Papers by Author: Andrzej Zbrowski

Abstract: The article presents the test results obtained from the “Research methods and systems for the investigation on impact resistance of elements of aero structures and land vehicles aimed at the assessment of passenger safety” R&D project that was jointly executed by the Institute of Aviation, the Institute for Sustainable Technologies – National Research Institute, and the PZL Mielec. The main objective of the project was to perform impact tests of the windscreen and the vertical stabilizer of the PZL M28 Skytruck. The experimental tests were conducted for real objects in full scale. The investigations were carried out using an original 250 mm pneumatic gun. Apart from the impact tests, the project was also focused on numerical simulations of impacts employing the Finite Element Method (test object modelling) and the Smoothed Particle Hydrodynamics methods (the model of the gelatine projectile). The authors compare the results of experimental tests and numerical simulations. They present the differences in the results obtained and analyse the reasons behind these discrepancies, and based on the analysis, they conclude that the main cause for them is the simplified mathematical model describing the behaviour of the material subjected to dynamic loads, which was used in numerical simulations.

Abstract: The article describes the influence the operating frequency of the transducer on the possibility to detect corrosion using the eddy current method. A bearing ring with two artificially made corrosion defects was used as a test object. The authors determined the characteristics of the defect’s signal value in the function of frequency. The results obtained were then compared to the peak-to-peak value of the signal for a model ring. The tests confirmed the possibility of automatic detection of corrosion on the surface of bearing rings using the eddy current method.

Abstract: The article presents the structure of a control system installed in a series of test devices for durability tests intended for different types of documents, i.e. cards or book that are electronically secured with RFID labels. In the system in question, the test methods simulate typical document manual handling and therefore enable the determination of the influence of mechanical loads on the technical condition of the document, and the possibility to read the data stored in it. To make the execution of tests possible according to defined standards, a set of necessary components of the control system responsible for control, communication and actuator functions was developed. The objective of the tasks undertaken was to develop the structure of a control system, in which all designed test devices would be included, and to which additional apparatus could be added. The designed structure of the control system enables the application of numerous components of the same type in all test devices under one control. The developed control system is composed of basic modules included in every device and configurable modules selected individually for each type of tests.

Abstract: The paper presents the structure of a control system incorporated into a process line for the production of documents secured with RFID labels. The line enables a flexible and easy manufacture of goods with different shapes and sizes in a low-cost experimental production undertaken to meet the needs of continuing improvement of prototypes and short series of innovative products with increased durability and higher level of security, which is possible to be obtained due to the application of electronic and graphical protection systems [1]. The line is intended for the assembly of multilayer documents. The documents are made of a raw stock in form of paper web, an RFID inlay and a protective film which all are glued together with the use of cold gluing and hot-melt techniques or in which a transfer tape with an adhesive film is applied. The tape and the elements mounted on it are transported and stopped by drive modules, whereas maintenance procedures are executed by actuators. These modules initiate proper strain of the tape, and as a result the material is flattened and a stable distance between the elements mounted on it is preserved. In the case of a start-stop operation and close distances between individual guide rollers, a proper tape strain and the time-space synchronization of all the modules constitute an important aspect of the control over the flexible technological system.

Abstract: The article presents the methodology, test stand and results of noncontact tests conducted using a laser sensor-equipped system for measuring displacement. The tests were carried out in an attempt to determine the sensitivity of the measurement system to the angular position of the sensor against the surface onto which the laser spot was projected. The scope of investigations constitutes a crucial problem dealing with the determination of tolerance of assembling a laser head in the measurement system for a laser penetrometer used for examining substance consistence. The tests were executed in the measurement range between 5 and 50 mm taking into account 5 angular positions of the laser sensor. The readings of the laser head were referred to the value of displacements adjusted with the use of a micrometric head. In the case of the tested system, the dispersion of measurement deviations was estimated as a function of the measured distance.

Abstract: The article presents the operation and structure of a dispersion adhesive applicator dedicated for printing industry. Contrary to the currently used solutions in which the length of the glue layer is defined by the geometry of the glue roller, the original device enables free formation of the relation between the bonding area and adhesive-free areas. Based on the analysis of geometrical and time dependencies characterising the designed device, a mechatronic control system was developed to enable repeated glue application synchronised with the markers commonly used in printing industry and applied onto the paper. Constructed based on a programmable PLC controller, the system has control over all crucial technological parameters of the process (temperature, glue amount, beginning and end of the bonding area). The user-device communication is interactive, and therefore an additional user panel (touch-screen) is employed. The developed solution was used for applying dispersion adhesives in a technological line for producing multilayer ID cards with RFID labels.

Abstract: The paper presents the structure of a precise parallel tri-axle manipulator with the functionality of progressing-tilting table. The end effector of the device is a platform, for which three coordinates of position are defined. The manipulator has three degrees of freedom: movement perpendicular to the base and rotation in two mutually perpendicular axes contained in the surface parallel to the base.The concept of the positioning mechanism is based on parallel tripod kinematics where the end effector – the platform – is seated on three active limbs – actuators. The use of parallel kinematics allowed modular construction of the positioning mechanism. The developed modular functional mechanism with minimal number of elements in kinematic chain ensures high positioning resolution. The concept of application of eccentric mechanism for platform positioning is an original idea in this solution. The compact construction allows applying the manipulator in medical devices that require meeting of the hygienic conditions in the medical test and research laboratories. The possibility of the utilisation of the precise manipulator covers wide areas of science and technology where precise positioning of the object is required, e.g. sample positioning for microscopes, scanning systems.

Abstract: The article presents the process of determining the speed of an unmanned rescue vehicle.The conducted investigations involved a measurement system developed for testing dynamic lorries. The application of a test system for low-speed all-terrain vehicles was possible due to a wide measurement range of sensors. Speed was tested employing two following methods:an indirect method consisting of the measurement of the instantaneous rotational speed of the wheel;a direct method consisting of the measurement of speed against the ground, taken with an optical speed sensor.The authors also describe the sources of interferences characteristic of both methods that include:the wheelspin affecting the correctness of speed determination in the indirect measurement;the unevenness of the surface (ground) hindering the correct operation of the optical speed sensor.The paper also presents the characteristics of the rotational speed of the wheels obtained in road and off-road conditions. Based on the obtained signals, linear speed was determined. Additionally, the article discusses methods for eliminating measurement disturbances.

Abstract: The article presents the structure and operation of the developed system for graphic personalisation of cards and paper sheets. The system is responsible for the input of unique graphics in the form of prints corresponding with suitable data recorded in the memory of a microprocessor. In the verification process, an electronic record is compared with alphanumerical information, and the conformity of digital graphics with the print is checked. The system was used in the construction of a process line for producing RFID-secured documents. The system has a modular structure and is composed of two modules responsible for the prints and automatic verification of graphic personalisation. The printing module enables the application of the print in the form of alphanumerical signs or unique graphic symbols and a barcode, which is conducted according to the structure of the database from which information on personalisation is obtained. The verification module compares the electronic record from the microprocessor with alphanumerical information and checks whether digital graphics agree with the print. Printing is performed using an inkjet printhead, whereas for the verification process, a digital line scan camera is applied. Mechatronic positioning systems enable the printhead and camera shift freely along the print and inspection area and allow changes in positioning speed parameters.

Abstract: The use of documents with RFID labels, particularly passports, is often equivalent to mechanical damage, the loss of printed data and many negative consequences stemming from them. The article presents a system for testing the mechanical durability of load damage considering such types of documents. Based on the results of the analyzed requirements, a set of testing devices has been developed in order to enable a complex assessment of the mechanical durability of electronically protected documents. The use of common solutions regarding individual testers enables the execution of both normative and programmable tests and facilitates an easy extension of the system for the modification of its individual devices.