SU847011A1 - Linear displacement pickup - Google Patents

Description

one

The invention relates to measurement techniques, in particular to the measurement of linear displacements, velocities.

A known linear displacement sensor, comprising a system of electromagnetic coils, mounted on. barrel connected in series, and a strong magnet in the piston. When the piston moves inside the barrel, an electromotive force arises in the coils, which is recorded by the oscilloscope 1.

However, this sensor does not provide a high accuracy measurement of linear movements of an object.

Closest to the proposed technical entity is a sensor containing a movable contact and a contact board, on the contact surface of which the sections of current-conducting material alternate with the sections of electrically insulating material, and the conductive sections are connected in series with each other through resistors. The width of the movable contact in the known sensor exceeds the width of the non-conductive portion on the contact surface 2.

In a known sensor, the output signal is proportional to

the magnitude of the measured displacement, which limits the range of the measured displacements with a given accuracy. In this case, the insignificant movement of the object, determined by the specified ACCURACY, should correspond to the change in the sensor signal, which should not be less than a certain value, determined by the properties of the recording device.

The purpose of the invention is to expand the range of measurable displacements and simplify the design of the sensor.

15

This goal is achieved by the fact that, in the linear displacement sensor, the contact board is made in the form of a rail of conductive material with transverse grooves filled with

20 electrically insulating material, while the width of the movable contact of the sensor is less than the width of the transverse groove. FIG. Figure 1 shows schematically a device in which the described sensor can be used to measure linear movements and speeds of movement of an object in the case when the object changes direction and speed of movement;

30 in FIG. 2 - curves, records, data on

oscilloscope tape in the particular case of moving the object.

The device contains a potentiometric sensor 1, a discrete sensor 2 described. A movable contact 3 rigidly connected with a moving object 4, an oscillograph oscilloscope 5. The sensitive element of the sensor 2 is designed as a rail made of conductive material with transverse grooves of a calibrated width on the contact surface. which are located on calibrated distances from each other and are filled with electrical insulator 7,

The length of the sections of reiki ln; is determined with the necessary accuracy by instrumental measurement.

When an object moves, contact 3 moves along the sensitive elements of sensors 1 and 2, and time stamps are recorded on the photosensitive tape 8 (FIG. 2) of the oscilloscope 5, curve 9 of sensor 1 and square pulse system 10 from sensor 2. Each pulse corresponds to a certain distance sensor rail 2.

Curve 9 allows you to set the direction of movement, the moments of the beginning and the cessation of movement of the object and gives a qualitative picture of the dynamics of movement, the change in speed of movement can be judged by the change in the slope of the tangent to curve 9, the average speed of movement of the object in each of the i-th sections em according to the formula

 V.

where H - the width of the i-site rake

sensor 2;

bt is the passage time by contact 3 of this portion of the rail, Distance jS, the object traveled during its time, is determined using the ratio

  (n-

+ th

+ iH

MI

where the indices n and k correspond to the numbers of the strips of the sensor 2, on which contact 3 was located at the beginning and end of the time interval b.t, and ННц and are parts of the lengths of the sections of the rail passed by contact 3 at the beginning and end of the reference time interval t. The error in determining the movements and velocities of the object in the given case does not depend on the class used

the oscilloscope and power supply units, and is determined by the accuracy of the instrumental measurement of the portions of the sensor and the accuracy of the timer. Since the time and length of the e-sections of the rail can be measured with high accuracy, this determines the high accuracy of finding the magnitudes of displacements and the image of the object's growth.

Since the output signal describing this part of the cell has the form of a system of square-wave pulses whose amplitude is constant (independent of the magnitude of the object's movement), the range of measured movements when using the sensor described

5 is limited only by the dimensions of the sensor itself.

The use of the proposed linear displacement sensor makes it possible to expand the range of measured displacements, to increase the accuracy of measuring large displacements. Tests of the described sensor showed that the error in determining the movements of the pistons of the pressure multiplier

5 decreased by more than an order of magnitude, and speed - more than 3 times.

Claims (1)

1. Tsiklis D.S., Rodina M.D. Electromagnetic method for measuring the speed of movement of a piston in an adiabatic installation. Instruments and Experimental Technique, 1968, No. 1, p. 190-191. . 2; Ageikin D.I. and others. Sensors of automatic coitrol systems and regulation. M., Mashgiz, 1959, p. 14-15 (prototype). //