Bandwidth constraints of disturbance observer in the presence of real parametric uncertainties

Sarıyıldız, Emre; Ohnishi, Kouhei

doi:10.1016/j.ejcon.2013.03.009

Cited by 35 publications

(16 citation statements)

References 23 publications

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“…They also limit the bandwidth of a DOB; however, the relation between the robustness of a system and the dynamic characteristics of the DOB's LPF and nominal plant has not been clearly reported yet [10,19,20]. Recently, it was shown by the authors that if a minimum-phase system has only real parametric uncertainties, then a DOB can guarantee the robustness of the system by increasing its bandwidth, and the stability margin of the system improves as the bandwidth of the DOB is increased [21]. However, it considers only the minimum-phase systems which have real parametric uncertainties when a first order DOB is used.…”

Section: Introductionmentioning

confidence: 99%

A Guide to Design Disturbance Observer

Sarıyıldız

Ohnishi

2013

Journal of Dynamic Systems, Measurement, and Control

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138

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The goal of this paper is to clarify the robustness and performance constraints in the design of control systems based on disturbance observer (DOB). Although the bandwidth constraints of a DOB have long been very well-known by experiences and observations, they have not been formulated and clearly reported yet. In this regard, the Bode and Poisson integral formulas are utilized in the robustness analysis so that the bandwidth constraints of a DOB are derived analytically. In this paper, it is shown that the bandwidth of a DOB has upper and lower bounds to obtain a good robustness if the plant has nonminimum phase zero(s) and pole(s), respectively. Besides that the performance of a system can be improved by using a higher order disturbance observer (HODOB); however, the robustness may deteriorate, and the bandwidth constraints become more severe. New analysis and design methods, which provide good robustness and predefined performance criteria, are proposed for the DOB based robust control systems. The validity of the proposals are verified by simulation results.

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Section: Introductionmentioning

confidence: 99%

A Guide to Design Disturbance Observer

Sarıyıldız

Ohnishi

2013

Journal of Dynamic Systems, Measurement, and Control

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138

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“…Despite an already long history of this solution, choice of an optimal DO filter still represents a frequently discussed problem (see e.g. [8]- [12] and the references therein). Thereby, in control of loops with time delays one has to cope with stronger constraints on robustness.…”

Section: Introductionmentioning

confidence: 99%

Robustness versus performance in PDO FPI Control of the IPDT plant

Huba

2015

2015 IEEE International Conference on Mechatronics (ICM)

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This paper deals with robustness evaluation of the predictive disturbance observer based filtered PI (PDO FPI) control. Robust performance of loops with integral plants, different order filters and with an uncertain dead time is examined by the performance portrait method. The analysis does not confirm the up to now accepted view that the best robustness corresponds to the 1st order filters. Features of robust performance measures in the time domain are discussed.

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“…The bandwidth of a DOB and the nominal inertia and torque coefficient of a motor are the fundamental design parameters of a DOB-based robust motion control system. The bandwidth of a DOB is desired to set as high as possible to estimate/suppress disturbances in a wide frequency range; however, it is limited by noise and robustness constraints [16], [17]. Several research studies have been conducted to improve the bandwidth of a DOB by suppressing the noise of velocity measurement [18]- [20].…”

Section: Introductionmentioning

confidence: 99%

Stability and Robustness of Disturbance-Observer-Based Motion Control Systems

Sarıyıldız

Ohnishi

2015

IEEE Trans. Ind. Electron.

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288

142

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This paper analyzes the robustness and stability of a disturbance observer (DOB) and a reaction torque observer (RTOB)-based robust motion control systems. Conventionally, a DOB is analyzed by using an ideal velocity measurement that is obtained without using a lowpass filter (LPF); however, it is impractical due to noise constraints. An LPF of velocity measurement changes the robustness of a DOB significantly and puts a new design constraint on the bandwidth of a DOB. An RTOB, which is used to estimate environmental impedance, is an application of a DOB. The stability of an RTOB-based robust force control system has not been reported yet since its oversimplified model is derived by assuming that an RTOB has a feedforward control structure. However, in reality, it has a feedback control structure; therefore, not only the performance but also the stability is affected by the design parameters of an RTOB. A new practical stability analysis method is proposed for an RTOB-based robust force control system. In addition to that, novel and practical design methods, which improve the robustness of a DOB and the stability and performance of an RTOB-based robust force control system, are proposed by using the new analysis methods. The validity of the proposals is verified by simulation and experimental results.Index Terms-Disturbance observer (DOB), motion control systems, reaction torque observer (RTOB), robustness and stability.

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Bandwidth constraints of disturbance observer in the presence of real parametric uncertainties

Cited by 35 publications

References 23 publications

A Guide to Design Disturbance Observer

A Guide to Design Disturbance Observer

Robustness versus performance in PDO FPI Control of the IPDT plant

Stability and Robustness of Disturbance-Observer-Based Motion Control Systems

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