Zdenek Bradac

Experimental Smart Grid

The paper deals with activities towards a design of a methodology to stabilize already existing electrical grids and at the same time utilize the maximum of electrical energy from renewable electrical energy sources. The authors believe that the first step towards a methodology is to create a thorough model of the electrical grid with connecting most suitable existing renewable as well as classic electric energy sources. There is also described an idea of an experimental smart grid, but the main attention is given to the physical realization of a laboratory model of the smart grid. The authors described an electronic design and an idea of control strategy to enhance a functionality, stability and effectiveness of the grids with a significant share of the renewable energy sources.

Wireless communication in automation

The paper shows the challenges associated with attempts to utilize Bluetooth communication interface for automation purposes like control and data acquisition. The paper describes major challenges, selected approach, first tests, first experiences with Bluetooth on Linux. and first prototypes of embedded devices used for testing. Moreover the paper discusses some specific challenges associated with utilization of wireless communication techniques (focused to Bluetooth) in automation. Finally the paper presents ideas (formal methods) that could be used to analyze, and improve reliability of such system, and approach (time triggered approach with clock synchronization) that could be used to improve the deterministicity of wireless communication channels.

Trends in Automation - investigation in Network Control Systems and Sensor Networks

Abstract Paper deals with two significant trends in the automation and control theory of the last decade. The problems are evoked by a lack between control theory and the automation praxis in the case of Networked Control Systems (NCS) and by penetration of wireless communication used in case of Sensor Networks. Authors define serious theoretical problems in Networked Control Systems analyses in the design of digital control such as non-periodical sampling period, variable delays in control feedback, lower dependability of feedback information and some other issues. Network Calculus is proposed as a possible mathematical and description tool. The paper also mentions an ambitious research program of the Deutsche Forschungsgemeinschaft to develop new theory of the NCS synthesis. In the second part of the paper the Sensor Networks as the new phenomenon in process values measurement and data acquisition systems are described. It is the opinion of the authors, that sensor networks represent totally other look on the utilization of sensors, than represents classical measurement engineering used in data acquisition systems.

On security of PAN wireless systems

This paper describes security features of ZigBee and Bluetooth PAN wireless networks. On examples of those two wireless systems are demonstrated challenges associated with utilization of present wireless systems for applications requiring secure data exchange. Recent penetration of wireless technologies into building and process automation applications even increases the need to fully understand the limitations of the security concepts used.

IMMUNE NAVIGATION CONTROL FOR STIGMERGY BASED FORAGING BEHAVIOUR OF AUTONOMOUS MOBILE ROBOTS

Abstract The paper presents a series of experiments in a simulated environment where two autonomous mobile robots gather randomly distributed objects and cluster them into one pile. The coordination of the robots’ movements is achieved through stigmergy (an indirect form of communication through the environment). In order to avoid the drawback of the random moves, necessary for stigmergy based foraging behaviour, the perceptive capabilities of the robots are enhanced by detectors for concentration of objects. An artificial immune network carries out the collision free goal following behaviour. Simulations confirm the improved performance of the foraging behaviour under the proposed immune navigation control.

Stabilisation of low voltage distribution networks with renewable energy sources

Abstract Recent development in the area of renewable energy sources (RES) shows, that situation in countries supporting a great growth of RES, particularly photovoltaic, leads to big problems. Modelling studies show that in a very near future there will be a big surplus of electrical energy production in networks of NN (low voltage networks). It would evoke necessity to transfer energy into higher voltage networks. However it will not be possible while protection systems of high voltage networks are developed for the opposite flow of energy. Contribution deals with possible solution of stability of NN distribution networks by means of smart metering – smart grid system. Proposal of electronic instrumentation of measurement and control is presented in the contribution.

Models of Pilot Behavior and Their Use to Evaluate the State of Pilot Training

Abstract This article discusses the possibilities of obtaining new information related to human behavior, namely the changes or progressive development of pilots’ abilities during training. The main assumption is that a pilot’s ability can be evaluated based on a corresponding behavioral model whose parameters are estimated using mathematical identification procedures. The mean values of the identified parameters are obtained via statistical methods. These parameters are then monitored and their changes evaluated. In this context, the paper introduces and examines relevant mathematical models of human (pilot) behavior, the pilot-aircraft interaction, and an example of the mathematical analysis.

Personal Navigation Algorithms Based on Wireless Networks and Inertial Sensors

Abstract The work aims at a development of positioning algorithm suitable for low-cost indoor or urban pedestrian navigation application. The sensor fusion was applied to increase the localization accuracy. Due to required low application cost only low grade inertial sensors and wireless network based ranging were taken into account. The wireless network was assumed to be preinstalled due to other required functionality (for example: building control) therefore only received signal strength (RSS) range measurement technique was considered. Wireless channel loss mapping method was proposed to overcome the natural uncertainties and restrictions in the RSS range measurements The available sensor and environment models are summarized first and the most appropriate ones are selected secondly. Their effective and novel application in the navigation task, and favorable fusion (Particle filtering) of all available information are the main objectives of this thesis.

Protocol gateways for HART sensors

Abstract The paper presents description of three different protocol gateways for interfacing HART pressure sensors. The gateways have been designed, programmed and realized as hardware prototypes. The first gateway is a wireless transducer between the HART interface of the sensor and a Bluetooth network. The second gateway connects the sensor to an Ethernet network with Modbus protocol. The third gateway is a wireless transducer for ZigBee networks. The gateways are based on embedded microcontrollers with the required interfaces. The software implementation is done in C using protocol libraries. Hardware and enclosure are designed for industrial applications. The gateways are adapted for use with HART pressure sensors.

Reliability Analysis of Systems with a Complex Structure Using Monte Carlo Approach

Abstract Nowadays the systems have often a complex structure and it is relatively difficult to ensure their reliability. Therefore it is important to predict reliability of systems already at design phase. This way is suitable for the prevention of the frequently failures. Prevention of frequently failures means a higher lifetime and cost savings for producer. This paper deals with a modern approach of quantitative reliability analysis – using the Monte Carlo statistical reliability analysis and its comparison with the conventional approaches. The Monte Carlo method is explained at a fundamental level with emphasis on its application in reliability analysis of systems with a complex structure.