Uncontrolled Disturbances Research Articles

A Concurrent-Engineering Approach Toward the Online Adaptive Control of Injection Molding Process

Injection molding is the most effective process to produce plastic parts of complex shape to the highest precision at the lowest cost. Considerable progress has been made over the last two decades in modeling and simulation of the molding dynamics. However, due to complex material properties and other uncontrollable disturbances, consistency of part quality cannot be assured in production. This paper presents a new approach to the problem. Based on the concept of Concurrent Engineering, we make full use of the power of simulation for the design of the part, the mold, and setting up process control parameters automatically. The control system consists of feed-forward and feedback loops with numerous sensors in each loop. With an online PC and a smart part-quality sensor, the system can control the variation of part weight many times better than existing methods.

Analysis, Estimation, Optimization and Control Under Uncontrolled Disturbances

Abstract The problems of accuracy analysis, estimation and control are take into account. The new approach, algorithms and techniques have been developed to solve the problems. This approach is based on replacement of initial problems on equivalent optimization problems, having minimax and maximin structure. The computerized decision support system is designed. The necessity of the new computerized system is connected to practical requirement to have not only new high-precision algorithms of the probabilistic problems solution, but also modern specialized software. The launcher controlled motion study is described.

Specification framework for robust control of a run-of-mine ore milling circuit

It is difficult in run-of-mine (ROM) milling circuits to control the particle size of the product and other important variables because the ore fed to the mill also acts as the main grinding medium. This results in significant uncontrolled disturbances and uncertainties. Before the μ-controller synthesis and analysis methodology can be applied to this multivariable control problem it is necessary to formalize the uncertainties and specifications in terms of a suitable general framework. The uncertainty description for an industrial milling circuit obtained from plant perturbation tests is used to motivate the choice and location of uncertainty weights within the plant transfer function matrix structure. The choice of performance weights based on their economic and plant-related importance is also discussed. The ROM milling circuit model with its uncertainty and performance weights is then cast into a general synthesis and analysis framework.

Transition experiments in a boundary layer with embedded streamwise vortices

The stability of a flat plate boundary layer modulated by stationary streamwise vortices was studied experimentally in the T-324 low speed wind tunnel in Novosibirsk. Vortices were generated inside the boundary layer by means of roughness elements arranged in a regular array along the spanwise (z-) direction. Transition is not caused directly by these structures, but by the growth of small amplitude traveling waves riding on top of the steady vortices. This situation is analogous to the transition process in Görtler and cross-flows. The waves were found to amplify up to a stage where higher harmonics are generated, leading to turbulent breakdown and disintegration of the spanwise boundary layer structure. For strong modulations, the observed instability is quite powerful, and can be excited ‘‘naturally’’ by small uncontrollable background disturbances. Controlled oscillations were then introduced by means of a vibrating ribbon, allowing a detailed investigation of the wave characteristics. The instability seems to be associated with the spanwise gradients of the mean flow, ∂U/∂z, and at all z-positions, the maximum wave amplitude was found at a wall-normal position where the mean velocity is equal to the phase velocity of the wave, U(y)=c, i.e., at the local critical layer. Unstable waves were observed at frequencies well above those for which Tollmien–Schlichting (TS) waves amplify in the Blasius boundary layer. Excitation at lower frequencies and milder basic flow modulations showed that TS-type waves may also develop. The relation between TS-type waves and the observed high-frequency instability is discussed in the light of previous authors’ findings.

Adaptive-intelligent control of robots and technological equipment of intelligent manufacturing

Methods of adaptive-intelligent control of robots and technological equipment of intelligent manufacturing (IM) with incomplete information on the plant conditions are discussed. Flexible algorithms are proposed for programming and sensor correction of movements which provide adaption to obstacles and uncertainly factors. Robust and adaptive control algorithms which compensate the uncontrollable disturbances and ensure the wanted character of transient process are synthesized. The conversational means and computeraided design technology for multi-microprocessor adaptive control systems of robots and technological equipment are described. The results of using the proposed methods in adaptive-intelligent control systems of robots and flexible manufacturing systems (FMS) for powder metallurgy, laser processing are presented.

Determination and properties of optimal controls for a coordinated hierarchical system in the presence of uncontrolled disturbances

Determination and properties of optimal controls for a coordinated hierarchical system in the presence of uncontrolled disturbances

Adaptive Control of Multidimensional Discrete Bilinear Systems

Adaptive regulators for controlling multidimensional stochastic bilinear systems with uncertain and changing within a wide range of parameters are considered. The methods of synthesis for adaptive re-gulation laws are proposed, under which a closed loop system has a ge-neralized minimum-variance. The controlled object in this case can be nonminimum-phase. The algorithms of the adaptive control law taking ac-count of uncontrolled coordinate disturbances are discribed.

Adaptive Control of Technological Equipment in Powder Metallurgy and Laser Treatment

Consideration has been given to methods of robust and adaptive control of robots and other technological equipment under condition of process information deficiency. Flexible algorithms for programming and sensor correction of move-ments to provide adaptations to factors of uncertainty have been proposed, and robust and adaptive control algorithms to compensate for uncontrolled disturbances and to ensure the desired attenuation characteristics of transients have been synthesized. The description of the results of application of the proposed methods for adaptive flexible manufacturing systems (FLIS) is presented.

A control system approach to cardiovascular reactivity: behavioral models that behave.

The control system mode of analysis of organism-environment interactions is described and used to derive an explanation of cardiovascular reactivity. This description reveals that a negative feedback control system continuously realizes a goal or purpose over time by producing output that negates the effects of unpredictable and uncontrollable disturbances on a physical variable corresponding to that purpose. Data from tracking experiments fit the control system analysis, but cannot be described by S-O-R analyses or by cognitive analyses that, unlike the control system analysis, do not correctly introduce physical time. Simple computer simulations of negative feedback control systems produce data that are almost perfectly correlated with each subject's behavior over time--these models behave. The existence of consistent behavioral results despite uncontrollable and unpredictable influences, the simple requirements for a negative feedback system, and the identification of continuously varying purposes as representing the unfolding of behavioral events over time argue for the testable hypothesis that most behavior is produced by negative feedback control. It is suggested that error in the operation of negative feedback control systems modulates cardiac performance. The ability of control systems to behave gives this explanation advantages over other theories of reactivity. A program for testing this explanation is described.

A cartilage-mimicking T-cell epitope on a 65K mycobacterial heat-shock protein: adjuvant arthritis as a model for human rheumatoid arthritis.

The way the immune system evolved has been commonly thought to have been influenced during evolution through selective pressure exerted by microbial invaders. So, immune recognition and the subsequent immune response have become significant means of the host to combat the attack of exogenous invaders. Since, however, the exogenous microbial world presents itself with a wealth of antigenic variety on each single organism, immune recognition can be selective at the antigen level. Teleologically, an unselected response would be a very inefficient maneuver inevitably leading to jamming of the system. Moreover, one could envisage more pertinent reasons for being selective, among them that responding to certain antigens might jeopardize the maintenance of self integrity. This means that a response directed to such antigens might cause uncontrollable disturbances in the balance of elements that interact in the immunological network and might lead to the ultimate development of immunopathology. This could happen when the exogenous stimulator antigen bears a resemblance to self molecules, a situation called antigenic mimicry.

On Optimal Control of Coal Separation Process

Recently more and more attention is paid to the methods of increasing the amount (yield) of coal concentrates obtained in separation process and having a desired ssh content. Proposed methods suggest homogenizetion of row coal in bunkers or on stock-piles, blending different concentrates separated st optimal incremental ash contents, monitoring of ash content in products snd influencing backwards the densities of separation. All above methods are based on the knowledge of mean washability characteristics of raw coal, while the variations of characteristics with time around their mean values are treated as uncontrolled disturbances in the process. The authors of this paper propose to apply simple methods of approximate identification of washability characteristics for instantaneous controlling of densities of separation according to the proposed algorithm.

Designing to Ensure the Safety of Operation in Automated Plants

It ia the task of a system ensuring the safety of operation to minimize the effects of uncontrollable disturbances. To ensure the safety of operation in a production process includes the following items: detection of dangerous situationsrealization of a strategy against these dangerous situationsA main point is the design of the technological (hardware) and algorithmic (software) structure of the system ensuring the safety of operation on the basis of modern measuring and process computer systems.The author represents examples for designing systems to ensure the sequence of operation in a process.

Cystinosis in the Federal Republic of Germany. Coordination and analysis of the data

In our survey, 101 infants and children with cystinosis were registered in the Federal Republic of Germany. Ninety-five patients showed the infantile type of cystinosis, five the adolescent type and one possibly the adult type. The minimum incidence rate of infantile and adolescent cystinosis in the FRG was 1 patient per 179 000 live-births. In contrast to other countries, cystinotic patients were evenly distributed in the FRG. Patients with cystinosis originated more frequently from rural communities than from large cities. Before 1968 most patients died before reaching terminal renal failure, usually due to uncontrolled disturbances of water and electrolyte metabolism. Since 1976 the causes of death other than uraemia have been rare and most patients with terminal renal failure have entered a renal replacement program.

A simple classification of the risk in cardiac surgery.

A new risk classification for patients undergoing cardiac surgery has been used for the last two years by the anaesthesiologists of the Montreal Heart Institute. The following factors known to be associated with a greater operative morbidity and mortality were selected: (1) poor left ventricular function, (2) congestive heart failure, (3) unstable angina or recent (less than 6 weeks) myocardial infarction, (4) age over 65 years, (5) severe obesity (Body Mass Index greater than 30), (6) reoperation, (7) emergency surgery, (8) other significant or uncontrolled systemic disturbances. Patients with none of the above factors were classified as normal risks; those presenting with one of those selected factors were classified as increased risks, and those with more than one factor were said to carry a high risk. In a prospective study of 500 consecutive open-heart surgery patients classified according to this method, we found that the operated population at normal risk (50 per cent of cases) had a mortality of 0.4 per cent, the patient group with increased risk (32 per cent of cases) had a mortality of 3.1 per cent, and the high risk group (18 per cent of cases) had a 12.2 per cent mortality. Furthermore, 50 deaths following open-heart surgery were assessed retrospectively using the classification; 58 per cent of these patients were classified as high risk, 34 per cent had an increased risk, and only eight per cent were found to be in the normal risk group. Thus, this new risk classification has proven to be a reliable and useful tool for preoperative assessment of patients undergoing open-heart surgery and for teaching purposes.

Follow-up of 514 consecutive patients with cardiopulmonary arrest outside the hospital

During the years 1974 of 1976, 514 patients with prehospital cardiopulmonary arrest were brought to the Hennepin County Medical Center (HCMC) Emergency Department. Of these, 344 patients (67%) were either dead on arrival or died in the emergency department despite efforts at resuscitation. The remaining 170 patients were admitted to the coronary care unit. Eighty-seven patients (51%) died in the coronary care unit, primarily from uncontrolled rhythm disturbances and/or cardiogenic shock. The remaining 83 patients (16% of the total group, 49% of those admitted to the hospital) were discharged alive from HCMC. In this group, 49 patients of the 83 long-term survivors were ambulatory with full mental function when discharged. The remaining 34 patients were trnasferred to chronic care facilities for medical treatment of on-going problems. Of the 49 ambulatory patients, satisfactory data for follow-up was obtained on 47. Their mortality rate was 15% in the first year and 50% in the second, primarily from sudden death syndrome.

Concept of a manufacturing system

There is no single concept of a manufacturing system covering all industries in every detail. It is necessary to examine the fundamental properties and characteristics of a range of systems and to consider the way they are synthesized and operated before consolidating general conclusions. What is seen depends very much on the viewpoint and the narrowness of the focusing range. Nevertheless there is much to be gained from a fundamental study of-all aspects of manufacturing systems and their interactions since there are opportunities for technology transfer between industries Manufacturing systems must be designed by taking into account both steady state and-dynamic performance, whilst ensuring there is an adequate number of controllable variables to compensate the effects of uncontrolled disturbances. The technological process part of the manufacturing system is synthesized from interacting unit-operation subsystems, and this itself is a subsystem of the overall business system. The business system has a c...

Complex production-quality evaluation by means of sample-identification methods

pamong measured attributes and objects, which requires their simultaneous multidimensional analysis for the purpose of obtaining a substantiated evaluation of their combined informational value. 3. The incommensurability of certain marginal indexes which are measured in different units (rubles, volts, seconds, etc.) and, which is even worse, in different scales (ratios, orders, nominal units, etc.). Their normalization consists of a separate and complex procedure of selecting a certain "adequate topology" in the space under consideration of the object's initial description [2]. 4. The multiplicity of local criteria which characterize the object's separate aspects and are often contradictory. In this connection the tasks of optimizing and evaluating the quality of the product as a whole should be treated as a problem of vector optimization [3]; otherwise paradoxical solutions would most probably be obtained [2]. 5. The presence of uncontrolled disturbances which are often very considerable in all the stages of theobject's designing, manufacturing, functioning, and investigation (documentation errors, "technological noise," measurement errors, etc.).

The concept of transition in quantum mechanics

The concept of quantum transition is critically examined from the perspective of the modern quantum theory of measurement. Historically rooted in the famous quantum jump of the Old Quantum Theory, the transition idea survives today in experimental jargon due to (1) the notion of uncontrollable disturbance of a system by measurement operations and (2) the wave-packet reduction hypothesis in several forms. Explicit counterexamples to both (1) and (2) are presented in terms of quantum measurement theory. It is concluded that the idea of transition, or quantum jump, can no longer be rationally comprehended within the framework of contemporary physical theory.

The application of a modified conditional probability computer to chemical process optimization

AbstractThe application of a conditional probability computer to the steady‐state optimization of a simple chemical process has been investigated. On the basis of the work of previous investigators, the memory structure of the conditional probability computer was modified in a way designed to accelerate the learning process and improve the predictive capabilities of the computer. The proposed modifications were studied by optimizing an analog simulation of a simple chemical process subjected to a variety of uncontrolled disturbances. The investigations served to delineate some of the special problems encountered in the application of a binary pattern recognition device such as the conditional probability computer to process optimization. The proposed modifications were successful in achieving significant acceleration in the learning process and improvement in predictive capabilities over that offered by a conventional conditional probability computer.

On self-adjusting control systems without test disturbance signals

The report presents and analyses one of the principles for designing an adaptive system to control time-varying processes. According to this principle, in the processes of self-adjusting, the dynamic characteristics of the system (plant and controller) and the effect of some uncontrolled external disturbances are taken into consideration. This controlled process is close, on the whole, to the predetermined (reference) behaviour in adjusting controller parameters. A high-speed computer, either a digital or an electronic analogue one, is supposed to be included in the loop of the adaptive control, depending upon the method of the process identification. Dynamic characteristics of the system are found by differential equations with time-constant coefficients, by means of which real and reference processes are approximated. In estimating reference values of controller coefficients, the sum of the squares of real coefficient value deviations from the reference ones is minimized. Mechanization problems of computing the above co-efficients by definite servos are discussed. The report deals with some particular applications of the given method for designing such an adaptive control system.