A “periodic signal parameter” (PSP) indicates periodic patterns in an autocorrelated vibration waveform and potential faults in a monitored machine. The PSP is calculated based on statistical measures derived from an autocorrelation waveform and characteristics of an associated vibration waveform. The PSP provides an indication of periodicity and a generalization of potential fault, whereas characteristics of the associated waveform indicate severity. A “periodic information plot” (PIP) is derived from a vibration signal processed using two analysis techniques to produce two X-Y graphs of the signal data that share a common X-axis. The PIP is created by correlating the Y-values on the two graphs based on the corresponding X-value. The amplitudes of Y-values in the PIP is derived from the two source graphs by multiplication, taking a ratio, averaging, or keeping the maximum value.

A “periodic signal parameter” (PSP) indicates periodic patterns in an autocorrelated vibration waveform and potential faults in a monitored machine. The PSP is calculated based on statistical measures derived from an autocorrelation waveform and characteristics of an associated vibration waveform. The PSP provides an indication of periodicity and a generalization of potential fault, whereas characteristics of the associated waveform indicate severity. A “periodic information plot” (PIP) is derived from a vibration signal processed using two analysis techniques to produce two X-Y graphs of the signal data that share a common X-axis. The PIP is created by correlating the Y-values on the two graphs based on the corresponding X-value. The amplitudes of Y-values in the PIP is derived from the two source graphs by multiplication, taking a ratio, averaging, or keeping the maximum value.

A measurement method includes: generating second measurement data by performing filter processing on first measurement data; calculating a first deflection amount based on an approximate equation of deflection of a structure; calculating a second deflection amount by performing filter processing on the first deflection amount; calculating a third deflection amount based on the second deflection amount and a first-order coefficient and a zero-order coefficient which are calculated based on the second measurement data and the second deflection amount; calculating an offset based on the zero-order coefficient, the second deflection amount, and the third deflection amount; calculating a static response by adding the offset and a product of the first-order coefficient and the first deflection amount; calculating a first dynamic response by subtracting the static response from the first measurement data; calculating a second dynamic response by attenuating an unnecessary signal from the first dynamic response; and calculating an attenuation rate of the second dynamic response based on an envelope amplitude of the second dynamic response.

A frequency domain feedforward compensation method based on a power exponential method for a seismic simulation shaking table is provided. According to the method, a frequency domain amplitude transfer function of a system is identified, the frequency domain amplitude transfer function is modified by adjusting the power and limiting an amplitude, then an inverse frequency domain amplitude transfer function is obtained, an amplitude and a phase of a driving acceleration signal are computed, finally a time domain driving acceleration signal is obtained by using the Euler's formula for computation in a complex domain and conducting inverse Fourier transform, the shaking table is driven again to collect an acceleration signal output by a table top, whether the acceleration signal meets a shaking table test waveform use requirement is determined, a test is finished under the condition that the acceleration signal meets the shaking table test waveform use requirement.

A sign detection device includes: a plurality of sensors disposed at a plurality of positions on a detection target object and configured to measure physical quantities at each position; a data acquisition unit for acquiring time-series fluctuation data of the physical quantities from the plurality of sensors; a calculation unit for calculating, from the time-series fluctuation data, a parameter indicating a correlation between the physical quantities at arbitrary two positions among the plurality of positions; and a detection unit for detecting a sign of sudden change in vibration of the detection object based on the parameter.

Oscillatory instabilities are ubiquitous of systems, and these usually arise out of low amplitude aperiodic oscillations. These oscillatory instabilities generally affect the performance and the lifespan of systems in an adverse manner. An apparatus and a method are disclosed here to estimate the rms value or the amplitude of limit cycle oscillations for control of the oscillatory instability.

An impact detection methodology is disclosed. Systems and methods can be utilized to detect impacts of concern such as collisions, falls, or other incidents. Systems and methods can be utilized to monitor an area and detect falls or collisions of an individual, for instance, as may require intervention to aid the subject. A system can include two or more accelerometers and a controller. The accelerometers can be in communication with the structure (e.g., within or on the walls or floor of a structure) and can monitor the structure for vibrations. The accelerometers can be coupled to a controller that is configured to process data obtained from the accelerometers and provide output with regard to the force and/or location of an impact within the structure.

According to one embodiment, a structure evaluation system according to an embodiment includes a plurality of sensors, a position locator, and an evaluator. The plurality of sensors detect elastic waves. The position locator locates positions of elastic wave sources by using the elastic waves among the plurality of elastic waves respectively detected by the plurality of sensors having an amplitude exceeding a threshold value determined according to positions of the sources of the plurality of elastic waves and the positions of the plurality of disposed sensors. The evaluator evaluates a deteriorated state of the structure on the basis of results of the position locating of the elastic wave sources which is performed by the position locator.

A device and a method for detecting states of a linear guideway including a sliding block and a slide rail are provided. The device includes a sensor located at a position corresponding to a side surface of the slide rail, and an analysis processer communicated with the sensor. The sensor detects the vibrating of the slide rail to generate a sensing signal. The analysis processer compares the sensing signal with at least one threshold, to determines occurrence of abnormalities. Therefore, the sensitivity for detection may be increased.

A device and a method for detecting states of a linear guideway including a sliding block and a slide rail are provided. The device includes a sensor located at a position corresponding to a side surface of the slide rail, and an analysis processer communicated with the sensor. The sensor detects the vibrating of the slide rail to generate a sensing signal. The analysis processer compares the sensing signal with at least one threshold, to determines occurrence of abnormalities. Therefore, the sensitivity for detection may be increased.