Generalized digital redesign method for linear feedback system based on N-delay control

Fujimoto, Hiroshi; Kawamura, Atsuo; Tomizuka, Masayoshi

doi:10.1109/3516.769537

Cited by 55 publications

(17 citation statements)

References 17 publications

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“…Various digital redesign techniques for continuous-time delay-free systems have been developed by several authors [12][13][14][15][16][17][18]. In general, the digital redesign techniques for analog systems can be classified into three approaches: The first approach, called the direct digital design approach, is to discretize the plant and then determine a digital controller for the discretized plant [12]; the second approach, called the digital redesign approach [12,13,[15][16][17][18], is to pre-design an analog controller for the analog plant and then carry out the digital redesign for the pre-designed analog controller; and the third approach, called the direct sampled-data approach [14], is to directly design a digital controller for the analog plant, which is still under development [6]. The direct digital design approach has difficulty to control the inter-sampling behaviour of the analog system with a relatively longer sampling period, whereas the digital redesign approach is able to take into consideration the inter-sampling behaviour of the analog plant.…”

Section: Observed-based Linear Quadratic Sub-optimal Digital Trackermentioning

confidence: 99%

The observer‐based linear quadratic sub‐optimal digital tracker for analog systems with input and state delays

Huang

Tsai

Provence

et al. 2003

Optim Control Appl Methods

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SUMMARYThis paper presents a new observer-based sub-optimal digital tracker for the continuous-time system with input and state time delays. We directly convert the continuous-time input-state delayed system into an equivalent discrete-time input-state delayed model and its extended discrete-time delay-free model. In addition, we directly discretize the linear quadratic performance index specified in the continuoustime domain into an equivalent decoupled discrete-time performance index using the newly developed extended delay-free model. As a consequence, the well-developed discrete-time optimal control theory for discrete-time delay-free system can be applied to determine the optimal digital tracker for the continuous-time input-state delayed system. When the states of the continuous-time input-state delayed system are not available for measurements, we develop a sub-optimal digital observer for the original continuous-time input-state delayed system using the state-matching digital redesign technique and the digital-to-analog model conversion technique. As a result, the proposed observer-based linear quadratic digital tracker is able to make the output of the digitally controlled continuous-time input-state delayed system sub-optimally track the desired reference signals. An illustrative example is presented to demonstrate the effectiveness of the proposed design methodology.

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Section: Observed-based Linear Quadratic Sub-optimal Digital Trackermentioning

confidence: 99%

The observer‐based linear quadratic sub‐optimal digital tracker for analog systems with input and state delays

Huang

Tsai

Provence

et al. 2003

Optim Control Appl Methods

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“…The methodology to convert an analog controller into its corresponding digital controller, so that states in the digitally controlled system match the original continuous controlled system precisely, is the so-called digital redesign. In recent years, Shieh et al and other authors have thoroughly investigated various types of digital redesign methods [5][6][7][8][9][10]. This interest by researchers has resulted in major advances in this area.…”

Section: Introductionmentioning

confidence: 96%

Digital redesign tracker for cascaded analog systems with state saturation and external loads

Tsai

Dunn

et al. 2005

Journal of the Franklin Institute

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“…Digital implementation is usually desired for achieving better reliability, lower cost, smaller size, increased flexibility and better performance. Digital redesign techniques are able to retain the physical insight of continuoustime design and maintain the essential system performance from their analogue counterparts (Kuo 1980;Sunkel, Shieh, and Zhang 1991;Rafee, Chen, and Malik 1997;Shieh, Wang, and Panicker 1998;Fujimoto, Kawamura, and Tomizuka 1999;Guo, Shieh, Chen, and Lin 2000). In this work, predictionbased digital redesign (Guo et al 2000), a technique that has been successfully employed to control the highly nonlinear chaotic systems, is used to convert the designed analogue controller into an equivalent digital controller.…”

Section: Introductionmentioning

confidence: 99%

Digital controller design for Bouc–Wen model with high-order hysteretic nonlinearities through approximated scalar sign function

Shieh

Zhang

et al. 2011

International Journal of Systems Science

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In the models of piezoelectric actuator (PEA) systems, the hysteresis effects are often described by the concise Bouc-Wen models; however, these models are nonlinear and non-smooth because of the existence of terms which involve the absolute-value function. In particular, a challenging control problem is posed when, due to the properties of certain materials, such absolute-value terms are of high order. This control problem has been rarely studied. This article proposes the use of the approximated scalar sign function (ASSF), which is a numerically stable and differentiable nonlinear function, to represent the hysteresis function, with single-order or high-order absolute-value terms. This innovative step leads to a nonlinear but sufficiently smooth model. Then, a systematic digital design methodology is presented, which involves the following steps: (1) establish an optimal linear model based upon the resulting smooth model, (2) adopt a PI-based analogue controller and (3) apply the predictionbased digital redesign technique for digital implementation. A digital observer is also developed for state reconstruction, and to improve the input disturbance rejection. The positioning control of a PEA system with a high-order hysteretic Bouc-Wen model is implemented to demonstrate the effectiveness of the proposed ASSF based modelling and controller design approaches.

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Generalized digital redesign method for linear feedback system based on N-delay control

Cited by 55 publications

References 17 publications

The observer‐based linear quadratic sub‐optimal digital tracker for analog systems with input and state delays

The observer‐based linear quadratic sub‐optimal digital tracker for analog systems with input and state delays

Digital redesign tracker for cascaded analog systems with state saturation and external loads

Digital controller design for Bouc–Wen model with high-order hysteretic nonlinearities through approximated scalar sign function

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