Physical and Metrological Approach for Feature’s Definition and Selection in Condition Monitoring

In this paper, a methodology is described aiming at emphasizing physical and metrological criteria in feature selection for condition monitoring of a real scale mechatronic system. The device is used for packaging applications according to the movements of its end effector, driven by a couple of brushless servomotors and a kinematic mechanical linkage. The approach is hybrid, meaning that the starting feature set is built with reference to both experimental data from different sensors and to the indication of a simplified kinematic and dynamic model of the mechanical linkage itself. A critical comparison and mixing of theoretical and experimental data, based also on a physical interpretation of differences, suggests some more features, with respect to the classical ones, of hybrid type, which could be mostly correlated to the effects of statuses and defects of the system to be identified. The whole procedure is step by step validated, in order to evaluate the variability of features, throughout the whole procedure. The variability is analyzed depending on the actions that are realized in order to define, select, and use the proposed features for data processing by advanced algorithms, like the most typically used classifiers and artificial neural networks. A comparison with the state-of-the-art automatic feature’s selection procedure is also presented. Experimental results show that the proposed methodology is able to classify with high accuracy many statuses of the mechatronic system, which are only slightly different as for set-up settings and/or mechanical wear and lubrication conditions of mechanical parts of the mechatronic system. Issues to be pursued to a more effective generalization of the method are also discussed

Effect of uncertainty of reliability data of instrumentation on risk assessment and prediction in process plant applications

Some aspects are discussed concerning the uncertainty causes in risk assessment techniques of industrial interest. Particular attention has been paid to the evaluation of the effect of uncertainty of reliability data of devices and instruments to be used in process plants on the evaluation of the occurrence frequency of the top event. The influence of measuring equipment, whose contribution to the whole uncertainty appears in some cases very important, has been analysed with reference to both operative and environmental aspects

Uncertainty Evaluation in Vision-Based Techniques for the Surface Analysis of Composite Material Components

In this paper, a methodology is discussed concerning the measurement of yarn’s angle of two different glass-reinforced polypropylene matrix materials, widely used in the production of automotive components. The measurement method is based on a vision system and image processing techniques for edge detection. Measurements of angles enable, if accurate, both useful suggestions for process optimization to be made, and the reliable validation of the simulation results of the thermoplastic process. Therefore, uncertainty evaluation of angle measurement is a mandatory pre-requisite. If the image acquisition and processing is considered, many aspects influence the whole accuracy of the method; the most important have been identified and their effects evaluated with reference to two different materials, which present different optical-type characteristics. The influence of piece geometry has also been taken into account, carrying out measurements on flat sheets and on a semi-spherical object, which is a reference standard shape, to verify the effect of thermoforming and to tune the process parameters. Complete uncertainty in the order of a few degrees has been obtained, which is satisfactory for purposes of simulation validation and consequent process optimization. The uncertainty budget also allowed individuation of the most relevant causes of uncertainty for measurement process improvement

Selective and validated data processing techniques for performance improvement of automatic lines

Optimization of the data processing techniques of accelerometers and force transducers allowed to get information about actions in order to improve the behavior of a cutting stage of a converting machinery for diapers production. In particular, different mechanical configurations have been studied and compared in order to reduce the solicitations due to the impacts between knives and anvil, to get clean and accurate cuts and to reduce wear of knives themselves. Reducing the uncertainty of measurements allowed to correctly individuate the best configuration for the pneumatic system that realize the coupling between anvil and knife. The size of pipes, the working pressure and the type of the fluid used in the coupling system have been examined. Experimental results obtained by means of acceleration and force measurements allowed to identify in a reproducible and coherent way the geometry of the pushing device and the working pressure range of the hydraulic fluid. The remarkable reduction of knife and anvil vibrations is expected to strongly reduce the wear of the cutting stage components

Selective and validated data processing techniques for performance improvement of automatic lines

Optimization of the data processing techniques of accelerometers and force transducers allowed to get information about actions in order to improve the behavior of a cutting stage of a converting machinery for diapers production. In particular, different mechanical configurations have been studied and compared in order to reduce the solicitations due to the impacts between knives and anvil, to get clean and accurate cuts and to reduce wear of knives themselves. Reducing the uncertainty of measurements allowed to correctly individuate the best configuration for the pneumatic system that realize the coupling between anvil and knife. The size of pipes, the working pressure and the type of the fluid used in the coupling system have been examined. Experimental results obtained by means of acceleration and force measurements allowed to identify in a reproducible and coherent way the geometry of the pushing device and the working pressure range of the hydraulic fluid. The remarkable reduction of knife and anvil vibrations is expected to strongly reduce the wear of the cutting stage components

Responsiveness and Precision of Digital IMUs under Linear and Curvilinear Motion Conditions for Local Navigation and Positioning in Advanced Smart Mobility

Sensors based on MEMS technology, in particular Inertial Measurement Units (IMUs), when installed on vehicles, provide a real-time full estimation of vehicles’ state vector (e.g., position, velocity, yaw angle, angular rate, acceleration), which is required for the planning and control of cars’ trajectories, as well as managing the in-car local navigation and positioning tasks. Moreover, data provided by the IMUs, integrated with the data of multiple inputs from other sensing systems (such as Lidar, cameras, and GPS) within the vehicle, and with the surrounding information exchanged in real time (vehicle to vehicle, vehicle to infrastructure, or vehicle to other entities), can be exploited to actualize the full implementation of “smart mobility” on a large scale. On the other hand, “smart mobility” (which is expected to improve road safety, reduce traffic congestion and environmental burden, and enhance the sustainability of mobility as a whole), to be safe and functional on a large scale, should be supported by highly accurate and trustworthy technologies based on precise and reliable sensors and systems. It is known that the accuracy and precision of data supplied by appropriately in-lab-calibrated IMUs (with respect to the primary or secondary standard in order to provide traceability to the International System of Units) allow guaranteeing high quality, reliable information managed by processing systems, since they are reproducible, repeatable, and traceable. In this work, the effective responsiveness and the related precision of digital IMUs, under sinusoidal linear and curvilinear motion conditions at 5 Hz, 10 Hz, and 20 Hz, are investigated on the basis of metrological approaches in laboratory standard conditions only. As a first step, in-lab calibrations allow one to reduce the variables of uncontrolled boundary conditions (e.g., occurring in vehicles in on-site tests) in order to identify the IMUs’ sensitivity in a stable and reproducible environment. For this purpose, a new calibration system, based on an oscillating rotating table was developed to reproduce the dynamic conditions of use in the field, and the results are compared with calibration data obtained on linear calibration benches