SU953569A1 - Device for measuring object movement speed - Google Patents

Description

 -The invention relates to instrument making and can be used for contactless measurement of vehicle speed relative to displacement surface. Non-contact velocity meters are known in which the image displacement of optical inhomogeneities of an object surface is converted at the output ({receiver frequency), which characterizes the speed l. Known devices only work in cases where the direction of travel is O or 180 and cannot be used. It is designed to measure the speed at side drift of an object (vehicle), since the direction of side drift is not known in advance. Most of the technical essence is a device containing an optical system, a matrix (1 heaters, the outputs of which are connected to the amplifier inputs, and a frequency meter 2. Known the device only works in cases where the direction of travel is O or 180 and cannot be used to measure speed during lateral drift of an object. The purpose of the invention is to measure the speed of movement during lateral demolition of an object. The goal is achieved by the fact that a peak detector and an amplitude selector are inputted to a device containing an optical system, a matrix (1 inverters, whose outputs are connected to the inputs of a di- (|) power amplifier and frequency meter, the output of the di-amplifier is connected to the input peak detector and an amplitude selector input, the outputs of which are connected respectively to the first and second inputs of the frequency meter, and the outputs of the matrix of photovoltaic devices are connected to the inputs of the differential amplifier random Fig. 1 shows a block diagram of the proposed device; Fig. 2 shows timing diagrams of operation of the device blocks. The image of the displacement surface 1 is projected by the optical system 2 onto the photomatrix plane 3. Each photomatch of the photomatrix 3 is connected randomly or with an inverting or direct input of the differential amplifier k. The output of the differential amplifier is connected to the input of the peak detector 5 and the input of the amplitude selector 6. The output of the peak detector 5 is connected to the first input stotomera 7. Yield amplitude selector coupled to the second input of the frequency counter 7. The device operates as follows. The resulting velocity vector of the object, for example, the transport medium I, relative to the surface 1 of the interface is V + V, where V is the cocjaB displacement of the velocity vector, the direction of which is parallel to the centerline of the vehicle; 7 The velocity vector of the side demolition of the vehicle. When, i.e. in lateral drift, the direction of the resultant vector V can take on any value. It is necessary that the frequency of the alternating voltage at the output of the differential amplifier k when moving the image projection of optical inhomogeneities of surface 1 on the plane of photomatrix 3 does not depend on the direction of the resulting velocity vector V, but only on its modulus | V /. When randomly connecting the outputs of photomatrix 3 with the inverting and direct input of the differential amplifier k, the alternation of positive and negative polarity at the output of the amplifier does not depend on the direction of motion, since the probability of the occurrence of voltage of positive polarity P is equal to the probability of direct voltage negative polarity irrespective of the direction of movement, i.e. P Psrr-, where N is the number of links of the photomatrix 3 with the differential amplifier k N / 2 is the number of inverting or direct 9 9k links. As a result of the random distribution of the direct and inverting links of the amplifier with the photomatrix 3, the signal at the output of the amplifier 4, rri, has a random amplitude and phase modulation. FIG. 2a shows a section of the waveform of the signal at the output of the differential amplifier +. The frequency of alternation of the extreme values of the signal at the output of the amplifier is a value that depends little on random amplitude and phase modulation. As shown in FIG. 26, the peak detector 5 at the moments of extreme values of the signal at the output of the differential amplifier k gives a standard pulse. The average frequency of the pulses at the output of the peak detector 5 is f IS .-- where d is the diameter of the photomatrices of the photomatrix 3; coefficient of laying of photoconverters 3; area photosensitive F Noy surface of the matrix 3; ; - the total number of photoconverters photomatrix 3; area j of the capacitor 3. When counting the number of pulses at the output of the peak detector 5, it is necessary to take into account the cases when, as a result of random phase and amplitude modulation, the amplitude of the signal at the output of the differential amplifier k and. below the absolute value of the sensitivity threshold of the peak detector 5. For this, the signal from the output of the differential amplifier k is also supplied to the input of the amplitude selector 6. The output of the amplitude selector 6 produces a voltage pulse in cases where the amplitude of the signal I and wi (in absolute value condition and. 5 | -U (/ 5U2., where U and U- are the threshold levels of the amplitude selector 7. The upper along | 3 U is approximately equal; the threshold of sensitivity of the peak detector 5, the lower threshold U-} is selected depending on the contrast conditions op tic inhomogeneities of the surface 1. As for the time being of Fig. 2a, in the time interval t, the amplitude of the signal at the output of the differential amplifier k is below the threshold U- and at the output of the peak detector 5 there are no pulses of extreme values 59 detector 5. Frequency meter 7 counts the number of pulses n over a certain time interval T- and determines the average frequency from the dependence f 5d JV /, and the digital indicator of the frequency meter 7 shows the value of speed) V / for the time interval T. the absence of pulses at the output of the amplitude selector 6; the frequency counter performs counting of pulses at a time interval selected from the device performance conditions. shown in FIG. 2b, at time t, an U / pulse appears at the output of the amplitude selector, and the frequency meter 7 stops counting the pulses at the output of the detector 5 and returns the speed value | V | over time on a digital indicator. At time t, an output pulse occurs at the output of the peak detector 5, which starts the frequency meter 9 7 for the next pulse counting cycle. which are connected to the inputs of a differential amplifier, and a frequency meter, characterized in that, in order to be able to measure the speed of movement at the side bevel of the object, and a peak detector and amplitude Elector, the output of the differential amplifier is connected to the input of the peak detector and an input ampgitudnogo selector, the outputs of which are respectively connected to first and second inputs of the frequency, and the outputs of the matrix are connected to photovoltaic differential amplifier inputs at random. Sources of information taken into account in the examination 1. UK patent number 1., cl. G 1 A, published. 1E7b. 2. The patent of Germany No. 2430439, cl. G 01 P 3/36, published. 1976 (prototype).

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Claims (1)

Claim A device for measuring the speed of an object’s movement, containing an optical system, a matrix of photoconverters *, outputs: which are connected to the inputs of a differential amplifier, and a frequency meter, characterized in that, in order to measure the speed of movement with a lateral bevel of the object, a peak a detector and an amplitude selector, while the output of the differential amplifier is connected to the input of the peak detector and the input of the amplitude selector, the outputs of which are connected respectively to the first and second inputs by a frequency pera, and the outputs of the matrix of photoconverters are connected to the inputs of the differential amplifier randomly.