SU543836A1 - Self-tuning mechanical frequency meter - Google Patents

Description

one

The invention relates to the measurement of mechanical quantities and can be used to measure the natural frequency of oscillations of mechanical parts.

Devices are known for determining the self-frequency of mechanical parts 3, based on the use of a damped oscillation method. In these devices, selective amplifiers are used to enhance bias amplifiers, which should tune-up to the frequency of the input electrical signal corresponding to the frequency of mechanical vibrations. The application of the known automatic tuning systems containing the frequency discriminator and the system of automatic control of the parameters of the oscillating level, with the rapidly decaying nature of the process, is impossible because of the inertia of the frequency discriminator.

The closest technical solution 20 is a device for determining the natural frequency of parts by the method of damped oscillations 2, the E of which is used to tune the selective pulse to the mechanical frequency. It contains K

sensor, selective amplifier based on an RC-filter with a double T-bridge, control circuit, valve, first pulse counter, connected in series to a counting pulse generator, connected through a frequency divider to the gate, second counter and pulses, the first input of which is connected to a generator , the second input is with the coincidence circuit, the trigger generator, the input of which is connected to the output of the coincidence circuit, and the output with the frequency meter.

However, the known device has a low speed, since the selective amplifier is tuned to the measured frequency in it by the operator for several part excitation cycles.

The aim of the invention is to increase the tuning speed of the measured chatot.

Claims (2)

This is achieved by the fact that the device is additionally equipped with a memory register, the input of which is connected to the output of the first pulse counter, and the resistors of the double T-shaped bridge are made in the form of digital controlled resistors, the control inputs of which are connected to the output of the memory register. Between the detuning of the oscillatory systems and the regulating action there is a rim, a one-to-one interrelation, since the period of natural oscillations of active moat with double T-shaped bridges is directly proportional to the value of the resistance of the arms of the bridge. This allows automatic tuning to the measured frequency during one period of the signal under study. The drawing shows a diagram of a device containing a sensor 1 that converts oscillations of a part into an electrical signal, a selective amplifier 2, the tunable dual T-shaped v.ocT, control circuit 3, a counting generator and 4 pulses 4, frequency divider 5 with a division factor equal to two valve 6, the first pulse counter 7, the coincidence circuit - codes 8, the second pulse counter 9, trigger generator 10, frequency meter 11, memory register 12, three digital controlled resistances 13-15 follows. Before the measurement, the selective amplifier 2 is tuned to the expected measurement frequency. When oscillations are excited into parts, for example by a shock, the free damped oscillations of the parts that occur during this process are converted by sensor 1 into electrical signals and fed to the input of selective amplifier 2. The output voltage of selective amplifier 2 goes to control circuit 3, which delays the frequency measurement for a time necessary to end the transition process in the part after it has been excited, and opens valve 6 for a time equal to one period of the voltage under study, after which the control circuit 3 is blocked . During the open state of the valve, 6 counted pulses from the output of the generator of counted pulses 4 through a divider frequency 5 with a division factor equal to two are fed to the first i / probe counter 7. The number of pulses received on this counter is proportional to the open state of the valve 6, t . e. the period of oscillations of the voltage under study. In addition, the counting pulses of the Generator counting pulses 4 are fed to the input of the second pulse counter 9, which operates in continuous mode. The outputs of all bits of counters 7 and 9 are fed to a matching circuit of code 8, the output of which a signal appears each time as soon as the number of pulses B of counter 9 becomes equal to the number of pulses in counter 7. The signal from the output of codes 8 sets the pulse counter to zero 9, after which a new cycle of counter operation 9 begins. The pulses from the output of the coincidence circuit of codes 8 are fed to the counting input of the trigger —former 10, and the frequency of the output voltage of the triggerformer 10 is measured by a frequency meter 11. At the same time, during the measurement The digital clock frequencies recorded in counter 7, and corresponding to the oscillation period of the tested NT, are transferred from control circuit 3 to memory register 12. The latter sets the values of digital controlled resistors 13, 14 and 15 corresponding to the adjusted tuning frequency value of the selective amplifier 2. Thus, when measuring the frequency of fast-damping processes, the proposed device automatically adjusts the measured frequency of the signal under investigation directly to the signal. measurement process. Claim of the invention Self-tuning mechanical frequency meter of mechanical coupling, containing sensor, selective amplifier based on PC-filter with double T-shaped bridge, control circuit, valve, first pulse counter, connected in series, counting pulse generator connected through a divider of the circuit with a valve the second counter of pulses, the first input of which is connected to the generator, the second input to the coincidence circuit, trigger generator, the input of which is connected to the output of the coincidence circuit; and the output - with a frequency meter, characterized in that, in order to increase the tuning speed to the measured frequency, it is a memory register, the input of which is connected to the output of the first counter and vm: ylcov, and the double T-bridge resistors are made in the form of digital controlled resistors, the j-governing inputs of which are connected to the output of the memory register. Sources of information taken into account during the examination: 1.B, X. Krivitsky Automatic tracking of the frequency of Energy, M ,, 1974 2. USSR author's certificate No. 474698, & 01 H 11 / CO, 1973 (prototype),