Utjecaj komunikacijskih prekida na zadovoljenje funkcionalnih zahtjeva IEC 61131-3 distribuiranih sustava upravljanja

The control software is frequently used in various systems that perform important and responsible tasks in industry. During its development, it is crucial to ensure that the solution is created in a way consistent with assumptions and meets all functional requirements. One of important steps consists of testing particular software units, separated from the rest of system, using the off-line simulator. However, test results can be different in case of a fully-connected system when external factors, such as communication issues, should be also taken into account. In this paper, the authors present a concept of specification and execution of system tests, using the dedicated test definition language, named CPTest+. It has been extended by the additional ASSERT_COM instruction, which performs an assertion that is able to detect problems related to external factors, including communication. To enable automatic and systematic testing, the dedicated metric has been proposed. It takes into account the current link status and archived results to calculate the probability that the test case has failed due to communication problems.Upravljački software je često korišten u sustavima koji obavljaju kritične zadatke u industriji. Tijekom njegovog razvoja, važno je osigurati zadovoljenje svih bitnih pretpostavki i funkcionalnih zahtjeva. Jedan od važnih koraka u razvoju navedenog softwarea je testiranje njegovih pojedinih cjelina korištenjem offline simulatora, neovisno o ostatku sustava. Međutim, rezultati testiranja mogu se bitnije razlikovati u slučaju potpuno povezanog sustava sa svim pripadajućim eksternim faktorima, kao što su komunikacijski problemi, koje je također potrebno uzeti u obzir. U ovom radu autori predstavljaju koncept definiranja i izvršenja testova sustava korištenjem jezika za namjensko definiranje testova, nazvanog CPTest+. On je proširen dodatnom ASSERT_COM naredbom koja obavlja provjeru s mogućnošću detekcije problema uzrokovanih vanjskim faktorima, npr. komunikacijom. Kako bi se omogućilo automatsko i sistematično testiranje predložen je namjenski mjerni sustav. On uzima u obzir trenutni status veze kao i arhivirane rezultate kako bi se odredila vjerojatnost neizvršenja testnog slučaja uslijed komunikacijskih problema

Novel approaches in hand rehabilitation

Hand rehabilitation is a constructive activity to gradually restore health and functionality of hand and fingers. Motion disabilities of hand and fingers are a common problem and can be a result of a wide variety of diseases and traumas. This problem is especially emphasized in the elderly population. Common methods in hand rehabilitation include physical therapy that should be performed frequently. However, patients tend not to follow the program strictly and perform exercises the wrong way, making progress slower or even stagnant. With the development of novel contactless and noninvasive sensors for tracking hand and finger motion the hand rehabilitation can be further upgraded. In this paper we looked into existing hand rehabilitation systems and presented a concept of a novel system by empowering capabilities of new sensors with virtual reality (VR) environment. The existing hand rehabilitation exercises were analysed, adapted and verified in order to be implemented into the system

SPRING BASED ON FLAT PERMANENT MAGNETS: DESIGN, ANALYSIS AND USE IN VARIABLE STIFFNESS ACTUATOR

Modern robot applications benefit from including variable stiffness actuators (VSA) in the kinematic chain. In this paper, we focus on VSA utilizing a magnetic spring made of two coaxial rings divided into alternately magnetized sections. The torque generated between the rings is opposite to the angular deflection from equilibrium and its value increases as the deflection grows – within a specific range of angles that we call a stable range. Beyond the stable range, the spring exhibits negative stiffness what causes problems with prediction and control. In order to avoid it, it is convenient to operate within a narrower range of angles that we call a safe range. The magnetic springs proposed so far utilize few pairs of arc magnets, and their safe ranges are significantly smaller than the stable ones. In order to broaden the safe range, we propose a different design of the magnetic spring, which is composed of flat magnets, as well as a new arrangement of VSA (called ATTRACTOR) utilizing the proposed spring. Correctness and usability of the concept are verified in FEM analyses and experiments performed on constructed VSA, which led to formulating models of the magnetic spring. The results show that choosing flat magnets over arc ones enables shaping spring characteristics in a way that broadens the safe range. An additional benefit is lowered cost, and the main disadvantage is a reduced maximal torque that the spring is capable of transmitting. The whole VSA can be perceived as promising construction for further development, miniaturization and possible application in modern robotic mechanisms

Results on a Pre-T_2 Space and Pre-Stability

This paper contains an equivalent statements of a pre-  space, where  are considered subsets of with the product topology. An equivalence relation between the preclosed set  and a pre-  space, and a relation between a pre-  space and the preclosed set  with some conditions on a function  are found. In addition, we have proved that the graph  of  is preclosed in if  is a pre-  space, where the equivalence relation  on  is open.      On the other hand, we introduce the definition of a pre-stable ( pre-stable) set by depending on the concept of a pre-neighborhood, where we get that every stable set is pre-stable. Moreover, we obtain that a pre-stable ( pre-stable) set is positively invariant (invariant), and we add a condition on this set to prove the converse. Finally, a relationship between, (i) a pre-stable ( pre-stable) set and its component (ii) a pre- space and a (positively critical point) critical point, are gotten

Analysis of a Shaftless Semi-Hard Magnetic Material Flywheel on Radial Hysteresis Self-Bearing Drives

Flywheel Energy Storage Systems are interesting solutions for energy storage, featuring advantageous characteristics when compared to other technologies. This has motivated research effort focusing mainly on cost aspects, system reliability and energy density improvement. In this context, a novel shaftless outer-rotor layout is proposed. It features a semi-hard magnetic FeCrCo 48/5 rotor coupled with two bearingless hysteresis drives. The novelty lies in the use of the semi-hard magnetic material, lending the proposed layout advantageous features thanks to its elevated mechanical strength and magnetic properties that enable the use of bearingless hysteresis drives. The paper presents a study of the proposed layout and an assessment of its energetic features. It also focuses on the modeling of the radial magnetic suspension, where the electromagnets providing the levitating forces are modeled through a one-dimensional approach. The Jiles–Atherton model is used to describe the magnetic hysteresis of the rotor material. The proposed flywheel features a mass of 61.2 kg, a storage capability of 600 Wh at the maximum speed of 18,000 rpm and achieves an energy density of 9.8 Wh/kg. The performance of the magnetic suspension is demonstrated to be satisfactory and the influence of the hysteresis of the rotor material is highlighted

A Pilot Study of Game Design in the Unity Environment as an Example of the Use of Neurogaming on the Basis of Brain–Computer Interface Technology to Improve Concentration

The article describes the practical use of Unity technology in neurogaming. For this purpose, the article describes Unity technology and brain–computer interface (BCI) technology based on the Emotiv EPOC + NeuroHeadset device. The process of creating the game world and the test results for the use of a device based on the BCI as a control interface for the created game are also presented. The game was created in the Unity graphics engine and the Visual Studio environment in C#. The game presented in the article is called “NeuroBall” due to the player’s object, which is a big red ball. The game will require full focus to make the ball move. The game will aim to improve the concentration and training of the user’s brain in a user-friendly environment. Through neurogaming, it will be possible to exercise and train a healthy brain, as well as diagnose and treat various symptoms of brain disorders. The project was entirely created in the Unity graphics engine in Unity version 2020.

Analysis of a user interface based on multimodal interaction to control a robotic arm for EOD applications

Una interfaz humano-robot global que satisfaga las necesidades de los Técnicos Especialistas en Desactivación de Artefactos Explosivos (TEDAX) para la manipulación de un brazo robótico es de suma importancia para que la tarea de manipulación de explosivos sea más segura e intuitiva, además de proporcionar una alta usabilidad y eficiencia. El objetivo de este artículo es evaluar el rendimiento de un sistema multimodal para un brazo robótico basado en una interfaz natural de usuario (NUI) y una interfaz gráfica de usuario (GUI). Se comparan las interfaces mencionadas para determinar la mejor configuración para el control del brazo robótico en aplicaciones de desactivación de artefactos explosivos (EOD) y mejorar la experiencia de usuario de los agentes TEDAX. Las pruebas se realizaron con el apoyo de agentes policiales de la Unidad de Desactivación de Artefactos Explosivos-Arequipa (UDEX-AQP), quienes evaluaron las interfaces desarrolladas para encontrar un sistema más intuitivo que genere la menor carga de estrés al operador, resultando que nuestra interfaz multimodal propuesta presenta mejores resultados en comparación con las interfaces tradicionales. La evaluación de las experiencias de laboratorio se basó en la medición de la carga de trabajo y usabilidad de cada interfaz evaluada

Adaptive Model for Biofeedback Data Flows Management in the Design of Interactive Immersive Environments

[Abstract] The interactivity of an immersive environment comes up from the relationship that is established between the user and the system. This relationship results in a set of data exchanges between human and technological actors. The real-time biofeedback devices allow to collect in real time the biodata generated by the user during the exhibition. The analysis, processing and conversion of these biodata into multimodal data allows to relate the stimuli with the emotions they trigger. This work describes an adaptive model for biofeedback data flows management used in the design of interactive immersive systems. The use of an affective algorithm allows to identify the types of emotions felt by the user and the respective intensities. The mapping between stimuli and emotions creates a set of biodata that can be used as elements of interaction that will readjust the stimuli generated by the system. The real-time interaction generated by the evolution of the user’s emotional state and the stimuli generated by the system allows him to adapt attitudes and behaviors to the situations he faces

Locomotion Control of Hexapod Walking Robot with Four Degrees of Freedom per Leg

V této práci představujeme nového šestinohého robota jménem HAntR, kterého jsme vytvořili dle potřeb Laboratoře výpočetní robotiky Centra umělé inteligence fakulty Elektrotechnické Českého vysokého učení technického v Praze. Jeho hlavním účelem jest vylepšit schopnosti pohybu v těžkém terénu původního robotu přidáním čtvrtého stupně volnosti každé noze. Na základě nově navržené nohy jsme také přepracovali celé tělo robotu tak, aby splnilo i další požadavky, jako například menší rozměry, či možnost osazení alespoň šesti Lithium-Iontovými monočlánky. V práci pečlivě popisujeme motivace a úvahy, které nás k výslednému návrhu vedly. Uvádíme řešení přímé i inverzní kinematické úlohy řešené pomocí podmínky na ideální orientaci konce nohy a uvažující i důležité kinematické singularity. Navržený robot byl vyzkoušen v několika experimentech, při kterých byl použit námi navržený řídicí systém napsaný v jazyce C++. Ukázalo se, že HAntR vydrží díky zvýšené energetické hustotě a lepšímu rozkladu sil v končetinách autonomně fungovat přes hodinu. Robot je také schopen jít rychlostí až 0.42m/s, což předčí mnohé srovnatelné roboty. Při experimentu, kdy robot stál na nakloněné rovině, bylo prokázáno zlepšení oproti předchozímu robotu. A také jsme dle pokynů této práce potvrdili, že i HAntR je schopen adaptivní chůze spoléhající pouze na poziční zpětnou vazbu.In this thesis a novel six-legged robot called HAntR is presented. The robot was developed according to needs of the Robotics Laboratory, at the Artificial Intelligent Center, Faculty of Electrical Engineering, Czech Technical University in Prague. Its main purpose is enhancing rough-terrain movement capabilities by upgrading a former design by adding fourth degree of freedom to each leg. We also revised robot torso to fit new leg design and incorporate other requirements such as smaller dimensions with space for at least six Lithium-Ion cells. We thoroughly describe motivations and considerations that led us to the presented particular solution. Further, the solutions of forward and inverse kinematic tasks with partial orientation constraint and important singularities avoidance are presented. The proposed design has been evaluated in several experimental deployments, which utilised developed software controller written in C++. Endurance tests showed, that HAntR is able to remotely operate for over an hour thanks to increased energy density. Maximal speed test resulted to 0.42m/s during tripod gait, which outpaces most of the comparable robotic platforms. Experiment where HAntR stood on platform with varying inclination showed qualitative improvement against former robot. Finally, in accord with the thesis assignment, we proved that HAntR is able to perform walking with adaptive gait using positional feedback only