Industrial Environmental Control Research Articles

An Improved Rete Algorithm with Branch Filtration

Environment state estimation and control action determination is the key step in industrial environment control. In some complex environments, decisive factors may be various, and each has multiple thresholds, a large number of matching operations have to be done by the controller, and it is a problem to do all rule judgments quickly and precisely. First, the problem is analyzed and main steps and characteristics of Rete network for estimation of multiple factors are given. Second, the improvement of conventional Rete algorithm, beforehand matching, is analyzed, and then, according to the properties of industrial environments, branch filtration, is introduced based on beforehand matching as a new improvement of Rete algorithm. Finally some tests are carried out, and by comparing with conventional Rete algorithm and the algorithm with beforehand matching, it can be seen that the improved Rete algorithm with branch filtration is effective in reducing unnecessary matching operations.

Tolerating partial failures on IEC 61499 applications

In a modern industrial environment control programs are distributed among several devices. This raises new challenges, especially in handling the failure modes. Automatic reconfiguration is a possible approach in dealing with partial failures. The authors have proposed an IEC 61499 based replication framework for building fault tolerant applications - thus a failure of one sub-component does not to jeopardize the execution of the whole application. The proposed framework is capable of supporting dynamic reconfiguration on all automation levels in an industrial cell in order to patronage a fault tolerant and seamless production line.

An architecture for adaptive fuzzy control in industrial environments

The paper presents an architecture for adaptive fuzzy control of industrial systems. Both conventional and adaptive fuzzy control can be designed. The control methodology can integrate a priori knowledge about the control and/or about the plant, with on-line control adaptation mechanisms to cope with time-varying and/or uncertain plant parameters. The paper presents the fuzzy control software architecture that can be integrated in industrial processing and communication structures. It includes four distinct modules: a mathematical fuzzy library, a graphical user interface (GUI), fuzzy controller, and industrial communication. Three types of adaptive fuzzy control methods have been studied, and compared: (1) direct adaptive, (2) indirect adaptive, and (3) combined direct/indirect adaptive. An experimental benchmark composed of two mechanically coupled electrical DC motors has been employed to study the performance of the presented control architectures. The first motor acts as an actuator, while the second motor is used to generate nonlinearities and/or time-varying load. Results indicate that all tested controllers have good performance in overcoming changes of DC motor load.

Framework for automatic quality control in industrial environments using distributed image processing

(TCP/IP) based, anonymous communication environment is introduced. The main system capabilities are central configurability and maintainability of the image processing nodes and the scalability of the framework. Furthermore a watchdog concept and IEC61131 conform signal integration comprising the Modbus/TCP protocol are integrated within the framework. A communication structure based on the tuplespace concept is presented. The possibility of integrating heterogeneous nodes is achieved by a consistent JavaTM implementation. As a proof of concept, a quality observation task at distributed observation points at a wire rolling mill is introduced. An image-processing algorithm based on least-squares fitting of parallel lines to observe quality relevant parameters is introduced and integrated as an exemplary machine vision implementation within the framework.

A distributed approach to achieve predictable Ethernet access control in industrial environments

This paper presents an overview of a new protocol, called the Predictable Ethernet Access Control protocol (PEAC), which overcomes the unpredictable behaviour of the CSMA/CD, thus guaranteeing deterministic access to the medium to hard real-time traffic. The PEAC is a distributed protocol able to support both hard real-time and non-real-time traffic in an integrated way. The PEAC does not require any modification to the standard hardware, so COTS hardware can be used. The paper outlines the PEAC protocol, presents a timing analysis and shows experimental results obtained in a real scenario.