SU370808A1 - DIGITAL DEVICE FOR DETERMINING POSITION55 - Google Patents

Description

one

The invention relates to digital devices for determining the position of an object by which the displacement of a movable element relative to a fixed one is measured. Such a digital device includes a counter, the digital content of which, converted to analog form, is continuously compared with the analog value representing the position of the moving element at the moment, resulting in a mismatch signal controlling the transmission of counting pulses to the counter.

In devices of this type, i.e., when the moving element is continuously moving, the magnitude of the error signal depends on the speed of movement, since the system exhibits inherent inertia, following the changes occurring in it.

A device for determining the position of an object of such a type in which a digital-to-analog data converter that receives information from a counter includes a precise section and a coarse section, which feed a correspondingly accurate and coarse section of a displacement transducer. The latter is designed in such a way that it can continuously compare this position of the rolling element with the digital content of the counter converted to analog form in order to form, respectively, exact and coarse signals that are mismatched, which through the control unit controls the counting operation of the exact and coarse sections

counter.

However, this kind of digital positioning device requires two separate servo systems to control the exact and coarse part of the signal respectively.

mismatch, and these servo systems receive a common input signal in the form of an analogue value representing the position of the mobile element. It is obvious that the equipment that requires a digital-to-analog converter to measure the transformer for the exact section, as well as a digital-to-analog converter and one measuring transformer for the coarse section,

is complex and expensive.

Moreover, in a well-known system, two different frequencies are used to power the exact and coarse sections respectively, which further increases the complexity

equipment, because the natural frequency dividers are required to obtain these two different frequencies from one oscillator (oscillator).

In the proposed digital device

said counter is adapted to selective operation with different counting rates depending on the speed of movement of the moving member.

FIG. 1 shows a block diagram of contours; in fig. 2 is a control device diagram used in the converter shown in FIG. one; in fig. Figure 3 shows the time separation of some signals present in the converter for the FNG. one.

In the embodiment of the device, as shown in FIG. 1, it can measure the displacement of a movable element relative to a predetermined starting point and give a numerical expression of the position of this element.

The proposed digital device is used to determine the position of an object in a system having an element capable of shifting 1 along one displacement pox. However, it is quite clear that such an implementation of the invention can be directly applied to work in a system having an element capable of moving along two or more axes or around two or more axes, since it is enough to supplement the system with a separate digital device. which will be described for each of the mentioned axes.

The device includes a transformer (in the form of a displacement transducer) having a stationary part 2 connected to a stationary element, for example, an axial equipment in which said converter is used, and a movable part 3 sliding, for example, along a certain axis and attached to the movable element this equipment. The transducer can be of the same type as described in US Pat. No. 2,799,835. It includes a pair of primary polar windings 4 and 5 that are phase-displaced in space and connected to the fixed part 2, and a multi-pole secondary winding 6 attached to the movable part 3. It is well known that in such a displacement transducer the position of the movable part relative to the fixed can be relative moving the secondary winding in relation to a pair of primary windings, this movement being represented as an angle measured in electrical degrees, and the pole division of the three windings 4, 5 6, corresponding to 360 EL. hail is equal to a known value, for example 2 mm.

The transformer that determines the position / continuously compares the signals supplied in an analog form to its input terminals 7 and S with an analog value applied to input 9 and representing this field, the moving part 5 and, therefore, the position of the secondary winding 6. This analog value is transmitted mobile equipment element 10, for example, a sled equipped with a reference pointer and capable of moving along the sliders in a certain direction. If the movable element 10 is rigidly connected to the movable part 5 of the transformer /, the analog value applied to the input 5 directly represents this position of the movable element 10 along the direction of movement; Moreover, the moving element 10 can be connected to the moving part 3 by means of mechanical transmission means, in which case the analog value fed to the input 9 is represented by the given position of the moving part 3.

The transformer / is connected via input terminals 7 and 8 with a digital-to-analogue information converter, which in turn receives information from a two-decade counter 12. Converter 11 is adapted to convert digital 1P1 information, which is transmitted, for example, binary code and in parallel form on its input terminals through transmission channel 13, to analog

information represented by the sine and cosine functions of the electrical angle expressed by said digital information; At that, it means that the maximum number that can be represented by the counter 12 is 360 e. grad., and pole division windings 4, 5, 6 transformer 1.

In particular, the converter //, receiving power from the sine wave generator 14,

having, for example, a frequency of 10 kHz, provides a sinusoidal signal to the input 7, which supplies the fixed winding 4. The latter has a frequency of 10 kHz and a maximum amplitude proportional to the sine of a given angle. The converter also delivers a sinusoidal signal having a frequency of 10 kHz and a maximum amplitude proportional to the cosines of the su danugo angle to output 8 feeding the stationary secondary

winding 5.

The digital-to-analog converter can be of any type, provided that its constituent parts are selected so that the switching time required by the converter to supply at its output aaial expression of a digital value supplied at its input to the transmission channel 13 is sufficiently short in relation to oscillation period of the generator (for example, 1/100). For this reason, switches mounted in the specified converter and controlled by the input of transmission channel 13 must be of an electronic type, for example, on transistors. (The reasons for this

the selection and the limitation on which the frequency selection for oscillator 14 depends will be explained below).

Therefore, at the output terminal 15 of the transformer /, a signal is obtained having a frequency of 10 kHz and a maximum amplitude proportional to the difference between the present position of the movable part 3 and the position expressed by digital information presently contained in the counter 12 with a phase shift of 90, or in 270 email. hail, relative to the generator signal, depending on whether the sign of the indicated difference is positive or negative (see Fig. 3, a c b). Based on the above, it can be seen that the present position refers to each pole division and that the above number represents the position within one pole division.

The analog error signal applied to transformer output 15 through the corresponding amplifier j6 is transmitted to control device 17, adapted to control the counting operation of counter 12, in order to change the digital information contained in it and thus significantly bring the specified error signal to zero. It is understood that the mismatch signal will be reduced to zero when, in the same way as the digital information, corresponds to the position of the movable part 3.

The control device 17 (see Fig. 2) receives the error discs at its input terminal and, based on this signal, performs three types of control functions. This device establishes: there is or not a mismatch; controls mismatch sign; distinguishes the order of the magnitude of the mentioned mismatch, determines (in the case of the described special device) whether it represents interleaving, corresponding to a hundredths or tenths of the pole that determines the position of the transformer. The analog mismatch signal, which is input to the device 17, through the corresponding amplifier 18 is connected to the input terminal 19 of the threshold circuit 20, which determines the level of sensitivity by the error (see Fig. 3, a) of the digital device for determining the composite of the object; moreover, the threshold circuit is adapted to energize either output 20 or output 20 according to whether the maximum amplitude of the sinusoidal voltage representing said error signal applied to input 19 is higher or lower than the voltage level of threshold threshold 20. The signals from the outputs 20 and 20 through the valves 21 and 22, controlled by the time switch signal L, are used respectively to excite and remove the excitation from the bistable element 23 that performs the function of storing during each period of the gene Ator / 4, regardless of whether an error or not. The presence of a mismatch signal exceeding a threshold a is detected by exciting the output of a 24 nom bistable element 23.

The output of the amplifier 18 also feeds the input 25 of the separation circuit 26, which is designed to supply the positive outputs and the negative half-waves of the sinusoidal voltage, which represent the error signal, to the outputs 26 and 26.

Outputs 26 and 26 through gates 27 and 28, which are controlled by a temporary switching signal A, are respectively used to excite and de-energize a bistable element 29 performing

the memory function during each period of the generator 14, regardless of whether the error signal voltage is positive m or negative. The presence of a positive or negative error signal is detected by activating the outputs 30 or 31 of the bistable element 29.

Outputs 30 and 31 control the circuits, respectively, mnn, and 32 and 33, while the output 24 of the stable element 23 controls both the "I. Therefore, if the threshold tracer 20 detects the presence of a mismatch, (.by the output 24 of the bistable element 23 will be suitably excited), either the output C terminal of the “AND 32, or the output pin of the 1M D of the“ H 33, will be excited, depending on whether exit 30 or exit 31 of the bistable was excited; ha 29, i.e., for 13) 1C bridges

which signal was mismatched - positive negative: nd. Moreover, if the threshold circuit 20 does not detect a mismatch (in this case, the output 24 of the bistable element 23 covovetste) is de-energized), then none of the lines 32 and 33 will be excited.

Finally, the analog error discrepancy is directly transmitted from the input terminal ycTpoiicTBa of control 17 to the input

clamp 34 of the threshold circuit itself, known to itself, adapted to excite either its output 35 or output 35 in accordance with the fact that the error signal exceeds the predetermined threshold level b (see fng. 3, b). In particular, the threshold level should be chosen so as to be equal to the maximum amplitude of the sinusoidal cngnal, which is 1/20 pole

the division determining the position of the transformer /, namely, 0.1 mm in accordance with the example under consideration; thus, the threshold circuit 35 serves to distinguish the mismatch corresponding to one tenth of the pole division, and the mismatch corresponding to the one hundredth of this division, exciting, respectively, either output 35, or output 35. These outputs through ventnly 36 and 37, respectively, the signals controlled by the signal BpeMentioro are configured to excite or remove the excited bistable element 38. serving for the memory function, during each period of the generator 14, independently

whether the mismatch amplitude is equal to the tenth or hundredth part of the pole division, and thus exciting either the output E or the output F.

The temporal non-connected signal from output A consists of a series of pulses received from a generator of sinusoidal waves 14. The latter feeds, in addition to the converter 11, from digital to analog, a square pulse former 39 (see Fig. 1), which controls the single-pole pulse former 40 having two outputs A to B. A shaper of unipolar pulses 40 generates, at the output L, a series of pulses (see Fig. 3, a and b), arising respectively at the points where the square wave coming from the square wave former 39,crosses the neutral axis in the downstream region: events, and; moreover, the same driver is able to generate at output B (see Fig. 3, a and b) a series of pulses that occur at exactly the same points, where the same will, is fed to the output of the formation of the right angle pulses, crosses the neutral axis in the upstream direction.

As already mentioned, the pulses from output A control the valves 21, 22, 27, 28, 36 and 37. In particular, for each oscillation period produced by the generator M, a pulse is generated at the output L; the latter establishes the moment when the bistable elements 23, 29 and 38 can change their state, and this change is such that it either excites or removes the excitation from the warning bistable elements depending on which valve is open - the first or second in of the cited pairs of vectors, 2 / and 22, 27 and 28, 36 and 37.

FIG. 3, a and b show various waveforms that occur at the output of the generator 14, which determines the position of the transformer /, the square ripper 39, the ramp 40, the splitter 26, and the control device 18 with the corresponding timing. In particular, FIG. 3, a and b, a positive error signal 15 is displayed, which at the initial moment is shifted in phase by 90 ° relative to the signal of generator 14. Therefore, the gating impulses L are first in phase with the positive half-waves of the error signal, which influences and the output 26 of the separator 26, by via the valve 27, the bistable element 29 is energized.

In the opposite case to that shown in FIG. 3, i.e., if the error signal 15 were negative, the gating pulses L would be in phase with the negative half-waves of the error signal, which excite the output 26 of the separator 26, whereby through the valve 28 from the stable element 29 the excitation would be removed.

Outputs C and D of the control device.

selectively opened in the manner described, are fed in order to allow the counter 12 to perform the counting operation in the forward and backward directions. Counter 2 is a reverse type counter that includes many decades, each of which consists of a binary counter. For example, in the implementation of the invention shown in FIG. 1, there are two decades 12 and 12 representing the hundredth and tenth, respectively. Moreover, these decades are so interconnected that decade 12 counts counting cycles of decade I2i, in other words, decade 12 feeds on a counting pulse from the previous decade 12 after the last received ten pulses, which caused it to perform a full counting cycle.

The outputs E to F of the control device 17, selectively excited in accordance with this description, are two channels that control the opening of the valves 4} and 42, respectively, which control the decades / 2 and 122 of the counter.

The counting pulses excited at output B of circuit 40 are applied to both valves 41 and 42; through these valves and, respectively, through channels 43 and 44, pulses are transmitted to selectively control the counting operation of either section 12i or section 122, depending on which of the valves (41 or 42) was activated by control device 17 through cables E or F. Therefore for each oscillation period excited by generator 14, circuit 40 supplies a pulse from output B, which controls the counting operation of one of the decades of counter 12 in accordance with the results of the control operations performed on the error signal by control unit 17 t, ustanovlenEgy pulse temporal nereklyuche1 and outlet A, to refer to a same period. In order for the output pulse L transmitted to the counter 12 to be effective and to force this counter to perform a counting operation, it is essential that one of the two control device valves be opened in such a way as to condition the counting operation for counting operations in direct or reverse directions.

Each effective pulse at output B causes a change in the digital content of counter 12 and, therefore, changes in analog signals at outputs 7 and S of the converter from digital to analog 11. Signals now represent the sine and cosine functions of a new digital number, respectively, counter. Thus, the new analog mismatch signal for Vits at the output 15 of the transformer / and will be, on the contrary, a sinusoidal voltage of 10 kHz. a maximum amplitude proportional to the difference between this position of the movable part 3 along the axis of displacement and the position represented by the new digital number contained in the counter 12, and a phase shift of 90 or 270 ° relative to the generator signal 14 in accordance with the polarity of the specified difference.

A new error signal through the amplifier 16 is connected to the input of control unit 17, which analyzes this signal in order to establish its amplitude and its polarity and to excite from its outputs that pair of outputs that characterizes the new state so that it controls the counting operation of the counter 12 in the direction and in the decade, which are able to reduce to zero the value of the specified mismatch. These internal operations are proceeding in the manner described, striving to bring the system into a state of equilibrium. In particular, when the movable part 3 stops, the equilibrium condition is reached at the error signal, the level of which is lower than the threshold level a, corresponding to the sensitivity of the system, and neither output C, and output D will be excited. Thus, the counter 12, no longer configured for performing counting operations, remains in that state for the entire time that part 3 remains stationary. In this case, the digital information transmitted by this counter corresponds to the effective given position of part 3 relative to part 2 within the pole division with an accuracy corresponding to the threshold level and sensitivity. In the opposite case, when the movable part 3 is in motion, the internal response of the system, as explained above, should allow the counter 12 to contain digital information continuously corresponding to the effective position of the movable part 3. This result is achieved only if the switch the elements, which were their system, are insignificantly related to the generator oscillator period 14. Thus, the control device 17 discriminates the error signal according to its polarity; moreover, it selects outputs E or F intended to control the counting operations in two different decades of counter 12 according to whether or not the threshold level L is higher than the specified error signal. In the case we are considering, the threshold level is equal to the magnitude of the mismatch representing 1/20 of the pole division, i.e., 0.1 mm. In general, the counter may include five decades (or other names in the case of using a system other than the binary-decimal system used in this description), thus mutually connected, that each decade counts counting cycles performed by the previous decade. Each decade can be selectively controlled either by the preceding decade or by the corresponding channel selected by the specified level unit in accordance with said error signal. In this case, the control unit

will include, n-1 circuits, similar to circuit 35, each with a different threshold level, representing a different range of the error signal amplitude, n-1, the circuits must be interconnected so that the control device can (distinguish channels corresponding to ranges of different magnitudes of the indicated error signal. If, for example, the counter includes three decades, adapted accordingly to the counting of the tenth, hundredth and thousandth parts of a millimeter, then the control device must be equipped two circuits, identical to circuit 35 and having a threshold level equal to the error amplitude representing 1/200 and 1/20 pole division, respectively, determining the position of the transformer related to this case, and it is arranged in such a way as to have three channels designed to control three decades of the counter. These three channels are respectively excited by the error signal lower than the level of the first threshold or between the levels of said two thresholds or higher than Hb said second threshold.

FIG. Figure 1 also shows a four-decade counter 43, which can consist of any number of decades, one example of four decades 43, 432, 43, 43i, identical to those contained in counter 12, and interconnected so that a reversible counter is implemented. The first two decades of 43 and 432 correspond to identical decades of 12 and 12 of counter 12, therefore, they are selectively controlled by the same channels 44 n, respectively 45.

Decades 43, 43, 43 “43 are interconnected in the form of a chain so that each decade counts counting cycles committed by the previous decade; Decades 43 and 43 are controlled only by the preceding decade, Decade 43 can be selectively controlled either by the pre-existing Decade 43 or channel 45, Decade 43 is controlled only by Channel 44.

The counting direction of counter 43 is set in the same way as for counter 12, using outputs C and D. While decades 43 and 43 count (in the same way as decades 12 and 122 of the internal counter), hundredths and, accordingly, tenth parts millimeters, sections 43z and 43 count the units and, accordingly, tens of millimeters contained in the effective displacement of the movable part 3.

The counter 43 is furthermore provided with means for zeroing or for changing its digital content and, moreover, for controlling the change of the sign of the reference point when the counting operation crosses the zero value. All these operations can be performed independently of the counter 12.

The operation of a digital device for determining the position during its expiration

Plutatsky occurs as follows. Suppose that the movable element 10 is represented by a sled equipped with yKa3aTevaeM reperm and able to slide along sliders along a certain direction; moreover, the sled can be set in motion manually or otherwise. In addition, it is assumed that the fixed element 3 is rigidly connected to the slide 10 and that the independent input 9 is powered by an analog value directly representing the position of the slide at the present time. Moreover, it is assumed that a digital position fixing device is used to measure the dimensions of the work piece along said direction. The first step is to place the pointer on the slide on one edge of that part of the part to be measured. By affecting the return means, the digital content of the counter 43 is eliminated, while the counter 12, in accordance with its own way of working, gives an indication of this position of the movable part 3 relative to the fixed part 2 relative to the pole division value. Successively, the slide 10 moves until the pointer coincides with the other edge of the part measured on the workpiece. Under these conditions, the counter 43 indicates the absolute digital value and the sign of the size being measured, while the counter 12 will give a digital indication of the new position reached by the moving part of the relatively fixed element always relative to the size of one pole division. In general, the sled 10 can slide at different speeds.

Consider the operation of the device for determining the position, which functions with non-displacement speeds, which are constant, but different in magnitude.

FIG. Fig. 3a shows a temporal plot of the error signal applied to the output 15 of the transformer that determines the position of the transformer, related to the low movement speed. The voltage level a represents the level of the circuit 20 (except for the voltage generated by the amplifier 18), i.e., in other words, the minimum error ratio to which the control device 17 is sensitive. Signal 46 is a sinusoidal voltage having a frequency identical to the generator frequency 12 (10 kHz), lagging 90 ° for a positive mismatch and having an amplitude modulated by the movement of the moving element 3, which occurs at a low stationary speed. This movement causes a sinusoidal change in the mismatch amnlititude within each pole division. Therefore, the error signal can be represented by a time stamp.

J. ,, sin,

ficom, as a function of H-sin 2t; /,

where // is a constant of permeability, depending on the ratio of the gain between the output of the generator 14 and the output 15 of the transformer /; y is the velocity of the non-displacing part of the sliding part 3; p-pole division. When operating at low speed, for example in the current case at a speed of 200, during an interval corresponding to several periods of oscillation of the error signal can be represented with sufficient accuracy

the function NOT --- sin2ir /

5Р

FIG. 3, and graph C represents the modulating function H-2n-t generated by sliding the movable part 3, i.e. the timeline that we would get for the error signal if the digital-to-analog converter converts 11 from a digital signal rather than a continuous signal than sinusoidal.

5 In accordance with the assumption made earlier, it is clear that the digital content of the counter 12 must correspond at each moment to the position of the movable part 3 relative to the fixed part 2 in the ripe 0 cases of one pole division. This position is expressed in tenths and hundredths of a millimeter in digits, but in the decades of 12 and 12, respectively. These digital readings are given up to the sensitivity of the system, which in our example is equal to 1/200 pole division, i.e. 10 microns.

When the slide of the slide 10 is performed at a constant low speed Y (in this

In case of a speed less than 100 .VLW / CUK) along the normal direction of movement, for example, in the positive direction, the analog error signal arising at the output 15 changes according to the schedule d.

 When the sinusoidal magnitude exceeds the value of the norm level d, the circuit 40 generates a time switching pulse A which coincides with the first positive peak e, and the control device can activate the outputs correctly.

Sequentially, half a time later, coinciding in time with point I, circuit 40 produces an impulse of counting on exit B, which, through gate 41, opened on channel F, causes decades of fractions 12 and 43 to read one division in the forward direction.

Changing the digital content of the counter 12 through the channel 13 produces a change

 analog signals at the outputs of the 7–8 converter from digital to analog and, therefore, the amplitude of the error signal at the output 15, which determines the position of the transformer 1.

65 Assumption previously made regarding

13

Converter 11, i.e., that its installation time is short with respect to the generator period, makes it possible to consider the oscillation of the magnitude of the error signal amplitude as instantaneous. Moreover, the assumption that the change in the digital content of counter 12, which occurs when one counter is counted in the forward direction, is such that it determines the sign reversal of the indicated error signal and the amplitude reduced to a value below the threshold level a, which means there is a phase reversal on graph d at point f. Therefore, the modulating function will begin to grow again, starting at a lower level, as shown in graph g. Graph g is similar to graph c and shifted in relation to the last by the value oh,: representing the time required for the movable part 3 displaced, and the speed Oi by a distance equal to 1/200 of the pole division, i.e. by 1 / 100 mm. While the sled 10 continues to slide in a positive direction at a constant speed, DI, function, movement, the movement continues in the manner described, it is clear that when moving the movable part 3 by one hundredth of the pole division, the decade / 2 counter moves forward by one division, and then, the moving part of the moving part is shifted by 0.1 mm, decade 12 will cause the decade to move forward in the direction by one division.

Under the same conditions, the speed of moving part 5 is so low that counter 12, always controlled by counting pulses B through channel 44, is able to function at the right pace, i.e., adapt its digital content to the actual position of said moving part. If the speed of movement of the slide 10 is sufficiently high (in this case, // // 200 Uj pf / 2Q), the conditions of functioning of the system change (see Fig. 3, b) and the error signal appearing at the output /. The transformer / can be expressed by the function H Sin for a time interval that is shorter than two periods of oscillation, as shown by graph i. Schedule /

represents the modulating function I

generated by moving the movable part 3, i.e., a timeline, which would have been obtained if the digital form was transformed into an analogue vatal 11 with a continuous signal rather than a sinusoidal one. The voltage level b represents the threshold level of the circuit 35, i.e. the error voltage, above which the control device selects channel E.

Thus, when sliding the slide 10 with a constant and high speed U2 (for example, 0.9) along the correct direction of movement, for example, in the positive 14

The BOM direction, the analog error signal, appearing at output 15, varies in accordance with schedule i. When the sinusoidal magnitude exceeds the threshold level b, the circuit 40 generates time switching pulses L in accordance with the first positive vertex k and the control device can then correctly excite channels C and. Consistently, as much as half a period in accordance with time e, circuit 40 produces a counting impulse B, which, through valve 42, opened at output E, causes decade of tenths 122 and 442 to read one division in the right direction.

Changing the digital content of counter 12, through the transfer channel 13, changes the analog signals appearing at the outputs 7 and 8 of the converter from digital to analog, and, therefore, the instantaneous change in the amplitude of the error signal that occurs at the output / 5 determining the position of the transformer, in the manner described for slow movement. Corresponding to FIG. 3, b, the assumption that the indicated change in the digital content of counter 12, when the last division of one division in the forward direction is such that it reduces the magnitude of the indicated error to a lower value than the threshold level b, means that the modulating function will begin to increase at , starting from a lower level, as shown in the graph m, which is similar to the graph /, but is shifted relative to it by an amount depending on the residual mismatch at the moment of switching /.

While the movement of the slide 10 continues in the positive direction

0 at a constant speed V2, the operation of the system continues in the manner described, and it is clear that every time the moving part 3 moves one tenth of a millimeter, the decade 12 of the counter 12 counts

5 one division in the forward direction under control of the counting pulses from output B, fed from output E to line 45.

At the same time, the counting speed of the counter 12 is high enough for the latter to function at an appropriate rate, i.e., that its digital content could follow the actual position of the moving part.

From the above description, it becomes quite clear that two different amplitudes of the error signal correspond to two different speeds of movement o, and V2 of the moving part. This allows the controller 17 to automatically select two different outputs F or E to control the counting operations of the counter 12.

Thus, it is obvious that the counter 12 can selectively function at two different count rates, corresponding to two

5 different speeds with which the G5 can 9

15

- be excited. Both of these different counting speeds can be obtained in a known way: by selectively applying counting pulses. In the corresponding decade of the counter through the respective channel.

The maximum allowable speed for moving the movable part 3 is jof / 20 (which corresponds to a speed of 1 m / s in the proposed embodiment), i.e. the rate at which the switching of the modulating function of the error signal has the same frequency as the generator; while the counter can still work at the same pace and perform counting operations. A suitable limit for the aforementioned speed can be set, for example, with the help of a torus, which takes effect at the maximum allowable speed.

A higher speed can be obtained simply by increasing the generator frequency f or increasing the division determining the position of the transformer. For these reasons, the frequency of the generator must be chosen in connection with the division of the transformer Y determining the position and with the maximum allowed speed of movement. In all cases, the increase in frequency / has a limit determined by the switching time of the elements constituting the system.

The considerations expressed regarding counter 12 can be applied to counter 43, since decade 43 and 432 correspond exactly to decade 12i and, accordingly, 122, while decade 43 and 43 representing the coarse section of counter 43, produce counting under the control of the exact section represented by decades 43i and 43. In addition, the counter 43 is equipped with tools that can be performed, for example manually, on the action, but return to its original position or shift, and the means to automatically change the division of the count when the count is crossed t is zero; moreover, the specified counter can function as an absolute or differential. Therefore, in the proposed positioning device, the following operations are possible: shifting the reference point and changing the positive direction of the axis for a constant reading in the forward direction without having to overflow the contents of the external counter.

Counter 43 allows the device to be located at any pre-existing position to be installed with sufficient accuracy and without loss of time, even after a long period of time or after a fault in the supply of current, i.e., in cases where the digital content of said counter is destroyed. Indeed, the assumption that the prop part of the position-determining transformer is provided with an absolute reference starting point, representing the absolute zero position of the equipment, and, in addition, assuming that it is possible to determine

sixteen

the position in the plan along the direct movable part with respect to this zero point, and the repetition of the installation of the movable part at a predetermined point, which is located at a known distance from the initial point of the absolute reference, is possible. This is possible when performing the next operation. At the start, the pointer of the movable part is aligned with the absolute reference point, and the counter 44 returns to its original position, then the movable part moves in the direction indicated by the position sign, which must be reached until the counter 43 shows the numerical value corresponding to the aforementioned known distance. On the other hand, if the position of a predetermined point is given by its distance relative to the reference point, the coordinates of which are relative to the absolute reference point are known, then the described procedure must first be repeated in such a way as to set the moving part to the relative reference point; when this is achieved, the counter 43 again returns to its original position. Thereafter, the movable element moves in the direction indicated by the number sign, which should be reached until the counter gives a digital indication corresponding to the indicated relative distance.

The accuracy of determining the position of the movable part of the positioning device of the present invention can be improved in a known manner, for example by measuring in analog form with appropriate residual mismatch means, if it is still present at exit 15, when the system is in its equilibrium state; moreover, the mentioned mismatch has a value lower than the sensitivity level of the given system.

It should be noted that in order for the quality of the device to determine the position, some measures are required to ensure the correct inversion of characters in the meter 12 or 44. In particular, a decade of tenths of D must remain de-energized for a short time near zero and at the same time a decade of hundredths must remain energized to allow decades of l2i and 431 to count in reverse and reverse (to zero) before the inversion of the sign in the counter occurs.

In contrast to known devices, the proposed device is simpler, since it requires only one servo system, selectively sensitive to two operating speeds; In addition, only one position sensing transformer is used to detect both the coarse and the exact error signal, and only one digital-to-analog converter is required to power the said counter. Finally, the presence of a threshold of sensitivity and prevents

17

the system becomes unstable when the movable part 3 is in a stationary state, i.e. it prevents the oscillation of the counters 12 and 43, and also prevents the counter 43 from alternately showing two points in contact with the actual position of the movable part 3. In order correctly eliminating this instability, which affects the last digit shown by sections 12 and 45 of both counters, it is sufficient to set the threshold and the value between 0.5-1.0 voltages corresponding to the error equal to one unit specified edney numbers (in this embodiment, a threshold must be present between the values of voltage Correspondingly vuyuschego Mismatch vaniyu 5 and 10 microns, respectively).

Subject invention

A digital device for determining the position of an object containing a displacement transducer, the movable part of which

connected to the object, and the windings of the fixed part are connected to the outputs of a digital-to-analog converter connected to a sinusoidal voltage generator and to a two-decade counter whose inputs are connected to the outputs of the error sign of the control device, one of the inputs of which is connected through an amplifier to the winding of a moving part of the displacement converter, characterized in that, in order to improve the accuracy of the device, a four-decade counter has been entered in it, the inputs of which are connected to the entrances of two-decade a counter, valves, a driver of unipolar pulses and a driver of rectangular pulses, the input of which is connected to a sinusoidal voltage generator, and the output is connected through a driver of unipolar pulses to another input

control devices and with the first inputs of the valves, the second inputs of which are connected to the outputs of the deviation value of the control device, and the outputs of the valves to the control inputs of the counters.

F1 / g.2 Fig.Z /