Abstract: The article describes an approach dedicated to a hybrid representation of mechatronic systems combining matrix and block notations. The main attention is focused on the identification of relationships between mechatronic machines in respect of functional reliability (analysed in the form of block and digraph notations) and rules that allow for the simplification of the reliability function in the systems of machines connected in parallel, series and complex arrangement. The author has adopted a functional representation based on system demonstration employing a binary function of reliability in which the equation is determined based on the method for setting minimum paths in the graph (structural representation of each subsystem). The introduced assumption allows reducing any structure to a serial connection of functional blocks. The author of the paper has also described a manner of implementation in real systems. This article does not include the description of the method used for determining the reliability function, but only theoretical assumptions used in case of identifying functional dependencies.
Abstract: The paper presents possibility of usage the formalism of structural reliability notation with an implementation of directed graphs and reliability functions recorded in accordance with the Perfect Disjunctive Normal Form notation (PDNF). The author presents the mathematical basis used for an identification of internal structures of mechatronic machines and reduction it to the series-connected blocks. The presented method is a hybrid combination of a binary analysis of evaluated reliability functions (stored in the form of matrixes that relate to defined graphs) and blocks with binary inputs and outputs.
Abstract: The paper presents the application of fuzzy logic principles to generation of audio instructions. The described subsystem forms a part of an information unit for the visually impaired, which is developed at the Institute of Production Machines, Systems and Robotics at Brno University of Technology. The unit will provide visually impaired users with the localization, navigation and obstacle avoidance functionality as well as enable them to independently traverse through previously unvisited (primarily urban) areas. The majority of sightless persons are able to traverse such areas only with human accompaniment that compensates their missing knowledge of the surrounding environment. The utilization of fuzzy techniques brings the human-like behaviour of the navigational interface and a scalable mechanism for generating navigational instructions.
Abstract: Recently, a significant increase in demand for high-end offices, public and administrative buildings with the installed reliable security, alarm and automatic fire tracking systems as well as requirements for possessing operating comfortable microclimate support systems have been registered in Lithuania. The failures of such systems and false alarms tend to be rather common due to the deleterious effects of electromagnetic disturbances. Therefore, the work analyzes the reasons and causes for the disorders of the previously mentioned systems and presents the findings of the experimental study on sensors.
Abstract: The paper presents application of the mechatronic concept for laboratory test to support a research activity. Laboratory test is taken into account as set of processes for which some number of environmental parameters must be controlled. This paper describes the laboratory stand for investigations of airflow phenomena, where modern data acquisition system is applied to control pressure, temperature and velocity of the air stream. To acquire and process a large number of data, the idea of virtual instruments is introduced to control system. Modern, high-level graphical language was used and the author’s program was developed. The presented solution of the laboratory stand allows increasing the accuracy of measurement, it is possible to observe all necessary parameters as rescaled to standard units and use this information in process steering. All technical solutions applied in the system assume flexibility for changes because of additional sensors, actuators and new signal processing and steering procedures.
Abstract: Piezoelectric actuators are widely used for the nano/micro positioning and adjustment systems. In the paper, the investigation on the oscillations of contacting surfaces of the piezoelectric thick-walled cylinder is presented. Piezoelectric cylinder is the main component of piezomechanical system named as piezo-screw and is used to turn the screw. This investigated piezomechanical system can be used for the precise positioning with a high resolution (less than 50 nanometers). Piezoelectric cylinder has radial polarization. Traveling-wave oscillations of the second circumferential modal shape (n = 2, m = 1) are excited. Three different electrode topologies are used to drive the screw. Electrodes are grouped into upper and low groups in both topology cases. Each group consists of six electrodes where positions of corresponding electrodes in upper and lower group are shifted by π/6. Numerical investigation of the traveling wave oscillation is performed and dependencies oscillation trajectories of contact surfaces on excitation schemes are determined when three different electrode topologies are used. Dependency of oscillations of contacting points upon length of the actuator is analyzed as well. Advantages and disadvantages of each excitation case are discussed.
Abstract: The paper describes the research results of modeling and control of proportional valve with synchronous motor type PMSM (Permanent Magnets Synchronous Motor). In the paper, a simulation model of the proposed valve was developed and described. The model included the square root flow characteristics, nonlinearity of the hydraulic actuator, valve dead zone and saturation of the flow. The study included the investigations of the basic characteristics, such as valve flow characteristic and step responses. In order to determine the basic parameters of the valve, the test stand was built, on which the new valve and the servo drive with this valve were tested. A servo drive control system was based on PLC with touch panel and inverter module. In the paper, the chosen investigations results of the valve and the servo drive system are presented and shortly discussed.
Abstract: In the paper, the structure of a typical washing machine, from the control point of view, is presented. Basic sensors, measuring elements and measuring methods are shortly described. Also drives and other output elements commonly used in washing machines are briefly presented. At first, the 32-bit STM32 microcontroller structure and then the design of washing machine controller is described. All modules are specified and their function and input/output signals are described. The important steps in controller setting in motion are presented. The paper ends with a short description of the implemented software.
Abstract: This paper describes a model identification method of a Micro Air Vehicle (MAV) for a further purpose of the robust control design. The identification procedure is based on logged real data collected from flight tests. For the identification purpose, both frequency and time-domain techniques are used. Identification results are presented for the lateral direction dynamics using the elevon (aileron deflection) as input and the roll angular rate as output. The MAV is a single-delta wing of the 0.84 m wingspan and 1.2 kg of total mass (ready to flight). The main goal of the system identification process is to achieve the best possible fit between the raw data and a dynamic model which is called a nominal model.
Abstract: Modern CAD/CAE allows supporting the process of design and construction at many stages, from concept development through specific engineering calculations to the creation of design documentation. In the case of constructing mechanisms, the kinematic and dynamic analysis of the proposed system is an important step in the introduced process. The paper presents an example of the kinematic and dynamic analysis of the Stewart platform using Siemens NX software [1, 2]. The conducted investigation has allowed determining the geometric characteristics of the mechanism of the Stewart platform as well as the geometric parameters of actuators and their location. A dynamic analysis of the platform helped with establishing the required motor forces for realizing the moves with the maximum speed and acceleration. This allowed the initial selection of the parameters of electric motors. Traffic analysis was also performed for investigating collisions between the parts of the hexapod and between the hexapod and its environment.