Patent UA-30843-C2 (UA)
Title: Method and device for measuring vibration displacements
Inventor: SIKORA LIUBOMYR STEPANOVYCH
Filed: 1998-06-10
Abstract: The present invention relates to the measurement and control technique and can be employed in equipment designed for measuring parameters of vibration oscillations of industrial objects. The proposed method for measuring vibration displacements consists in generating a sounding light beam, directing the sounding light beam at the monitored object, receiving the light beam reflected from the object surface, projecting the reflected light beam on the light-sensitive pad of a two-coordinate photoreceiver, which is oriented correspondingly in the spatial coordinate system coupled with the object, to form a control optical image of the object, amplifying the output signals of the photoreceiver, and extracting the components of these signals that correspond to the vibration displacements of the object. The distinctive feature of the proposed method is that the sounding light beam is generated as pulses of laser coherent radiation with a specified frequency and the control optical image of the object is pillow-shaped, with uniform distribution of the light radiation intensity over the image area. The output electric signals of the photoreceiver channels are filtered and optimized for extracting the signal components with intensity proportional to the maximal energy of the optical radiation, using for that the process of charging a capacitor of a specified capacity connected into a series resonance circuit with parameters that match the parameters of the pulse laser radiation. Then the said signals are amplified, repeatedly filtered, then amplified, and filtered by a carrier-frequency filter, the maximal levels of the signals are restricted, and the signals are integrated over a sliding time interval. Then the signals are summed, subtracted, and employed for generating the signals that are proportional to displacements of the object relative to the initial position. The said signals are compared with reference signals and control signals are generated according to the comparison results. The device for realization of the method contains an optical radiation source, an optical system, a unit for forming a control optical image, a reflecting element installed at the monitored object, a two-coordinate photoreceiver, a signal processor, a radiation intensity sensor, a stochastic data processor, a vibration displacement indicator, a scaling amplifier, and a control signal generating unit. The optical radiation source contains a semiconductor laser with a power supply unit, and a square pulse generator for modulation of the laser radiation. The signal processor has two channels, each containing an optimized band-pass filter, three amplifiers, a band-pass filter, a signal level limiter, a signal envelope detector, a sliding time interval integrator, and an adder. The input of the first channel adder is connected to the output of the second channel integrator. The inverse input of second channel adder is connected to the output of the first channel integrator. The output of the first channel adder is connected to the radiation intensity detector. The output of the second channel adder is connected to the input of the vibration displacement indicator and the input of the scaling amplifier. The output of the scaling amplifier is connected in series to the filter, the unit for forming a control optical image, the stochastic data processor, and the control signal-generating unit. Additionally, the proposed device contains a random-access memory, an actuator, and a matching unit. The input of the random-access memory is connected to the first output of the processor. The second and the third outputs of the signal processor are connected to the corresponding inputs of the matching unit. The output of the random-access memory is connected to the actuator. The proposed method allows the functional characteristics of the measuring device to be improved and provides the measurement range of 0.001 … 2.000 mm with high accuracy. The proposed measuring device provides the possibility to measure vibration displacements as well as to monitor the object states and control the object. 2 p. p. c., 5 ill.