SU732803A1 - Servo system - Google Patents

Description

The invention relates to an automatic machine, a boom and can be used in automatic systems for remote transmission of an angle for industrial and special purposes.

Known devices of potentiometric synchronous communication with unlimited rotation angle [C and [2].

The closest in technical essence to the proposed is a device containing a master and receiving potentiometers connected to the first voltage source, the movable contacts of which are connected respectively with the first and second inputs of the first adder (2].

However, this device is characterized by insufficient accuracy.

'The purpose of the invention is to increase the accuracy of; device

This goal is achieved by the fact that a second adder, a key, an element And, a zero-organ, a second and third voltage sources, and a first and second limit switches, the first inputs of which are mechanically connected respectively to the movable contacts of the master and receiver potentiometers, are introduced into the known potentiometric synchronous communication device , the output of the first limit switch is connected to the third input of the first adder and the first input of the second adder, the output of the second limit switch to the fourth input of the first adder and to the second input of the second adder, the second and third voltage sources are connected respectively to the first input of the key and the first input of the zero-yurgan, the input of which is connected to the movable contact of the master potentiometer, the first input of the element And is connected to the output of the zero organ, the second input to the output of the second adder, and output - with a second key input, the output of which is connected to the fifth input of the first adder.

Figure 1 presents a functional diagram of a tracking system; figure 2 - graphs of the changes in potentials taken from the potentiometer engines depending on the angle of rotation - - £ <d).

The circuit contains a master potentiometer 1, a receiving potentiometer 2, a first adder 3, a first and second switch, switches 4 and 5, a key 6, an element And 7; zero-organ 8, second adder 9, first, second and third voltage sources 10, 11 and 12, in addition, the potentials taken from the movable contacts of the master and receiver potentiometers and the angles of rotation of the movable contacts of the master and receiver potentiometers and the angle of rotation between the terminals of the master are indicated and receiving cc potentiometers.

The device operates as follows.

Suppose that the rotation angle cС between the terminals of the master 1 and the receiving 2 potentiometers is 180 °, the load does not affect the shape of the graphs 41 = f (d-4) and '(' r = f (dz); potentials, 4 * 2 r are measured relative to the point of zero potential; the comparison error in the absolute value of the potential Vi and half the supply voltage and _pmT / _{2 of the} third power supply 12 is zero; the operation angles of the first and second limit switches 4 and 5 are exactly equal to 0 ° and 180 ° limit switches are open within 0-180 and closed within 180 ° - 360; potentials 4ι,, sign pr it is written down before entering the first adder 3 in accordance with the state of the first and second limit switches 4 and 5, that is, the potentials, Чт and 4 ·} are positive when the limit switches 4, 5 are open and negative, when the limit switches are closed 4 and 5, respectively.

Consider the formation of a mismatch signal E with a change in the angle of rotation cL, within the following limits;

-90 ° <oC <90 °, 90 ° <OF) <270 °

When the angle of rotation ^ varies, from -90 ° to 90 °, the potential 4 <is lower in absolute value of the supply voltage 1) _pit ) 2 of the third voltage source 12, while from the zero-organ 8 through the And 7 element, the inhibit switch 6 is applied to the key 6 voltage, resulting in a potential 4 ^ equal to zero.

The mismatch signal generated in the first adder 4 according to the law (1) is determined from the expression _r _ ^and pit, G ^and pit,> ^and pit, ^£ 460 ^ 1 \ 460 ° / ΑβΟ ^<OL -T ° SP · ^(2>

This expression is true when the absolute value of the error angle (sTs- cij) at ^e 90 (see. Fi g 2) when the angle of rotation of di, in the range from 90 ° to 270 41 potential larger in absolute value polo fault voltage (U _Pit | 2) In this case, the null-organ 8 generates a permission signal supplied to the input of element And 7. For different signs (conditions) of the first and second limit switches 4 and 5, another output signal is generated at the output of the second adder 9, element And 7. With the same signs of the first and second th limit switches 4 and 5, a second adder 9 produces prohibiting voltage. If there are two enable signals, the And 7 element generates an output enable signal supplied to switch 6, through which, in this case, potential 4) g equal to twice the supply voltage (2 U pit) of the second voltage source 11 is passed to the input of adder 3. Before the final by summing (1) to the potential 4 ^, a sign is assigned in accordance with the state of the second limit switch 5 (positive when the limit switch is open and negative when the switch 5 is closed).

Thus, with different signs (states) of the first and second limit switches 4 and 5, the potential jump is compensated by 2 and _pit , when the angle of rotation οί-i varies from 99 to 270 °. Mismatch signal £ (1) for.

these limits of rotation angle clj will be determined from the expression

480 \ 48O ^Λ 2 ^_Ο / Ι8Ο at 180 ° <(oLi and 0 ^ 2) * 270 ° or 9 0 ° <(ct _l and d 2) <180 ° (4) (180 ° 0 ^ 2 ^ 270 ] 90 ° <0¼ <180 (5) gy „.„ At (90 ° <ci-2 <180 °?

(180 ° <bC <270 ° J

Expressions 3,4,5 remain true when the absolute value of the mismatch angle (tii - cd) is less than 90 ° (see Fig. 2).

The final mismatch signal E for any values in the device is determined from the expression £ = -> ⁽⁶⁾ at (cX- - οό ₂ ) <90 °.

In the general case, the angle of rotation between the terminals of potentiometers 1 and 2 can be less than 180 °, and the following limitation with <

(dj - ct ₂ ) <2 \ and the coefficient of the magnitude of the voltage of the error signal K included in the expression of the error signal 8 in the general form

E = K (- with € ₂ ), (8) will vary within

U lit _2-SKL (9)

360 ° -oL 'sC

Based on the foregoing, the load i.e. the input resistances of the first adder 3 and zero-organ 8 should be selected taking into account the permissible decrease in the coefficient K (8.9); if the comparison error in the absolute value of the potential and half the supply voltage is not equal to the tolerance on the maximum permissible mismatch angle (with £ ^ -о * -2> (6.7 should be reduced by the value of this error; error in the operation angles of the first and second limit switches 4 and 5 leads to an increase in the error of the synchronous communication device near the angles of 0 ° and ci by the value of this error, in this regard, the error of the first and second limit switches 4 and 5 should be less than the error of the functional dependence of the master and potentiometers 1 and 2, which, as a rule, is not less than 0.3 - 0.5 °. An error of limit switches of the order of 0.1 is easily achievable when using, for example, optocouplers; signs of potentials ^, Ψ £, Ч'т,, can be attributed either directly in the first adder 3 or determined by the phase of the alternating supply voltage or the polarity of the constant supply voltage with separate supply of each potentiometer, key 6 and zero-organ 8.

The use of limit switches and logical signal processing in the invention makes it possible to use the simplest type of ring potentiometer in it, and the error in transmitting the angle practically does not exceed the error in the functional dependence of the potentiometer and does not contain methodological errors; in comparison with known devices, the error of synchronous communication in the invention is reduced by 3 and 4 times.

Claims (2)

The invention relates to automatics and can be used in automatic systems for the remote transmission of the angle of industrial and special purpose. Potentiometric synchronous communication devices are known with an unlimited rotation angle T. and 2. The closest in technical essence to the present invention is a device comprising setting and receiving potentiometers, the moving contacts of which are connected to the first voltage source respectively to the first and second inputs of the first adder 2. However, this device is characterized by insufficient accuracy. The purpose of the invention is to increase the accuracy of carrying devices. This goal is achieved by introducing a second adder, a key, an I element, a null organ, a second and a third voltage source, and the first and second limit switches, the first inputs of which are mechanically connected to the moving contacts of the master and receiving potentiometers, the output of the first limit switch is connected to the third input of the first adder and the first input of the second adder, the output of the second limit switch is connected to the fourth input of the first adder and to the second input of the second adder, the second and third voltage sources are connected respectively to the first input of the key and the first input of the zero- body, the input of which is connected to the moving contact of the setting potentiometer, the first EQUIPMENT of the element I is connected to the output of the nullorgan, the second input - to the output the second adder, and the output with the second input of the key, the output of which is connected to the fifth input of the first adder. Fig. 1 shows a functional diagram of a tracking system; 2 shows graphs of potentials taken from potentiometer sliders as a function of angle of rotation a and f-fCd.). The circuit contains the driver .potenxtHOMBTp 1, the receiving potentiometer 2, the first cyN &amp; iaTop 3, the first and second koytsevnye switches 4 n 5, the key b, the element And 7; null organ 8, second adder 9, first, second and third voltage sources 10, 11 and 12, in addition, the potentials are indicated, removed from the moving contacts of the setting and receiving potentiometer H (Hg) and fjf the rotation angles of the moving contacts of the setting and receiving potentiometers and “ij / angle of rotation between the findings of the hoisting and receiving potentiometers cC. The device works as follows. Suppose that the angle of rotation between the terminals of master 1 and receiver 2 potentiometers is 180, the load does not affect the shape of the graphs H f (d-) and 2 f 0 g); potential; The h, t, ts are measured relative to the point of zero potential; the comparison error in the absolute value of the potential% and half voltage of the third power source 12 is equal to zero; the angles of operation of the primary and second limit switches 4 and 5 are exactly equal to and I80f the limit switches are open within 0-180 ° and closed within 180 ° - to the potentials 4 2 I Chas the sign is assigned to the input to the first adder 3 in accordance with the state of the first and second limit switches 4 and 5, i.e. Pents Ч, .1.1 and / are positive with open limit switches 4, 5, respectively, and negative, with closed limit switches 4 and 5, respectively. Consider the formation of the error signal 6 when changing the angle of rotation ct, in the following limits; -90 ° oL 90, 90 0.1 270 °. When changing the angle of rotation about, in the range from -90 ° to 90 potential f. , is less in absolute value of the supply voltage and | c) 2 of the third voltage source 12, while the prohibiting voltage is applied from the null organ 8 through the AND 7 element to the key 6, as a result of which the potential 4 is zero. The error signal generated in the first adder 4 according to the law., V is determined from the expression E-rfevc.). V (This expression remains true to the absolute value of the mismatch angle (.2) by the Meniaii 90 (see Fig. 1). rotation oi-i, in the range of 90 dO 270, the potential is greater in absolute magnitude of the half of the supply voltage (Unin this, the null organ 8 produces a resolution of the short signal supplied to the input of the And 7 element. For different signs (states) of the first and second the limit switches 4 and 5 at the output of the second adder 9 is generated here one the decisive signal, also supplied to the element And 7. With the same signs of the first and second limit switches 4 and 5, the second adder 9 generates a prohibitive voltage. If there are two enabling signals, the element And 7 produces an output signal supplied to the key b, through which, in this case, the potential if. ,, equal to twice the supply voltage (2 and pit) of the second voltage source 11 is passed to the adder 3. Before the final summation (1) of the potential 4j, the sign is assigned torogo limit switch 5 (positive when the open limit switch when the negative and the switch 5 closed). Thus, at different signs (conditions) of the first and second limit switches 4 and 5, the potential jump is compensated. z value 2 ipit7 when changing the angle, turning cL in the range from 90 to 270. Mismatch signal (1) for these limits of variation of the angle over the op 5 t will be determined from the expression .T l.-c-. -180 -18o ° G at 180 (oi-f and) 270 ° or at 90 ° (n} -., 180 ° 27Q 90 ° ct 180 ,, J.- ,, X- ™,) - (60 2 mu - Cri, at (90 ° 180 (180 ct 270 Expressions 3,4,5 oc: are valid when the magnitude of the error angle is absolute (d is less than 90 f, see fi g 2). The final error signal for any values in the device determined from the expression (90 °. In the general case, the rotation angle between the terminals of potentiometers 1 and 2 can be less than 180, while the magnitude of the error angle (ct oL.} imposes the following constraint (ot - d-2.) T and coefficient mismatch voltage values K (di - ct) will vary within the limits and pit 1 к-tJ pт i К Based on the above, the load, i.e., the input resistances of the first adder 3 and zero Authority 8 must be selected taking into account the allowable reduction of the coefficient K (8.9); if the comparison error in absolute magnitude of the potential φ and half a voltage is not equal to power 0, the admission to the maximum permissible error angle ((6, should be reduced by the magnitude of this error; the error in the angles of operation of the first and second limit switches 4 and 5 leads to an increase in the error of the synchronous communication device near the angles o and ci by the value of this O {11ibki, therefore the error of the first and second limit switches 4 and 5 should be be less than the magnitude of the error of the functional dependence of the setting and receiving potentiometers 1 and 2, which, as a rule, is not less than 0.3 - 0.5. An error of the limit switches of the order of 0.1 is easily achieved when using, for example, optocouplers; signs of potentials 4, f2 i Ch, g can be assigned both directly in the first adder 3, and determined by the phase of the alternating supply voltage or the polarity of the constant supply voltage with separate supply of each potential, key 6 and null organ B The use of coke circuit breakers and logical signal processing in the invention makes it possible to apply the simplest type of ring potentiometer, with the error in transmitting the angle practically not exceeding the functional error of the potentiometer and not INH methodological errors; In comparison with the known devices, the synchronous communication error in the invention is reduced by 3 and 4 times. Claims The following system, containing a voltage source connected to a master and a receiving potentiometer, the movable contacts of which are connected correspondingly to the first and second inputs of the first summatr, characterized in that7 it contains a second adder to improve the accuracy of the ycTf , key, element And, zero-body, the second and third voltage sources and the first and second limit switches, the first inputs of which are mechanically connected respectively to the moving contacts of the potential and the receiving potential The output of the first limit switch is connected to the third input of the first adder and the first input of the second adder, the output of the second limit switch to the fourth input of the first accumulator and the second input of the second adder, the second and third voltage sources are connected respectively to the first key input and the first the input of the zero-organ, the input of which is connected to the movable contact of the potentiometer, the first input of the element I is connected to the output of the zero-organ, the second input to the output of the second adder, and the output to the second input om key, the output of which is connected to the fifth input of the first adder. Sources of information taken into account in the examination 1.Sverchyk DV Remote transmissions. M., Energie, 1974, p.64. 2.Ahmetzhanov A.A. High-precision automatic corner transmission systems. M., Energia p.28 (prototype). Fig, 1  and m at 90 d, -90  (c) at 80 a / State, -; 70 80 / Гъ d, 90 FIG. 2