Domenico Capriglione, Marco Carratù, Marcantonio Catelani, Lorenzo Ciani, Gabriele Patrizi, Antonio Pietrosanto, Paolo Sommella
Vibration Step Test for Performance Analysis of Inertial Measurement Unit

Nowadays Inertial Measurement Units are largely implemented in several applications, such as automotive and self‑driving vehicles, Unmanned Aerial Vehicles, cellular phones, robotics, artificial intelligence and many others. Despite this, recent literature doesn’t cover properly both the characterization of the dynamical metrological performances and the reliability analysis when microelectronic devices operate under real environmental conditions. Trying to fill this gap, the characterization of an Inertial Measurement Unit under vibration condition is proposed in this work by means of a step-test vibration profile to test the behavior of an inertial platform subjected to a sinusoidal vibration at different frequencies. Starting from the widely known sine sweep vibration profile, a customized test plan has been developed basing on a frequency step up of a sinusoidal stimulus over time to investigate the frequency response of the inertial platforms. The application to a set of real devices has confirmed that the proposed test allows identifying the effects of mechanical stress on the metrological performances of microelectromechanical sensors over a frequency domain. The developed test plan could also be used to investigate whether or not sinusoidal vibrations at certain frequencies trigger some failure mechanisms that are normally quiescent.

Tomislav Burazović
Condition monitoring and maintenance of industrial processes, plants and complex systems: measurements and methods

Maintenance of industrial processes, plants and complex systems is, of course, extremely important to ensure the quality of work performed, ensure employee safety, timely prediction of the necessary downtime, which of course affects business efficiency. The service life of the plant is extended by regular maintenance inspections and monitoring of malfunctions to eliminate the onset of failure even in the event of complete deviations to avoid a major system failure. Recently, the system has been monitored using automatic BMS / SCADA systems, in addition to which additional regular visual inspections of the system are performed, and the system is preventively maintained in working cycles. With the help of various probes we monitor input and output data parameters in critical places, such as temperatures at heating and cooling stations, pressures in pipelines and liquids and gases, percentages of oxygen in plants with various technical gases, pressure drops on critical filters, pump speed, percentage of fan load, percentage of valve openness. In addition, the positions of doors, fire dampers, flue windows and more are monitored by position. As we can see there are a number of essential parameters that need to be monitored in the synergy of reflection with the automated system.

Marcantonio Catelani, Lorenzo Ciani, Giulia Guidi, Diego Galar
A Practical Solution for HVAC Life Estimation Using Failure Models

Heating, ventilation, and air conditioning (HVAC) is the technology of indoor and vehicular environmental comfort. The objectives of HVAC systems are to provide an acceptable level of occupancy comfort and process function, to maintain good indoor air quality, and to keep system costs and energy requirements to a minimum. Performing a reliability prediction provides an awareness of potential equipment degradation during the equipment life cycle. Reliability under a range of conditions is one of the most important requirements to guarantee in HVAC installed on trains. Predicting the reliability of mechanical equipment requires the consideration of its exposure to the environment and subjection to a wide range of stress levels such as impact loading. Often analysist find an unavailability of failure data in handbooks and problems for acquiring data for mechanical components, so the mentioned problems demonstrates the need for reliability prediction models. The paper deals with a HVAC installed on a high-speed train and evaluates the failure rates through the failure rate models suggested by the handbooks in order to assess a model which includes all the mechanical parts.

Joachim Lapsien
Leak Test Of Encapsulated Systems With The Test Medium Compressed Air

Encapsulated test parts, like microswitches, clocks, relays, sensor systems, lamps, electronic control units are used in diverse industrial applications. Therefore these components have to fulfill a variety of requirements. This includes leak tightness against dirt and moisture (e.g. IP 67), as the penetration of liquids can cause serious malfunction. In the definition of the IP protection classes a description how to perform a suitable laboratory test is given. In the production line, this laboratory test cannot be transferred and used. Widespread is the use of the test medium compressed air for the 100 % inline leak testing in industrial production lines. The test medium compressed air can be used down to an air leak rate of 10-3 mbar*l/s (depending on the test part). As waterproof usually an air leak rate of 10-2 mbar*l/s is assumed. By encapsulated test parts the inside of the test part cannot be filled with pressurized air. These test parts are tested in a hood, which is put under pressure. The pressure decay caused by a leakage into the internal volume of the test part is detected with high resolution. The concept of this test method and specific details to be considered are described.

Ivanka Lovrenčić Mikelić
Evolution of Quality Management System at the Ruđer Bošković Institute

Requests for laboratory accreditation according to the ISO/IEC 17025 standard have become more and more frequent, both to commercial and scientific laboratories. Although Ruđer Bošković Institute (RBI) is a scientific institute whose primary role is scientific research, it also provides professional services to public/customers. Traditionally, these services were not expected to be accredited. However, customers’ needs changed and the need for accredited services provided by the RBI’s laboratories emerged. Therefore, the need for quality management system (QMS) complying with the ISO/IEC 17025 standard’s requirements occurred at RBI. Development of the QMS at Ruđer Bošković Institute has been presented from different perspectives, long-term and short-term, and the time needed for its development was given in years, or working hours where possible. Its evolution in phases, from the initial idea through establishing and implementation of different QMSs in individual laboratories to establishing and implementation of the uniform QMS at the Institute level applicable to all RBI laboratories preparing for accreditation, is presented. The longest phase was the first phase of the awareness development and the emerging of the idea for the need of QMS and laboratory accreditation. The first critical point was the necessity of the first laboratory QMS and obtaining of the first certificate of accreditation in 2008. The second critical point was in 2015 when favourable conditions for establishing the QMS at the RBI level were met and the uniform QMS was established and its implementation began. Validity of the RBI’s uniform QMS was confirmed in 2017 when the first laboratory obtained accreditation based on this system. Altogether, approximately 20–25 years were needed from the initial idea to proven successful application of the uniform RBI’s QMS. At RBI, only selected commercial services are subjected to accreditation, while flexibility needed for scientific research is maintained. The regulator’s and large customers’ requests for accredited services were the principal motivation for QMS establishing and its implementation and, accordingly, for laboratory accreditation.