The main aim of this article is to present the usage of type-2 fuzzy logic controller to control a shape memory actuator. One of the main advantages of the fuzzy systems is that they do not require creating any mathematical model of the controlled plant which simplifies the control task. However, a dynamic system model was created to adjust the proportional–integral–derivative controller parameters. Different types of controllers were tested experimentally by controlling the position of the commercially available shape memory alloy actuator NM70 made by Miga Motor company. Despite its small size, it distinguishes itself by its strength. To enhance real-time performance, simplified interval fuzzy sets were used. The algorithm was implemented in the ATmega32 microcontroller. The dedicated PC application was also built. The obtained results confirmed that type-2 fuzzy controller performed efficiently with a nonlinear plant which is difficult to control. The research also proved that interval type-2 controllers, which are a simplified version of the general type-2 controllers, are very efficient. They can handle uncertainties without increasing drastically the computational complexity. Experimental data comparison of the proportional–integral–derivative reference with the fuzzy logic controller type-2 and type-1 clearly indicates the superiority of the former, especially in reducing overshooting.

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 Young's 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.

The measurement of stress in concrete structures is a complex issue. This paper presents a new measurement system called a self-acoustic system (SAS), which uses frequency measurements of acoustic waves to determine the condition of concrete structures. The SAS uses a positive feedback loop between ultrasonic heads, which causes excitation to a stable limit cycle. The frequency of this cycle is related to the propagation time of an acoustic wave, which directly depends on stresses in the test object. The coupling mechanism between acoustic wave propagation speed and stress is the elastoacoustic effect described in this paper. Thus, the proposed system enables the coupling between the limit cycle frequency and the stress degree of the concrete structure. This paper presents a machine learning algorithm to analyse the frequency spectrum of the SAS system. The proposed solution is a real-time classifier that enables online analysis of the frequency spectrum from the SAS system. With this approach, an autonomous system for stress condition identification of concrete structures is built and described.