Modelling of Forces Acting on a System of the UAV Launcher, Based on Passive Magnetic Suspensions with Superconductors

Modern sea operations used for exploration and reconnaissance purposes are becoming more and more dependent on unmanned air vehicles (UAV). With the development of an increasing number of UAVs directed to the needs of the navy, various take-off and landing systems are being tested. An alternative to the traditionally used catapults is magnetic catapults, which enable continuous power control, properly increasing the acceleration of the starting machine and at the same time enabling full automation of the launching process. The paper presents the developed of the physical model and theoretical analyzes the forces and torques acting on the launcher system using passive magnetic suspensions with high-temperature superconductors. The launcher was modeled as a configuration of three elements: tracks built from neodymium magnets generating the magnetic field, a starting cart driven by a linear engine and a UAV taking off or landing on the launcher cart. The set of assumptions regarding the characteristics of the environment, the structure of the system elements, kinematic constraints were made. The article consists also the theoretical analysis of external interactions having a decisive influence on the dynamics of the system. The analysis considers the couplings resulting from mutual interactions of individual elements of the system. Theoretical considerations were supplemented with a comparative analysis of numerical and experimental studies of the UAV launch process from the launcher which allowed the verification of the key parameters of the analyzed forces

Koncepcja wykorzystania czujników Halla do pomiarów pola magnetycznego ponad torami wyrzutni magnetycznej

The growing demand for commercial unmanned aerial vehicles (UAV) requires that innovative technical solutions for the critical aspects of UAV servicing, must be researched. The magnetic catapult discussed in this work is an interesting alternative to the existing UAV deployment or launch platforms. This paper presents the research designed to facilitate the measurement and analysis of the position of a launch truck applied in a UAV magnetic catapult with tracks. The measurement system discussed herein comprised a transducer connected to Hall sensors which were spaced evenly at the base of a superconductor pod. A displacement of the superconductor pod relative to the magnetic field resulted in the variation of the voltage output from individual Hall sensors. A proprietary algorithm was developed and controlled stepper motors which displaced the assembly of the superconductor pod with the Hall sensors along the test track of the UAV magnetic catapult. At the same time as the displacement was sensed by the Hall sensors, they were reading the real-time magnetic strength; it was therefore critical for the microcontroller, which executed the control algorithm, to operate at a sufficient processing frequency (speed). The proprietary control algorithm was executed by an ATMEL ATmega2560 RISC processor. The processor system read the status of every Hall sensor in the assembly and compared it to the reference voltage outputs stored in the microcontroller’s memory. The difference between the voltage output reading and the reference voltage outputs and the superconductor pod’s geometry was used to determine the superconductor pod’s position along the magnetic tracks of the UAV magnetic catapult.Rosnące zapotrzebowanie na komercyjne bezzałogowe statki powietrzne (BSP) wymaga poszukiwań nowatorskich rozwiązań technicznych, związanych z krytycznymi aspektami obsługi tychże obiektów. Interesującą alternatywą dla istniejących rozwiązań jest analizowana w pracy wyrzutnia magnetyczna. W pracy zaprezentowano badania umożliwiające pomiar i analizę położenia wózka startowego wyrzutni bezzałogowych statków powietrznych (BSP) na torach magnetycznych. Prezentowany w pracy układ pomiarowy składa się z przetwornika połączonego z czujnikami Halla rozmieszczonymi równomiernie u podstawy pojemnika z nadprzewodnikami. Zmiana płożenia pojemnika względem pola magnetycznego powoduje zmianę napięcia wyjściowego poszczególnych czujników Halla. Opracowany algorytm steruje silnikami krokowymi, które przesuwają pojemnik z czujnikami względem badanego toru. W tym samym czasie czujniki odczytują wartość pola w czasie rzeczywistym, dlatego istotne jest, aby mikrokontroler realizujący algorytm działał z odpowiednio dużą prędkością. Do realizacji autorskiego algorytmu został użyty procesor RISC produkcji ATMEL ATmega2560. Układ mikroprocesorowy odczytuje stan każdego czujnika i porównuje go z danymi zapisanymi w pamięci. Na podstawie różnicy odczytu i geometrii pojemnika wyznaczane jest jego płożenie na torach magnetycznych

Bifurcation Flight Dynamic Analysis of a Strake-Wing Micro Aerial Vehicle

Non-linear phenomena are particularly important in -flight dynamics of micro-class unmanned aerial vehicles. Susceptibility to atmospheric turbulence and high manoeuvrability of such aircraft under critical flight conditions cover non-linear aerodynamics and inertia coupling. The theory of dynamical systems provides methodology for studying systems of non-linear ordinary differential equations. The bifurcation theory forms part of this theory and deals with stability changes leading to qualitatively different system responses. These changes are called bifurcations. There is a number of papers, the authors of which applied the bifurcation theory for analysing aircraft flight dynamics. This article analyses the dynamics of critical micro aerial vehicle flight regimes. The flight dynamics under such conditions is highly non-linear, therefore the bifurcation theory can be applied in the course of the analysis. The application of the theory of dynamical systems enabled predicting the nature of micro aerial vehicle motion instability caused by bifurcations and analysing the post-bifurcation microdrone motion. This article presents the application of bifurcation analysis, complemented with time-domain simulations, to understand the open-loop dynamics of strake-wing micro aerial vehicle model by identifying the attractors of the dynamic system that manages upset behaviour. A number of factors have been identified to cause potential critical states, including non-oscillating spirals and oscillatory spins. The analysis shows that these spirals and spins are connected in a one-parameter space and that due to improper operation of the autopilot on the spiral, it is possible to enter the oscillatory spin

Control System Design and Methods for Collaborative Robots: Review

Collaborative robots cooperate with humans to assist them in undertaking simple-to-complex tasks in several fields, including industry, education, agriculture, healthcare services, security, and space exploration. These robots play a vital role in the revolution of Industry 4.0, which defines new standards of manufacturing and the organization of products in the industry. Incorporating collaborative robots in the workspace improves efficiency, but it also introduces several safety risks. Effective safety measures then become indispensable to ensure safe and robust interaction. This paper presents the review of low-level control methodologies of a collaborative robot to assess the current status of human–robot collaboration over the last decade. First, we discuss the classification of human–robot collaboration, architectures of systems and the complex requirements on control strategies. The most commonly used control approaches were presented and discussed. Several methods of control, reported in industrial applications, are elaborated upon with a prime focus on HR-collaborative assembly operations. Since the physical HRC is a critical control problem for the co-manipulation task, this article identifies key control challenges such as the prediction of human intentions, safety, and human-caused disturbances in motion synchronization; the proposed solutions were analyzed afterwards. The discussion at the end of the paper summarizes the features of the control systems that should be incorporated within the systematic framework to allow the execution of a robotic task from global task planning to low-level control implementation for safe and robust interactions

Control System Design and Methods for Collaborative Robots: Review

Collaborative robots cooperate with humans to assist them in undertaking simple-to-complex tasks in several fields, including industry, education, agriculture, healthcare services, security, and space exploration. These robots play a vital role in the revolution of Industry 4.0, which defines new standards of manufacturing and the organization of products in the industry. Incorporating collaborative robots in the workspace improves efficiency, but it also introduces several safety risks. Effective safety measures then become indispensable to ensure safe and robust interaction. This paper presents the review of low-level control methodologies of a collaborative robot to assess the current status of human–robot collaboration over the last decade. First, we discuss the classification of human–robot collaboration, architectures of systems and the complex requirements on control strategies. The most commonly used control approaches were presented and discussed. Several methods of control, reported in industrial applications, are elaborated upon with a prime focus on HR-collaborative assembly operations. Since the physical HRC is a critical control problem for the co-manipulation task, this article identifies key control challenges such as the prediction of human intentions, safety, and human-caused disturbances in motion synchronization; the proposed solutions were analyzed afterwards. The discussion at the end of the paper summarizes the features of the control systems that should be incorporated within the systematic framework to allow the execution of a robotic task from global task planning to low-level control implementation for safe and robust interactions

The Use of Hall Effect Sensors in Magnetic Levitation Systems

abstractEN: This paper presents a new method of non-contact measurement and control of the magnetic field strength. The article discusses at first magnetic levitation phenomena and commercial Mag-Lev suspensions systems. Then it explains the Hall effect physics and example use of Hall effect sensor in educational magnetic levitation device. Next it lists some example constructions of Hall effect sensors. Finally it reveals potential new use of Hall-sensor in control system of unmanned aircraft catapult using Meissner effect.score: 7collation: 271-27

LQR and Fuzzy Logic Control for the Three-Area Power System

The three-area power system is widely considered a suitable example to test load frequency control of the distributed generation system. In this article, for such a system, for the power stabilization task, we introduce two controllers: Linear Quadratic Regulator (LQR), which is model-based, and Fuzzy Logic Controller (FLC), which is data-based. The purpose is to compare the two approaches from the point of view of (i) ease of implementation and tuning, and (ii) robustness to changes in the model. The model, together with controls strategies, has been implemented in the MATLAB software. Then, it has been tested for different simulation scenarios, taking into account the disturbances and faulty tie-lines between areas. Various quality measures allow to compare the performance of each control strategy. The comparison in terms of parameter change and load disturbances prompt us to propose suitable metrics and advice notes on the application of each controller

LQR and Fuzzy Logic Control for the Three-Area Power System

The three-area power system is widely considered a suitable example to test load frequency control of the distributed generation system. In this article, for such a system, for the power stabilization task, we introduce two controllers: Linear Quadratic Regulator (LQR), which is model-based, and Fuzzy Logic Controller (FLC), which is data-based. The purpose is to compare the two approaches from the point of view of (i) ease of implementation and tuning, and (ii) robustness to changes in the model. The model, together with controls strategies, has been implemented in the MATLAB software. Then, it has been tested for different simulation scenarios, taking into account the disturbances and faulty tie-lines between areas. Various quality measures allow to compare the performance of each control strategy. The comparison in terms of parameter change and load disturbances prompt us to propose suitable metrics and advice notes on the application of each controller