Showing papers on "Process variable published in 1998"

Statistical process control integration systems and methods for monitoring manufacturing processes

Abstract: A method and system for monitoring process parameters associated with a manufacturing or testing process. The system includes: at least one machine which is used in the manufacturing or testing process; at least one sensing device, coupled to the at least one machine, for measuring a process parameter associated with the at least one machine; and a controller, coupled to the at least one sensing device, for receiving and storing measured data from the at least one sensing device. The method includes the acts of: measuring a value of a process parameter associated with a machine used in the manufacturing or testing process; converting the measured value of the process parameter into a digital data signal having a specified data format; transmitting the digital data signal to a controller; and storing the digital data signal in a database.

Polymerization process controller

Abstract: A batch polymerization process controller using inferential sensing to determine the integral reaction heat which in turn is used to indicate the degree of polymerization of the reaction mixture batch. The system uses a reaction temperature compared with a desired temperature, and the result is used as a feedback to monitor and control the process. One version of the process controller also uses a feedforward signal which is an integral reaction heat indication from a process model. In another version of the process controller, the integral reaction heat is compared with a desired integral reaction heat, and result is used as another feedback to monitor and control the process. Heat production and reaction temperature profiles may be used, along with the thermokinetic equations to determine the polymerization process and reactor models which are utilized by the process controller to optimize the polymerization process in terms of efficient use of cooling water and desired polymerization of each mixture batch.

Method of predicting overshoot in a control system response

Abstract: A process control system including a method of suppressing overshoot of a process variable beyond the process value setpoint by predicting the overshoot by observing a waveform associated with the process variable, observing the waveform associated with the process variable, without regard to time scaled or to amplitude scale, taking corrective action to reduce or eliminate said overshoot by utilizing a fuzzy logic module with a proportional integral derivative control to take corrective action of the process variable.

System and method for closed loop autotuning of PID controllers

Abstract: A system and method for automatically tuning a PID controller resident within a PID control loop. The PID control loop includes a PID controller and a process. The process supplies a process variable which is compared to the loop input. The result of the comparison is supplied to the PID controller, and the PID controller drives the process. A relay is applied to the loop input. The relay compares a set point value to the process variable. If the set point value is greater than the process variable, the relay drives the loop input with a first amplitude value. If the set point value is less than the process variable, the relay drives the loop input with a second amplitude value. In response to the set point relay, the process variable develops a sustained oscillation. The period and amplitude of the sustained oscillation are measured. A new set of PID controller parameters are calculated from the period and amplitude of sustained oscillation. In particular, the oscillation period and amplitude are used to calculated a time constant and dead time for a standard process model. The time constant and dead time are used to calculate the new PID controller parameters either (a) directly through the formulae associated with the Ziegler-Nichols reaction curve method, or (b) through the intermediate step of calculating an ultimate period and frequency from the time constant and deadtime.

Automated process parameter resetting for injection moulding: a fuzzy-neuro approach

Abstract: Optimal process parameter setting for injection moulding is difficult to achieve due to a large number of factors involved. Current practice in industry is to adjust the parameters based on the products' defects of test-run through trial and error. This process, however, requires enormous experience and is often time consuming. This paper reports an intelligent system employing fuzzy sets and neural networks which is able to predict the process parameter resetting automatically to achieve better product quality. The system is designed to be used in the test-run of injection moulding. Seven commonly encountered injection moulded product defects (short shot, flash, sink-mark, flow-mark, weld line, cracking, and warpage) and two key injection mould parameters (part flow length and flow thickness) are used as system input which are described using fuzzy terms. On the other hand, nine process parameter adjusters (pressure, speed, resin temperature, clamping force, holding time, mould temperature, injection holding pressure, back pressure, and cooling time) are the system output. A back-propagation neural network has been constructed and trained using a large number of {defects}→ {parameter adjusters} expert rules. The system is able to predict the exact amount to be adjusted for each parameter towards reducing or eliminating the observed defects. Testing in several real cases showed that the system produced satisfying results.

Method for multiple process parameter matching

Abstract: A computer-implemented method for matching parameters of outputs generated by a first and second process The first process generates a first output having a characteristic measurable by a first parameter, and the second process generates a second output having the characteristic measurable by a second parameter A computer having a processing unit and memory is provided The computer generates a first model of the first parameter for the first process and a second model of the second parameter for the second process The computer generates a first simulated output of the first process using the first model A correction, which is a function of the second model and which compensates for the effect of the second process on the second parameter, is applied to the first simulated output to obtain a corrected output The second process is applied to the corrected output to generate with the computer thereby a third output matching the first parameter of the first output

Method for regulating a smooth running of an internal combustion engine

Abstract: A method for regulating the smooth running of a multicylinder internal combustion engine. An inverse linear path model estimates a characteristic process variable from state variables of the internal combustion engine, that is to say actual values, in particular engine speed, fuel quantity, operating temperature, charging pressure, etc. A desired value is compared with the actual value that is determined from state variables of the internal combustion engine by a measuring element. The actual value shows the rotational acceleration contribution of each cylinder. The difference between the actual value and the desired value is supplied to a controller that corrects the combustion in the individual cylinders in such a way that the actual value approaches the desired value. This ensures that the regulation for the smooth running of the engine takes effect both for stationary and non-stationary operating phases of the internal combustion engine.

Process and arrangement for controlling the temperature of a medium

Abstract: An arrangement and a process for controlling the temperature of a medium, particularly of the cooling water temperature of a motor vehicle engine. At least two energy-consuming units influence the temperature to be controlled, of which at least one can be controlled with respect to its output. A control unit adjusts the output of these units for causing a required influencing of the temperature. The output of each temperature-influencing unit is adjusted by means of a previously determined, energy-minimal characteristic diagram K E which indicates for each system condition the operating point of the absolutely minimal energy consumption of the energy-consuming units for controlling the temperature according to a respective desired value.

Method for controlling a time-lagged process with compensation, and a controlling device for carrying out said method

Abstract: The invention relates to a method for controlling a time-lagged process (P) with compensation, especially for controlling temperature. After a set-point step change, the manipulated variable (y) is set to a first constant value in a controlled mode, an IT1 model is identified using the step response, and a PI controller is parametrized. Said PI controller adjusts the process (P) to a second stationary state (x = x1). A more exact process model with compensation is then determined and used to adjust the controller. The invention is suitable for use with adaptive controllers.

Magnetron-sputtered hard material coatings on thermoplastic polymers for clean room applications

Abstract: Even under demanding environments, such as clean rooms, polymers are already used in different ranges of applications. The wear and particle generation within a specific particle size under mechanical stress is a limiting factor, as are high material and cleaning costs. Building on this state-of-the-art basis, our aim was to develop an innovative material concept that would allow the application of a thermoplastic polymer coated with a thin hard material (thickness up to 2.5 μm). Therefore, it was necessary to improve the wear resistance, the adherence between the polymer and the coating as well as to reduce the interaction with the aluminum (A6061) counterbody which functions as the tribological partner in the application. To align the aims and economics of the project, the production process consisted of only two phases: first, the injection moulding process that was then followed by a MSIP process including a plasma pretreatment. In this investigation, poly(butyleneterephthalate) (PBT), poly(amide) 6.6 (PA 6.6) and poly(carbonate) PC were chosen as substrate material. The coating materials presented here were based on titanium (Ti-N). The thin films were deposited by magnetron sputter ion plating (MSIP) because of its low defect rate and wide range of parameter variation possibilities to reduce the thermal stress during the coating process. The process parameter's influence on the microstructure, extending from amorphous to columnar (crystalline) as well as the film thickness were analysed by SEM. Selected results of different plasma pretreatments to improve the adhesion for specific polymers will be discussed and presented. It will be shown that it is possible to improve the adherence between the film and the plastic substrate and to reduce the particle generation after the appropriate etching and coating process has taken place.

Alarm event generator apparatus, means and system

Abstract: An alarm event generation method and apparatus for signaling an alarm ( 436, 1400 ) for a process control system ( 100 ). The process control system ( 100 ) monitors a production run using a computer system ( 108 ). The computer system ( 108 ) collects process data corresponding to the production run from operator workstations ( 104, 106 ) and stores the process data in a process data database ( 110 ). The process data includes a plurality of process parameter counts ( 430 ) each corresponding to a process parameter type ( 428 ). The process parameter counts ( 430 ) are polled from the computer system ( 108 ). Each process parameter count ( 430 ) has a corresponding manufacturing limit ( 434 ) to which it is compared. When a polled process parameter count ( 430 ) exceeds its corresponding manufacturing limit ( 434 ), an alarm ( 436, 1400 ) is signaled. While an alarm ( 436, 1400 ) is being signaled, the computer system ( 108 ) is prevented from collecting and storing process data.

Network control system, process management method in this system, and recording medium on which a process management program is recorded

Abstract: In a controlled object, a process variable of a controlled object process is detected by a sensor and its detection time is measured by a timer. A process signal transmitting device transmits, as a process signal, the process variable and the detection time to a control apparatus. A control variable calculating device calculates a control variable based on the received process variable and a control reference value, and transmits a control signal including the control variable and the received process variable detection time to the controlled object. In the controlled object, a control signal receiving device calculates a transmission delay, that is, a difference between control signal reception time that is measured by the timer and the transmitted process variable detection time, corrects the control variable by processing it in accordance with the transmission delay, and drives an actuator by using the corrected control variable.

Assessment of molding quality achieved by pressure injection molding machine

Abstract: A known procedure relates mean graphs relating process parameters with desired quality and that achieved in practice, establishing the acceptable range of a process variable. In this new development, the standard deviation is calculated in addition as a function of a controlling parameter to obtain the standard deviation normal to the mean curve (Mn), in order to insert the region of acceptability on the graphical representation. Preferred features: The first (dependent) parameter is the pressure, preferably hydraulic or mold cavity pressure, the second parameter (independent) is the cycle time, i.e. the curve determined, yields pressure in terms of cycle time. Further alternative relationships treated in the same manner are: velocity of the displacement unit and cycle time; displacement stroke and cycle time; cavity- or hydraulic pressure and stroke of the positive displacement unit; and finally, velocity of the positive displacement unit and its stroke.

Spray Forming Commercial Products: Principles and Practice

Abstract: Spray forming in the Osprey mode utilizes the sequential steps of atomization and droplet consolidation to produce near-net-shape preforms. The process is described in terms of operational and material parameters, advantages relative to ingot and powder metallurgy, and product forms. A brief overview is given of the models developed to describe the process in order to optimize yield, microstructure and properties, and to control the shape of the product. Metallurgical characteristics and properties are assessed in comparison to counterpart ingot metallurgy alloys. Commercial applications of the process are illustrated; these include the spray forming of billets, rolls, rings and tubing.

Control of refined pulp quality by adjusting high temperature pre-heat residence time

Abstract: A method for refining lignocellulose-containing material into pulp in a disc refiner comprises preheating the material to a temperature greater than the glass transition temperature of lignin in the material, and holding this temperature for under one minute. The heated material is then subject to high speed refining in a disc refiner to produce pulp. The resulting pulp may then be subject to secondary refining steps to produce paper quality pulp. The preheat retention time is preferably in the range of 5-30 seconds, and can be controlled as a process variable to optimize energy savings, pulp strength, and optical qualities. High quality pulp can be obtained with preheat at high temperature and low retention time, followed by primary refining at disc speed of at least 2300 rpm.

Process-Parameter Optimization

Abstract: The abrasive water jet-cutting process is characterized by a large number of process parameters that determine efficiency, economy, and quality of the whole process. Therefore, optimization of the process is a primary requirement for a successful application.

Method and device for assisting model parameter preparation

Abstract: PROBLEM TO BE SOLVED: To provide a method and a device therefor to reduce the frequency of extraction of model parameters from samples of an element by utilizing information regarding set target element characteristics and the variance guarantee range of the element characteristics and to assist the preparation of a set of model parameters, which have desired element characteristics and also have continuity in characteristic. SOLUTION: Model parameter sensitivity to element characteristics is calculated (step 102), process parameter sensitivity to a model parameter is calculated (104), and the variation quantity of the process parameter is estimated by using the difference between the desired element characteristics and element characteristics that a reference model parameter set shows and the found model parameter and the sensitivity of the process parameter (106), and a model parameter set having the desired element characteristics is calculated by using the obtained variation quantity, process parameter sensitivity, and reference model parameter set (108).

Process integration of an interlevel dielectric (ILDO) module using a building-in reliability approach

Abstract: Process integration is approached from a built-in reliability perspective in order to develop a pre-metal inter-level dielectric (ILDO) module which may be integrated into a submicron CMOS process with embedded nonvolatile memory. The approach involves developing a fundamental understanding of the process parameters that modulate parasitics and impact reliability. The benefit of such an approach is a relatively simple process integration while achieving a highly manufacturable and reliable process. Several ILDO films have been characterized to understand the physical and chemical composition, process parameter dependencies, and gettering properties in order to define a process window from which to integrate the most manufacturable process.

Process and installation for making continuously cast pieces

Abstract: The method concerns production of continuously cast (preferably steel) billets (7) A process parameter determined during casting is compared with a limit value, and the result is used to decide on the subsequent treatment of the billet Either the continuous billet (7) or the separated billet (7') still in its hot state is machined to remove its surface or near-surface faults, with the machining process activated and deactivated on the basis of relevant process parameters The installation includes a machine (10) for machining at least one surface region of the billet (7) or (7') This machine is controlled on the basis of process parameters such as casting speed, melt temperature, melt level fluctuations in the mould (6), the chemical composition of the melt etc

Method and device for monitoring process data

Abstract: PROBLEM TO BE SOLVED: To quickly monitor process data by previously defining and monitoring inclinations related to plural process variables. SOLUTION: Monitoring scenario definition for defining an inclination monitoring pattern related to plural process variables to be monitored is used, and when a monitoring start condition is satisfied, monitoring to be executed while dynamically changing upper and lower limit values is started (step S2). If a process variable is deviated from the upper and lower limit values (step S6), whether a pattern having the same direction as the defined inclination monitoring pattern exists or not is judged (step S7). When the pattern exists, monitoring to be executed by shifting relative time up to the pattern and monitoring to be executed by returning the advanced time to the original state are successively executed (step S8), and when the pattern does not exist, an operator is informed of abnormality generation (step S12).

Method and arrangement for controlling an operating variable of a motor vehicle

Abstract: The invention is directed to a method and an arrangement for controlling an operating variable of a motor vehicle. A friction-burdened actuator assembly, which influences the operating variable, is actuated via a drive signal. This drive signal is formed on the basis of a desired value of the operating variable. The drive signal is additionally changed in response to a desired change of the operating variable to transfer the actuator assembly out of a steady state condition preferably so as to effect an actual change of the operating variable. In this way, the static friction of the actuator assembly, which is in opposition to the change of the operating variable, is overcome. Furthermore, the drive signal can be additionally changed in the sense of a reduction of the change of the operating variable when the operating variable approaches the desired value thereof.

Treatment of waste water

Abstract: Process for optimisation of the biological chemical break-down of substances which are difficult to break down in aqueous solution using chemical oxidation agents, uses: (a) the bio-reactor intermittently operated, while the oxidation reactor is operated as a batch reactor; (b) the process parameter controlled by measuring the total oxygen content (TOC) at the bio-reactor inlet or outlet Also provided is an assembly for carrying out the process above

Product development using process monitoring and NDE data fusion

Abstract: Composite process/product development relies on both process monitoring information and nondestructive evaluation measurements for determining application suitability. In the past these activities have been performed and analyzed independently. Our present approach is to present the process monitoring and NDE data together in a data fusion workstation. This methodology leads to final product acceptance based on a combined process monitoring and NDE criteria. The data fusion work station combines process parameter and NDE data in a single workspace enabling all the data to be used in the acceptance/rejection decision process. An example application is the induction welding process, a unique joining method for assembling primary composite structure, that offers significant cost and weight advantages over traditional fasted structure. The determination of the required time, temperature and pressure conditions used in the process to achieve a complete weld is being aided by the use of ultrasonic inspection techniques. Full waveform ultrasonic inspection data is employed to evaluate the quality of spar cap to skin fit, an essential element of the welding process, and is processed to find a parameter that can be used for weld acceptance. Certification of the completed weld incorporates the data fusion methodology.

Process parameter optimisation method e.g. for steel industry

Abstract: The parameter optimisation method involves using a gradient estimation provided by a processor, with a new parameter value provided by subtracting a function value for the search direction from the previous parameter value. A second function value is calculated from the new parameter value and the gradient is calculated via a RLS algorithm.The new parameter value can be generated using a random principle.