Scaling and bandwidth-parameterization based controller tuning
04 Jun 2003-Vol. 6, pp 4989-4996
TL;DR: A new set of tools, including controller scaling, controller parameterization and practical optimization, is presented to standardize controller tuning, which moves controller tuning in the direction of science.
Abstract: A new set of tools, including controller scaling, controller parameterization and practical optimization, is presented to standardize controller tuning. Controller scaling is used to frequency-scale an existing controller for a large class of plants, eliminating the repetitive controller tuning process for plants that differ mainly in gain and bandwidth. Controller parameterization makes the controller parameters a function of a single variable, the loop-gain bandwidth, and greatly simplifies the tuning process. Practical optimization is defined by maximizing the bandwidth subject to the physical constraints, which determine the limiting factors in performance. Collectively, these new tools move controller tuning in the direction of science.
Citations
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TL;DR: This survey gives a systematic and comprehensive tutorial and summary on the existing disturbance/uncertainty estimation and attenuation techniques, most notably, DOBC, active disturbance rejection control, disturbance accommodation control, and composite hierarchical antidisturbance control.
Abstract: Disturbance-observer-based control (DOBC) and related methods have been researched and applied in various industrial sectors in the last four decades. This survey, at first time, gives a systematic and comprehensive tutorial and summary on the existing disturbance/uncertainty estimation and attenuation techniques, most notably, DOBC, active disturbance rejection control, disturbance accommodation control, and composite hierarchical antidisturbance control. In all of these methods, disturbance and uncertainty are, in general, lumped together, and an observation mechanism is employed to estimate the total disturbance. This paper first reviews a number of widely used linear and nonlinear disturbance/uncertainty estimation techniques and then discusses and compares various compensation techniques and the procedures of integrating disturbance/uncertainty compensation with a (predesigned) linear/nonlinear controller. It also provides concise tutorials of the main methods in this area with clear descriptions of their features. The application of this group of methods in various industrial sections is reviewed, with emphasis on the commercialization of some algorithms. The survey is ended with the discussion of future directions.
1,849 citations
Cites background from "Scaling and bandwidth-parameterizat..."
...To address these issues, Gao refined and proposed the linear and parameterized version of ADRC in 2003 [84]....
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...ADRC was introduced to the international community largely by Gao [14], [84]....
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14 Jun 2006
TL;DR: In this paper, it is shown that the unknown dynamics and disturbance can be actively estimated and compensated in real time and this makes the feedback control more robust and less dependent on the detailed mathematical model of the physical process.
Abstract: The question addressed in this paper is: just what do we need to know about a process in order to control it? With active disturbance rejection, perhaps we don't need to know as much as we were told. In fact, it is shown that the unknown dynamics and disturbance can be actively estimated and compensated in real time and this makes the feedback control more robust and less dependent on the detailed mathematical model of the physical process. In this paper we first examine the basic premises in the existing paradigms, from which it is argued that a paradigm shift is necessary. Using a motion control metaphor, the basis of such a shift, the active disturbance rejection control, is introduced. Stability analysis and applications are presented. Finally, the characteristics and significance of the new paradigm are discussed.
803 citations
TL;DR: The main idea is to transform the error equation of objective system with its extended state observer into a asymptotical stable system with a small disturbance, for which the effect of total disturbance error is eliminated by the high-gain.
666 citations
Cites background from "Scaling and bandwidth-parameterizat..."
...Unfortunately, although huge applications have been carried out in engineering applications since then (see e.g., Hou et al. [2001], Miklosovic, Gao [2005], Zheng et al. [2008], Zheng, Dong et al. [2007], Zheng, Gao [2010], Copyright by the International Federation of Automatic Control (IFAC) 1855 Zheng, Cheng et al. [2007], Zhou, Gao [2007]) , the choice of functions gi is essentially experiential....
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...[2001], Miklosovic, Gao [2005], Zheng et al. [2008], Zheng, Dong et al. [2007], Zheng, Gao [2010], Preprints of the 18th IFAC World Congress Milano (Italy) August 28 - September 2, 2011...
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...[2007], Zhou, Gao [2007]) , the choice of functions gi is essentially experiential....
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...[2007], Zhou, Gao [2007]) , the choice of functions gi is essentially experiential. In order to apply conveniently in practice, Gao [2003] proposed the following linear extended state observer (LESO in short in what follows), a special case of (1):...
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...[2001], Miklosovic, Gao [2005], Zheng et al. [2008], Zheng, Dong et al....
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TL;DR: Several breakthroughs for control of nonlinear uncertain systems, made possible by ADRC, are discussed and the latest results in theoretical analysis of the ADRC-based control systems are introduced.
Abstract: The methodology of ADRC and the progress of its theoretical analysis are reviewed in the paper. Several breakthroughs for control of nonlinear uncertain systems, made possible by ADRC, are discussed. The key in employing ADRC, which is to accurately determine the “total disturbance” that affects the output of the system, is illuminated. The latest results in theoretical analysis of the ADRC-based control systems are introduced.
629 citations
Cites background or methods from "Scaling and bandwidth-parameterizat..."
...To render the idea clear and controller easy to implement and to tune, a parameterized linear ADRC (LADRC) was proposed in [72], where nonlinear gains are replaced with linear ones and tuning is reduced to the adjustment of one variable, the bandwidth, which is the common terminology used by engineers....
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...In [72], the linear ESO (LESO), which is based on the nonlinear form (9), was proposed, i....
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TL;DR: A feedback linearization (FL)-based control law made implementable using an extended state observer (ESO) is proposed for the trajectory tracking control of a flexible-joint robotic system and the closed-loop stability of the system under the proposed observer-controller structure is established.
Abstract: In this paper, a feedback linearization (FL)-based control law made implementable using an extended state observer (ESO) is proposed for the trajectory tracking control of a flexible-joint robotic system. The FL-based controller cannot be implemented unless the full transformed state vector is available. The design also requires exact knowledge of the system model making the controller performance sensitive to uncertainties. To address these issues, an ESO is designed, which estimates the state vector, as well as the uncertainties in an integrated manner. The FL controller uses the states estimated by ESO, and the effect of uncertainties is compensated by augmenting the FL controller with the ESO-estimated uncertainties. The closed-loop stability of the system under the proposed observer-controller structure is established. The effectiveness of the ESO in the estimation of the states and uncertainties and the effectiveness of the FL + ESO controller in tracking are demonstrated through simulations. Lastly, the efficacy of the proposed approach is validated through experimentation on Quanser's flexible-joint module.
424 citations
References
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TL;DR: In this paper, the three principal control effects found in present controllers are examined and practical names and units of measurement are proposed for each effect and corresponding units for a classification of industrial processes in terms of two principal characteristics affecting their controllability.
Abstract: In this paper, the three principal control effects found in present controllers are examined and practical names and units of measurement are proposed for each effect. Corresponding units are proposed for a classification of industrial processes in terms of the two principal characteristics affecting their controllability. Formulas are given which enable the controller settings to be determined from the experimental or calculated values of the lag and unit reaction rate of the process to be controlled
5,412 citations
04 Dec 2001
TL;DR: An alternative framework for control design is presented, which compliments the existing theory and represents a control strategy that is rather independent of mathematical models of the plants, thus achieving inherent robustness and reducing design complexity.
Abstract: An alternative framework for control design is presented in this paper. It compliments the existing theory in that: 1) it actively and systematically explores the use of nonlinear control mechanisms for better performance, even for linear plants; 2) it represents a control strategy that is rather independent of mathematical models of the plants, thus achieving inherent robustness and reducing design complexity. An overview of this design philosophy and associated algorithms are first introduced, followed by the summaries of preliminary analysis results and practical applications. It is evident that the proposed framework lends itself well in providing innovative solutions to practical problems while maintaining the simplicity and the intuitiveness of the existing technology, namely PID.
440 citations
371 citations
TL;DR: In this paper, some approaches, which take advantage of some nonlinear characters to be independent of the models and the external disturbances, are introduced, taking advantage of the fact that there are many special characters existing in the nonlinear world.
137 citations
"Scaling and bandwidth-parameterizat..." refers methods in this paper
...This is a special case of the ADRC controller originally proposed by Han in [8, 9], which uses nonlinear gains in place of the linear ones in (4....
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TL;DR: A nonlinear PID and active disturbance rejection framework is introduced that complements the existing theory and represents a control strategy that is rather independent of mathematical models of the plants, thus achieving inherent robustness and reducing design complexity.
Abstract: With the rapid advance of digital control hardware, it is time to take the simple but effective proportional-integral-derivative (PID) control technology to the next level of performance and robustness. For this purpose, a nonlinear PID and active disturbance rejection framework are introduced in this paper. It complements the existing theory in that (1) it actively and systematically explores the use of nonlinear control mechanisms for better performance, even for linear plants; (2) it represents a control strategy that is rather independent of mathematical models of the plants, thus achieving inherent robustness and reducing design complexity. Stability analysis, as well as software/hardware test results, are presented. It is evident that the proposed framework lends itself well in seeking innovative solutions to practical problems while maintaining the simplicity and the intuitiveness of the existing technology.
98 citations