Linear Closed-Loop Control of Fluid Instabilities and Noise-Induced Perturbations: A Review of Approaches and Tools1

2016 ◽  
Vol 68 (2) ◽  
Author(s):  
Denis Sipp ◽  
Peter J. Schmid
Keyword(s):  
Large Scale ◽  
Closed Loop ◽  
Closed Loop Control ◽  
Control Input ◽  
Input Output ◽  
Control Laws ◽  
Loop Control ◽  
Stability Robustness ◽  
Data Control ◽  
Galerkin Models

This review article is concerned with the design of linear reduced-order models and control laws for closed-loop control of instabilities in transitional flows. For oscillator flows, such as open-cavity flows, we suggest the use of optimal control techniques with Galerkin models based on unstable global modes and balanced modes. Particular attention has to be paid to stability–robustness properties of the control law. Specifically, we show that large delays and strong amplification between the control input and the estimation sensor may be detrimental both to performance and robustness. For amplifier flows, such as backward-facing step flow, the requirement to account for the upstream disturbance environment rules out Galerkin models. In this case, an upstream sensor is introduced to detect incoming perturbations, and identification methods are used to fit a model structure to available input–output data. Control laws, obtained by direct inversion of the input–output relations, are found to be robust when applied to the large-scale numerical simulation. All the concepts are presented in a step-by-step manner, and numerical codes are provided for the interested reader.

Multi-Stage System Identification of a Gas Turbine

2017 ◽  
Author(s):  
Amit Pandey ◽  
Maurício de Oliveira ◽  
Chad M. Holcomb
Keyword(s):  
Gas Turbine ◽  
Closed Loop ◽  
Open Loop ◽  
Loop System ◽  
Closed Loop Control ◽  
Input Output ◽  
Open Loop System ◽  
Loop Control ◽  
Multi Stage ◽  
Identification Techniques

Several techniques have recently been proposed to identify open-loop system models from input-output data obtained while the plant is operating under closed-loop control. So called multi-stage identification techniques are particularly useful in industrial applications where obtaining input-output information in the absence of closed-loop control is often difficult. These open-loop system models can then be employed in the design of more sophisticated closed-loop controllers. This paper introduces a methodology to identify linear open-loop models of gas turbine engines using a multi-stage identification procedure. The procedure utilizes closed-loop data to identify a closed-loop sensitivity function in the first stage and extracts the open-loop plant model in the second stage. The closed-loop data can be obtained by any sufficiently informative experiment from a plant in operation or simulation. We present simulation results here. This is the logical process to follow since using experimentation is often prohibitively expensive and unpractical. Both identification stages use standard open-loop identification techniques. We then propose a series of techniques to validate the accuracy of the identified models against first principles simulations in both the time and frequency domains. Finally, the potential to use these models for control design is discussed.

Wireless closed-loop control of centrifugo-pneumatic valving towards large-scale microfluidic process integration

2018 ◽  
Author(s):  
David J. Kinahan ◽  
Sarai M. Delgado ◽  
Lourdes A.N. Julius ◽  
Adam Mallette ◽  
David Saenz-Ardila ◽  
...  
Keyword(s):  
Large Scale ◽  
Closed Loop ◽  
Process Integration ◽  
Closed Loop Control ◽  
Loop Control

Closed-Loop Control of the Frequency Response of the Virtual Brain Model

2017 ◽  
Author(s):  
Christine Beauchene ◽  
Alexander Leonessa ◽  
Subhradeep Roy ◽  
James Simon ◽  
Nicole Abaid
Keyword(s):  
Large Scale ◽  
Closed Loop ◽  
Brain Connectivity ◽  
Brain Activity ◽  
Closed Loop Control ◽  
Loop Control ◽  
Non Invasive ◽  
Frequency Mismatch ◽  
Stimulation Method ◽  
The Difference

The brain is a highly complex network and analyzing brain connectivity is a nontrivial task. Consequently, the neuroscience community created a large-scale, customizable, mathematical model which simulates brain activity called The Virtual Brain (TVB). Using TVB, we seek to control electroencephalography (EEG) measured brain states using auditory inputs, through TVB. A safe non-invasive brain stimulation method is binaural beats (BB) which arise from the brain’s interpretation of two pure tones, with a small frequency mismatch, delivered independently to each ear. A third phantom BB, whose frequency is equal to the difference of the two presented tones, is produced. This paper details the development and proof-of-concept testing of a simulation environment for an EEG-based closed-loop control of TVB using BB. Results suggest that the connectivity networks, constructed from simulated EEG, may change with certain BB stimulation frequency. In this work, we demonstrate that a linear controller can successfully modulate TVB connectivity.

Exploiting All Programmable SoCs in Neural Signal Analysis: A Closed-Loop Control for Large-Scale CMOS Multielectrode Arrays

2018 ◽  
Vol 12 (4) ◽  
pp. 839-850 ◽  
Author(s):  
Giovanni Pietro Seu ◽  
Gian Nicola Angotzi ◽  
Fabio Boi ◽  
Luigi Raffo ◽  
Luca Berdondini ◽  
...  
Keyword(s):  
Signal Analysis ◽  
Large Scale ◽  
Closed Loop ◽  
Closed Loop Control ◽  
Multielectrode Arrays ◽  
Neural Signal ◽  
Loop Control ◽  
Neural Signal Analysis

scholarly journals Implicit Euler Implementation of Twisting Controller and Super-Twisting Observer without Numerical Chattering: Precise Quasi-Static MEMS Mirrors Control

2019 ◽  
Vol 256 ◽  
pp. 03004 ◽  
Author(s):  
Dong Luo ◽  
Xiaogang Xiong ◽  
Shanhai Jin ◽  
Wei Chen
Keyword(s):  
Sliding Mode Control ◽  
Closed Loop ◽  
Sliding Mode ◽  
Industrial Applications ◽  
Euler Method ◽  
Open Loop ◽  
Closed Loop Control ◽  
Control Input ◽  
Loop Control ◽  
Mode Control

The quasi-static operations of MEMS mirror are very sensitive to undesired oscillations due to its very low damping. It has been shown that closed-loop control can be superior to reduce those oscillations than open-loop control in the literature. For the closed-loop control, the conventional way of implementing sliding mode control (SMC) algorithm is forward Euler method, which results in numerical chattering in the control input and output. This paper proposes an implicit Euler implementation scheme of super twisting observer and twisting control for a commercial MEMS mirror actuated by an electrostatic staggered vertical comb (SVC) drive structure. The famous super-twisting algorithm is used as an observer and twisting SMC is used as a controller. Both are discretized by an implicit Euler integration method, and their implementation algorithms are provided. Simulations verify that, as compared to traditional sliding mode control implementation, the proposed scheme reduces the chattering both in trajectory tracking output and control input in presence of model uncertainties and external disturbances. The comparison demonstrates the potential applications of the proposed scheme in industrial applications in terms of feasibility and performance.

Research on the Cooperative Control Method for Trajectory Tracking of Automatic Guided Vehicle Based on Dynamic Position/Force

2013 ◽  
Vol 457-458 ◽  
pp. 1298-1302 ◽  
Author(s):  
Xuan Zuo Liu ◽  
Qiao Yun Yan ◽  
Fei Yun Tang
Keyword(s):  
Trajectory Tracking ◽  
Cooperative Control ◽  
Closed Loop ◽  
Control Structure ◽  
Sliding Mode ◽  
Closed Loop Control ◽  
Control Input ◽  
External Interference ◽  
Loop Control ◽  
Automatic Guided Vehicle

AbstractConsidering the influence of the dynamic characteristic of automatic guided vehicle (AGV) on trajectory tracking controlling, double closed loop control structure is proposed to realize the position/force cooperative control. The outer loop controlling uses backstepping to design corresponding position controller for kinematics model of AGV, while the inner control uses the integral sliding mode controlling. Self-adaptive controlling law is used to estimate the uncertain external interference in the driving force controller and stability of AGV trajectories tracking proof is proposed. In order to make the system achieve better control performance and prevent the occurrence of severe wobble, the hyperbolic tangent function in the control law of sliding mode control replaces the sign function to ensure a continuously smooth control input and states of the system. In the Matlab/simulink environment, tracking a given splayed trajectory generated by the S function to verify the double closed loop control structure and the effectiveness of the control algorithm proposed in this paper.

A Multi-Purpose Temperature Control Method for MEMS Microheaters Without a Separate Temperature Sensor

2006 ◽  
Author(s):  
Byunghoon Bae ◽  
Junghoon Yeom ◽  
Bruce R. Flachsbart ◽  
Yanjun Tang ◽  
Richard I. Masel ◽  
...  
Keyword(s):  
Temperature Sensor ◽  
Closed Loop ◽  
Control Method ◽  
Electrical Heating ◽  
Thermal Mass ◽  
Closed Loop Control ◽  
Control Input ◽  
Response Delay ◽  
Loop Control ◽  
Finite Distance

In this paper, a temperature-controlled method that does not use a separate temperature sensor is presented for different MEMS electrical resistance heaters. Instead of using a Resistance Temperature Detectors (RTD) sensor or micro-thermocouple for closed-loop control of the temperature, which will have a finite distance between the heater and sensor and a response delay due to the thermal mass of the substrate on which the sensor resides, we use the change in resistance with temperature of the electrical heating element itself for the control input.

Active control of transonic buffet flow

2017 ◽  
Vol 824 ◽  
pp. 312-351 ◽  
Author(s):  
Chuanqiang Gao ◽  
Weiwei Zhang ◽  
Jiaqing Kou ◽  
Yilang Liu ◽  
Zhengyin Ye
Keyword(s):  
Feedback Control ◽  
Design Flow ◽  
Complex Conjugate ◽  
Control Input ◽  
Input Output ◽  
Linear Quadratic ◽  
Unstable Flow ◽  
Control Laws ◽  
Loop Control ◽  
Transonic Buffet

Transonic buffet is a phenomenon of aerodynamic instability with shock wave motions which occurs at certain combinations of Mach number and mean angle of attack, and which limits the aircraft flight envelope. The objective of this study is to develop a modelling method for unstable flow with oscillating shock waves and moving boundaries, and to perform model-based feedback control of the two-dimensional buffet flow by means of trailing-edge flap oscillations. System identification based on the ARX algorithm is first used to derive a linear model of the input–output dynamics between the flap rotation (the control input) and the lift and pitching moment coefficients (system outputs). The model features a pair of unstable complex-conjugate poles at the characteristic buffet frequency. An appropriate reduced-order model (ROM) with a lower dimension is further obtained by a balanced truncation method that keeps the pair of unstable poles in the unstable subspace but truncates the dynamics in the stable subspace. Based on this balanced ROM, two kinds of feedback control are designed by pole assignment and linear quadratic methods respectively. These independent designs, however, result in similar suboptimal static output feedback control laws. When introduced in numerical simulations, they are both able to completely suppress the buffet instability. Furthermore, the resulting controllers are even able to stabilize buffet flows with nonlinear disturbances and in off-design flow conditions, thus implying their robustness. The analysis of the feedback control laws indicates that parameters (frequency and phase) corresponding to the ‘anti-resonance’ of the linear input–output model are vital for optimal control. The best performance is obtained when the control operates close to the ‘anti-resonance’, which is supported by the optimal frequency and the phase of the open-loop control as well as by the optimal phase of the closed-loop control.

Sign in / Sign up

Export Citation Format

Share Document