An Adaptive Periodic-Disturbance Observer for Periodic-Disturbance Suppression

Muramatsu, Hisayoshi; Katsura, Seiichiro

doi:10.1109/tii.2018.2804338

Cited by 101 publications

(35 citation statements)

References 25 publications

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“…Control derived by the pseudospectral method will be numerically revealed using MATLAB via a general optimization program [27]. By comparison, recall classical compensators and those designed to control flexible systems [28][29][30][31][32][33][34] ubiquitously command maneuvers in the direction of the desired end state. To validate this claim, reviews of classical compensators [35] and frequency domain shaping filters [36] were performed by Wie and Agrawal, respectively.…”

Section: Of 18mentioning

confidence: 99%

Optimization Provenance of Whiplash Compensation for Flexible Space Robotics

Sands

2019

Aerospace

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Automatic controls refer to the application of control theory to regulate systems or processes without human intervention, and the notion is often usefully applied to space applications. A key part of controlling flexible space robotics is the control-structures interaction of a light, flexible structure whose first resonant modes lie within the bandwidth of the controller. In this instance, the designed-control excites the problematic resonances of the highly flexible structure. This manuscript reveals a novel compensator capable of minimum-time performance of an in-plane maneuver with zero residual vibration (ZV) and zero residual vibration-derivative (ZVD) at the end of the maneuver. The novel compensator has a whiplash nature of first commanding maneuver states in the opposite direction of the desired end state. For a flexible spacecraft simulator (FSS) free-floating planar robotic arm, this paper will first derive the model of the flexible system in detail from first principles. Hamilton's principle is augmented with the adjoint equation to produce the Euler-Lagrange equation which is manipulated to prove equivalence with Newton's law. Extensive efforts are expended modeling the free-free vibration equations of the flexible system, and this extensive modeling yields an unexpected control profile-a whiplash compensator. Equations of motion are derived using both the Euler-Lagrange method and Newton's law as validation. Variables are then scaled for efficient computation. Next, general purposed pseudospectral optimization software is used to seek an optimal control, proceeding afterwards to validate optimality via six theoretical optimization necessary conditions: (1) Hamiltonian minimization condition; (2) adjoint equations; (3) terminal transversality condition; (4) Hamiltonian final value condition; (5) Hamiltonian evolution equation; and lastly (6) Bellman's principle. The results are novel and unique in that they initially command full control in the opposite direction from the desired end state, while no such results are seen using classical control methods including classical methods augmented with structural filters typically employed for controlling highly flexible multi-body systems. The manuscript also opens an interesting question of what to declare when the six optimality necessary conditions are not necessarily in agreement (we choose here not to declare finding the optimal control, instead calling it suboptimal).Aerospace 2019, 6, 93 2 of 18 highly flexible structure. In order to optimize the control of such challenging systems, a brief review of mechanics and ubiquitous control techniques is warranted.Mechanical motion of mass in six degrees of freedom is completely described by separate treatment of three degrees of freedom of translation plus three additional degrees of freedom of rotation as articulated in the year 1830 [1] and expanded and modernized over the following two centuries [2][3][4][5][6][7][8][9][10][11][12][13]. Translational degrees of freedom are governed by Newton's law, whil...

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Section: Of 18mentioning

confidence: 99%

Optimization Provenance of Whiplash Compensation for Flexible Space Robotics

Sands

2019

Aerospace

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“…In addition to those successful real-life applications, several modified DOBC methods have also been developed from different theoretical aspects. 1) Integrating Multiple Disturbance Models: Inspired by the internal model principle [15], appropriately utilizing different disturbance models, DOBC methods for nonlinear systems subject to polynomial disturbances are proposed in [16], [17] and subject to periodic disturbances with known and fixed frequencies are proposed in [18] and with unknown time-varying frequencies are proposed in [19]. Besides, these DOBC methods have already been applied in motion control systems to suppress ripples in torque/speed/position [9], [20].…”

Section: Introductionmentioning

confidence: 99%

Disturbance Rejection for Nonlinear Uncertain Systems With Output Measurement Errors: Application to a Helicopter Model

Yan

Zhang

Liu

et al. 2020

IEEE Trans. Ind. Inf.

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As a virtual sensor, disturbance observer provides an alternative approach to reconstruct lumped disturbances (including external disturbances and system uncertainties) based upon system states/outputs measured by physical sensors. Not surprisingly, measurement errors bring adverse effects on the control performance and even the stability of the closed-loop system. Toward this end, this paper investigates the problem of disturbance observer based control for a class of disturbed uncertain nonlinear systems in the presence of unknown output measurement errors. Instead of inheriting from the estimation-error-driven structure of Luenberger type observer, the proposed disturbance observer only explicitly uses the control input. It has been proved that the proposed method endows the closed-loop system with strong robustness against output measurement errors and system uncertainties. With rigorous analysis under the semiglobal stability criterion, the guideline of gain choice based upon the proposed structure is provided. To better demonstrate feature and validity of the proposed method, numerical simulation and comparative experiments of a helicopter model are implemented.

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“…However, periodic disturbances from spaceborne equipment result in difficulty in retaining stability in the attitude of spacecraft. The application of spaceborne microwave imaging instruments has substantially improved the image definition, but poor effects on attitude accuracy are also brought about by their known-law rotating imbalance [4][5][6]. Furthermore, characteristics like flexibility and low weight make spacecraft vulnerable to vibrations caused by numerous sources [7].…”

Section: Introductionmentioning

confidence: 99%

A Study on Optimal Compensation Design for Meteorological Satellites in the Presence of Periodic Disturbance

Cui

Fan

et al. 2018

Applied Sciences

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Featured Application: This work may be used to improve the accuracy of attitude stability of flexible meteorological satellites.Abstract: Periodic disturbance may cause serious effects on the attitude of meteorological satellites, and the attenuation of periodic disturbance is required. In this paper, a fundamental study on the optimal design of constant compensations against known-law periodic disturbance for meteorological satellites is investigated. An analytical solution for the relationship between the frequency and amplitude ratios and the response of a typical second-order vibration system is firstly derived. The compensation and disturbance torques are determined according to practical engineering. The criteria for designing the optimal compensations are based on the analytical and simulation results. Then, the criteria are applied to a flexible spacecraft actuated by constant control torque in the presence of sustained periodic disturbance. The optimal compensation torque parameters for spacecraft are acquired based on former criteria. The compensate effectiveness of the optimal compensation torque is provided and compared with results of other selections in the frequency and amplitude ratio domain. Numerical simulation results and experimental results clearly demonstrate the good performance of proposed criteria. This work provides a significant reference for the vibration attenuation of meteorological satellites in the present of periodic disturbance.

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An Adaptive Periodic-Disturbance Observer for Periodic-Disturbance Suppression

Cited by 101 publications

References 25 publications

Optimization Provenance of Whiplash Compensation for Flexible Space Robotics

Optimization Provenance of Whiplash Compensation for Flexible Space Robotics

Disturbance Rejection for Nonlinear Uncertain Systems With Output Measurement Errors: Application to a Helicopter Model

A Study on Optimal Compensation Design for Meteorological Satellites in the Presence of Periodic Disturbance

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