Simulation and predictive control of the gas transportation system in a large industrial zone

The article describes an approach to the operational and supervisory control of a gas transmission system for large industrial zones using a model predictive control, as well as analytical and simulation methods. The operational and supervisory control of the gas transportation system covers the time horizon from several hours to several days and involves performing several cyclically repeated actions. The authors propose a time series predictive model of the gas consumption parameter considering temperature weather conditions, which is extended based on accounting for the correlation relationships between the consumption volumes of each consumer. The control methods used today, reacting to the current deviations from the planned regime, a priori do not allow achieving the best results. A significant increase in the stability of control and a reduction in the cost of fuel and energy resources can be achieved by using the control method based on predictive models. In this case, the control object model is used to predict its behavior within the selected time horizon, and optimal control actions are selected on this basis. The process of predicting and selecting control actions is periodically repeated, constantly changing the time horizon boundaries. The described method of changing the flow diagram consists either in changing all the flows at the same time or in a preemptive and smooth transition based on the introduction of a weighted flow diagram for various stationary modes, provided that their mismatch is minimized at neighboring time intervals corresponding to the intervals of constancy of consumption requests.

Influencia de la telemetría en la competitividad del servicio de transporte de gasoducto virtual

La finalidad investigativa de este artículo es determinar la influencia del sistema de telemetría en la competitividad del servicio de transporte de Gasoducto Virtual, ya que la telemetría nos permite optimizar el desempeño de las operaciones, facilitando la gestión de la empresa elevando la productividad mediante el sistema de Supervisión, Control y Adquisición de Datos (SCADA; en inglés, Supervisory Control And Data Acquisition) y el Sistema de Posicionamiento Global (GPS; en inglés, Global Positioning System), Para ello, la metodología empleada es tipo aplicado, con enfoque cuantitativo, diseño no experimental de corte transversal, además, su método es hipotético-deductivo y desarrolla un nivel correlacional. Para esta investigación se aplicó un instrumento de tipo encuesta, a una muestra de 31 clientes de la empresa de transporte El Gran Z. que fue revisado y certificado por juicio de expertos, Cronbach en 0.966; este valor indica que es altamente fiable. El resultado al que arriba esta investigación es que existe una influencia significativa del sistema de la telemetría (SCADA y GPS) en la competitividad del Servicio de transporte de GNC.

Rare roll event modeling of unmanned catamaran

Статья посвящена вопросу моделирования редких событий, которые возникают при качке катамарана. Система управления автономного катамарана должна уметь распознавать нежелательные ситуации, которые могут привести к осуществлению редких событий. В данной статье приводится несколько методов, позволяющих проводить моделирование редких событий и делать оценку риска возникновения редкого события. Методы основываются на теории больших уклонений. Первый метод позволяет оценить возможные «ожидаемые потери» при достижении редкого события путём оценки скорости убывания вероятности компонентов вектора состояния в редком состоянии. Оценка осуществляется путём расчёта квазипотенциалов из аттрактора до порогового значения состояния. Второй метод позволяет оценить вероятность движения вдоль наиболее вероятной траектории к редкому событию. Оценка осуществляется путём сравнения вектора состояния с состояниями на наиболее вероятной траектории к редкому событию. Точность оценок зависит от вектора состояния. Приводится сравнение с результатами, полученными с помощью метода Монте-Карло. Указанные методы могут быть использованы для создания систем супервизорного управления и систем поддержки принятия решений при оценке рискованности совершения морских переходов. The article is devoted to the issue of modeling rare events that occur when a catamaran is pitching. The control system of an autonomous catamaran should be able to recognize undesirable situations that can lead to the rare events. This article provides several methods for modeling rare events and making estimation of risk of a rare event occurrence. The methods are based on the large deviations theory for dynamical systems. The first method allows to estimate possible losses via calculation of the probability decreasing rate of the state vector components in a rare state. The estimation is carried out by calculating the quasipotential from the state close to the attractor to the threshold state. The second method allows to estimate the probability of moving along the most likely trajectory to a rare event. The evaluation is carried out by comparing the studied state vector with the states on the most likely trajectory. The accuracy of the estimates depends on the studied state vector. A comparison with the results obtained using the Monte Carlo method. These methods can be used to create supervisory control systems and decision support systems when assessing the riskiness of sea navigation.

Machine Learning Based Approach to a Crane Load Estimation

In the presence of increasing demands for safety and efficiency of material handling systems, the development of advanced supervisory control, monitoring, data acquisition and diagnostic systems is involved, especially for large industrial cranes. The important part of such systems is the continuous monitoring of a crane load. The crane load monitoring system proposed in the paper is based on a fuzzy model that estimates a payload mass transferred by a crane based on measuring the crane girder deflection and trolley position. The model was identified using the fuzzy subtractive clustering and least mean square with the data collected during experiments carried out on the laboratory scaled overhead crane.

Electric Power Steering Power Circuit Health Assessment and Mitigation Strategy

With recent developments of energy efficient design and control for electric motors, electrical subsystems and components have become integral parts of main actuators in vehicle systems (e.g., steering and propulsion systems). To ensure proper vehicle operations, it is important to make sure that electrical power is properly transmitted through the power circuit from vehicle power source to the electric motor. However, degradation in the power circuit health, which often manifests itself as increased resistance, may affect power transmission and degrade the system performance. For example, in Electric Power Steering (EPS) systems, if the EPS power circuit resistance is increased and the EPS is drawing power to assist the driver, voltage at the EPS module will drop significantly, causing the EPS to reset and, consequently, Loss of Assist (LOA) incidents. Due to compliance in the steering system and suspension design, drivers often feel that the steering system is fighting back when an LOA incident occurs. While previous work has partially addressed this issue by developing algorithms that estimate resistance increase in EPS power circuits, this paper further validates and refines the algorithms for vehicle on-board and off-board implementations using test drive data collected. Since on-board and off-board implementations impose different limits on signal sampling rates, a total of 250 and 465 minutes of data are respectively collected with various vehicle speeds and steering maneuvers. Moreover, a supervisory control solution, referred to as EPS Anti-Loss-of-Assist (ALOA), is proposed that gradually and proactively reduces EPS torque assist as resistance in the EPS power circuit increases so that the EPS voltage is kept above a resetting threshold. Stationary steering tests of the proposed solution as well as demonstrations on parking lot maneuvers at General Motors Milford Proving Grounds are conducted. The stationary steering tests and demonstrations show that, with the proposed supervisory control, negative effects of increased EPS power circuit resistance can be mitigated without noticeable changes in normal driving experience.

Online Activation and Deactivation of a Petri Net Supervisor

This paper highlights algebraic and mathematical properties in symmetry with Petri nets in order to control automated systems such as flexible workshops, which represent one of the most important examples in industry and for discrete event systems in general. This project deals with the problem of forbidden state transition by using a new application of the theory of regions for supervisory control. In the literature, most control synthesis methods suffer greatly from a cumbersome calculation burden of the Petri net supervisor given the complex exploration of the state graph. Our new methodology lightens the computational load of the Petri net supervisor by choosing specific regions on the reachability graph, on which the control is calculated offline using CPLEX. The determined controller is activated online if the process enters the chosen region, and deactivated otherwise. All our experiments were applied in a flexible workshop implemented in our research laboratory, which was used to engrave selected models on glass blocks of different colors.