Application Of Feedforward Control Research Articles

Robust Input Shaping Commands with First-Order Actuators.

This paper presents robust input shaping commands with first-order actuators utilizing a classical robust input shaper for practical applications in input shaping technology. An ideal input shaping command can deviate due to actuator dynamics so that the modified command has a detrimental effect on the performance of oscillation reduction in feedforward control applications. A zero-vibration-derivative (ZVDF) shaper with first-order actuators is analytically proposed using a phasor-vector approach, an exponential function for the approximation of the dynamic response of first-order actuators and the usage of the ZVD shaper. In addition, an equivalent transformation is utilized based on the superposition principle for the convenient inclusion of first-order actuator dynamics and is applied to the individual segment input command. The residual deflection and robustness of the proposed robust input shaping commands are numerically evaluated and compared with those of a conventional ZVD shaper with respect to the parameter uncertainties of flexible systems and actuators. The robust input shaping commands that are possible with first-order actuators are experimentally validated, presenting a better robustness and residual deflection reduction performance than the classical ZVD shaper on a mini bridge crane.

Control methodology for tensioned web considering thermal behavior in roll-to-roll manufacturing systems

The roll-to-roll manufacturing system is utilized for processing flexible webs into functional films, offering high productivity through continuous multi-stage processing. In the converting span, which encompasses coating, printing, and drying processes, precise tension control and appropriate tension settings are crucial to ensure the quality of the final product. Particularly during the drying process, where solvent removal occurs, thermal deformation of the web induces additional elongation, amplifying the impact of tension on coating layer quality and printing patterns. Consequently, the drying process necessitates more accurate tension control compared to other span, necessitating the application of feedforward control that considers web thermal deformation. However, the current tension control logic employs an imprecise temperature distribution within the dry span as an input, resulting in inadequate tension control performance and defects such as uneven coating layers and registration errors. This research presents the development of a feedforward tension controller that employs Finite Element Method (FEM)-based web temperature distribution inputs to enhance tension control performance during the drying span. The tension control performance was compared and analyzed based on the drying span web temperature prediction method, affirming that higher accuracy in predicting the web temperature distribution leads to improved tension control performance. Experimental results from an industrial-scale roll-to-roll system demonstrate that the proposed model enhances tension control accuracy during the drying process by 27.76% compared to the existing control logic. Furthermore, the effectiveness of the tension control logic in enhancing the surface quality of functional layers was confirmed through surface quality analysis using solid oxide fuel cell (SOFC) electrolyte layers.

The application of feedforward control in the nursing emergency management of COVID-19

Objective: To explore the application of feedforward control in the nursing emergency management of COVID-19.Methods: The feedforward control theory was applied to the emergency management of COVID-19 nursing, including grasping the latest epidemic information, preparing for the early stage, formulating nursing workflow, implementing flexible management, standardizing isolation and protection measures, unifying nursing document record format, and implementing humanistic care. Results: During the period of support to Wuhan, the nursing work in the isolated area was orderly, the nursing staff's job satisfaction was high, no nursing errors and hospital infections occurred. Conclusion: Efficient feedforward control in the nursing emergency management that could avoid work blindness to a certain extent and play a guiding role in maintaining the normal operation of treatment and nursing work and protecting the safety of patients and medical staff in the ward during the epidemic period of COVID-19.

Enhancement of Power Quality using Fast Acting Unified Power Quality Conditioner (UPQC)

The Unified Power Quality Conditioner (UPQC) is the most flexible solution for all power quality problems. The UPQC is one of the APF family members where shunt and series APF functionalities are integrated together to achieve superior control over several power quality problems simultaneously. Reference signal extraction is the most important part of any control. Feedback control requires the minimum information about the process also the corrective action is taken when the control variable is changed but it has some drawbacks that it does not provide any predictive action for any known disturbance. The proposed control technique uses feed forward plus feedback control with synchronously rotating reference frame based reference signal extraction that not only measures the disturbances (voltage sag here) but also take corrective action to compensate for the same before they actually disturb the system. The applications of feed forward control along with the feedback control are able to compensate for the measured disturbance with the desired speed of response that enables faster restoration of voltage at load end. The suggested method is implemented by simulation in MATLAB/SIMULINK to demonstrate the improvement in response time.

Application of feedforward control in nursing defects in operation room

目的 探讨手术室护理的前馈控制对于减少护理缺陷和提高手术治疗效果的影响。 方法 选取116例手术患者作为研究对象，将其分为观察组(前馈控制)59例和对照组(常规护理管理)57例，比较两组患者的手术治疗效果，评价手术室护理质量。 结果 与对照组相比，观察组患者对于护理的满意率(93.22%比77.97%，χ2＝19.211，P<0.05)相对更高，而投诉率(1.69%比5.26%，χ2＝14.328)、护理缺陷发生率(0.00%比3.51%，χ2＝16.947，P<0.05)相对更低。与前馈控制运用前相比，前馈控制运用后的手术室护理质量得以显著提升，在专业技能[(93.25±4.74)分比(81.36±5.21)分，t＝8.314，P<0.05]、器械管理[(93.82±4.92)分比(82.29±5.47)分，t＝7.255，P<0.05]、风险管控[(95.08±4.12)分比(83.34±4.97)分，t＝7.042，P<0.05]以及护患沟通[(95.64±3.42)分比(85.52±4.86)分，t＝7.297，P<0.05]等方面的评分明显更高。 结论 手术室护理的前馈控制对于减少护理缺陷和提高手术治疗效果有着积极的帮助和影响。

Passive and Active Control of the Radiated Sound Power from a Submarine Excited by Propeller Forces

To improve the stealth of a submarine, the sound power radiated from the hull can be reduced using active noise and vibration control. In this article, active control is applied to minimize hull excitation by propeller forces transmitted through the shaft. The dominant propeller axial force fluctuations are directly related to blade passage and the phase of the force is determined by the absolute angle of the propeller shaft. Because the propeller forces are deterministic, the application of feedforward control is appropriate. Numerical finite element/boundary element (FE/BE) models of a submarine have been developed to find the transfer functions. Different control strategies are investigated in which active control is applied to the propeller/shafting system and/or to the submarine hull. Active vibration control and discrete structural acoustic sensing based on the far field radiated sound power were considered for development of the cost function. In addition, the performance of a system in which active control is combined with passive control using a resonance changer is investigated. It is shown that the combination of tuned control actuators and a resonance changer results in a significant reduction of radiated sound power.

A Modeling Approach towards Improving Compliance of Treated Water Quality to Reduce Manpower and Chemicals

In water treatment processes, the individual unit operations are complex, non-linear and poorly understood. Whilst many models have been developed to improve process understanding, these are rarely in a form easily exploited by the control engineer. Attempts to improve the performance of water treatment works through the application of improved control and measurement have had variable success. This paper discusses investigations into the application of feed forward control on the clarification process of a small-scale pilot plant. The application aimed towards maximizing the efficiency of the chemical coagulation process. To achieve this, a simple computer program written in Visual Basic version 6 models to a chief the process operating conditions. Mathematical models based on historical plant data covering 18 months analyzed by stepwise multiple regression analysis. The following parameters were important determinants of coagulant dose and pH control reagents: river turbidity, pH, temperature, total dissolved solids, and plant flowrate. A predictive equation developed from the data, of the form: Al2(SO4)3 (mg/L) = a*Q + b*Turb + c*TDS + d*pH + e*Temp + f. The aim of this model is to provide water treatment operators with a tool that enables prediction of chemical reagents and treatment conditions for selected removal of turbidity, based on raw water quality data. While for adjusting pH, whether lime or soda ash are added, the pretreatment of water supplies involves the use to decrease the acidity, to soften, and to clear drinking water, calcium oxide (CaO), commonly known as quicklime or burnt lime. The addition of lime is with the form: CaO (mg/L) = j + k *pH. And for soda ash sodium percarbonateNa2CO3 the addition form is: Na2CO3 (mg/L) = m + n*pH. The advantages of software program are significant in the operation of water treatment plant. The program designed as an aid, so the user can still customize and optimize the computer suggested design. Users are able to move forward in adjusting or optimizing the design in minutes, which is difficult for manual system. This system was an initial system, many new features and functions have to be added to the program to enhance the functions and make it commercially robust. It concluded that this system is very powerful tool in improving compliance of treated water quality to reduce labor and chemicals and to facilitate the organizations and individuals with better understanding on how their actions can have a direct impact on the treatment.

Application of Feedforward Control to A Vibration Isolation System Using Negative Stiffness Suspension

This paper presents a vibration isolation system using negative stiffness suspension. The vibration isolation system is developed by combining a positive stiffness suspension in series with a negative stiffness suspension. The developed system could realize zero-compliance to direct disturbance, as well as ground vibration isolation. In the previous system, the ground vibration and, the static and low frequency sinusoidal direct disturbances were efficiently suppressed. However, there was a reverse action in case of impulse or step wise disturbance. Therefore, a peak was appeared which was, sometimes, larger than the displacement caused by the step load. This unpleasant response might hamper the objective function of many advanced systems. In this research, a feedforward controller is added in combination with zero-power control to overcome this problem. Some experimental results are presented to verify the proposed control system in a vibration isolation apparatus.

4B11 Application of Feedforward Control to a Vibration Isolation System Using Negative Stiffness Suspension

This paper presents a vibration isolation system using negative stiffness suspension. The vibration isolation system is developed by combining a positive stiffness suspension in series with a negative stiffness suspension. The developed system could realize zero-compliance to direct disturbance, as well as ground vibration isolation. In the previous system, the ground vibration and, the static and low frequency sinusoidal direct disturbances were efficiently suppressed. However, there was a reverse action in case of impulse or step wise disturbance. Therefore, a peak was appeared which was, sometimes, larger than the displacement caused by the step load. This unpleasant response might hamper the objective function of many advanced systems. In this research, a feedforward controller is added in combination with zero-power control to overcome this problem. Some experimental results are presented to verify the proposed control system in a vibration isolation apparatus.

Estimating the number of uncorrelated disturbance sources in structural systems

The number of input signals used as reference inputs for feedforward control applications is limited due to cost, computational burden, input processing capability, and installation constraints. Identifying an optimal subset of reference sensors from a larger set capable of conveying the dynamics important in the performance path can result in greater performance with reduced complexity and order in the active control system. However, before determining an appropriate subset of sensors, the number of exogenous disturbance sources must be determined. Principal component analysis can be used to determine the number of uncorrelated disturbances acting on a structural system. Singular value decomposition of a covariance matrix of measured sensor signals is used to determine the number of independent disturbances present in the dynamic system. Limitations imposed by sample data length, path dynamics, and noise can limit the ability to resolve the number of exogenous disturbance sources. To estimate the number of secondary disturbance sources, a controller can be used to minimize the response due to the dominant signal source. It is then possible to identify the significant secondary sources. This can lead to improved estimation of the minimum number of reference sensors required for feedforward control in structural and structural acoustic systems.

The application of feedforward control in a direct expansion (DX) air conditioning plant

A computerized feedforward controller for a DX air conditioning plant has been developed to avoid the use of problematic measurement of air conditions immediately downstream of a cooling coil for control action. The feedforward controller was based on a mathematical model for capacity control using the principle of energy conservation. A safety control procedure was also included as part of the control algorithms to ensure the safe operation of the plant. Experimental tests on the controllability of the controller confirmed that both control accuracy and sensitivity could be achieved. The control algorithms involved is expected to have wide application for controlling DX air conditioning systems.

Application of Feedforward Control for an Air Spring Type Isolated Table.

Application of Feedforward Control for an Air Spring Type Isolated Table.

Performance surfaces of minimum effort estimators and controllers

The performance surfaces of two classes of minimum effort adaptive filter are studied. Eigenvalue spreads of the cost functions of minimum weight vector norm and minimum output variance algorithms are examined for both estimation and feedforward control applications. Results support the widespread practical use of the "leaky LMS" algorithm.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

New roles for feedforward in multivariable control by individual channel design

Abstract Considerable though the benefits of feedback control are, they do not extend to ameliorating adverse multivariable plant dynamical characteristics that are of a structural nature. Feedforward control on the other hand, is shown in this paper to complement multivariable feedback control in a simple but powerful way by providing a strikingly direct resolution of such structural difficulties as non-minimum phase plant behaviour, plant excessive structure sensitivity (uncertainty in the number of channel RHPZs), plant excessive phase sensitivity, and decoupling without increasing system uncertainty. This use of feedforward is believed to be new and is completely different from the well-known application of feedforward control to anticipate and counteract the effect of some known plant disturbance before it affects the output, as widely used in the process industries. The paper ends with a complete statement of the philosophy and methodology of multivariable control, feedforward and feedback, within t...

Applications of feedforward control to distillation columns

The literature abounds with papers on feedforward control of distillation columns. Few of these papers, however, discuss successful commercial applications. They are, for the most part, theoretical developments of various approaches to feedforward control or evaluation of various control models on simulated or laboratory columns. This has created a credibility gap between the control engineer and universities on one hand; and the engineers responsible for operating the columns on the other. This credibility gap is particularly disturbing when one considers that there are presently in operation in the United States and Canada more than 150 columns under feedforward control. According to the latest survey of industrial and engineering chemistry, only four of these applications have been described: one in 1964, one in 1965, one in 1968, and one in 1969. These reports provide only a portion of the history of each application. This paper presents complete documentation on three different applications of feedforward control to distillation. Since each of the columns was an operating column with control problems, “before and after” comparisons are made. Each case history is divided into the following parts: one, a description of the actual operating and control problems which existed. Two, a description of the analysis of the problem and design of an appropriate feedforward system. Three, implementation and startup of the feedforward system. Four, performance of the feedforward system. Five, economic evaluation of the benefits derived from the controls. The three columns described are a 200 tray superfractionator, a refinery debutanizer, and a gasoline plant depropanizer.

Applications of Feedforward Control to Distillation Columns

The literature abounds with papers on feedforward control of distillation columns. Few of these papers, however, discuss successful commercial applications. They are, for the most part, theoretical developments of various approaches to feedforward control or evaluation of various control models on simulated or laboratory columns. This has created a credibility gap between the control engineer and universities on one hand; and the engineers responsible for operating the columns on the other. This credibility gap is particularly disturbing when one considers that there are presently in operation in the United States and Canada more than 150 columns under feedforward control. According to the latest survey of industrial and engineering chemistry, only four of these applications have been described: one in 1964, one in 1965, one in 1968, and one in 1969. These reports provide only a portion of the history of each application.This paper presents complete documentation on three different applications of feedforward control to distillation. Since each of the columns was an operating column with control problems, “before and after” comparisons are made.Each case history is divided into the following parts: one, a description of the actual operating and control problems which existed. Two, a description of the analysis of the problem and design of an appropriate feedforward system. Three, implementation and startup of the feedforward system. Four, performance of the feedforward system. Five, economic evaluation of the benefits derived from the controls.The three columns described are a 200 tray super-fractionator, a refinery debutanizer, and a gasoline plant depropanizer.

Distillation, feedforward control with intermediate feedback control trays

Feedback control systems for distillation columns are often based on controlling the temperatures of intermediate trays near the top and/or bottom of the column. This paper studies the application of feedforward control to this kind of column. In addition to adjusting manipulative variables like reflux and/or vapor boilup, the feedforward controller must also change feedback controller set points. Nonlinear steadystate and linear dynamic synthesis techniques are used to design the six feedforward controllers required. Effectiveness when applied to a nonlinear column is illustrated by digital simulation of a 20-tray binary column. Combined feedback/feedforward control performance is compared with feedback control alone.

Nonlinear feedforward control of chemical reactors

AbstractThis paper illustrates the synthesis of nonlinear feedforward controllers for chemical reactors. In most of the theoretical development and application of feedforward control only linear systems have been considered. There are, however, no inherent linear limitations in feedforward control. Since chemical reactors are usually nonlinear, the effectiveness of control should be improved by including nonlinearities in the design of feedforward controllers. This is particularly true for batch reactors because of the large changes in variables during a batch cycle. Continuous stirred‐tank reactors are studied with single and consecutive reactions of first and higher order. Effectiveness of linear and nonlinear feedforward controllers is compared for disturbances of various magnitude and direction. Feedforward control of batch and tubular reactors is also discussed.