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The paper discusses a self tuning control algorithm for a multivariable plant applied to a grammage cross profile control of a paper machine. The plant model represents the steady-state couplings as well as the dynamics behaviour of the system. The control algorithm handles special situations including the case where the numper of measurments is not equal to the numper of actuators and the case where special actuators are locked. The whole identification algorithm with a specical filter and an estimation of the required measurment accuary for a succesful identification of the steady-state couplings will be discussed. The paper shows how to proof the stability of the control system including the cases of locked actuators and identification errors. Finally, the whole conrol system is verified by in house simulations and at a real plant. The obtained control results are discussed.

Proportional Integral Derivative (PID) controller tuning is an area of interest for researchers in many areas of science and engineering. This paper presents a new algorithm for PID controller tuning based on a combination of bacteria foraging and particle swarm optimization. BFO algorithm has recently emerged as a very powerful technique for real parameter optimization. To overcome delay in an optimization, combine the features of BFOA and PSO for tuning the PID controller. This new algorithm is proposed to combine both the algorithms to get better optimization values. The real time prototype model of paper machine is designed and controlled by using PIC microcontroller embedded with the programming in C language.

Failure to utilize valving and automation techniques has restricted the complexity of fluidic operations that can be performed in paper microfluidic devices. We developed a toolkit of paper microfluidic valves and methods for automatic valve actuation using movable paper strips and fluid-triggered expanding elements. To the best of our knowledge, this is the first functional demonstration of this valving strategy in paper microfluidics. After introduction of fluids on devices, valves can actuate automatically a) after a certain period of time, or b) after the passage of a certain volume of fluid. Timing of valve actuation can be tuned with greater than 8.5% accuracy by changing lengths of timing wicks, and we present timed on-valves, off-valves, and diversion (channel-switching) valves. The actuators require ~30 μl fluid to actuate and the time required to switch from one state to another ranges from ~5 s for short to ~50s for longer wicks. For volume-metered actuation, the size of a metering pad can be adjusted to tune actuation volume, and we present two methods – both methods can achieve greater than 9% accuracy. Finally, we demonstrate the use of these valves in a device that conducts a multi-step assay for the detection of the malaria protein PfHRP2. Although slightly more complex than devices that do not have moving parts, this valving and automation toolkit considerably expands the capabilities of paper microfluidic devices. Components of this toolkit can be used to conduct arbitrarily complex, multi-step fluidic operations on paper-based devices, as demonstrated in the malaria assay device.

This paper defines the efficiency similarity of different motor driving devices. Based on the efficiency function characteristics which can be approximately considered a concave, non-negative function through the origin, we present a kind of optimal control method for a felt driven by three different motors in paper machine. It gives the minimum total power consumption. The optimal control method is to keep the same torque rate for each motor driving device. This method is independent of the linearity or nonlinearity of the system and has no need for the system’s state equation or transfer function. Since the shapes of efficiency functions in nature are similar, the conclusion can also be applied to the energy optimization of other general devices.

This paper is focuses modeling of the last part of the paper machine – the drying section. Paper is dried by letting it pass through a series of steam heated group of cylinders and the evaporation is thus performed by the latent heat of vaporization of the steam. The moisture in the paper is controlled by adjusting the set point of the steam presure controllers to the cylinders. There exist several incentives to focus on the performance of the moisture control. The time to perform a grade change is often limited by the moisture and shorter grade change time is directly correlated to economic profit. The plant model is identified periodically and the changes in its dynamic characteristics are observed. Periodic identification gives a great advantage over the conventional controller tuning methods, which uses the plant model at the nominal operating conditions. A variety of model structures are available to assist in modelling a system. Model for the drying process of Paper industry is established based on gathering 1000 groups of 2500 real-time sample data. Based on the collection of data, that was adapted to both the conventional and intelligent modelling process. Finally the suitable model is tuned with the suitable controller for optimal control of the drying process.

It is an important factor that the paper tension for web press printing and roll paper manufacture. Especially commerce web press is the more important. The commerce web press has not only the first tension control, but also the second tension control. The second tension control would control tension wave restrict accurate bound. The simulation method was discussed about paper tape tension the second tension control on some problems of high speed Web press controlling system in actual adjustment course, and different respond graph was obtained on the different controlling parameter by MATLAB and controlling system capability target. Intuitionistic and exact foundation was offered for system analysis, comparison and choice arithmetic, which benefits the further research.

This system can exchange toilet paper automatically only installing on ready-made goods toilet paper holder. Measurement of the distance between the toilet paper and the toilet paper holder is using the infrared distance sensor and depending on its value, an automatic exchange of toilet paper to move the servo motor by using the Arduino.

After introducing the principle of ventilation and dehumidification for closed steam hood, the key and difficulty points of its control are analyzed. Aiming at the production line of coating white board with surface sizing and high steam consumption, DCS system of steam hood based on SIMATIC S7-300 PLC is designed. The hardware structure and control algorithms are illustrated in detail. The control system has been applied on the paper machine with nearly 10 board paper plants of the coating white board paper base in Fuyang, Zhejiang province, and the good energy-saving control effect has been obtained.

Switchgear and Protection are the two vital terminology of Electrical power system. Normally the components of any switchgear needs better protection schemes to be set for a composite power system. Many explorers worked on artificial intelligent breaker but an indulgence of fuzzy theory is nevertheless very absent in case of buchholz relay. Here in this paper discussion has been drawn in favor of the Artificial Intelligent Buchholz (AIB) relay where inputs are level of transformer oil and rate of oil rising due to over current. To fit with the transformer tank it is needed to measure level of transformer oil and the rate at which volume increasing. The constructional feature of a rate of rise pressure relay is taken into account in this work along with the working principle of a buchholz relay. The change in the inputs will give a crisp output to change the contacts state from normally closed to normally open by tripping via alarm circuit indeed like the basic buchholz relay does. The entire concept has been developed under MATLAB environment using Mamdani based Fuzzy Inference System. Experimental output data validates the implementation of Transformer Protection by Using Fuzzy Logic Based Artificial Intelligent Buchholz Relay. Keywords: AIB Relay, incipient fault, Fuzzy inference system, mamdani, rate of rise pressure relay, transformer oil

Total Pressure and Stock Level in the headbox of a paper machine control the quality of paper produced and cross directional flow at the slice. Thus, these are the important parameters to be controlled. With the advancement in artificial intelligence, mathematical approaches that demand high degree of precision has been avoided by using the best estimates in the research work. Soft computing technique i.e. fuzzy logic is used in this paper and the simulation results are compared with classical PID controller.

The article introduces each component of feeding paper machine of printing press which are press feet mechanism, paper separation mechanism and paper transfer mechanism, the function and the principle of work. Each mechanism is undertook a variety of designs and we choose the best design of each structure according to its functions. Design adopted is as follows: Press feet mechanism adopts the cam-linkage mechanism; Paper separation mechanism adopts the cam-linkage slider mechanism; Paper transfer mechanism adopts the conjugate cam-linkage slider mechanism. The machine is simple, practical and reliable.

The modern headbox has many attributes that are highly significant for all paper-makers. Uniformity of flow, absence of streaks and large eddies, headbox stability and ease of operation are required features for all paper grades. Consistency in a headbox is a very important parameter in paper mills in their various stages of operations. Without the knowledge of consistency, it is not possible to optimize productivity with optimal quality. In the present study, a multivariable, linearized, state space model of a paper machine headbox was selected for control of consistency and liquid level in the headbox of a paper machine using the advanced control strategy Model Predictive Control (MPC). MPC uses a model to predict the process output along a future time horizon. It performs the calculation of a control sequence to optimize a performance index. It is based on receding horizon strategy so that at each instant the horizon is moved towards the future, involving the application of the first control s...

This paper studied some kinds of realization modes of speed chain compute, load distribution and operation aimed at the realization of paper machine driving system. The frequency conversion control system based on PLC cooperating with digital manipulator was brought forward. It was mainly made up of three parts: PLC, frequency converter and digital manipulator. It used PLC to realize digital speed chain and load distribution. And it exchanged data and parameters by communication through field bus network. The results indicate that the problems of speed chain compute, load distribution and operation were solved effectively by data gathering and computing with PLC, so it is a driving system of high performance.

Small motions will result in heavy influence to the production in high-speed paper machine, therefore, decoupling control is necessary. This passage Puts forward the opposite angles strategies to solve the function of decoupling aiming at solving the difficulty that occurs in practice, like the characteristic of hard-coupling and non-linear. According to the mathematics model of the flow box, decoupling the quantity of the two couplings in the processes. Meanwhile, Introduces the SIEMENS S7-300 PLC and the DCS system that is realized by the it.

The paper presents the modelling of a mixed traffic flow in which look-ahead controlled vehicles with a speed control are driven together with conventional vehicles. Since the speed profile of the lookahead control may differ from that of the conventional vehicle, the structure of the traffic flow changes. The paper analyses the impact of vehicles applying look-ahead control strategy on the traffic flow. In a simulation-based analysis it is shown that the fundamental diagram of the traffic network changes. A new mixed-traffic model incorporates the nonlinearity of the traffic dynamics using a polynomial formula, in which the look-ahead cruise control is considered with a parameter-dependent form. Using these nonlinear forms the impact of the look-ahead vehicles on the stability of the traffic is examined through controlled invariant sets. In this analysis the sum-of-squares programming method is applied. The results are demonstrated through simulation examples using the VISSIM simulation environment.

The minimum variance controller has been extensively used as a benchmark in the performance assessment of both univariate and multivariate control loops when time delay is the fundamental performance limitation. In this paper, the spatial and temporal performance limitations in the cross-directional (CD) control of paper machines are analyzed. The idea of minimum variance benchmarking is extended to the CD process based on these performance limitations. Based on an industrial CD controller, a user-specified benchmark, which is more practical and less aggressive, is also proposed. In addition, several related performance indices are proposed for the CD process based on both the minimum variance benchmark and the user-specified benchmark. Illustrative examples from a paper machine simulator and industrial data sets are provided to show the effectiveness of the proposed performance indices.

In this contribution, the dynamical behavior of a paper-making system is presented and an advanced controller is developed to minimize the amount of recycled paper used in the paper making process. The advanced controller is a model based control strategy, and therefore, a model is developed in order to evaluate the loss of paper during the transition between two points of operation. The wastage model is adapted to be used in the cost function of an in-house developed predictive control algorithm. Performance evaluation is described and the corresponding results are presented.

A rule-based expert system for the integrated control and supervision of the dry-end sections of a paper machine is proposed. This system is capable of recognizing all the normal and abnormal changes in process operating conditions, including acceleration of sections, threading of paper sheet, nip pressure activation, activation and deactivation of tension control loops, change of parent roll, and sheet break. A core part of the system is the supervision of the sensorless tension control of the dry-end sections, assuring its long-term stability.

Origami is a traditional Japanese craft that is based on the folding of the designed structure and can be widely used by industry. Origami folding is not a difficult task for human hands; however, folding by robot hands is such a challenge. In this paper, we suggest a novel approach for designing the origami-performing robotic systems. The main idea of the proposed method is to simulate the forming crease lines in origami models and folding behavior of a sheet of paper by robot end-effectors. The simulation approach becomes the main option in the real-world related with a robotic activity. Our investigation results show that many design parameters of a robot such as geometrical and topological, shape and configuration of the robotic arms, type of forces and their distributions, and others can be defined by the simulation of the folding origami structures. It means that the results of the simulation can be used as a basis of the final robot design without a series of experimental tests. Problems of the numerical simulation, including paper material structure, simulation origami model, the distribution and values of the applying forces, and others are considered carefully. The results of the design process of the robotic system based on the simulation of origami crease forming confirm our idea to use simulation approach with LS-DYNA solver to build the origami-performing robot for complex origami structures. The origami model “Star” was taken as an example to demonstrate the method for the different types of the creases in origami.

This paper solves the controller tuning problem of machine-directional predictive control for multiple-input–multiple-output (MIMO) paper-making processes represented as superposition of first-order-plus-dead-time (FOPDT) components with uncertain model parameters. A user-friendly multi-variable tuning problem is formulated based on user-specified time domain specifications and then simplified based on the structure of the closed-loop system. Based on the simplified tuning problem and a proposed performance evaluation technique, a fast multi-variable tuning technique is developed by ignoring the constraints of the MPC. In addition, a technique to predict the computation time of the tuning algorithm is proposed. The efficiency of the proposed method is verified through Honeywell real time simulator platform with a MIMO paper-making process obtained from real data from an industrial site.

In the present work, the problem of controlling recipe transitions in a paper-making process is addressed, in order to avoid paper breakage and reduce paper waste. A decoupling control scheme is proposed, based on the control of speed differences between contiguous motors. This guarantees smooth and fast transitions of all the motor speeds along the production line. A front-tracking scheme is also employed, in order to adapt the recipe change to the actual plant conditions. A simulation model has been constructed and validated for a real industrial paper-making plant, and the effectiveness of the proposed control algorithm has been tested by means of simulation.

Wind turbine rotor imbalances may be created by a multitude of causes, e.g. pitch misalignment, blade erosion. In such situations, machines experience undesired vibrations, which cannot be compensated or mitigated by the controllers generally adopted by industry today. This happens because the control action may be collective or both collective and cyclic, but, in order to cope with imbalances, it is necessary to employ a fully individual control which allows a blade to move independently from the others. In this paper we present a new individual pitch control algorithm able to simultaneously target the imbalance and reduce oscillating loads at frequencies multiple of the rotor revolution. The effectiveness of the proposed control is demonstrated in a high-fidelity simulation environment.

The pulp and paper plants operation control system is a package software for the pulp and paper industry. The pulp and paper industry has been many problems, such as severe competition, increase of fixed costs, unstable exchange quotations. This package software solves these problems. This package provides an integration of process control and Operation control, combination of standard equipment, easy customized function of business application software, and remote operation function. This package software runs on open platform computer. This package consists of the operation database, communication adapter subsystem, optimal plan subsystem, quality control subsystem, roll handling subsystem, and remote operation subsystem.In the future, we will plans the extension of pulp and paper plants operation control system, such as feedback function of process data and performance data of operation and integration of production system and sale system.

Electronic line-shafting control has demonstrated very promising features when applied to paper machine drives. To apply this new control methodology, it is necessary to develop a starting procedure for each individual section and a method for setting the parameters of the virtual line-shaft drive and in-shafts. This paper proposes and evaluates startup and commissioning procedures for electronically line-shafted paper machine drives. The procedure for acceleration of the individual sections is implemented using virtual variable-ratio gearboxes that emulate the physical clutches and conical pulleys used in the era of line-shafts. System stiffness is implemented using virtual in-shafts with active damping. Evaluation shows that the proposed virtual clutch/conical pulley assembly and active damping allow smooth acceleration of each section and maintain well-behaved response during load disturbances for all operating conditions, even with different numbers of sections effectively connected.

The model of a paper machine is very complex and difficult to describe completely by a mathematical model. There are a lot of parameters in both the wet and dry end of the machine and there is a very large time delay in the system which effects the quality of the paper being produced. Although the PID controller is widely used for these types of applications, it is often not tuned very well. In this work, a newly developed algorithm (Munro, The systematic design of PID controllers, IEE Colloquium in Robust Control: Theory, Software and Applications, Austin Court, Birmingham, 1999) is used for tuning the PID controller. Along with this controller, a Smith-predictive controller is applied to the plant and the transient and steady-state behaviours of these controllers are compared. Hardware and software implementations of the closed-loop control are also presented in the paper.

Recently, La Papelera del Plata implemented the Paper Machine IT project in zarate, Buenos Aires. The integration of control system with supervisory sensor based systems, actuator systems, PLC systems and drives was considered the most important. True system integration requires system level interoperability. ABB has achieved this by offering a wide range of pulp & paper solutions built upon a common system platform. This paper describes how this project was executed and presents the results achieved by La Papelera del Plata paper mill through the application of integrated system solutions, on the Advant Open Control System (OCS) with Master software foundation.

In this paper a robotic boat setup for research and education in control is presented. It was designed for students to develop their practical experience and validate theoretical results at the course “Control Methods for Robotic Applications”, which is being taught at the Department of Control Systems and Informatics of ITMO University. Four use cases of this setup are suggested in the paper. They are aimed to design controllers of various structures.

A retention control system trial was performed for the wet part of a papermaking machine. By introducing two intelligent pulp and ash (filler) low consistency sensors (Kajaani : RM-200 M) to the stock supply line of head box and the white water (WW) filtrate line of wire part, we can monitor its wet end process conditions continuously. The retention control system using these sensors stabilizes the wet part process by controlling WW consistency, that is by an appropriate action of the retention aid dosage using a gap added PI (Proportional plus Integral) controller. As many grades production is running and grade changes are run frequently in this paper machine, it is difficult to determine the target set value (SV) of WW consistency. So we developed a new algorithm to judge the process stability by itself and to determine the SV target value of WW consistency automatically.

Because of tightened quality requirements of the control of CD (Cross Direction) profiles dilution control headboxes are getting more common. Dilution control utilizing white water makes the short circulation more complicated compared to the traditional short circulation. This paper discusses control problems related to the short circulation of the paper machine having a dilution headbox. A list of the most common disturbance sources is given based on the experience gained from production machines. Consistency control applications based on Kajaani RMi consistency analyzer are presented with results. Control applications are dilution water consistency control, break time headbox ash consistency control and thick stock ash content feedforward control. These applications are used to improve the stability of the machine during normal operation and to recover faster from web breaks.

This paper describes the design of a multi-input multi-output (MIMO) digital-linear-quadratic-regulator (DLQR) control system for the headbox of a paper machine. The complete design procedure is described from development of a mathematical model of the nonlinear headbox system, through experimental identification of linear model, to demonstration of closed-loop system performance on a laboratory-scale mock-up of an actual headbox. The important role of computer-aided-design tools is illustrated using Matlab and associated toolboxes. The control algorithm is implemented on a personal computer running the Labtech Notebook control program. The controlled system satisfactorily controls set point changes in total pressure and water level, and rejects disturbances in feedwater pressure. The material presented in the paper is used in a senior level course in digital process control at the University of Idaho. The course is jointly offered by the chemical and electrical engineering departments.

The pressurized headbox is one of the most important pieces of equipment on a modern paper machine. It is a special two-inputs-twooutputs process, and proper matching of input and output of control loops is very important. Relative gain analysis and computer simulation based on a mathematics model of the pressurized headbox shows that the common used configuration in paper industry is not the best. For this kind of configuration, a multi variable predictive control algorithm is designed. Computer simulation shows that this kind of control algorithm can deal with the headbox control very well. A control system with this kind of controller for full scale pressurized headbox has a good performance with excellent control precision, very short response time and very small offsets.

In controlling uncertain processes, it is decisive to utilize information provided by measurements in order to estimate parameters and states. Nonlinear Model Predictive Control (NMPC) is a popular method to implement feedback control and deal with uncertainties. Conventional NMPC or nominal control, however, sometimes does not provide enough information for system estimation, leading to unsatisfactory performance. Dual control attempts to strike a balance between the two goals of enhancing system estimation and optimizing the nominal objective function. In this paper, we analyze the performance of these strategies through the interplay between the performance control task and the information gain task in connection with Optimal Experimental Design. Examples illustrate the conflict and agreement between the two tasks and explain why in some cases nominal control performs well. It is also observed that measurement noise provides excitation helping to improve the quality of estimates.

Production rates in modern paper machines are increasing all the time. This poses challenging requirements for control of different subprocesses in the paper machine, e.g. for the headbox. Currently, scalar controllers are used for headbox control in industrial practice almost everywhere. Headbox control has been a favorite example of multivariable control in many simulation and laboratory studies but not in industry. This paper presents an application of multivariable PI controller to the paper machine headbox. The procedure takes into account the limited tests that can be performed in practice, simplicity in structure and tuning, and realization using modern distributed automation systems.

Presented in this paper is a novel method to improve machine-direction moisture profile in paper machine.Kalman Filter is employed to compensate the time-varying dead time in moisture control loop. Effect of moisture-basis weight interaction is deliberately utilized in building the control scheme. Stability analysis is tried out in Laplace plane in classical manner.

In this paper, a robust controller for the paper machine benchmark problem is designed using H ∞ loop-shaping techniques. The weighting functions are tuned to minimize the effect of a sinusoidal disturbance in the filler retention level.

The paper presents four issues. The 1st is the introduction of the new web-tension control method which is useful for the control of paper-machine and versatile converting machines. The 2 nd is the performance in efficiency and torque control of GTO inverter which have been successful for energy-saving and center-drive-winder. The 3rd is the software-package for the maintenance of inverters. The last is the introduction of smart controller which is useful for revamping or improvement of old control-systems.

Demands for small-scale and low-cost robots have witnessed a great increase in recent years [1–5]. This paper introduces the design and fabrication of a novel, simple, low-cost and designer-friendly locomotive robot. The materials and tools to build the robot originate from everyday life. The robot is pneumatically powered and manually controlled by simply pumping and vacuuming the syringe repeatedly, which realizes reliable locomotion by folding and opening of the planes. In order to realize this complicated motion, a “3D Sticky Actuator” is developed. The motion and force analysis of actuator are then modelled by the numerical method to develop the relations between design parameters. This suggests a systematic and user interactive way of manufacturing various shapes of the actuator, depending on user-defined road condition (e.g. obstacles and slopes) and other constraints. One key advantage of the paper-based robot is suggested by its high feasibility.

A robust tuning problem for a two-degree-of-freedom model predictive controller is explored for single-input, single-output uncertain paper-making processes. The objective is to achieve satisfactory closed-loop responses, as measured by overshoots, settling times and output oscillations with user-specified parametric uncertainties. As the output variation cannot be easily specified by the end users, two methods are proposed to connect a total variation specification to user-friendly indices, based on which two algorithms are designed to solve the tuning problem. An application to a process extracted from the pulp and paper industry is employed to verify the effectiveness of the proposed algorithms.

Model predictive control is a modem method which was used in many different applications. One of the applications are electrical machines. Designing a controller for a synchronous drive has shown to be a challenging task. Many papers substitute one or more controllers in the cascade structure. Nevertheless, this approach calculates only the suboptimal trajectory, not the optimal trajectory. This paper presents a linearization approach of nonlinear model predictive controller and its preparation for implementation. Simulation is performed to verify presented ideas and its results are shown and discussed at the end of the paper.

This paper deals with the use of dynamic programming method for the creation of optimal process control of paper web heating in the drying part of the paper machine, Results of the synthesized system are given. The main aim of research is to establish the efficiency of dynamic programming method under the influence of various sizes of disturbances on the control object. Using the method of simulation modeling it is conducted experimental researches of developed control system with the implementation of dynamic programming method adapted to this process. The proposed software solution allows effectively control the process of paper web heating in a wide range of disturbances. Dynamic programming method, which was implemented in the work, allows calculating the optimal values of control actions in each drying cylinder, which leads to solving the problem of process control while minimizing control criteria. The proposed solution can be used as part of the overall control process of the paper web drying in the drying part of the paper machine. The results will be used in the future to modify the dynamic programming method to integrate into it elements of prediction of perturbations and real-time correction of control actions.

In paper mill plants, the competition for increasing efficiency and reducing costs is a primary purpose. Fault detection and diagnosis can help by minimize the loss of production. In particular for the stock preparation sub-process a signal based fault detection and isolation procedure is developed. Multi-Scale Principal Component Analysis (MSPCA) is used to monitor some critical variables of the stock preparation of a paper mill plant in order to diagnose faults and malfunctions. MSPCA simultaneously extracts both, cross correlation across the sensors (PCA approach) and auto-correlation within a sensor (Wavelet approach). The advantage of MSPCA is validated on considered paper mill plant where several sensors are installed to control and monitor the automation system.

The paper mainly introduces the application of closed hood in process of paper produce. This closed hood control system bases on PLC and inverter. In this system, the data collection, calculation, loop control and the communication of PC are completed by PLC. This control system has been applied in medium and small automation transform paper machine. It is practically showed that the output of machine and the stability have been improved by the control system.

Electromagnetic dryer is a new kind of paper machine dryer which bases on the electromagnetic induction technique. This paper adopts PIC18F8680 MCU with fuzzy control technology to design electromagnetic dryer control system, and its hardware and the software design has been completed. The simulation experiment shows that the intelligent control system for electromagnetic dryer is reliable with good real-time and high precision.

Retention control has largely remained unsolved, although it is one of the most important control loops still to be closed in the paper machine. In this paper retention modelling is done using multivariable time-series approach. Based on careful selection of vanables and model structure, several new control strategies are developed. Different feedback controls are successfully tested on a pilot paper machine. It is believed to be the first time when successful retention control has been reported in the literature.

This paper presents an industrial application of multivariable combined self–tuning control techniques to a paper machine. The papermaking process is taken as a MIMO system with unequal time–lag, some time–varying parameters and unstable inverses. In order to design a suitable control scheme for the process, a new control strategy, called multivariable combined self–tuner(MCST), with the U–D factorization recursive algorithm is proposed. The capability of the proposed scheme is demonstrated by its application to the basis weight loop and the moisture loop of the Long Wire Paper Machine(LWPM) at Juxian Paper Mill, Shandong, P.R. China.

This paper presents an efficient real-time method of sensor fault detection, isolation and estimation for a class of MIMO nonlinear time-varying stochastic systems. The sensor faults may be a jump or slow drift type. The presented approach is based on the combination of the separate-bias estimation algorithm to randomly time-varying bias of nonlinear systems proposed by the authors and the modified Bayes' decision algorithm. The proposed technique is used to design a sensor fault diagnostics system for the headbox of an actual paper machine. Actual headbox data have demonstrated the effectiveness of the proposed method