Broadband Dynamic Modification Using Feedforward Control

1995 ◽  
Author(s):  
Thomas E. Alberts ◽  
Hemanshu R. Pota
Keyword(s):  
Steady State ◽  
Feedforward Control ◽  
Design Procedure ◽  
Harmonic Excitation ◽  
Flexible Structure ◽  
Minimum Phase ◽  
Original Result ◽  
Modal Expansion ◽  
General Proof ◽  
Dynamic Modification

Abstract This paper presents a general proof of a result due to Fuller and Burdisso, that asserts that system eigenvalues can be modified using feedforward control. The original result applies to the case of steady-state harmonic excitation. This paper extends that work to allow for broadband excitation. The results apply to any flexible structure representable using modal expansion, and are applicable to systems with non-minimum phase zeros. A design procedure is presented to allow arbitrary assignment of the controlled system’s poles, using a fixed feedforward compensator.

Broadband Dynamic Modification Using Feedforward Control

1997 ◽  
Vol 119 (4) ◽  
pp. 700-706 ◽  
Author(s):  
Thomas E. Alberts ◽  
Hemanshu R. Pota
Keyword(s):  
Steady State ◽  
Feedforward Control ◽  
Acoustic Noise ◽  
Harmonic Excitation ◽  
Research Community ◽  
Design Technique ◽  
Nonminimum Phase ◽  
Modal Expansion ◽  
Control Research ◽  
Dynamic Modification

Recently published results arising from the acoustic noise control research community, demonstrate that system dynamics can be modified using feedforward control. Initial investigations applied to known disturbances in the form of steady-state harmonic excitation. This paper further explores feedforward dynamic modification, provides a proof of the nature of the modification, extends the method to allow for broadband excitation, and introduces a design technique for arbitrary assignment of transfer function poles. The results apply to any structure representable using modal expansion, and are applicable to systems with nonminimum phase zeros.

scholarly journals Robust guaranteed performance PID controller design for non-minimum phase plants

2018 ◽  
Vol 69 (2) ◽  
pp. 117-127
Author(s):  
Štefan Bucz ◽  
Alena Kozáková ◽  
Vojtech Veselý
Keyword(s):  
Time Domain ◽  
Closed Loop ◽  
Controller Design ◽  
Design Method ◽  
Design Procedure ◽  
Uncertain System ◽  
Harmonic Excitation ◽  
Minimum Phase ◽  
Performance Specification ◽  
Gain Margin

AbstractThe paper presents a new original robust PID design method for non-minimum phase plants to achieve closed-loop performance prescribed by the process technologist in terms of settling time and maximum overshoot, respectively. The proposed design procedure has two steps: first, the uncertain system is identified using external harmonic excitation signal with frequency, second, the controller of the nominal system is designed for specified gain margin. A couple of parameters is obtained from the time domain performance specification using quadratic regression curves, the so-called performance Bparabolas so, as to simultaneously satisfy robust closed-loop stability conditions. The main benefits of the proposed method are universal applicability for systems with both fast and slow dominant dynamics as well as performance specification using time domain criteria. The proposed PID design method has been verified on a set of benchmark systems.

Nonlinear Vibrations of Viscoelastic Plane Truss Under Harmonic Excitation

2014 ◽  
Vol 14 (04) ◽  
pp. 1450009 ◽  
Author(s):  
Andrew Yee Tak Leung ◽  
Hong Xiang Yang ◽  
Ping Zhu
Keyword(s):  
Steady State ◽  
Fractional Derivatives ◽  
Harmonic Excitation ◽  
Homotopy Continuation ◽  
Response Curves ◽  
System A ◽  
Structural Responses ◽  
Voigt Model ◽  
Two Degree Of Freedom ◽  
Steady State Solutions

This paper is concerned with the steady state bifurcations of a harmonically excited two-member plane truss system. A two-degree-of-freedom Duffing system having nonlinear fractional derivatives is derived to govern the dynamic behaviors of the truss system. Viscoelastic properties are described by the fractional Kelvin–Voigt model based on the Caputo definition. The combined method of harmonic balance and polynomial homotopy continuation is adopted to obtain steady state solutions analytically. A parametric study is conducted with the help of amplitude-response curves. Despite its seeming simplicity, the mechanical system exhibits a wide variety of structural responses. The primary and sub-harmonic resonances and chaos are found in specific regions of system parameters. The dynamic snap-through phenomena are observed when the forcing amplitude exceeds some critical values. Moreover, it has been shown that, suppression of undesirable responses can be achieved via changing of viscosity of the system.

A Design Method for Modified Smith Predictors for Non-Minimum-Phase Time-Delay Plants with Multiple Feedback-Connected Time-Delays

2010 ◽  
Vol 36 ◽  
pp. 253-262 ◽  
Author(s):  
Iwanori Murakami ◽  
Nghia Thi Mai ◽  
Kou Yamada ◽  
Takaaki Hagiwara ◽  
Yoshinori Ando ◽  
...  
Keyword(s):  
Steady State ◽  
Time Delay ◽  
Time Delays ◽  
Large Time ◽  
Design Method ◽  
Smith Predictor ◽  
Minimum Phase ◽  
Effective Time ◽  
Phase Time ◽  
Step Disturbance

In this paper, we examine a design method for modified Smith predictors for non-minimum-phase time-delay plants with multiple feedback-connected time-delays. The Smith predictor is proposed by Smith to overcome time-delay and known as an effective time-delay compensator for a plant with large time-delay. The Smith predictor by Smith cannot be used for plants having an integral mode, because a step disturbance will result in a steady state error. Several papers considered the problem to design modified Smith predictors for unstable plants. However, no paper examines a design method for modified Smith predictors for non-minimum-phase time-delay plants with multiple feedback-connected time-delays. In this paper, we examine a design method for modified Smith predictors for non-minimum-phase time-delay plants with multiple feedback-connected time-delays.

Vibration Control of a Multi-Layer Piezoelectric Cylindrical Shell

1997 ◽  
Author(s):  
Jinhao Qiu ◽  
Junji Tani
Keyword(s):  
Cylindrical Shell ◽  
Feedforward Control ◽  
Equations Of Motion ◽  
Good Control ◽  
Expansion Method ◽  
Piezoelectric Sensor ◽  
State Equation ◽  
Integrated Sensor ◽  
Modal Expansion ◽  
Modal Expansion Method

Abstract Equations of motion for multi-layer piezoelectric cylindrical shells and the equations of the integrated piezoelectric sensors are derived. The state equation is obtained by solving the equations of motion with modal expansion method. The feedback control, feedforward control, and their combination are applied in the control of forced vibration of the piezoelectric cylindrical shell with integrated sensor and actuators. The simulation and experimental results show that good control effectiveness can be obtained by using the integrated piezoelectric sensor and actuators in conjunction with the combination of feedback and feedforward control methods.

Stability of negative feedback

2021 ◽  
pp. 377-403
Author(s):  
Geoffrey Brooker
Keyword(s):  
Negative Feedback ◽  
Design Procedure ◽  
Feedback System ◽  
Conditional Stability ◽  
Phase Lag ◽  
Minimum Phase ◽  
Safety Margins ◽  
Nyquist Stability ◽  
Nyquist Plots ◽  
Frequency Dependences

“Stability of negative feedback” discusses the measures that must be taken to guarantee that a negative-feedback system is stable. Examples are given of frequency dependences using Bode and Nyquist plots. Safety margins are quantified by means of gain margins and phase margins; the desirability of a minimum-phase-lag network. A design procedure is formulated. There is discussion of Nyquist (conditional) stability, and how it may be achieved by judicious introduction of a non-linearity. A demonstration circuit shows that these measures can yield Nyquist stability with safety.

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