Frequency-based nonlinear controller design for regulating systems subjected to time-domain constraints

Frequency-domain based feedback control of flow separation using synthetic jets

“…If the nonlinear output p(t) is periodic and its derivative is piecewise smooth on the periodic interval 0 ≤ t ≤ 1/ f u [16], p(t) can be expanded to a Fourier series…”

Frequency-domain based feedback control of flow separation using synthetic jets

“…If the nonlinear output p(t) is periodic and its derivative is piecewise smooth on the periodic interval 0 ≤ t ≤ 1/ f u [16], p(t) can be expanded to a Fourier series…”

A simple hybrid/switching strategy for improving linear controllers

“…Let Now the key point is to modify the zero-pole block with nonlinear elements, as it was done in [3]. However, in the present paper the modification is made on the block diagram of a zero-pole or phase lead-lag block.…”

“…1 shows a simple two-window compensator. Another use of the nonlinear elements is presented in [3], where performance specifications were unachievable with a linear controller. After designing a linear block, a lead compensator is extracted and its equation is modified with an odd nonlinear term multiplied by a coefficient.…”

NARMAX Identification Based Closed-Loop Control of Flow Separation over NACA 0015 Airfoil

“…It is also seen that the identified baseline pressure signal has higher strength compared with the cases for the controlled flow. In this study, to compute the describing function for a NARMAX system, a method combining the low-pass filtering introduced by Slotine and Li [121] and the harmonic balance method developed by Glass [127] was developed. Then, a MATLAB script was constructed and utilized to find the approximate frequency responses for different jet frequencies using a small perturbation approach.…”

Frequency-domain based feedback control of flow separation using synthetic jets

“…If the nonlinear output p(t) is periodic and its derivative is piecewise smooth on the periodic interval 0 ≤ t ≤ 1/ f u [16], p(t) can be expanded to a Fourier series…”

A simple hybrid/switching strategy for improving linear controllers

“…Let Now the key point is to modify the zero-pole block with nonlinear elements, as it was done in [3]. However, in the present paper the modification is made on the block diagram of a zero-pole or phase lead-lag block.…”

“…1 shows a simple two-window compensator. Another use of the nonlinear elements is presented in [3], where performance specifications were unachievable with a linear controller. After designing a linear block, a lead compensator is extracted and its equation is modified with an odd nonlinear term multiplied by a coefficient.…”

NARMAX Identification Based Closed-Loop Control of Flow Separation over NACA 0015 Airfoil

“…It is also seen that the identified baseline pressure signal has higher strength compared with the cases for the controlled flow. In this study, to compute the describing function for a NARMAX system, a method combining the low-pass filtering introduced by Slotine and Li [121] and the harmonic balance method developed by Glass [127] was developed. Then, a MATLAB script was constructed and utilized to find the approximate frequency responses for different jet frequencies using a small perturbation approach.…”

Frequency-domain based feedback control of flow separation using synthetic jets

“…If the nonlinear output p(t) is periodic and its derivative is piecewise smooth on the periodic interval 0 ≤ t ≤ 1/ f u [16], p(t) can be expanded to a Fourier series…”

A simple hybrid/switching strategy for improving linear controllers

“…Let Now the key point is to modify the zero-pole block with nonlinear elements, as it was done in [3]. However, in the present paper the modification is made on the block diagram of a zero-pole or phase lead-lag block.…”

“…1 shows a simple two-window compensator. Another use of the nonlinear elements is presented in [3], where performance specifications were unachievable with a linear controller. After designing a linear block, a lead compensator is extracted and its equation is modified with an odd nonlinear term multiplied by a coefficient.…”

NARMAX Identification Based Closed-Loop Control of Flow Separation over NACA 0015 Airfoil

“…It is also seen that the identified baseline pressure signal has higher strength compared with the cases for the controlled flow. In this study, to compute the describing function for a NARMAX system, a method combining the low-pass filtering introduced by Slotine and Li [121] and the harmonic balance method developed by Glass [127] was developed. Then, a MATLAB script was constructed and utilized to find the approximate frequency responses for different jet frequencies using a small perturbation approach.…”