Perm National Research Polytechnic University

The following strategies for tuning a spinning sound mode generator are considered: 1) maximizing the dynamic range between the target mode and the other modes in the duct; 2) minimizing the discrepancy between the calculated and experimental distribution of acoustic pressure at the microphones in the duct; 3) minimizing the discrepancy between the calculated and experimental distribution of acoustic pressure at the far-field microphones. A generator of 8 acoustic drivers with a circular cross-section duct with a diameter of 0.23 m was used. Measurements were carried out with both microphones installed flush into the duct wall (a circular array of 20 microphones, an axial array of 11 microphones and 8 additional microphones) and far-field microphones (10 microphones were installed on an arc with a radius of 2 m from the axis of the generator duct section center in the range of the polar angle varying from 0 to 90 degrees in equal increments). The experiments were conducted in an acoustic anechoic chamber at PNRPU. It was established that all the proposed strategies for tuning the spinning sound mode generator are feasible, because in all cases, when tuning the generator, it was possible to improve the considered characteristics of the sound field (increase the dynamic range of the target mode or obtain the distribution of sound pressure over the microphones closer to the calculated one) relative to the initial state.

Transforming MXene Impurities into Luminescent Assets Laser irradiation transforms aluminum impurities of MXenes into embedded ruby centers featuring narrowband luminescence. This technique offers minimally destructive grain-resolved purity control, repurposing flaws into functional probes. More details can be found in the Research Article by Ilya A. Zavidovskiy, Valentyn S. Volkov, Sergey M. Novikov, Alexey D. Bolshakov, and co-workers (DOI: 10.1002/adom.202501407).

This article addresses the development of algorithms for automatic mobile robot motion control in static environments with obstacles, aiming for safe and effective navigation to a target while avoiding collisions. It compares two key approaches: finite automata, characterized by discrete switching between "move to goal" and "obstacle avoidance" states, and fuzzy logic, which enables smoother transitions and adaptive control under sensor uncertainty. An original Logical-Dynamic Automatic Control System based on fuzzy logic principles is proposed. This system utilizes three specialized fuzzy controllers: an obstacle avoidance controller using data from three lidar sensors (right, left, center); a goal-seeking controller operating on the robot’s angular deviation from the target; and a group fuzzy controller-coordinator. The coordinator dynamically weighs and combines the control actions from the first two controllers, prioritizing obstacle avoidance when necessary. The proposed LogicalDynamic Automatic Control System’s effectiveness was evaluated through computer simulations in MATLAB Simulink using the Mobile Robotics Simulation Toolbox. А differential drive robot’s motion was simulated in environments containing various static obstacles. Performance was compared against a baseline finite automaton model using metrics such as trajectory length, time to reach the goal, average speed, and an integral objective function. The simulations demonstrated that the LogicalDynamic Automatic Control System provides smoother wheel angular velocity changes, reduces abrupt mode switching, and enhances overall control efficiency by 2.22 % compared to the automaton-based approach, highlighting its potential for practical application. This fuzzy logic approach shows promise for real-world robotic systems.

The influence of the initial roughness Ra of the working surface of a 3D-printed tool electrode on the quality of the machined workpiece surface is studied experimentally in the copy piercing electrical discharge machining of 12Kh18N10T stainless steel; the tool electrode is produced by selective laser machining (SLM). Preliminary machining of the tool electrode’s working surface reduces the roughness Ra of the machined surface by 6–8%. The initial roughness Ra of the working surface has no influence on the microrelief of the machined surface (the crater morphology and the defect distribution).

This study is dedicated to determining the propagation parameters of radio signals both inside and outside the pipeline space at carrier frequencies of 2.4 and 5 GHz. The most efficient equipment for transmitting and receiving signals within the pipeline space was identified as “Mikrotik.” The minimum signal level at the frequency of 2.4 GHz was found to be –18 dBm, and at 5 GHz, –26 dBm in a pipeline 40 m long. The dependences for determining the signal level inside the pipeline space based on the distance of the in-pipe robotic complex were presented, taking into account correlation coefficients of the radio signal for the in-pipe environment. During data transmission and reception, the signal level did not drop below –68 dBm or –61 dBm at 2.4 GHz over distances up to 2100 m. For data transmission and reception at 5 GHz, the signal level did not fall below –80 and –74 dBm.