Ireneusz Dominik

Low Frequency Damage Analysis of Electric Pylon Model by Fuzzy Logic Application

The paper presents a proposition of a new method for calculating the damage degree of electric pylon model by fuzzy logic application. Damage changes in constructions manifest themselves in small but detectable variations of frequency. The change of the speed of wave propagation, which is associated with the change of the natural frequency in the system, is caused by the deformation of the examined material. This phenomenon can be used for an indirect analysis of the construction damage. The main aim of the article is presentation of the results of the vibrations analyse of the electric pylons. In the preliminary tests the research was conducted on the simulation data of the electric pylon of power grid. Eight construction elements of pylon in different positions were chosen to simulate the damage by decreasing step by step the Youngs modulus. The simulation data was obtained on the basis of the stiffness matrix updated in conjunction with the Finite Element Method. The preliminary research presented in the paper is aiming at creating the software which can monitor in real time the state of electric pylons.

Implementation of the Type-2 Fuzzy Controller in PLC

The main aim of the presented research work was to develop type-2 fuzzy logic controller, which by its own design should be “more intelligent” than type-1. Along with the intelligence it should provide better results in solving a particular problem. Type-2 fuzzy logic controller is not well-known and it is rarely used at present. The idea of type-2 fuzzy logic set was presented by Zadeh in 1975, shortly after the presentation of type-1 fuzzy set. At the beginning scientists and researchers worked on type-1. Only after developing type-1 the attention was directed towards the type-2. The first applications of type-2 fuzzy logic in control appeared in 2003. The fuzzy logic controller type-2 was tested experimentally by controlling a non-linear object: a shape memory alloy (SMA) actuator DM-01PL, made by Miga Motor company, which despite small size distinguishes itself by its 9 N strength. Comparison of experimental data of the fuzzy logic controller type-2 and type-1 clearly indicates the superiority of the former, particularly in reducing signal overshoots.

The SMA Wires Application in the Braille Monitor

The main aim of the research was to establish whether SMA wires are suitable to build a Braille tactile display. The particular goals were to design, fabricate and programme a device, which would be cheap, convenient and easy to use, and would work independently from the PC. The prototype was to have one letter at least and be ready to add more letters in the future. In the article the conception of the prototype design is presented. The single pin was designed in the shape of a vertical cylinder of 3 mm in diameter. A significant disadvantage of modern Braille monitors is the length of the piezo crystals that prevents engineers from building large matrices. Thanks to SMA wires the possibility to build a large matrix is unlimited. Having built a Braille letter prototype the research on the selection of an appropriate control method was launched. Eventually, it was decided that all of the control tasks would be covered by one single chip – the PIC18F4455 processor. This unit had all the necessary peripherals, such as USB, timers, as well as enough speed to run the software. The designed device has proved that SMA wires can be used for this kind of application [2]. It has also demonstrated that graphic Braille monitors can be built. In the current stage of research, this design is not ready for mass production, but additional research can lead to the improvement of this device.

Self-Excited Acoustical System for Stress Measurement in Mass Rocks

The paper is devoted to theoretical end experimental studies of the low-frequency Self-excited Acoustical System (SAS), which allows monitoring stress changes in various elastic media including metals, concrete and mass rocks. The main principle of the SAS system is using a vibration exciter and vibration receiver placed on a sample with a positive feedback, which causes the excitation of the system. Stress changes manifest themselves in small but detectable variations of resonance frequency which can be used to indirectly measure stress changes in the material. In the paper the considerations concerning working frequency of SAS were performed. It was suggested that in the case of stress variation in mass rock monitoring, the low frequency (even infrasound) band should be selected, in contrast to the stress monitoring in columns of marble or concrete, where frequencies from an acoustic band should be used. Computer simulations conducted in the MATLAB-Simulink environment were based on the research performed in the laboratories. They focused on finding a relationship between the compressing force and velocity of sound in a specimen made of concrete. Results of the simulations allowed to state that the frequency of self-excited oscillations of simulated SAS change linearly with the pressing force. In the next step the laboratory experiments were carried out. The impact on stress measurement parameters such as: the position of sensors, actuator, and the influence of geometrical shape and dimensions of the sample. A sample of sandstone compressed in a frame by a hydraulic press was used in the study. The results proved the applicability of the design system. Additionally, the new possible applications of SAS were suggested, such as monitoring stress variations of stresses in mass rock, particularly in the active seismic zones.

Advanced Controlling of the Prototype of SMA Linear Actuator

During research on SMA wires the prototype of linear position actuator was built. The shape memory alloy (SMA) wires used in construction of the actuator are nonlinear and time variant. Thus, it was decided to use a fuzzy controller to control the actuator. However, because of the nature of SMA wires which work by changes of their temperature, after a few minutes of continuous work the actuator did not work accurately. In other words, the existing singleton values in a knowledge base were inappropriate. That is why each time after longer continuous work of the actuator it was needed to manually find and change the mentioned values. It took a lot of time and effort so eventually it was decided to create a real time auto-tuning algorithm which could identify crucial parameters of the actuator each time when it was needed. Together with initial values learning algorithm the advanced controlling of SMA actuator was created.

Application of the Ionic Polymer-Metal Composite Sensor Array Indisplacement Measurement

An Ionic Polymer-Metal Composite (abbr. IPMC) is a type of a smart materialconsisting of two layers of noble metal and an ion-conducting layer between them. Smart ma-terials are generally capable of actuating and sensing. Mechanical deformation of the IPMCbeam produces an electric potential di erence (in the order of mV) proportional to the tipdisplacement on the electrodes. In this paper, the sensing capabilities of IPMC samples will beinvestigated. The composites are manufactured in a form of a thin (0.3 mm) plate, which arecut into rectangular samples. Tests will be performed on separate samples and two electricallyconnected samples. Response to various frequencies will be tested for each sample and for twomechanically and electrically coupled samples, creating a simple sensor array.

Laboratory Research on Energy Harvesting of Ionic Polymer Metal Composite

The aim of this paper is to present the results of laboratory research on Ionic Polymer-Metal Composite (IPMC), in context of energy harvesting applications. IPMC is a novel type of material, a smart polymer, which can work as a sensor or an actuator. One of its biggest advantages is low actuating voltage of about 4V (with 120mA current), what makes it very energy-efficient. Step response for various input amplitudes of two IPMC samples is shown. Also, a voltage generated in response to mechanical deformation of the composite is measured, and a hysteresis loop is plotted. Lastly, the changes of properties of the IPMC caused by long-term actuation are researched. These results are necessary to build an energy harvesting system utilizing IPMC. A simple gripper built with IPMC is also presented.

Interval Type-2 Fuzzy Logic Control of DM Series Shape Memory Actuator

In the article implementation of type-2 fuzzy controller in a microprocessor Arduino is described. The interval type-2 fuzzy sets were used to shorten the cycle time of the algorithm. The type-2 fuzzy logic controller was tested experimentally by controlling position of the shape memory alloy actuator DM series produced by Miga Motor company, the worldwide leader in the field of shape memory alloys applications. The actuator despite small size distinguishes itself by its strength. The obtained results confirmed that type-2 fuzzy controller performed efficiently with difficult to control nonlinear plant. The implemented algorithm can handle uncertainties without increasing drastically the computational complexity. To reduce the response time of the control system an additional accelerating pulse was added to the algorithm.

Fuzzy Logic Control of Rotational Inverted Pendulum

The rotational inverted pendulum is a structure that was primarily developed by Katsuhisa Furuta. It is widely used thorough the control laboratories to demonstrate the effectiveness of nonlinear control algorithms. The rotational inverted pendulum is a nonlinear system of fourth order with a single input variable. In this article the full dynamic equations of motion of the rotational inverted pendulum are derived using Lagrangian formulation. Consequently, a comparison of obtained mathematical model with other models described and available in literature is conducted by means of computer simulations. Eventually, a complete energy build-up swing-up algorithm and fuzzy stabilization algorithm for the system are developed. The control algorithm is then implemented on a PLC device in order to control the existing laboratory stand available at the Department of Process Control [1]. The algorithm is implemented with the use of ladder logic and structured text programming language. The robustness of elaborated balancing control is verified by subsequent real-time tests conducted on the laboratory stand.

Fuzzy Logic Controller for Position Actuator SMA

Shape Memory Alloys SMA attracts more and more interest and nowadays many research centers are working on developing more accurate and applicable actuators. A tangible effect of using SMA materials is considerable simplification of the constructions used so far, which entails obvious economic benefits. Along with the increase in the volume of production and decrease in the cost of production, SMA materials become increasingly available on the consumer market. In the article the use of SMA wire to build and control linear position actuators was presented. The SMA actuator is characterized by one of the highest in technology weight ratios, which describes the ratio of maximum external load to its own weight. It allows for building miniature devices which are extremely efficient. Generally SMA wires are applied as on-off objects. After initial research and building several prototypes the gear transmission was chosen. It was decided to realize an actuator which can work in both directions of displacement, and so allow for the elimination of a return spring, which is a unique solution.