Closed Control System Research Articles

Identification of the parameters of controlled objects in closed systems

Matters of applying the correlation approach to solving the problem of identifying controlled objects in closed control systems are examined. It is established that identifiability in a closed system is determined by the type of auto- and cross-correlation functions of stochastic processes at the input and output of the object as well as by the magnitude of the transmission channel delay of the control actions and by the transfer function of the controller. The possibility of using identification criteria in the form of equalities of cross-correlation functions of the output variable and disturbance of the control action is substantiated. A comparison of the correlation method of identifying the parameters of an object in closed systems and least-squares method showed the applicability of the latter approach to a limited class of closed systems.

Design and Analysis of the Bellows Fatigue Test-Bed Based on Electro-Hydraulic Proportional Position Control

Electro-hydraulic proportional closed control system is designed which fully integrated electrical and hydraulic advantages of both. The dynamic mathematic model of the hydraulic system is built and the dynamic characteristics of the system are analyzed accurately. The advanced PID controller is adopted to correct the system, and have improved the dynamic quality of the system. In this paper, the hydraulic system is simulated on the basis of the Simulink and DSHplus professional hydraulic simulation software and the results of simulation prove that the qualities of the system can satisfy with the requirement much better.

Effects of uncertainties and errors on a Lyapunov control

A Lyapunov (open-loop) control is often confronted with uncertainties and errors in practical applications. In this paper, we analyse the robustness of the Lyapunov control against the uncertainties and errors in quantum control systems. The analysis is carried out by examining the uncertainties and errors and calculating the control fidelity under the influence of the certainties and errors. Two examples, a closed control system and an open control system, are presented to illustrate the general formalism, discussions on the effect caused by the uncertainties and errors are given.

On stability conditions of a control system for a linear heat transfer object bounded from one side

Using the Efros' theorem from the theory of functions of a complex variable, we derive bounds on the norms of operators that describe the dynamics of linear distributed heat transfer objects and objects with similar dynamic properties. These results are applied to studying stability conditions for single- and double-layered one-dimensional heat transfer objects bounded from one side. For each of the studied objects, results of previous works imply a sufficient stability condition for a closed control system that consists of the object and its feedback.

Open Architecture Automotive Electronic Control System Based on Quantum Frame and SAE J1939

In consideration of the shortcoming of the close automotive electronic control system, through the analysis to the requirement of the open system and existing way to establish an open system, an open architecture automotive electronic control system based on quantum frame and SAE J1939 is established adopting the advanced software technology of embedded system. The quantum frame is used as the software bus, the SAE J1939 is used to defined the application information standard. Further more, the hierarchy of the application software, the protocol of each bus and the web structure of the system is proposed.

Adaptive RBF neural network control of robot with actuator nonlinearities

In this paper, an adaptive neural network control scheme for robot manipulators with actuator nonlinearities is presented. The control scheme consists of an adaptive neural network controller and an actuator nonlinearities compensator. Since the actuator nonlinearities are usually included in the robot driving motor, a compensator using radial basis function (RBF) network is proposed to estimate the actuator nonlinearities and eliminate their effects. Subsequently, an adaptive neural network controller that neither requires the evaluation of inverse dynamical model nor the time-consuming training process is given. In addition, GL matrix and its product operator are introduced to help prove the stability of the closed control system. Considering the adaptive neural network controller and the RBF network compensator as the whole control scheme, the closed-loop system is proved to be uniformly ultimately bounded (UUB). The whole scheme provides a general procedure to control the robot manipulators with actuator nonlinearities. Simulation results verify the effectiveness of the designed scheme and the theoretical discussion.

Synchronous electric drive of an elevator operating in close control system

A sample synchronous motor with permanent magnets has been tested in the model of a gearless drive and the results are presented. With the help of mathematical simulation, comparative calculations of synchronous motors with different geometrical sizes are carried out for two types of elevators.

Endocrine functions of brain in adult and developing mammals

The main prerequisite for organism's viability is the maintenance of the internal environment despite changes in the external environment, which is provided by the neuroendocrine control system. The key unit in this system is hypothalamus exerting endocrine effects on certain peripheral organs and anterior pituitary. Physiologically active substances of neuronal origin enter blood vessels in the neurohemal parts of hypothalamus where no blood-brain barrier exists. In other parts of the adult brain, the arrival of physiologically active substances is blocked by the blood-brain barrier. According to the generally accepted concept, the neuroendocrine system formation in ontogeny starts with the maturation of peripheral endocrine glands, which initially function autonomously and then are controlled by the anterior pituitary. The brain is engaged in neuroendocrine control after its maturation completes, which results in a closed control system typical of adult mammals. Since neurons start to secrete physiologically active substances soon after their formation and long before interneuronal connections are formed, these cells are thought to have an effect on brain development as inducers. Considering that there is no blood-brain barrier during this period, we proposed the hypothesis that the developing brain functions as a multipotent endocrine organ. This means that tens of physiologically active substances arrive from the brain to the systemic circulation and have an endocrine effect on the whole body development. Dopamine, serotonin, and gonadotropin-releasing hormone were selected as marker physiologically active substances of cerebral origin to test this hypothesis. In adult animals, they act as neurotransmitters or neuromodulators transmitting information from neuron to neuron as well as neurohormones arriving from the hypothalamus with portal blood to the anterior pituitary. Perinatal rats--before the blood-brain barrier is formed--proved to have equally high concentration of dopamine, serotonin, and gonadotropin-releasing hormone in the systemic circulation as in the adult portal system. After the brain-blood barrier is formed, the blood concentration of dopamine and gonadotropin-releasing hormone drops to zero, which indirectly confirms their cerebral origin. Moreover, the decrease in the blood concentration of dopamine, serotonin, and gonadotropin-releasing hormone before the brain-blood barrier formation after the microsurgical disruption of neurons that synthesize them or inhibition of dopamine and serotonin synthesis in the brain directly confirm their cerebral origin. Before the blood-brain barrier formation, dopamine, serotonin, gonadotropin-releasing hormone, and likely many other physiologically active substances of cerebral origin can have endocrine effects on peripheral target organs--anterior pituitary, gonads, kidney, heart, blood vessels, and the proper brain. Although the period of brain functioning as an endocrine organ is not long, it is crucial for the body development since physiologically active substances exert irreversible effects on the targets as morphogenetic factors during this period. Thus, the developing brain from the neuron formation to the establishment of the blood-brain barrier functions as a multipotent endocrine organ participating in endocrine control of the whole body development.

Synthesis and modeling of the H ∞-system of magnetic control of the plasma in the tokamak-reactor

The article deals with the development of a two-contour system of magnetic control of the position, current, and shape of the plasma in the tokamak-reactor. The H∞-theory of control is used for the synthesis of a scalar and a multidimensional feedback controller. The controllers are synthesized on the basis of the multidimensional linear model DINA-L of an object (plasma in the tokamak). The linear model DINA-L is obtained from the nonlinear model implemented by the plasmophysical DINA code for conditions of the international thermonuclear experimental reactor (ITER). The numerical modeling of a closed control system is carried out on the linear DINA-L model and the nonlinear DINA model of an object at disturbances of the type of small disruptions. The modeling results for both of the cases were superimposed on each other, which showed their good coincidence at the acceptable quality of control of the synthesized system.

An agent-based Web service workflow model for inter-enterprise collaboration

Abstract The service-orientated computing paradigm is transforming traditional workflow management from a close and centralized control system into a worldwide dynamic business process. A complete workflow serving inter-enterprise collaboration should include both internal processes and ad hoc external processes. This paper presents an agent-based workflow model to address this challenge. In the proposed model, agent-based technology provides the workflow coordination at both inter- and intra-enterprise levels while Web service-based technology provides infrastructures for messaging, service description and workflow enactment. A proof-of-concept prototype system simulating the order entry, partner search and selection, and contracting in a virtual enterprise creation scenario is implemented to demonstrate the dynamic workflow definition and execution for inter-enterprise collaboration.

Simultaneous measurements of local tissue temperature and blood perfusion rate in the canine prostate during radio frequency thermal therapy

Local tissue temperature and blood perfusion rate were measured simultaneously to study thermoregulation in the canine prostate during transurethral radio-frequency (RF) thermal therapy. Thermistor bead microprobes measured interstitial temperatures and a thermal clearance method measured the prostatic blood perfusion rate under both normal and hyperthermic conditions. Increase in local tissue temperature induced by the RF heating increased blood perfusion throughout the entirety of most prostates. The onset of the initial increase in blood perfusion was sometimes triggered by a temporal temperature gradient at low tissue temperatures. When tissue temperature was higher than 41 degrees C, however, the magnitude and the spatial gradient of temperature may play significant roles. It was found that the temperature elevation in response to the RF heating was closely coupled with local blood flow. The resulting decrease in or stabilization of tissue temperature suggested that blood flow might act as a negative feedback of tissue temperature in a closed control system. Results from this experiment provide insights into the regulation of local perfusion under hyperthermia. The information is important for accurate predictions of temperature during transurethral RF thermal therapy.

Endocrine aspects of development: new challenges for the control of incubation process

An increased knowledge of endocrine systems during incubation not only results in a better understanding of fundamental aspects of embryonic development, but also may lead to new practical applications. A first and immediate aspect is the possibility of early sex diagnosis based on current knowledge of sex determination. The current practice of killing day-old male chicks of layers results essentially from the improved efficiency of modern egg and meat lines, which were selected in opposite directions. The disposal of unwanted male chicks from layer lines causes increased welfare and ethical concern. Therefore, attempts have been made to interfere with sex determination or to identify the unwanted gender of the embryo at a certain stage of development (e.g. based on endocrine differences) where public concern is no longer a point of resistance against elimination. Thyroid hormones as well as glucocorticoids are known to be involved in several events leading to hatch and in the quality of the hatchling. Both seem to be strongly influenced by a common hypothalamic factor in the late chick embryo: corticotrophin-releasing hormone (CRH), CRH-related urocortines or analogues for CRH-receptor activity may be combined with in ovo vaccination for stimulating or synchronizing hatching activity. A next question to be asked is whether incubation conditions that produce the best hatchability also automatically result in chicks of the highest quality with the best desired postnatal performance. During prenatal development, most of the functional systems develop from an open loop system without feedback into a closed control system with feedback. This is already documented for endocrine systems such as the thyroid, the corticotroph and the gonadal axis. For functional systems, critical periods seem to exist and it is presumed that these coincide with the transition from an open into a closed feedback control system. In consequence, variation in incubation conditions such as temperature may induce a lifelong determination of physiological control systems, most probably via long-term changes in the expression of related effector genes and this may be defined as epigenetic adaptation. This opens possibilities to improve incubation conditions, not only in view of hatchability/chick quality but also taking long-term effects into account. Also it may redirect, at least to some extent, development as a function of the aims set forward, e.g. metabolic conditioning.

10506 多入力多出力非線形システムに対するロバスト制御系の一設計法とその応用(Visual Presentation Contest)

The feedback linearization problem is one of the most important control problems for nonlinear systems. Yamada and Nitta propose a design method of approximate linearization method that can apply almost all multivariable nonlinear systems. However their approximate linearization method does not guarantee the stability of the closed control system even if the uncertainty of the plant does not exist. Furthermore the method by Yamada and Nitta does not consider the stability of the closed control system when the uncertainty of the plant exists. In this paper, we examine a design method for robustly stabilizing controllers for multivariable nonlinear systems to which the exact linearization method is not applicable.

Blood perfusion measurements in the canine prostate during transurethral hyperthermia.

Using a thermal pulse decay technique, blood perfusion rates were measured within different regions in the canine prostate under normal and hyperthermic conditions induced either by the microwave or the radio frequency heating. Results indicate that, under the normal condition, the periurethral region is most highly perfused with an average rate of 0.60 +/- 0.25 ml/min/gm (n = 4) while the perfusion rate is 0.34 +/- 0.22 ml/min/gm (n = 10) in parenchyma. An approximately 3.5 fold increase in perfusion from the respective baselines was observed in both regions when the local tissue temperature was raised to 41.5 degrees C by the microwave heating. Another 0.5 fold increase was found in parenchyma after the tissue was further heated to 43.1 degrees C at which oscillatory behaviors in tissue temperature have been observed. To further study the cause of these oscillatory behaviors, the instantaneous blood perfusion response to changes in local tissue temperature was investigated using the radio frequency heating. It has been revealed that blood flow acts as a feedback of local tissue temperature in a closed control system. The thermally stimulated blood perfusion increase appeared to be a function of tissue temperature and its temporal gradient. Results from this study have shown experimental evidences of local thermoregulation in the prostate during hyperthermia.

Convex Optimization Via Feedbacks

Three dynamical systems are associated with a problem of convex optimization in a finite-dimensional space. For system trajectories $ x(t) $, the ratios $ x(t)/t $ are, respectively, (i) solution tracking (staying within the solution set $ X^0 $), (ii) solution abandoning (reaching $ X^0 $ as time $ t $ goes back to the initial instant), and (iii) solution approaching (approaching $ X^0 $ as time $ t $ goes to infinity). The systems represent a closed control system with appropriate feedbacks. In typical cases, the structure of the trajectories is simple enough. For instance, for a problem of quadratic programming with linear and box constraints, solution-approaching dynamics are described by a piecewise-linear ODE with a finite number of polyhedral domains of linearity. Finding the order of visiting these domains yields an analytic resolution of the original problem; a detailed analysis is given for a particular example. A discrete-time approach is outlined.

Minimization of a functional over the set of causal operators of causal Hilbert space

The minimization problem for a quadratic functional defined on the set of nonwarning (causal) operators acting in a causal Hilbert space can be regarded as an abstrat analog of the Wiener problem on constructing the optimal nonwarning filter. A similar problem also arises in the linear control problem with the quadratic performance criterion (in this case the transfer operators of a closed control system serve as causal ones). The introduction of causal operators in filtering theory and control theory is a mathematical expression of the causality principle, which must be taken into account for a number of problems. In the present paper we attempt to systematize the mathematical foundations of the abstract linear filtering theory, for which its basic results are expressed in terms of operators describing the filtering problem. We introduce and study a class of finite operators, a natural generalization of the class of causal operators, and give a solution of the minimization problem for a quadratic positive functional defined on the set of causal operators acting in a “discrete” causal space. Bibliography: 54 titles.

Vibration control for two-link flexible manipulator using a wrist force sensor.

This paper reports on the vibration control of a flexible space manipulator in which the tip deflection of each flexible link is fed back in a closed control system. A simple dynamic model is derived using the static deflection model to derive the system dynamics equations of a flexible manipulator. A force/torque sensor incorporated in the manipulator's wrist is proposed as a new type of sensors to estimate the deflection. To investigate the effectiveness of this control method, a two-link flexible SCARA manipulator system was constructed. This manipulator was 1.5 m long and was floating on a base-plate using air bearings capable of handling a 40kg payload. The experimental results showed that the deflection feedback realized the same effect on the vibration control as the general method of strain gauge output feedback.

Hydraulic Capacity of Control Devices for Water Table Management Systems

In the design of water table management systems, the hydraulic capacity of the drain tubes and the outlet are usually assumed to be adequate to carry drainage and runoff from the fields and, thus, outlet limitations are not addressed. Unfortunately, some of the devices developed for closed control systems may sacrifice a portion of the outflow pipe area in the control mechanism and restrict the outflow rate. Three commercial outflow control devices were evaluated for outflow rate and were compared to a hypothetical flashboard riser system. Each of the devices restricts the flow by about 70% as compared to the flashboard riser when the head is about 0.15 m (0.5 ft). However, at an area of about 0.45 ha (1.11 ac), the flow capacity of the 15 cm (6 in.) tubing will begin to limit the mainline outflow rates for the site and system conditions in the analysis. With proper design, currently-available, commercial flow-control devices will be of sufficient capacity and will not be a limiting factor in determining drainage system performance.

Comparison of Adaptive Control Algorithms of Multivariable Processes with Varying Delays

The report, deals with generalization, estimation and compari son of new algorithms of the digital self-tuning controllers CSTCD design for multivariable production processes with unknown and varying time delays in control channels, the value of which is taken into account in the law of control. The algorithms of STC design are developed for control systems design in chemical and petrochemical industries. They make it possible to design digital STC of optimal structure, to compensate for process’s unknown and varying time delays represented in implicit form, to estimate process delays included in explicit form in STC law of control, to realize multirate sampling of input and output coordinates in separate control loops of multidimensional system, to conduct adaptive tuning of digital STC parameters on the basis of identification in real time varying dynamic parameters of a process with closed control system. The developed algorithms of STC design can be used for linear and nonlinear processes, taking place in determinate and stochastic medium.

Analysis procedure of robot’s loading performance by using actual data

The usage of robots in manufacturing systems is increase. For material handling, the robot loads and unloads a workpiece on and from the given position of a machine, respectively. A robot without a closed control system may fail in such a performance. In order to analyze the stochastic property of the robot’s loading performance, playback accuracy on a given position is measured under given experimental conditions and them a statistical procedure on the measured data is described. run test is used to determine whether the loading failure of any one cycle is random or not. Proposed method using real data of 400 consecutive cycles can be applied to build an analytical model on a manufacturing system using robots as material handling equiplment.