Regulation of Hydrogen Peroxide Dosage in a Heterogeneous Photo-Fenton Process

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2167
Author(s):  
Karla Estefanía Saldaña-Flores ◽  
René Alejandro Flores-Estrella ◽  
Victor Alcaraz-Gonzalez ◽  
Elvis Carissimi ◽  
Bruna Gonçalves de Souza ◽  
...  
Keyword(s):  
Gallic Acid ◽  
Organic Compounds ◽  
Closed Loop ◽  
Transfer Functions ◽  
Direct Synthesis ◽  
Synthesis Method ◽  
Open Loop ◽  
Fenton Process ◽  
Control Approach ◽  
Curve Method

In this work, a classical linear control approach for the peroxide (H2O2) dosage in a photo-Fenton process is presented as a suitable solution for improving the efficiency in the treatment of recalcitrant organic compounds that cannot be degraded by classical wastewater treatment processes like anaerobic digestion. Experiments were carried out to degrade Lignin, Melanoidin, and Gallic acid, which are typical recalcitrant organic compounds present in some kinds of effluents such as vinasses from the Tequila and Cachaça industries. Experiments were carried in Open-Loop mode for obtaining the degradation model for the three compounds in the form of a Transfer Function, and in Closed-Loop mode for controlling the concentration of each compound. First-order Transfer Functions were obtained using the reaction curve method, and then, based on these models, the parameters of Proportional Integral controllers were calculated using the direct synthesis method. In the Closed-Loop experiments, the Total Organic Carbon removal was 39% for lignin, 7% for melanoidin, and 29% for Gallic acid, which were greater than those obtained in the Open-Loop experiments.

Analysis of the Idling Start of the Moving Coil Linear Compressor

2008 ◽  
Author(s):  
Yingbai Xie ◽  
Xiuzhi Huang ◽  
Liyong Lun ◽  
Ganglei Sun
Keyword(s):  
Closed Loop ◽  
Transfer Functions ◽  
Load Condition ◽  
Open Loop ◽  
Reciprocating Compressor ◽  
Piston Motion ◽  
Linear Compressor ◽  
Simulation Results ◽  
The Stability ◽  
Stability Time

The linear compressor is driven by a linear motor. Because it has no crankcase, the piston motion and its control of the linear compressor are differing from that of the conventional reciprocating compressor. For a moving coil linear compressor, mechanical and electromagnetism system are modeled. The open loop and closed loop transfer functions of the system in no-load condition are obtained derived from these equations. The Matlab software is applied to analyze the stability, time domain and frequency domain of the system. Simulation results show that the linear compressor is stable, but the overshoot is relative high, which must be adjusted. This conclusion will be benefit for the design of the idling start of the moving coil linear compressor.

Closed-loop identification of carotid sinus baroreflex open-loop transfer characteristics in rabbits

1997 ◽  
Vol 273 (2) ◽  
pp. H1024-H1031 ◽  
Author(s):  
T. Kawada ◽  
M. Sugimachi ◽  
T. Sato ◽  
H. Miyano ◽  
T. Shishido ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Closed Loop ◽  
Transfer Functions ◽  
Carotid Sinus ◽  
Open Loop ◽  
Parametric Models ◽  
Efferent Nerve ◽  
Transfer Characteristics ◽  
Carotid Sinus Baroreflex ◽  
Closed Loop Identification

In the circulatory system, a change in blood pressure operates through the baroreflex to alter sympathetic efferent nerve activity, which in turn affects blood pressure. Existence of this closed feedback loop makes it difficult to identify the baroreflex open-loop transfer characteristics by means of conventional frequency domain approaches. Although several investigators have demonstrated the advantages of the time domain approach using parametric models such as the autoregressive moving average model, specification of the model structure critically affects their results. Thus we investigated the applicability of a nonparametric closed-loop identification technique to the carotid sinus baroreflex system by using an exogenous perturbation according to a binary white-noise sequence. To validate the identification method, we compared the transfer functions estimated by the closed-loop identification with those estimated by open-loop identification. The transfer functions determined by the two identification methods did not differ statistically in their fitted parameters. We conclude that exogenous perturbation to the baroreflex system enables us to estimate the open-loop baroreflex transfer characteristics under closed-loop conditions.

Point Control of a One-Link Flexible Manipulator

1986 ◽  
Vol 53 (1) ◽  
pp. 23-27 ◽  
Author(s):  
S. B. Skaar ◽  
D. Tucker
Keyword(s):  
Transfer Functions ◽  
Control Strategies ◽  
Open Loop ◽  
Flexible Manipulator ◽  
Distributed Parameter ◽  
Loop Control ◽  
Control Approach ◽  
Alternative Approach ◽  
Single Link ◽  
Point Control

An alternative approach to the control of nonrigid, distributed parameter systems is presented. Transfer functions that relate the response of points on the system to a controlling force or torque are used in place of ordinary differential equations, which represent an approximation to the system dynamics. The implications of this “point control” approach are discussed with regard to plant modeling accuracy, uncontrolled regions, open-loop and closed-loop control strategies, system identification, and feedback estimation. Sample optimal control histories are illustrated for a single-link manipulator member with end load.

EXPERIMENTAL RESULTS FOR THE SMALL-SIGNAL STUDY OF THE PWM BOOST DC–DC CONVERTER WITH AN INTEGRAL-LEAD CONTROLLER

1995 ◽  
Vol 05 (04) ◽  
pp. 747-755 ◽  
Author(s):  
MARIAN K. KAZIMIERCZUK ◽  
ROBERT C. CRAVENS, II
Keyword(s):  
Closed Loop ◽  
Transfer Functions ◽  
Low Frequency ◽  
Input Voltage ◽  
Open Loop ◽  
Small Signal ◽  
Loop Control ◽  
Pulse Width Modulated ◽  
Bode Plots ◽  
Step Responses

An experimental verification of previously derived small-signal low-frequency open- and closed-loop characteristics and step responses of a voltage-mode-controlled pulse-width-modulated (PWM) boost DC–DC converter is presented. The Bode plots of the voltage transfer function of the control circuit, the converter and the PWM modulator, the open-loop control-to-output and input-to-output transfer functions, the loop gain, and the closed-loop control-to-output and input-to-output transfer functions are measured. The step responses to the changes in the input voltage, the duty cycle, and the reference voltage are measured. The theoretical results were in good agreement with the measured results. The small-signal model of the converter is experimentally verified.

Calculating Open Loop Transfer Functions from Closed Loop Measurements

1958 ◽  
Vol 5 (3) ◽  
pp. 289-297 ◽  
Author(s):  
N. R. Goodman ◽  
S. Katz
Keyword(s):  
Closed Loop ◽  
Transfer Functions ◽  
Open Loop

scholarly journals A dual-loop tracking control approach to precise nanopositioning

2018 ◽  
Vol 25 (3) ◽  
pp. 666-674 ◽  
Author(s):  
Mohammed Altaher ◽  
Douglas Russell ◽  
Sumeet S. Aphale
Keyword(s):  
Closed Loop ◽  
Reference Signal ◽  
Open Loop ◽  
Performance Criteria ◽  
Control Technique ◽  
Loop Control ◽  
Control Approach ◽  
First Order ◽  
Integral Controller ◽  
Double Integrator

Nanopositioners are mechanical devices that can accurately move with a resolution in the nanometer scale. Due to their mechanical construction and the piezoelectric actuators popularly employed in nanopositioners, these devices have severe performance limitations due to resonance, hysteresis and creep. A number of techniques to control nanopositioners, both in open-loop and closed-loop, have been reported in the literature. Closed-loop techniques clearly outperform open-loop techniques due to several desirable characteristics, such as robustness, high-bandwidth, absence of the need for tuning and high stability, along with others. The most popular closed-loop control technique reported is one where a damping controller is first employed in an inner loop to damp the mechanical resonance of the nanopositioner, thereby increasing achievable bandwidth. Consequently, a tracking controller, typically an Integral controller or a proportional–integral controller, is implemented in the outer loop to enforce tracking of the reference signal, thereby reducing the positioning errors due to hysteresis and creep dynamics of the employed actuator. The most popular trajectory a nanopositioner is forced to track is a raster scan, which is generated by making one axis of the nanopositioner follow a triangular trajectory and the other follow a slow ramp or staircase. It is quite clear that a triangle wave (a finite velocity, zero acceleration signal) cannot be perfectly tracked by a first-order integrator and a double integrator is necessary to deliver error-free tracking. However, due to the phase profile of the damped closed-loop system, implementing a double integrator is difficult. This paper proposes a method by which to implement two integrators focused on the tracking performance. Criteria for gain selection, stability analysis, error analysis, simulations, and experimental results are provided. These demonstrate a reduction in positioning error by 50%, when compared to the traditional damping plus first-order integral tracking approach.

scholarly journals Control of Third Order Processes Using Optimized Synthesis PI Controller

2018 ◽  
Vol 7 (2.24) ◽  
pp. 200
Author(s):  
G Suganya ◽  
E Govinda Kumar
Keyword(s):  
Closed Loop ◽  
Design Method ◽  
Direct Synthesis ◽  
Synthesis Method ◽  
Variable Parameter ◽  
Pi Controller ◽  
Process Variables ◽  
Third Order ◽  
Severe Problem ◽  
Tuning Methods

 In closed loop system with PI controller, the most and severe problem is peak overshoot minimization in the closed loop response and tuning the proportional plus integral (PI) controller parameters. This paper deals with the two different tuning methods for obtain the PI controller settings. These methods are used to tune the parameters of PI controller and the closed loop performances of two methods are analyzed for the control of third order processes. From the closed loop responses, the time responses are move to unstable characteristics and the process variables are oscillates due to PI parameters are tuned using Ziegler-Nichols method and direct synthesis method respectively. The control loop performance of the control of third order process is improved with optimized parameters of PI controller. In direct synthesis method, the variable parameter of PI controller is obtained with Genetic algorithm. The controller parameter of PI controller is obtained from optimized variable parameters and results are reveals that the performance of closed loop is enhanced with the elimination of peak overshoot and minimization of oscillation levels in the process variables. Simulation results are confirmation that the proposed design method is better to the Ziegler-Nichols method and direct synthesis method. Furthermore, the proposed method was applied to the control of two different categories of third order processes.  

Performance assessment of controller designed for electrical systems with second order dynamics

2020 ◽  
Vol 39 (6) ◽  
pp. 1345-1362
Author(s):  
K. Ghousiya Begum
Keyword(s):  
Design Methodology ◽  
Transfer Functions ◽  
Direct Synthesis ◽  
Synthesis Method ◽  
Second Order ◽  
Reference Tracking ◽  
Content Type ◽  
Electrical Systems ◽  
Error Index ◽  
Index Value

Purpose An assessment technique that analyzes the servo and regulatory characteristics of the proportional integral derivative controller is designed for time-delayed second-order stable processes. Design/methodology/approach The minimum theoretical error expression for integral of the absolute errors (IAE_o) is obtained from the preferred servo and regulatory transfer functions dependent on the step changes in reference and load variables. Findings The error-based index is outlined to estimate the controller that is derived using internal model-based control or direct synthesis method. The ratio between derived IAE_o and the IAE_actual gained from the loop response that experiences step input variations gives rise to a dimensionless error index. This error index measures the behaviour of the controller by considering the index value. If the error index value is larger than 0.8, then the effort taken by the controller is good or else retuning is expected. Originality/value The efficacy of the index to validate the controller is verified by applying on a few second-order electrical processes. The results are simulated for both reference tracking and load rejection tasks to demonstrate the rationality of the presented index.

A near-optimal decentralized control approach for polynomial nonlinear interconnected systems

2020 ◽  
pp. 014233122097743
Author(s):  
Mohamed Sadok Attia ◽  
Mohamed Karim Bouafoura ◽  
Naceur Benhadj Braiek
Keyword(s):  
Optimal Control ◽  
Closed Loop ◽  
Sufficient Conditions ◽  
Open Loop ◽  
System Stability ◽  
Gronwall Lemma ◽  
Interconnected System ◽  
Control Approach ◽  
State Dependent ◽  
And Control

This article tackles the decentralized near-optimal control problem for the class of nonlinear polynomial interconnected system based on a shifted Legendre polynomials direct approach. The proposed method converts the interconnected optimal control problems into a nonlinear programming one with multiple constraints. In light of the formulated NLP optimization, state and control coefficients are used to design a nonlinear decentralized state feedback controller. Overall closed-loop system stability sufficient conditions are investigated with the help of Grönwall lemma. The triple inverted pendulum case is considered for simulation. Satisfactory results are obtained in both open-loop and closed-loop schemes with comparison to collocation and state-dependent Riccati equation techniques.

Remarks on the Modelling of Active Structures With Colocated Piezoelectric Actuators and Sensors

1995 ◽  
Author(s):  
N. Loix ◽  
A. Preumont
Keyword(s):  
High Frequency ◽  
Closed Loop ◽  
Transfer Functions ◽  
Open Loop ◽  
Loop System ◽  
Closed Loop System ◽  
Local Effects ◽  
Open Loop System ◽  
Active Structures ◽  
Modelling Techniques

Abstract This paper aims to attract the attention of the designers of active structures on the importance of evaluating properly the feedthrough component of the open-loop transfer functions. It is shown that overlooking the feedthrough component can change significantly the location of the zeros of the open-loop system and, as a result, alter drastically the performance of the closed-loop system. The feedthrough term may result from the quasi-static contribution of the high frequency modes or from local effects that are neglected by over-simplified modelling techniques (e.g. plate or beam instead of shell). The problem is illustrated with a cantilever beam provided with strain actuators.

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