Lyubomyr Demkiv

Lviv Polytechnic National University · Institute of Power Engineering and Control Systems

An application of stereo thermal vision to perform preliminary inspection operations of electrical power lines by a particular class of small Unmanned Aerial Vehicles (UAVs), aka Micro Unmanned Aerial Vehicles (MAVs), is presented in this paper. The proposed hardware and software setup allows the detection of overheated power equipment, one of the...

In this paper, we describe a system for combating real fires with sprayed liquid extinguishing agent using a team of multirotor UAVs. The system design relies on onboard sensors and operates without the need for human intervention throughout its complex mission, from its takeoff to landing. The core UAV platform can estimate its state, self-localiz...

Large enough structured neural networks are used for solving the tasks to recognize distorted images involving computer systems. One such neural network that can completely restore a distorted image is a fully connected pseudospin (dipole) neural network that possesses associative memory. When submitting some image to its input, it automatically se...

An application of stereo thermal vision to perform preliminary inspection operations of electrical power lines by a particular class of small Unmanned Aerial Vehicles (UAVs), aka Micro Unmanned Aerial Vehicles (MAVs), is presented in this paper. The proposed hardware and software setup allows the detection of overheated power equipment, one of the...

In this article, a fuzzy controller tuned by reinforcement learning is proposed. The developed algorithm utilizes a fuzzy logic theory and a reinforcement learning for fine-tuning parameters of the membership function for the fuzzy controller. Apart from the fuzzy controller developed, a fuzzy corrector of reference input (set-point) signal to the...

In deformable terrain conditions, the tire-surface gripping may be characterized by drastic, rapid, and frequent changes, and, thus, the response time of traction control systems (TCS) of off-road vehicles is crucial for real-time mobility improvements. To advance TCS performance, the time boundaries for the TCS response time is established in the...

A fast convergence speed of an observer helps improve the capability to track the states of a system for an arbitrary divergence between a real and an estimated initial conditions. This property of the observers is significantly useful if a system has fast dynamics and its states change rapidly. Thus, the convergence time is one of the main perform...

Existing literature on vehicle traction dynamics were reviewed for a variety of vehicle and tire dynamic models, some of which consider the pneumatic tires’ relaxation as a property of vehicle transient dynamics. In general, unlike the lateral relaxation counterpart, the longitudinal tire relaxation characteristics were mostly overlooked in tire tr...

Some sensors in electronic controls may be not available or not feasible for terrain vehicle applications due to severe environmental conditions. The ultimate goal of this paper is to study and demonstrate a possibility to reduce the dependence of terrain mobility controls from sensors. The approach is based on designing reliable observers that can...

Various vehicle and tire dynamics models with different levels of complexity have been developed and used for predicting and studying vehicle traction and handling. This paper offers an overview of research work that was done on the tire relaxation length and time constant in the longitudinal and lateral directions with regard to tire/vehicle tract...

In modern ground vehicle electronics (traction control, torque vectoring systems) with a response time of 100msec to 160msec, the actual control occurs after the vehicle has reached a critical motion situation. Thus, these systems can introduce negative effects of tire-soil power losses, loss of terrain mobility, and unstable motion rather than pre...

Dynamic system with nonlinearities has been considered. This system has been divided into a set of linear subsystems. A fuzzy controller of the considered system has been synthesized. It takes into account nonlinearities of the system and provides smooth switching between controllers of the linear subsystems. An unstable subsystem has been utilized...

In this paper a dynamical system with variable coefficients is considered. For it a subset of subsystems is constructed. Each subsystem is obtained via Tailor series expansion. For each subsystem a desired control is synthesized. To synthesis control of the total system fuzzy logic controller is used. Stability analysis of investigated system is he...

A two-mass fuzzy control system is considered. For fuzzification process, classical both linear and nonlinear membership functions are used. To find optimal values of membership function’s parameters, genetic algorithm is used. To take into account values of both output and intermediate parameters of the system, a penalty function is considered. Re...

Purpose. To improve the dynamic performance of the of the arc furnaces electrode movement automatic control system with acceptable overshoot of interjacent coordinates. Methodology. Fuzzy sets for the synthesis of control actions in certain points of the state space are applied. For the values of interjacent coordinates to be within acceptable limi...

For electrodes movement system of arc furnace impact of nonlinearities on the system is analyzed. Fuzzy controller, which provides a quick pass of the system to steady state at the absence of fluctuations in the output system's coordinate, is synthesized. To reduce a complexity of the rule base, a natural fuzzy controller is used. To synthesis the...

A new approach for construction of quality functional at multicriteria optimization is proposed. A two-mass dynamical system which consists of two subsystems is considered. A case when in the area of large errors unstable subsystem dominates is considered. Function L is chosen for switching between subsystems and its optimal parameters are found.

A dynamic system consisted of two subsystems, one of which is unstable is considered. The influence of fuzzy regulator’s membership function type on the electromechanical system is investigated. The optimum values of membership functions parameters are found.

У першій частині даної роботі, на прикладі двомасової системи, розглянуто принцип побудови системи керування, що поєднує властивості двох підсистем керування за повним вектором стану. Досліджено стійкість загальної системи в залежності від стійкості кожної з підсистем, з яких вона складається.

Poisson equation in polyhedral domain Ω ⊂ R n , n = 2,3 with boundary Γ, when Dirichlet conditions are given on all faces or on all but one where Neimann conditions are given, is considered. Traditional difference schemes with semi-constant steps along axes precisely approximate Dirichlet conditions hence it is expected that their accuracy order in...

The main goal of this paper is to generalize the results, obtained in [1] to the case of quasi-linear ordinary differential equations of the second order with the third kind boundary conditions. It is a continuation of the paper series in which we have obtained weight a priori estimates of accuracy for difference schemes for linear parabolic type e...

While solving the elliptic equations in the canonical domain with the Dirichlet boundary conditions by the grid method, it is obviously, that boundary conditions are satisfied precisely. Therefore it is necessary to expect, that close to the domain boundary the accuracy of the corresponding difference scheme should be higher, than in the middle of...

For difference schemes the initial-boundary problem for quasi-linear parabolic-type equations, ’a priori weight estimates’ of the error have been found. These estimates show how much the accuracy of difference schemes near the boundary of a time rectangle is higher than in the middle of it. Sufficient conditions of smoothness of the coefficients an...