Relay Feedback

Wang, Qingguo; Lee, Tong Heng; Lin, Chong

doi:10.1007/978-1-4471-0041-6

Cited by 75 publications

(7 citation statements)

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“…The small value of t, especially along Γ-K (t ∼ 12 -26 meV ), is puzzling. It is estimated that the super exchange interaction J is 12 and 24 meV in Na x CoO 2 [3]. Apparently, the small t observed here is the effective t ef f , which is renormalized from the original band t, estimated to be ∼ 130 meV (the total band width is 12t ∼ 1.6 eV ) [11,14].…”

mentioning

confidence: 70%

ARPES onNa0.6CoO2: Fermi Surface and Unusual Band Dispersion

et al. 2004

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The electronic structure of single crystals Na0.6CoO2, which are closely related to the superconducting Na0.3CoO2.yH2O (Tc ∼ 5K), is studied by angle-resolved photoelectron spectroscopy. While the measured Fermi surface is found to be consistent with the prediction of a local density band theory, the energy dispersion is highly renormalized, with an anisotropy along the two principle axes (Γ-K, Γ-M ). Our ARPES result also indicates that an extended flat band is formed slightly above EF along Γ-K. In addition, an unusual band splitting is observed in the vicinity of the Fermi surface along the Γ-M direction, which differs from the predicted bilayer splitting.

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mentioning

confidence: 70%

ARPES onNa0.6CoO2: Fermi Surface and Unusual Band Dispersion

et al. 2004

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“…The method for estimating the model uses a frequency response fitting. All the methods presented provide the second-order model with time delay (8). The estimated model parameters for all presented and proposed methods for process G P4 are given in Table 8.…”

Section: Casementioning

confidence: 99%

“…The most common frequency-domain identification method is a relay feedback identification method [2,8,9]. Several variants of relay identification methods have been proposed in the literature [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

A Simple Analytical Method for Estimation of the Five-Parameter Model: Second-Order with Zero Plus Time Delay

Kos

Vrančić

2021

Mathematics

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Process models play an important role in the process industry. They are used for simulation purposes, quality control, fault detection, and control design. Many researchers have been engaged in model identification. However, it is difficult to find an analytical identification method that provides a good model and requires a relatively simple experiment. This is the advantage of the method of moments. In this paper, an analytical method based on the measurement of the process moments (characteristic areas) is proposed, to identify the five-parameter model (second-order process with zero plus time delay) from either the closed-loop or open-loop time responses of the process (in the time-domain), or the general-order transfer function with time delay (in the frequency-domain). The only parameter required by the user is the type of process (minimum phase or non-minimum phase process), which in practice can be easily determined from the time response of the process. The method can also be used to reduce the higher-order process model. The proposed identification method was tested on several illustrative examples, and compared to other identification methods. The comparison with existing methods showed the superiority of the proposed method. Moreover, the tests confirmed that the algorithm of the proposed method works properly for a wide family of process models, even in the presence of moderate process noise.

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“…Relay feedback has been studied intensively for more than a century. 18 It has been applied in various control systems such as auto-tuning of process controllers, 19,20 current controllers, 21 servomechanism. 22 It is also useful in system identification 23,24 and parameter identification such as process model parameters in under-damped second order plus dead time processes, 25 indoor temperature lag in variable air volume systems 26 and backlash in two-mass systems.…”

Section: Introductionmentioning

confidence: 99%

Position-insensitive estimation of mass from limit cycle of velocity feedback relay system with Spring

Mizuno

Egawa

Takasaki

et al. 2021

Measurement and Control

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Mass measurement using relay feedback of velocity and restoring force compensation is investigated for determining the mass of an object under weightless conditions. In the measurement system, the velocity of the object is fed back through a relay with hysteresis and the force acting on the object is switched from a positive value to a negative value when the velocity reaches a positive threshold and vice versa. As a result, a limit cycle is induced in the measurement system and the mass is estimated based on the period of the limit cycle. In addition, restoring force compensation with a spring is introduced to avoid the drift of the trajectory. This compensation makes the static equilibrium state unique. However, the trajectory still drifts slightly. It causes some error in measurement when a simple formula of estimating mass is applied. To eliminate such an error, a new formula is derived to estimate the mass independently of the position of the trajectory that is determined by the switching positions in the relay actions. When the switching positions deflect from the origin at which the spring is in the natural length, the trajectory is not at the center and becomes asymmetric. It is analytically shown that the period of the limit cycle is minimum when the switching positions are at the origin. It indicates that mass is overestimated with the simple estimation formula when the trajectory is not at the center. The validity of the modified formula and the analytical results are confirmed experimentally.

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Relay Feedback

Cited by 75 publications

References 0 publications

ARPES onNa0.6CoO2: Fermi Surface and Unusual Band Dispersion

ARPES onNa0.6CoO2: Fermi Surface and Unusual Band Dispersion

A Simple Analytical Method for Estimation of the Five-Parameter Model: Second-Order with Zero Plus Time Delay

Position-insensitive estimation of mass from limit cycle of velocity feedback relay system with Spring

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