists of two steps. First, we develop a novel charge sensing circuit that provides an explicit access to observe any disturbance that might impact the static sensing. Second, by introducing cascaded observers, a self-improvement sensing scheme is developed. High accuracy displacement estimate can, thus, be reconstructed by fusing the reference signal, the observed disturbance, and the original sensing signal together. Experimental validations demonstrate the expected stable performance. The root-mean-square sensing errors are well below 1%. The developed self-sensing technique is a competitive solution for nanopositioning applications, also due to its self-contained, immunity to environmental disturbance, and plug-and-play features.
4.
Chen Yang*; Nicolas Verbeek; Fangzhou Xia; Yi Wang; Kamal Youcef-Toumi
Modeling and Control of Piezoelectric Hysteresis: A Polynomial-Based Fractional Order Disturbance Compensation Approach Journal Article
In: IEEE Transactions on Industrial Electronics, vol. 68, no. 4, pp. 3348-3358, 2021.
Abstract | Links | BibTeX | Tags: Actuator, Experimentation, Instrumentation, Mechatronics, Modeling & Simulation, Motion Control, Piezoelectricity, Theory
@article{2020IEEETIE,
title = {Modeling and Control of Piezoelectric Hysteresis: A Polynomial-Based Fractional Order Disturbance Compensation Approach},
author = {Chen Yang* and Nicolas Verbeek and Fangzhou Xia and Yi Wang and Kamal Youcef-Toumi},
url = {https://ieeexplore.ieee.org/document/9027124},
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
journal = {IEEE Transactions on Industrial Electronics},
volume = {68},
number = {4},
pages = {3348-3358},
publisher = {IEEE},
abstract = {Piezoelectric hysteresis is a critical issue that significantly degrades the motion accuracy of piezo-actuated nanopositioners. Such an issue is difficult to be precisely modeled and compensated for, primarily due to its asymmetric, rate, and input amplitude-dependent characteristics. This article proposes a novel method to deal with this challenge. Specifically, a polynomial-based fractional order disturbance model is proposed to accommodate and characterize the complex hysteresis effect. In this model, the rate dependence is captured by a general method of implementing curve fitting in Bode magnitude plot. The inverse model for control purposes is immediately available from the original one. The proposed method does not require expensive computational resources. In fact, this article shows that this controller can be easily implemented in an analog manner, which brings the advantages of high bandwidth and low cost. Extensive modeling and tracking experiments are carried out to demonstrate the effectiveness of the proposed method. It is shown that the piezoelectric hysteresis nonlinearity can be significantly suppressed over a wide bandwidth.},
keywords = {Actuator, Experimentation, Instrumentation, Mechatronics, Modeling & Simulation, Motion Control, Piezoelectricity, Theory},
pubstate = {published},
tppubtype = {article}
}
Piezoelectric hysteresis is a critical issue that significantly degrades the motion accuracy of piezo-actuated nanopositioners. Such an issue is difficult to be precisely modeled and compensated for, primarily due to its asymmetric, rate, and input amplitude-dependent characteristics. This article proposes a novel method to deal with this challenge. Specifically, a polynomial-based fractional order disturbance model is proposed to accommodate and characterize the complex hysteresis effect. In this model, the rate dependence is captured by a general method of implementing curve fitting in Bode magnitude plot. The inverse model for control purposes is immediately available from the original one. The proposed method does not require expensive computational resources. In fact, this article shows that this controller can be easily implemented in an analog manner, which brings the advantages of high bandwidth and low cost. Extensive modeling and tracking experiments are carried out to demonstrate the effectiveness of the proposed method. It is shown that the piezoelectric hysteresis nonlinearity can be significantly suppressed over a wide bandwidth.
2019
3.
Fangzhou Xia*; Chen Yang; Yi Wang; Kamal Youcef-Toumi
Bandwidth Based Repetitive Controller Design for a Modular Multi-actuated AFM Scanner Proceedings Article
In: IEEE American Control Conference (ACC), pp. 3776-3781, 2019, ISSN: 0743-1619.
Abstract | Links | BibTeX | Tags: Atomic Force Microscopy, Instrumentation, Mechatronics, Modeling & Simulation, Motion Control, Piezoelectricity, Theory
@inproceedings{2019ACC_1,
title = {Bandwidth Based Repetitive Controller Design for a Modular Multi-actuated AFM Scanner},
author = {Fangzhou Xia* and Chen Yang and Yi Wang and Kamal Youcef-Toumi},
url = {https://ieeexplore.ieee.org/document/8814642},
doi = {10.23919/ACC.2019.8814642},
issn = {0743-1619},
year = {2019},
date = {2019-07-01},
urldate = {2019-07-01},
booktitle = {IEEE American Control Conference (ACC)},
pages = {3776-3781},
abstract = {High-Speed Atomic Force Micrscopy (HSAFM) enables visualization of dynamic processes and helps with understanding of fundamental behaviors at the nano-scale. Ideally, the HSAFM video frames should have high fidelity, high resolution, and a wide scanning range. Unfortunately, it is very difficult for scanners to simultaneously achieve high scanning bandwidth and large range. Since the first bending mode of large piezos is a major limiting factor, we propose an alternative design by stacking multiple short range piezo actuators. This approach allows significant increase of scanner bandwidth (over 20 kHz) while maintaining large travel range (over 20 μm). The modular design also facilitates the easy adjustment of scanner travel range. In this paper, we first discuss the design and assembly of this scanner. We then present the modeling and control of this multi-actuated scanner. A comparative study is then given on the performance of different controllers. These include a PID controller, a LQR based controller and a bandwidth based repetitive controller. The proposed algorithm provides significant improvement in tracking performance when utilized with the scanner using optimized input trajectories.},
keywords = {Atomic Force Microscopy, Instrumentation, Mechatronics, Modeling & Simulation, Motion Control, Piezoelectricity, Theory},
pubstate = {published},
tppubtype = {inproceedings}
}
High-Speed Atomic Force Micrscopy (HSAFM) enables visualization of dynamic processes and helps with understanding of fundamental behaviors at the nano-scale. Ideally, the HSAFM video frames should have high fidelity, high resolution, and a wide scanning range. Unfortunately, it is very difficult for scanners to simultaneously achieve high scanning bandwidth and large range. Since the first bending mode of large piezos is a major limiting factor, we propose an alternative design by stacking multiple short range piezo actuators. This approach allows significant increase of scanner bandwidth (over 20 kHz) while maintaining large travel range (over 20 μm). The modular design also facilitates the easy adjustment of scanner travel range. In this paper, we first discuss the design and assembly of this scanner. We then present the modeling and control of this multi-actuated scanner. A comparative study is then given on the performance of different controllers. These include a PID controller, a LQR based controller and a bandwidth based repetitive controller. The proposed algorithm provides significant improvement in tracking performance when utilized with the scanner using optimized input trajectories.
2018
2.
Fangzhou Xia*; Stephen Truncale; Yi Wang; Kamal Youcef-Toumi
Design and Control of a Multi-actuated High-bandwidth and Large-range Scanner for Atomic Force Microscopy Proceedings Article
In: IEEE American Control Conference (ACC), pp. 4330-4335, 2018, ISSN: 2378-5861.
Abstract | Links | BibTeX | Tags: Atomic Force Microscopy, Experimentation, Instrumentation, Mechatronics, Modeling & Simulation, Motion Control, Piezoelectricity
@inproceedings{2018ACC,
title = {Design and Control of a Multi-actuated High-bandwidth and Large-range Scanner for Atomic Force Microscopy},
author = {Fangzhou Xia* and Stephen Truncale and Yi Wang and Kamal Youcef-Toumi},
url = {https://ieeexplore.ieee.org/document/8431801},
doi = {10.23919/ACC.2018.8431801},
issn = {2378-5861},
year = {2018},
date = {2018-06-01},
urldate = {2018-06-01},
booktitle = {IEEE American Control Conference (ACC)},
pages = {4330-4335},
abstract = {Atomic force microscopes (AFMs) with high-speed and large-range capabilities open up possibilities for many new applications. It is desirable to have a large scanning range along with zooming ability to obtain high resolution and high frame-rate imaging. Such capabilities will increase the imaging throughput and allow more sophisticated observations at the nanoscale. Unfortunately, in-plane scanning of conventional piezo tube scanners typically covers a large range of hundreds of microns but has limited bandwidth up to several hundred Hertz. The main focus of this paper is the multi-actuated piezo scanner design and control algorithm to achieve high-speed tracking. Three design strategies for structure bandwidth and operational range consideration are presented and evaluated. The non-linear hysteresis effect of the piezo actuators is modeled using the Preisach hysteresis model. PID control, iterative learning control and repetitive control strategies were investigated in simulation. Based on the controllers performance, the repetitive controller is implemented on a high-speed FPGA device and experimentally verified. The new AFM scanner design is capable of 10 kHz tracking at 3 μm range and 200 Hz tracking at 100 μm range.},
keywords = {Atomic Force Microscopy, Experimentation, Instrumentation, Mechatronics, Modeling & Simulation, Motion Control, Piezoelectricity},
pubstate = {published},
tppubtype = {inproceedings}
}
Atomic force microscopes (AFMs) with high-speed and large-range capabilities open up possibilities for many new applications. It is desirable to have a large scanning range along with zooming ability to obtain high resolution and high frame-rate imaging. Such capabilities will increase the imaging throughput and allow more sophisticated observations at the nanoscale. Unfortunately, in-plane scanning of conventional piezo tube scanners typically covers a large range of hundreds of microns but has limited bandwidth up to several hundred Hertz. The main focus of this paper is the multi-actuated piezo scanner design and control algorithm to achieve high-speed tracking. Three design strategies for structure bandwidth and operational range consideration are presented and evaluated. The non-linear hysteresis effect of the piezo actuators is modeled using the Preisach hysteresis model. PID control, iterative learning control and repetitive control strategies were investigated in simulation. Based on the controllers performance, the repetitive controller is implemented on a high-speed FPGA device and experimentally verified. The new AFM scanner design is capable of 10 kHz tracking at 3 μm range and 200 Hz tracking at 100 μm range.
1.
Chen Yang*; Changle Li; Fangzhou Xia; Yanhe Zhu; Jie Zhao; Kamal Youcef-Toumi
Charge controller with decoupled and self-compensating configurations for linear operation of piezoelectric actuators in a wide bandwidth Journal Article
In: IEEE Transactions on Industrial Electronics, vol. 66, no. 7, pp. 5392-5402, 2018.
Abstract | Links | BibTeX | Tags: Atomic Force Microscopy, Experimentation, Instrumentation, Mechatronics, Motion Control, Piezoelectricity, Theory
@article{2018IEEETIE,
title = {Charge controller with decoupled and self-compensating configurations for linear operation of piezoelectric actuators in a wide bandwidth},
author = {Chen Yang* and Changle Li and Fangzhou Xia and Yanhe Zhu and Jie Zhao and Kamal Youcef-Toumi},
url = {https://ieeexplore.ieee.org/document/8466119},
year = {2018},
date = {2018-01-01},
urldate = {2018-01-01},
journal = {IEEE Transactions on Industrial Electronics},
volume = {66},
number = {7},
pages = {5392-5402},
publisher = {IEEE},
abstract = {Charge control is a well-known sensorless approach to operate piezoelectric actuators, which has been proposed for more than 30 years. However, it is rarely used in industry because the implemented controllers suffer from the issues of limited low-frequency performance, long settling time, floating-load, and loss of stroke, etc. In this paper, a novel controller circuit dedicated to overcome these issues is presented. In the proposed scheme, a grounded-load charge controller with decoupled configuration is developed, which separates high-frequency and low-frequency paths, thus achieving arbitrarily low transition frequency without increasing the settling time. Based on this, a self-compensating configuration is further proposed and integrated into the controller circuit, which makes full use of controller output to improve its own control performance at low frequencies. Experimental results show that the presented charge controller can effectively reduce more than 88% of the hysteretic nonlinearity even when operating close to the transition frequency. To demonstrate its practical value, we then integrate it into a custom-designed high-speed atomic force microscope system. By comparing images obtained from using voltage drive and charge controller, it is clear that the piezoelectric hysteresis has been significantly reduced in a wide bandwidth.},
keywords = {Atomic Force Microscopy, Experimentation, Instrumentation, Mechatronics, Motion Control, Piezoelectricity, Theory},
pubstate = {published},
tppubtype = {article}
}
Charge control is a well-known sensorless approach to operate piezoelectric actuators, which has been proposed for more than 30 years. However, it is rarely used in industry because the implemented controllers suffer from the issues of limited low-frequency performance, long settling time, floating-load, and loss of stroke, etc. In this paper, a novel controller circuit dedicated to overcome these issues is presented. In the proposed scheme, a grounded-load charge controller with decoupled configuration is developed, which separates high-frequency and low-frequency paths, thus achieving arbitrarily low transition frequency without increasing the settling time. Based on this, a self-compensating configuration is further proposed and integrated into the controller circuit, which makes full use of controller output to improve its own control performance at low frequencies. Experimental results show that the presented charge controller can effectively reduce more than 88% of the hysteretic nonlinearity even when operating close to the transition frequency. To demonstrate its practical value, we then integrate it into a custom-designed high-speed atomic force microscope system. By comparing images obtained from using voltage drive and charge controller, it is clear that the piezoelectric hysteresis has been significantly reduced in a wide bandwidth.
Dr. Fangzhou Xia
Research Scientist
Mechanical Engineering Department
Physics Department
Massachusetts Institute of Technology