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Growth in application fields of unmanned aerial vehicles (UAVs) and an increase in their total number are followed by higher and higher expectations imposed on improvements in UAV propulsion and energy management systems. Most commercial vertical takeoff and landing (VTOL) UAVs employ a constant pitch propeller that forces a mission execution tradeoff in the majority of cases. An alternative solution, presented here, consists of the use of a variable pitch propeller. The paper summarizes experimental measurements of the propulsion system equipped with an innovative variable pitch rotor. The investigations incorporated characteristics of the rotor for no wind conditions and a new approach to optimize pitch settings in hover flight as a function of UAV weight and energy consumption. As UAV battery capacity is always limited, efficient energy management is the only way to increase UAV mission performance. The study shows that use of a variable pitch propeller can increase the maximal takeoff weight of the aircraft and improve power efficiency in hover, especially if load varies for different missions. The maximal thrust measured was 31% higher with respect to the original blade settings. The coefficient of thrust during hover showed an increase of 2.6% up to 7.5% for various pitch angles with respect to the original fixed propeller.

In this paper, the authors present a novel construction of an automatic balancing device applicable to balancing shafts working in a heavily polluted environment. The novelty of the presented system lies in the fact that its utilization requires no changes to be made in the already existing shafts. Also, the system is capable of working during the operation of the balanced shaft, so there is no need to stop it. The propulsion system is based on eddy current braking, therefore no wires need to be used in the device. During the development process of the system, three iterations of the device were created. Each iteration is presented, described, and discussed. The advantages and drawbacks of each version are pointed out and explained thoroughly. The correctness of the design was verified by the created devices that were assembled and fixed on shafts to prove the design assumptions.

This paper presents an analysis of acoustic emission and performance data of a UAV rotor equipped with a variable pitch propeller. The proposed study aims to show propeller noise features that indicate stall flow regime on the blade. Analysis of the noise characteristics around the propeller in terms of power spectral density allow to detect the stall. The study shows that a microphone located at different angles around the propeller can provide data sufficient to determine if the blade angle of attack has forced the propeller into the stall regime. In this range, the propeller’s efficiency in hover decreases and leads to an increase in power consumption. The reresearch is a suggests a method of data treatment to obtain a single parameter indicating a blade stall.

The developments in surgical robotics suggest that it will be possible to entrust surgical robots with a wider range of tasks. So far, it has not been possible to automate the surgery procedures related to soft tissue. Thus, the objective of the conducted studies was to confirm the hypothesis that the surgery telemanipulator can be equipped with certain routines supporting the surgeon in leading the surgical tools and increasing motion accuracy during stereotypical movements. As the first step in facilitating the surgery, an algorithm will be developed which will concurrently provide automation and allow the surgeon to maintain full control over the slave robot. The algorithm will assist the surgeon in performing typical movement sequences. This kind of support must, however, be preceded by determining the reference points for accurately defining the position of the stitched tissue. It is in relation to these points that the tool's trajectory will be created, along which the master manipulator will guide the surgeon's hand. The paper presents the first stage, concerning the selection of movements for which the support algorithm will be used. The work also contains an analysis of surgical movement repeatability. The suturing movement was investigated in detail by experimental research in order to determine motion repeatability and verify the position of the stitched tissue. Tool trajectory was determined by a motion capture stereovision system. The study has demonstrated that the suturing movement could be considered as repeatable; however, the trajectories performed by different surgeons exhibit some individual characteristics.