다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Piezo-actuated stages have become more and more promising in nanopositioning applications due to the excellent advantages of the fast response time, large mechanical force, and extremely fine resolution. Modeling and control are critical to achieve objectives for high-precision motion. However, piezo-actuated stages themselves suffer from the inherent drawbacks produced by the inherent creep and hysteresis nonlinearities and vibration caused by the lightly damped resonant dynamics, which make modeling and control of such systems challenging. To address these challenges, various techniques have been reported in the literature. This paper surveys and discusses the progresses of different modeling and control approaches for piezo-actuated nanopositioning stages and highlights new opportunities for the extended studies.

Modeling and Control of Piezo-Actuated Nanopositioning Stages: A Survey

This paper proposes an improved sliding mode control with perturbation estimation (SMCPE) featuring a PID-type sliding surface and adaptive gains for the motion tracking control of a micromanipulator system with piezoelectric actuation One advantage of the proposed controller lies in that its implementation only requires the online estimation of perturbation and control gains without acquiring the knowledge of bounds on system uncertainties The dynamic model of the system with Bouc-Wen hysteresis is established and identified through particle swarm optimization (PSO) approach, and the controller is designed based on Lyapunov stability analysis A high-gain observer is adopted to estimate the full state from the only measurable position information Experimental results demonstrate that the performance of proposed controller is superior to that of conventional SMCPE in both set-point regulation and motion tracking control Moreover, a submicron accuracy tracking and contouring is achieved by the micromanipulator with dominant hysteresis compensated for a low magnitude level, which validates the feasibility of the proposed controller in the field of micro/nano scale manipulation as well

Adaptive Sliding Mode Control With Perturbation Estimation and PID Sliding Surface for Motion Tracking of a Piezo-Driven Micromanipulator

This note presents a modification of the integrated friction model structure proposed by Swevers et al. (2000), called the Leuven model. The Leuven model structure allows accurate modeling both in the presliding and the sliding regimes without the use of a switching function. The model incorporates a hysteresis function with nonlocal memory and arbitrary transition curves. This note presents two modifications of the Leuven model. A first modification overcomes a recently detected shortcoming of the original Leuven model: a discontinuity in the friction force which occurs during certain transitions in presliding. A second modification, using the general Maxwell slip model to implement the hysteresis force, eliminates the problem of stack overflow, which can occur with the implementation of the hysteresis force.

Technical Note: modification of the Leuven integrated friction model structure

The Prandtl-Ishlinskii (PI) model is widely utilized in hysteresis modeling and compensation of piezoelectric actuators For systems with rate-independent hysteresis, the inverse PI model is analytically feasible and it can be adopted as a feedforward compensator for the hysteretic nonlinearity of piezoelectric actuators However, for the rate-dependent PI model, the applicable valid inversion methodology is not yet available Although simply replacing all the rate-independent terms in the conventional inversion law with the rate-dependent terms can achieve acceptable results at very slow trajectories However, a large theoretical modeling error is inevitable at fast trajectories, which is investigated through simulations This paper proposes a new direct approach to derive the inverse PI model directly from experimental data As no inversion calculation is involved, the proposed direct approach is efficient and the theoretical modeling error can be avoided In order to validate the accuracy of the direct approach, a number of experiments have been implemented on a piezo-driven compliant mechanism by utilizing the inverse PI model as a feedforward controller The tracking performance of the mechanism is significantly improved by the direct approach

A Novel Direct Inverse Modeling Approach for Hysteresis Compensation of Piezoelectric Actuator in Feedforward Applications

In this paper, precision tracking control of piezoelectric-actuated systems is discussed. In order to obtain precision tracking control, a modified Prandtl–Ishlinskii (MPI) model is used to model the hysteresis nonlinearity. Then, the inverse MPI model is used to reduce the hysteresis nonlinearity, and a sliding-mode controller is used to compensate for the remaining nonlinear uncertainty and disturbances. In general, the piezoelectric-actuated system can be modeled as a linear model coupled with a hysteresis. When the linear model is identified, it is used to design the sliding-mode controller. Finally, this design method is applied to the motion control of a nano-stage, and experimental results are presented to verify the usefulness of this method.

Precision tracking control of a piezoelectric-actuated system

This paper presents the sliding-mode control of a three-degrees-of-freedom nanopositioner (Z, θx, θy). This nanopositioner is actuated by piezoelectric actuators. Capacitive gap sensors are used for position feedback. In order to design the feedback controller, the open-loop characteristics of this nanopositioner are investigated. Based on the results of the investigation, each pair of piezoelectric actuators and corresponding gap sensors is treated as an independent system and modeled as a first-order linear model coupled with hysteresis. When the model is identified and the hysteresis nonlinearity is linearized, a linear system model with uncertainty is used to design the controller. When designing the controller, the sliding-mode disturbance (uncertainty) estimation and compensation scheme is used. The structure of the proposed controller is similar to that of a proportional integral derivative controller. Thus, it can be easily implemented. Experimental results show that 3-nm tracking resolution can be obtained. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society

Sliding-mode control of a three-degrees-of-freedom nanopositioner

In this paper, precision tracking control of piezoelectric-actuated systems is discussed. In order to obtain precision tracking control, Prandtl-Ishlinskii (PI) model is used to model the hysteresis nonlinearity. Then, the inverse PI model is used to reduce the hysteresis nonlinearity and a sliding-mode controller is used to compensate the remaining nonlinear uncertainty and disturbances. The piezoelectric-actuated system is modeled as a linear model coupled with a hysteresis. The linear model is identified then it is used to design the sliding-mode controller. Finally, experimental results are presented to verify the usefulness of this method.

https://www.advantech.gr/med07/papers/T23-002-403.pdf

This paper concerns the development of a sliding-mode tracking controller with friction compensation for a precision positioning stage with cross-roller guides. Experiments including prerolling and rolling friction regimes are conducted, and then a two-stage parameter estimation algorithm is used to identify the parameters of a friction dynamic model (Dynamic NonLinear Regression with direct application of eXcitation, DNLRX, model). This model allows the estimation of the friction force in combination with the system dynamics against displacement, and can be used as a feed-forward controller to compensate for the friction effect. To compensate for model error and uncertain disturbances, an integral sliding-mode controller with a disturbance estimation scheme is designed and combined with the DNLRX feed-forward controller to control the motion of a precision stage. Experimental results show that with the proposed controller, tracking performance can be improved.

Sliding-Mode Tracking Control With DNLRX Model-Based Friction Compensation for the Precision Stage

Some time ago, an interferometer-based metrological scanning probe microscope (SPM) was developed at the Institute of Process Measurement and Sensor Technology of the Ilmenau University of Technology, Germany. The specialty of this SPM is the combined deflection detection system that comprises an interferometer and a beam deflection. Due to this system it is possible to simultaneously measure the displacement, bending and torsion of the probe (cantilever). The SPM is integrated into a nanopositioning and nanomeasuring machine (NPM machine) and allows measurements with a resolution of 0.1 nm over a range of 25 mm ? 25 mm ? 5 mm. Excellent results were achieved for measurements of calibrated step height and lateral standards and these results are comparable to the calibration values from the Physikalisch-Technische Bundesanstalt (PTB) (Dorozhovets N et al 2007 Proc. SPIE 6616 661624?1?7). The disadvantage was a low attainable scanning speed and accordingly large expenditure of time. Control dynamics and scanning speed are limited because of the high masses of the stage and corner mirror of the machine. For the vertical axis an additional high-speed piezoelectric drive is integrated in the SPM in order to increase the measuring dynamics. The movement of the piezoelectric drive is controlled and traceable measured by the interferometer. Hence, nonlinearity and hysteresis in the actuator do not affect the measurement. The outcome of this is an improvement of the bending control of the cantilever and much higher scan speeds of up to 200 ?m?s?1.

http://iopscience.iop.org/article/10.1088/0957-0233/22/9/094012/pdf

Jing-Chung Shen

Papers

Precision tracking control of a piezoelectric-actuated system

Sliding-mode control of a three-degrees-of-freedom nanopositioner

Precision tracking control of a piezoelectric-actuated system

Sliding-Mode Tracking Control With DNLRX Model-Based Friction Compensation for the Precision Stage

Novel control scheme for a high-speed metrological scanning probe microscope