Research

14 pages, 3093 KiB

Open AccessArticle

Design and Simulation of a Single Piezoelectric-Driven Rotary Actuator with Double-Layer Flexible Mechanism

by Zhiyong Guo, Pengchao Zhao, Wenchao Zhang, Yanling Tian and Gaofeng Hu

Actuators 2023, 12(6), 231; https://doi.org/10.3390/act12060231 - 02 Jun 2023

Viewed by 1396

A novel pure rotary actuator with a double-layer flexible mechanism (RA-DFM), which is driven by a single piezoelectric ceramic in the lower mechanism and generates rotational motion in the upper mechanism, is proposed in this paper. The output of piezoelectric ceramic is successively [...] Read more.

A novel pure rotary actuator with a double-layer flexible mechanism (RA-DFM), which is driven by a single piezoelectric ceramic in the lower mechanism and generates rotational motion in the upper mechanism, is proposed in this paper. The output of piezoelectric ceramic is successively amplified using an enhanced double Scott–Russell mechanism and two lever-type mechanisms to obtain a large rotation range. The static, kinematic and dynamic properties of the RA-DFM are numerically analyzed, and the actual output of the piezoelectric is analyzed considering the input stiffness. The geometric parameters of the RA-DFM are optimized based on the constructed numerical models. Finite element analysis has been implemented to validate the correctness of the theoretical models and further evaluate the output property. The simulation results show the maximal rotation angle of the RA-DFM is 15.14 mrad with 0.44% center drift. Full article

(This article belongs to the Special Issue Actuating, Sensing, Control, and Instrumentation for Ultra Precision Engineering)

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12 pages, 4914 KiB

Open AccessCommunication

Analytical Modeling of Density and Young’s Modulus Identification of Adsorbate with Microcantilever Resonator

by Yue Yang, Yanling Tian, Xianping Liu, Yumeng Song and Hui Tang

Actuators 2022, 11(11), 335; https://doi.org/10.3390/act11110335 - 18 Nov 2022

Cited by 1 | Viewed by 1163

Abstract

Density and Young’s modulus are critical parameters in biological research, which can be used to characterize molecules, cells, or tissues in the diagnosis of severe diseases. Microcantilever resonators are ideal tools to measure the physical parameters of small objects at the micro/nanoscale. In [...] Read more.

Density and Young’s modulus are critical parameters in biological research, which can be used to characterize molecules, cells, or tissues in the diagnosis of severe diseases. Microcantilever resonators are ideal tools to measure the physical parameters of small objects at the micro/nanoscale. In this study, a mathematical model was built based on the Rayleigh–Ritz method with the consideration of the first five-order bending natural frequencies. The mathematical model can be used to detect the density and Young’s modulus of an adsorbate on a cantilever resonator with a single measurement. The influence of different order natural frequencies and the adsorbate position on the measurement accuracy and reliability was analyzed. This study revealed that the frequency pairs and the relative position of the adsorbate on the cantilever are two important factors that affect the accuracy and reliability of the measurement. Choosing appropriate frequency pairs can help to improve the accuracy and reliability of measurement. Finally, the results of finite element analysis verified the proposed method. Full article

(This article belongs to the Special Issue Actuating, Sensing, Control, and Instrumentation for Ultra Precision Engineering)

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11 pages, 3478 KiB

Open AccessArticle

Design and Analysis of a Compliant End-Effector for Robotic Polishing Using Flexible Beams

by Yanding Qin, Haitao Wu, Zhiyuan Li, Ning Sun and Lei Sun

Actuators 2022, 11(10), 284; https://doi.org/10.3390/act11100284 - 05 Oct 2022

Cited by 4 | Viewed by 2151

Abstract

The contact force between the polishing tool and the workpiece is crucial in determining the surface quality in robotic polishing. Different from rigid end-effectors, this paper presents a novel compliant end-effector (CEE) for robotic polishing using flexible beams. The flexibility of the CEE [...] Read more.

The contact force between the polishing tool and the workpiece is crucial in determining the surface quality in robotic polishing. Different from rigid end-effectors, this paper presents a novel compliant end-effector (CEE) for robotic polishing using flexible beams. The flexibility of the CEE helps to suppress the excessive displacement caused by the inertia of the polishing robot and avoids damaging the polishing tool and workpiece surface. In addition, the contact force can also be precisely estimated via the measurement of the CEE’s displacement using a capacitive position sensor. The design, modeling and experimental validation of the CEE are presented. Firstly, the analytical model of the CEE is established using the stiffness matrix method. Subsequently, the analytical model is verified by finite element analysis. Further, a prototype is manufactured, and its characteristics and performance are experimentally tested. The equivalent stiffness is measured to be 0.335 N/μm, and the first natural frequency along its working direction is 42.1 Hz. Finally, the contact force measurement using the CEE is compared with a force sensor. Under open-loop condition, the resolution of the contact force measurement is found to be 0.025 N, which makes the fine tuning of the contact force possible in robotic polishing. Full article

(This article belongs to the Special Issue Actuating, Sensing, Control, and Instrumentation for Ultra Precision Engineering)

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15 pages, 2736 KiB

Open AccessArticle

Development of a Sinusoidal Corrugated Dual-Axial Flexure Mechanism for Planar Nanopositioning

by Yuhan Niu, Xingyou Chen, Li Chen, Zhiwei Zhu and Peng Huang

Actuators 2022, 11(10), 276; https://doi.org/10.3390/act11100276 - 29 Sep 2022

Cited by 2 | Viewed by 1711

Abstract

Taking advantage of the concurrent stretching and bending property of corrugated flexure hinges, a sinusoidal corrugated flexure linkage was proposed and applied for the construction of a corrugated dual-axial mechanism with structural symmetry and decoupled planar motion guidance. Castigliano’s second theorem was employed [...] Read more.

Taking advantage of the concurrent stretching and bending property of corrugated flexure hinges, a sinusoidal corrugated flexure linkage was proposed and applied for the construction of a corrugated dual-axial mechanism with structural symmetry and decoupled planar motion guidance. Castigliano’s second theorem was employed to derive the complete compliance for a basic sinusoidal corrugated flexure unit, and matrix-based compliance modeling was then applied to find the stiffness of the sinusoidal corrugated flexure linkage and the corrugated dual-axial mechanism. Using established analytical models, the influence of structural parameters on the stiffness of both the corrugated flexure linkage and the dual-axial mechanism were investigated, with further verification by finite element analysis, with errors less than 20% compared to the analytical results for all cases. In addition, the stiffness of the corrugated flexure mechanism was practically tested, and its deviation between practical and analytical was around 7.4%. Further, the feasibility of the mechanism was demonstrated by successfully applying it for a magnetic planar nanopositioning stage, for which both open-loop and closed-loop performances were systematically examined. The stage has a stroke around 130

μ

m for the two axes and a maximum cross-talk less than 2.5%, and the natural frequency is around 590 Hz. Full article

(This article belongs to the Special Issue Actuating, Sensing, Control, and Instrumentation for Ultra Precision Engineering)

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15 pages, 6673 KiB

Open AccessArticle

Design and Testing of a Hollow Continuum Magnetic Millirobot with Multimodal Motion

by Yuanhe Chen, Zichen Xu and Qingsong Xu

Actuators 2022, 11(10), 269; https://doi.org/10.3390/act11100269 - 20 Sep 2022

Cited by 3 | Viewed by 1776

Abstract

Magnetic continuum millirobots have presented outstanding potential in ultrahigh-precision engineering including minimally invasive surgery, due to their flexible mechanical structures and dexterous manipulation. Traditional continuum millirobots exhibit limited cargo-loading capacity, which restricts their application. Herein, we propose a novel design scheme of a [...] Read more.

Magnetic continuum millirobots have presented outstanding potential in ultrahigh-precision engineering including minimally invasive surgery, due to their flexible mechanical structures and dexterous manipulation. Traditional continuum millirobots exhibit limited cargo-loading capacity, which restricts their application. Herein, we propose a novel design scheme of a magnetically actuated untethered hollow continuum millirobot. The millirobot is composed of silicone as the mainframe structure and two tiny magnets for actuation. To improve the loading capacity, partial silicone is removed to create a flexible cavity, which enables cargo delivery and potential in vivo sampling functions under wireless magnetic actuation. Theoretical analysis and experimental testing are conducted to reveal the effectiveness of the proposed design. The soft structure brings a new strategy to achieve multimodal motion including rolling, tumbling, and swinging. Moreover, the magnet part can generate a powerful magnetic force output for dexterous manipulation. These functionalities lay a foundation for playing a greater role in next-generation biomedical applications. Full article

(This article belongs to the Special Issue Actuating, Sensing, Control, and Instrumentation for Ultra Precision Engineering)

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17 pages, 5309 KiB

Open AccessArticle

Design, Modeling, Testing, and Control of a Novel Fully Flexure-Based Displacement Reduction Mechanism Driven by Voice Coil Motor

by Yunzhuang Chen and Leijie Lai

Actuators 2022, 11(8), 228; https://doi.org/10.3390/act11080228 - 08 Aug 2022

Cited by 1 | Viewed by 2335

Abstract

This paper presents a flexure-based displacement reduction mechanism driven by a voice coil motor to improve the motion resolution and eliminate the hysteresis nonlinearity of the traditional piezo-actuated micropositioning/nanopositioning stages. The mechanism is composed of three groups of compound bridge-type displacement reduction mechanisms, [...] Read more.

This paper presents a flexure-based displacement reduction mechanism driven by a voice coil motor to improve the motion resolution and eliminate the hysteresis nonlinearity of the traditional piezo-actuated micropositioning/nanopositioning stages. The mechanism is composed of three groups of compound bridge-type displacement reduction mechanisms, which adopt distributed-compliance rectangular beams to reduce the concentration of stress and improve the dynamic performance of the mechanism. The symmetrical distribution of the structure can eliminate the parasitic displacement of the mechanism and avoid the bending moment and lateral stress applied to the voice coil motor. Firstly, the analytical model of the mechanism is obtained by the stiffness matrix method. The theoretical displacement reduction ratio, input stiffness, and natural frequency of the displacement reduction mechanism are obtained by solving the analytical model. Then, through the static analysis and modal analysis of the mechanism with the Ansys software, the accuracy of the analytical model is verified, and the experimental prototype is also constructed for performance tests. The results show that the maximum stroke of the mechanism is 197.43 μm with motion resolution of 40 nm. The natural frequency is 291 Hz, and the input stiffness is 28.50 N/mm. Finally, the trajectory tracking experiment is carried out to verify the positioning performance of the mechanism. The experimental results show that the designed feedback controller has good stability, and the introduction of the feedforward controller and disturbance observer can greatly reduce the tracking errors. Full article

(This article belongs to the Special Issue Actuating, Sensing, Control, and Instrumentation for Ultra Precision Engineering)

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15 pages, 4258 KiB

Open AccessArticle

Research on the Influence of Friction Pairs on the Output Characteristics of the Piezoelectric Ultrasonic Actuator

by Jie Deng, Jianfei Cheng, Yuntian Guan, He Li, Fei Lu and Weishan Chen

Actuators 2022, 11(8), 212; https://doi.org/10.3390/act11080212 - 30 Jul 2022

Cited by 1 | Viewed by 1608

Abstract

The piezoelectric ultrasonic actuator is driven by the friction coupling between the stator and mover. Its friction pairs are very important, but there are few studies on the long-term output stability. Therefore, zirconia (ZrO₂) is selected as a stator material to [...] Read more.

The piezoelectric ultrasonic actuator is driven by the friction coupling between the stator and mover. Its friction pairs are very important, but there are few studies on the long-term output stability. Therefore, zirconia (ZrO₂) is selected as a stator material to form friction pairs with four different wear-resistant materials: silicon nitride (Si₃N₄), ZrO₂, bearing steel (GCr₁₅) and polyether ether ketone (PEEK). Experiments show that the friction pair composed of ZrO₂-Si₃N₄ is the best, and the attenuation percentage of the speed from the initial state to the end state in the speed rising stage of 50 m is 3.66%. A linear piezoelectric platform is developed based on the best friction pair; a maximum speed of 426.2 mm/s and a resolution of 85 nm are achieved. Full article

(This article belongs to the Special Issue Actuating, Sensing, Control, and Instrumentation for Ultra Precision Engineering)

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13 pages, 4052 KiB

Open AccessArticle

An Inertial Impact Piezoelectric Actuator Designed by the Asymmetric Friction Principle and Achieved by Laser Texturing of the Driving Feet

by Wuxiang Sun, Yanwei Liu, Xuan Li, Zhi Xu, Zhaojun Yang and Hu Huang

Actuators 2022, 11(8), 211; https://doi.org/10.3390/act11080211 - 30 Jul 2022

Cited by 5 | Viewed by 1955

Abstract

An asymmetric friction principle is newly proposed for the design of inertial impact piezoelectric actuators. There are two ways to achieve asymmetric frictions: either by tuning the positive pressure or by tuning the friction coefficient. Compared with tuning the positive pressure by an [...] Read more.

An asymmetric friction principle is newly proposed for the design of inertial impact piezoelectric actuators. There are two ways to achieve asymmetric frictions: either by tuning the positive pressure or by tuning the friction coefficient. Compared with tuning the positive pressure by an asymmetric structure, the structural parameters can be reduced by employing a symmetric structure and tuning the friction coefficient. In this study, an asymmetric friction inertial impact actuator was developed using a symmetric compliant mechanism (SCM), and the asymmetric frictions were realized by laser texturing of the driving feet at one end of the SCM. Four kinds of microstructures were initially fabricated on the driving feet, and their friction properties were experimentally tested. Accordingly, two kinds of microstructures, namely T_a and T_b microstructures, were selected. Output characteristics of the actuator with these two microstructures were measured and comparatively analyzed. The experimental results indicate that the actuator could achieve stable step motion, and the output characteristics were affected by the fabricated microstructure, as it determined the friction coefficient. The actuator with the T_b microstructure achieved a maximum speed of 2.523 mm/s, a resolution of 188 nm, a vertical loading capacity of 2 N and a horizontal loading capacity of 0.6 N, whereas the actuator with the T_a microstructure had a higher resolution of 74 nm. This study provides a novel idea for the design of asymmetric friction inertial impact actuators by tuning the friction coefficient. Full article

(This article belongs to the Special Issue Actuating, Sensing, Control, and Instrumentation for Ultra Precision Engineering)

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29 pages, 5992 KiB

Open AccessArticle

Integrated Development of a Topology-Optimized Compliant Mechanism for Precise Positioning

by Yaoyuan Hu, Bingfeng Ju and Wule Zhu

Actuators 2022, 11(7), 179; https://doi.org/10.3390/act11070179 - 27 Jun 2022

Cited by 1 | Viewed by 1763

Abstract

A scheme for modelling and controlling a two-dimensional positioning system with a topology-optimized compliant mechanism is presented. The system is designed to ensure a relatively large workspace and exhibit robustness against system nonlinearities. A detailed design procedure based on topology optimization is presented, [...] Read more.

A scheme for modelling and controlling a two-dimensional positioning system with a topology-optimized compliant mechanism is presented. The system is designed to ensure a relatively large workspace and exhibit robustness against system nonlinearities. A detailed design procedure based on topology optimization is presented, and a nonlinear description of the designed mechanism is developed as a starting point for further precise position control. The theoretical model is shown to be suitable for a considerably larger working range without losing consistency. A backstepping controller is employed to manipulate the nonlinearities in the model resulting from the geometrical and material nonlinearity of the mechanical structure. The hysteresis of the piezoelectric actuator is also taken into consideration. An experimental verification of the controller demonstrates that the proposed design approach improves the performance of compliant mechanism and satisfies the needs for precision positioning. Full article

(This article belongs to the Special Issue Actuating, Sensing, Control, and Instrumentation for Ultra Precision Engineering)

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13 pages, 28313 KiB

Open AccessArticle

Position Tracking for Multi-Channel Double-Crystal Monochromator Scanning Based on Iterative Learning Control

by Siyu He, Haolin Lu, Zhao Feng and Xiaohui Xiao

Actuators 2022, 11(7), 177; https://doi.org/10.3390/act11070177 - 23 Jun 2022

Cited by 1 | Viewed by 1655

Abstract

As a core component of the X-ray absorption fine structure spectroscopy (XAFS) system, the multi-channel double-crystal monochromator (DCM) can improve the time resolution of the system significantly. In contrast to the conventional single-channel DCM, the multi-channel DCM includes more pairs of crystals that [...] Read more.

As a core component of the X-ray absorption fine structure spectroscopy (XAFS) system, the multi-channel double-crystal monochromator (DCM) can improve the time resolution of the system significantly. In contrast to the conventional single-channel DCM, the multi-channel DCM includes more pairs of crystals that are located separately in the master and slave motor axis with the same driving direction. However, a mismatched parallelism in the pitch direction, which can result from the manual mounting operation between the two separated crystals, directly affects the performance of the flux and the angular stability of the monochromatic beam. This poses a significant challenge to the precision position tracking of this system. In this paper, the mounting errors were translated into repetitive errors in the slave motor when the master motor was rotated at a constant velocity. Therefore, the iterative learning control (ILC) was considered in order to improve the tracking accuracy of the slave motor motion. The zero-magnitude error controller (ZMETC) was used to calculate the learning function to accelerate the convergence of the control inputs, and the convergence conditions of the control signal and error were also given. To validate the effectiveness of the proposed method, comparative experiments were performed on the motor motion platform. Experimental results indicated that the ILC effectively decreased the parallelism errors of the multi-channel DCM under various trajectories by comparing them with feedback controllers and the ZMETC, respectively. Full article

(This article belongs to the Special Issue Actuating, Sensing, Control, and Instrumentation for Ultra Precision Engineering)

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18 pages, 9014 KiB

Open AccessArticle

Development of a Novel Dual Servo Magnetic Levitation Stage

by Dahoon Ahn, Ji-Won Jin, Hyeeun Yun and Jaeheon Jeong

Actuators 2022, 11(6), 147; https://doi.org/10.3390/act11060147 - 30 May 2022

Cited by 5 | Viewed by 2805

Abstract

The main objective of this paper is to propose, design, and control a novel dual servo magnetic levitation stage which is precise and vacuum compatible. The dual servo mechanism, comprising a coarse stage and a fine stage, was applied to a magnetic levitation [...] Read more.

The main objective of this paper is to propose, design, and control a novel dual servo magnetic levitation stage which is precise and vacuum compatible. The dual servo mechanism, comprising a coarse stage and a fine stage, was applied to a magnetic levitation stage system for the first time. The dual servo stage achieves high precision and a long stroke at the same time. The fine stage, which comprises voice coil motors, achieves high-precision motion by overcoming the limit of the coarse stage, the form of which is a planar motor. The planar motor was mathematically modeled and analyzed with respect to the main design parameters, after which the fine stage was optimally designed to be driven by high force. Both stages including a common heat exchanger were manufactured, and the heat exchanger cools down the heat given off from the planar motor and voice coil motors. The position measuring system consisted of laser interferometers and capacitive sensors, and the integrated dual servo stage was controlled with a master–slave control scheme. The experimental results showed a precision of 10 nm, thus confirming the suitability of the developed magnetic levitation stage for a high-precision fabrication process such as wafer lithography. Full article

(This article belongs to the Special Issue Actuating, Sensing, Control, and Instrumentation for Ultra Precision Engineering)

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14 pages, 7614 KiB

Open AccessArticle

Development of a Parallel Dual-Stage Compliant Nanopositioning System

by Xu Yang, Lichao Ji, Ying Shang, Wule Zhu and Shizhen Li

Actuators 2022, 11(5), 136; https://doi.org/10.3390/act11050136 - 13 May 2022

Cited by 4 | Viewed by 2445

Abstract

This paper presents a novel parallel dual-stage compliant nanopositioning system (PDCNS), aimed at nanoscale positioning for microscale manipulation. In the developed PDCNS, the coarse stage actuated by the voice coil motor and the fine stage driven by the piezoelectric actuator are integrated in [...] Read more.

This paper presents a novel parallel dual-stage compliant nanopositioning system (PDCNS), aimed at nanoscale positioning for microscale manipulation. In the developed PDCNS, the coarse stage actuated by the voice coil motor and the fine stage driven by the piezoelectric actuator are integrated in a parallel manner by a specially devised A-shaped compliant mechanism, which leads to many excellent performances, such as good resolution and large stroke and broadband. To enhance the closed-loop-positioning capability of the proposed PDCNS, a double-servo cooperative control (DSCC) strategy is specially constructed. The performance of the proposed PDCNS is evaluated by analytical model, finite element analysis, and experimental research. Results show that the first-order resonance frequency of the designed A-shaped compliant mechanism can reach 99.7 Hz. Combined with the designed DSCC, the developed PDCNS prototype is demonstrated to provide a stroke of 1.49 mm and a positioning resolution of ≤50 nm. Full article

(This article belongs to the Special Issue Actuating, Sensing, Control, and Instrumentation for Ultra Precision Engineering)

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14 pages, 4570 KiB

Open AccessArticle

Hysteresis Modeling and Compensation of Piezoelectric Actuators Using Gaussian Process with High-Dimensional Input

by Yixuan Meng, Xiangyuan Wang, Linlin Li, Weiwei Huang and Limin Zhu

Actuators 2022, 11(5), 115; https://doi.org/10.3390/act11050115 - 20 Apr 2022

Cited by 6 | Viewed by 2324

Abstract

Rate-dependent hysteresis seriously deteriorates the positioning accuracy of the piezoelectric actuators, especially when tracking high-frequency signals. As a widely-used nonparametric Bayesian method, the Gaussian process (GP) has proven its effectiveness in nonlinear hysteresis modeling. In this paper, the dimension of the input to [...] Read more.

Rate-dependent hysteresis seriously deteriorates the positioning accuracy of the piezoelectric actuators, especially when tracking high-frequency signals. As a widely-used nonparametric Bayesian method, the Gaussian process (GP) has proven its effectiveness in nonlinear hysteresis modeling. In this paper, the dimension of the input to the GP model is extended to consider more dynamic features of the tracking signal so as to improve the rate-dependent hysteresis modeling accuracy. In contrast with the traditional training set containing only the position and speed information, the acceleration and jerk information, as well as their temporal distribution information, is also included in the input of the model. An inverse hysteresis compensator (IHC) is established in the same way, and open-loop and closed-loop controllers are developed by using the IHC. Experimental results on a PEA stage show that with the increase in the input dimension, the hysteresis modeling accuracy improves greatly and, thus, the controllers based on IHC can achieve a better tracking performance. Full article

(This article belongs to the Special Issue Actuating, Sensing, Control, and Instrumentation for Ultra Precision Engineering)

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