DD223538A1 - METHOD AND CIRCUIT ARRANGEMENT FOR CONTINUOUS TOOL-FREE SPACING MEASUREMENT - Google Patents

Abstract

The invention finds application in contactless distance measurements, in particular in the spatial orientation of nonstationary machines. According to the invention, a defined number of ultrasound pulses with a defined pulse duty factor are transmitted, the ultrasonic pulses reflected by the obstacle being counted in the presence of the same pulse ratio, and the respective distance values to the obstacle being determined after the known propagation time being reached when a preselected number of received pulses is reached. Fig. 1

Description

Title of the invention

Method and circuit arrangement for continuous non-contact distance measurement

Field of application of the invention

The invention finds its application in contactless distance measurement, in particular in the spatial orientation of non-stationary machines.

Characteristic of the Known Technical Solutions In known technical solutions of distance measurement by means of ultrasound, the transit time or phase shift between the transmitted and received signals is measured. Either none (DD - WP 150 657 and DE - OS 31 01 410) or only an inadequate (DD - VVP 154 182) meaning of the suppression of noise is attributed.

In the first two solutions, the ultrasound oscillator is switched over between transmission and reception, the duration of the echo, as the current counter reading, corresponding to the distance to the relevant object.

Each incoming interference signal with the same carrier frequency, as used in the respective circuit arrangement, leads to Meßwertverfälschungen.

The VYP 154 182 has the formation of a long pulse as an identifier for the received signal to be transmitted to the content. Achieved with it

However, only a conditional security on the transmission line. If an interference signal hits with just this pulse length, this variant also becomes unusable. Acoustic interference suppression is not carried out by generel.l.

Every acoustic interference signal with the related transmission frequency leads to incorrect measured values. ·

Object of the invention

The aim of the invention is to eliminate the deficiencies mentioned in the prior art 'and to ensure a continuous, insensitive to background noise, ultrasonic distance measurement.

Explanation of the essence of the invention

The invention has for its object to realize a circuit arrangement for spatial orientation by means of ultrasound using known electronic assemblies by a novel method for non-contact distance measurement.

According to the invention, this object is achieved in that a defined number of ultrasound pulses sent with a defined duty cycle, the ultrasonic pulses reflected from the obstacle counted in the presence of the same duty cycle and the respective distance values are determined obstacle to the obstacle after the known travel time measurement upon reaching a preselected number of pulses. According to the invention, a generator is connected via a frequency divider for the modulation frequency to a gate, which is connected via an amplifier together with the output of a frequency divider for the modulation frequency and controlled by a microcomputer via a pulse counter transmit-receive trigger on a transmission gate whose output is connected to the x-coordinate transmit-receive port, the y-coordinate transmit-receive port and the receive port, the transmit-receive ports being controlled by a microcomputer's threshold switch be controlled, each with an ultrasonic transducer and the receiving port with the negated output of the transmit-receive trigger circuit technology are linked.

The output of the receive gate is via a selective amplifier, demodulator and receive pulse counter with the microcomputer and the stop input of a distance counter whose start input to the output of the frequency divider for the modulation frequency and clock input to the output of the frequency divider for the carrier frequency in Connection, is interconnected, the data outputs of the distance counter and an external level sensor are also in communication with the microcomputer.

The operation of the circuit arrangement is based on the emission of a pulse duration modulated carrier frequency which must correspond to the resonant frequency of the sound transducer. Immediately after transmission, the sound transducer is switched to reception. A defined number of the known transmission pulse number must be received in order to be able to calculate from the transit time of the sound signal the distance of the sensor system from the reflecting surface presented by the current counter reading which is transferred to the computer. Once the distance in a coordinate has been determined, the microcomputer disconnects the transducer for the just-determined coordinate via a threshold switch and addresses the ultrasonic transducer for the other coordinate. The send and receive gate is responsible for the respective choice of coordinates.

By a generator, the carrier frequency signal is formed via a frequency divider, which is controlled by a gate, controlled by a further frequency divider, pulse-modulated. The carrier frequency signal also serves as a clock provision for the distance counter. With a pulse counter, which can be preset, it switches over from transmit to receive after the desired number of transmit pulses via a transmit-receive trigger. The necessary transmission power is provided by an amplifier. The received signal passes through a selective amplifier, which is tuned to the carrier frequency, to a demodulator and starts a receive pulse counter. When the required number of pulses has been reached, the distance counter is stopped and the READY signal indicates to the computer that a new counter reading has been scheduled. The computer accepts the counter reading for the purpose of converting it into the analog distance value and acknowledges by the signal RESET for all counters or possibly the changeover of the coordinate.

embodiment

The invention will be explained in more detail below using an exemplary embodiment.

The associated figure shows the circuit arrangement according to the invention. With a quartz generator 1, the carrier frequency and the modulation frequency are provided via the frequency divider 2 and 3. Both frequencies reach a gate 9, which via an amplifier 10 together with the output of a frequency divider for the modulation frequency 3 and from a microcomputer 18 via a pulse counter 4 controlled transmit-receive trigger 5 to a send gate 6, the output with the x-coordinate transmission-reception Yor 7, the y-coordinate transmission-reception gate 12, and the reception port 11 are in communication. The gates 6, 7, 11 and 12 are preferably formed by two-way optocouplers. The transmit-receive ports 7 and 12, which are controlled by a threshold value switch 19 from the microcomputer 18, are each coupled to an ultrasonic transducer 8, 13. The receive gate 11 is connected to the negated output of the transmit-receive trigger 5, wherein the output of the receive gate 1 T via a selective amplifier 14, demodulator 15 and receive pulse counter 16 with the microcomputer 18 and the stop input of a distance counter 17th is interconnected. The start input of the distance counter 17 is linked to the output of the frequency divider for the modulation frequency 3 and the clock input to the output of the frequency divider for the carrier frequency 2 circuitry, wherein the data outputs of the distance counter 17 and an external level sensor 20 also with the computer 18 communicate. The external limit sensor 20 is preferably formed by a tactile distance sensor.

Claims (2)

Erfi η Dungs entitlement 1. A method for continuous non-contact distance measurement, characterized in that a defined number of ultrasound pulses sent with a defined duty cycle, counting the obstacle reflected ultrasonic pulses in the presence of the same duty cycle and upon reaching a preselected number of received pulses, the respective distance values to the obstacle after the known transit time measurement he with-. be telt. 2. A circuit arrangement for carrying out the method according to claim 1, characterized in that a generator (1) via a frequency divider for the carrier frequency (2) and a frequency divider for the modulation frequency (3) with a gate (9) is in communication, which via an amplifier (10) together with the output of a frequency divider for the modulation frequency (3) and of a microcomputer (18) via a pulse counter (4) controlled transmit-receive trigger (5) is connected to a transmission gate (6) the output of which is in communication with the x-coordinate transmit-receive port (7), the y-coordinate transmit-receive port (12), and the receive port (11), the transmit-receive ports -Tore (7, 12), which are controlled by a threshold value switch (19) from the microcomputer (18), each with an ultrasonic transducer (8, 13) and the receiving port (11) with the negated output of the transmit-receive trigger (5) are linked by circuitry and that the output of the receiving gate (11) via a selective amplifier (14), demodulator (15) and receive pulse counter (16) with the microcomputer (18) and the stop input of a distance counter (17) whose start input to the output of Frequency divider for the modulation frequency (3) and clock input to the output of the frequency divider for the carrier frequency (2) is connected, the data outputs of the distance counter (17) and an external limit (20) also with the microcomputer (18 ) stay in contact. - For this 1 sheet drawings -