Marcin Jasiński

The Active Magnetorheological Support as an Element of Damping of Vibrations Transferred from the Ground to Large-Scale Structure Supports

The active support of a large-scale structure, made up of two elements was designed and manufactured. The first of them - piezoelectric actuator, enables the simulations of vibrations transferred from the ground to the structure. In order to minimize vibrations transmitted through the ground to the construction, the second element of the active support - a system based on magnetorheological dampers was used. The active support enables the simulations of vibrations from the ground using a piezoelectric stack controlled in a reverse feedback loop. Control signals of the feedback loop are: the volume of deformation and vibrations in the selected structures node.

Distributed System for Monitoring of the Large Scale Infrastructure Structures Based on Analysis of Changes of its Static and Dynamic Properties

The complexity and diversity of civil engineering structures impose requirements on the monitoring systems, which are difficult to be satisfied. In the paper the concept of the distributed diagnostic system capable of monitoring the technical state of critical elements of large infrastructure objects like steel trusses, supermarket buildings, exposition halls, bridges etc. is discussed. Adaptation of such systems is essential for online assessment of technical state of the infrastructure objects and could limit the possibility of catastrophic disasters with loss of people. As a source of information data from strain gauges, passive magnetic field sensors and acceleration sensors applied to the construction are considered. For the process of selection of sensors and diagnostic methods the mathematical model of the construction and the physical test stand were used.

Use of Condition Monitoring in the Proactive Maintenance Strategy

The objectives of the presented paper are to better understand the mechanism of failure development in the dynamic mechanical systems. It is important to consider carefully the present changes in technical conditions of elements of the system when planning the requirements to a proactive risk management’s strategy. While a dynamical system traditionally is modeled by structural decomposition, in the paper the dynamic behavior of system is modeled by decomposition of the behavior flow into events and errors accompanying occurrence of failure. From this point of view the nonlinear model of failure occurrence is analyzed to realizing long term benefits of a proactive maintenance strategy. The models describe the effect on the evolution at the process variables for each hypothesized fault failure. In the paper it is also analyzed the impact of nonlinearity of the sub-section on the behavior of the whole system.

Autonomous Agricultural Robot—Conception of Inertial Navigation System

The aim of the paper was to propose conception of autonomous robot for sowing and wide row planting. Autonomous work of the robot in range of traction and agronomic processes will be implemented on the basis of data from a many sensors (cameras, position and distance). Positive test results will allow for the use of the robot in organic crops requiring mechanical removal of weeds or in crops with application of selective liquid agrochemicals limited to the minimum. Until control systems can be perfected and development cost recouped, the growth in autonomous field production systems will come in fits to starts. So that very important is mentioned in this paper, inertial navigation system.

Using of Entropy Method in Failure Diagnostics

Occurring of failure is accompanied by changing of energy distribution of vibroacoustic signal generated by a dynamic system. Hence, comparing the energy distributions of signals observed for technical conditions without failure and for failure states of dynamic model one has access to information about the formation and development of damaging process. The tool to estimate the probability distribution changes corresponding to changes in the distribution of signal energy can be failure oriented measure of information. The paper discusses the problem of proper selection of entropy methods, for detecting and the identification of the failures, both for the signals generated by the actual dynamic systems and simulated one. Particular attention was paid to the possibility of using bispectral entropy and singular entropy change for example signals generated during the formation and propagation of the gear tooth crack. The next interesting resultants of analyzing changes was in the entropy energy of vibration signal recorded during the tests on the back to back test-bed. It was given the observation the chosen harmonic and its modulated bands. During analysis we determined energy change as a function of time in the bands of different widths around the successive harmonics engagement. On the basis of such a limited energy of signal, the technical state of entropy was calculated.

Use of Bispectral Measures in Machines Faults Diagnostics—Examples

It is common knows that the power spectrum based methods cannot detect the phase relationship between different frequency components and additionally suppresses the phase information. It is therefore necessary to explore spectral measures of higher order, like the bispectral measures, to detect various forms of phase coupling between frequency components. In the paper was analyzed the impact of nonlinearity of the sub-section on the behaviour of the whole system by using of bispectral measures: diagonal bispectrum, maximum bispectrum and residual bispectrum. The results pointed to high sensitivity of bispectral measures to changes of the signal’s frequency structure and to the possibility of using these relations while constructing models of development of degradation-and-fatigue-related processes. In the paper was build effective and sensitive diagnostic measure of quality changes of fatigue crack growth at low-amplitude fatigue testing, fatigue process of toothed wheel damage or electric motors bearings faults. To do this, It was create a new measure (nobody else didn’t that way) which is able to extract the relevant diagnostic information. Integral of bispectral noise from bispectral maximum diagrams and integral of bispectral noise from bispectral residual diagrams were calculated with maximum given level (everything higher than maximum level was equalized to this maximum level) for every measurements.

Autonomous Agricultural Robot – Testing of the Vision System for Plants/Weed Classification

The aim of the paper was to present results of the vision system for plants/weeds classification testing of autonomous robot for sowing and wide row planting. Autonomous work of the robot in range of traction and agronomic processes will be implemented on the basis of data from a many sensors (cameras, position and distance). Positive test results will allow for the use of the robot in organic crops requiring mechanical removal of weeds or in crops with application of selective liquid agrochemicals limited to the minimum. Unless the control systems are improved and development costs are compensated, the production of autonomous agricultural systems will increase. So that very important is mentioned in this paper, vision system of plant/weed classification. The vision system for sugar beet/weed and sweet corn/weed classification was build and tested. The position of each plant must be determined for intra-row weeding. This means that plants have to be classified into two classes, i.e., sugar beet (sweet corn) or weed.