Adding robustness to nominal output-feedback controllers for uncertain nonlinear systems: A nonlinear version of disturbance observer

Back, Juhoon; Shim, Hyungbo

doi:10.1016/j.automatica.2008.02.024

Cited by 214 publications

(129 citation statements)

References 21 publications

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“…Consequently, a disturbance observer has been used, not only for improving the robustness and bandwidth of the control system, but also for estimation the external force for examples, [11]- [12]. It has been confirmed that a robust force control can be obtained, when a disturbance observer is implemented as the feed forward control for a disturbance force compensation loop.…”

Section: Disturbance Observermentioning

confidence: 91%

Design for Sensorless Force Control of Flexible Robot by Using Resonance Ratio Control Based on Coefficient Diagram Method

et al. 2013

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Original scientific paperGenerally, the flexible robot system can be modeled as the two-mass system which consists of a motor and load connected by a spring. Thus, its elasticity causes resonance in the system. By using the conventional PID controller, this method cannot perform well in this situation. Much research has proceeded with the aim of reducing vibration. A new effective control method, the resonance ratio control, has been introduced as a new way to guarantee the robustness and suppress the oscillation during task executions for a position and force control. In this paper, three techniques are proposed for improving the performance of resonance ratio control. Firstly, a new multi encoder based disturbance observer (MEDOB) is shown to estimate the disturbance force on the load side. The proposed observer is not necessary to identify the nominal spring coefficient. Secondly, coefficient diagram method (CDM) has been applied to calculate a new gain of the force controller. A new resonance ratio gain has been presented as 2.0. Finally, the MEDOB and load side disturbance observer (LDOB) are employed to identify a spring coefficient of flexible robot system. By using the proposed identification method, it is simple to identify the spring coefficient and easy to implement in the real flexible robot system. The effectiveness of the proposed identification method is verified by simulation and experimental results.Key words: Disturbance observer, Two-mass system, Coefficient diagram method, Resonance ratio control Sinteza bezsenzornog upravljanja silom za fleksibilnog robota korištenjem upravljanja omjerom rezonancija temeljenim na metodi koeficijentnog dijagrama. Općenito, sustav fleksibilnog robota može se modelirati kao dvomaseni sustav koji se sastoji od motora i tereta povezanih oprugom. Rezonancija sustava posljedica je elastičnosti opruge. Korištenje konvencionalnog PID regulatora ne daje zadovoljavajuće performanse u ovoj situaciji. Provedena su mnoga istraživanja s ciljem smanjenja vibracija. Tako je uvedena nova učinkovita metoda upravljanja, upravljanje omjerom rezonancija, kao novi način da se osigura robusnost i priguše oscilacije tijekom izvršavanja zadatka putem upravljanja pozicijom i silom. U ovom radu predložene su tri tehnike za poboljšanje performansi upravljanja omjerom rezonancija. Prvo, pokazano je kako novi observer poremećaja temeljen na više enkodera (MEDOB) estimira poremećajnu silu na strani tereta. Predloženi observer nije nužan za identifikaciju nominalnog koeficijenta opruge. Drugo, metoda koeficijentnog dijagrama (CDM) je primijenjena za proračun novog pojačanja regulatora sile. Iznos 2.0 je odre en kao novo pojačanje omjera rezonancija. Konačno, MEDOB i observer poremećaja na strani tereta (LDOB) korišteni su za identifikaciju koeficijenta opruge sustava fleksibilnog robota. Predložena metoda identifikacije jednostavna je za implementaciju na stvarni sustav, te se pomoću nje jednostavno identificira koeficijent opruge. Učinkovitost predložene metode identifikacije provjerena je...

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Section: Disturbance Observermentioning

confidence: 91%

Design for Sensorless Force Control of Flexible Robot by Using Resonance Ratio Control Based on Coefficient Diagram Method

et al. 2013

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“…14) Thus, the proof of Theorem 1 is easily derived from the proof of the original theorem in 'Section 3.2' of the previous research. 14) …”

Section: Decoupling Using Ndobmentioning

confidence: 99%

“…Recently, the NDOB 14) was introduced to cancel out such disturbance terms so that the resulting system is decoupled. Moreover, the NDOB compensates the parameter uncertainties of the system model.…”

Section: Decoupling Using Ndobmentioning

confidence: 99%

Non-interactive Looper and Strip Tension Control for Hot Finishing Mill Using Nonlinear Disturbance Observer

2012

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In this paper, we propose a non-interactive looper and strip tension control method for a hot finishing mill based on the nonlinear dynamic model. Using the NDOB (nonlinear disturbance observer), the nonlinear looper-tension dynamic system is decoupled into two independent SISO (single-input, single-output) subsystems, and moreover, the model uncertainties and the external disturbances generated from forward slip, strip thickness variation and outgoing strip speed are compensated. A modified TSM (terminal sliding mode) controller is utilized to control the looper angle while the output-feedback controller regulates the strip tension by adjusting the incoming roll speed. Hardware experiment with the 2-stand hardware looper simulator was performed to verify the effectiveness of the proposed approach.KEY WORDS: hot finishing mill; looper tension control; nonlinear disturbance observer; non-interactive control.

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“…In [2], the authors propose an extension of the method proposed in [8] to fully actuated non-linear systems. The proposed extended method consists in estimating external or internal disturbances in order to compensate them.…”

Section: Introductionmentioning

confidence: 99%

Estimation-based disturbance rejection in control for limit cycle generation on inertia wheel inverted pendulum testbed

Andary

Chemori

Krut

2009

2009 IEEE/RSJ International Conference on Intelligent Robots and Systems

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Abstract-This paper deals with constant disturbances rejection in limit cycle tracking for an underactuated mechanical system. The feedback controler presented in [1] is enhanced to handle constant disturbances by using online iterative estimation of an equivalent disturbance which is easily compensated by adding the estimated value to the output of the system. The effectiveness of the proposed method is demonstrated through real-time experiments on an inertia wheel inverted pendulum. Constant disturbances are introduced either as a weight asymmetrically fixed to the pendulum body, or by the use of a bad calibrated sensor.

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Adding robustness to nominal output-feedback controllers for uncertain nonlinear systems: A nonlinear version of disturbance observer

Cited by 214 publications

References 21 publications

Design for Sensorless Force Control of Flexible Robot by Using Resonance Ratio Control Based on Coefficient Diagram Method

Design for Sensorless Force Control of Flexible Robot by Using Resonance Ratio Control Based on Coefficient Diagram Method

Non-interactive Looper and Strip Tension Control for Hot Finishing Mill Using Nonlinear Disturbance Observer

Estimation-based disturbance rejection in control for limit cycle generation on inertia wheel inverted pendulum testbed

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