DE1085230B - Method for the automatic positioning of a mechanical organ - Google Patents

Description

GERMAN

In industry it often happens that a mechanical organ is automatically put into the correct position must bring; it is generally a matter of shifting its center of gravity, an which may be followed by one or two rotations around two main axes.

These various linear and rotary movements must be independent of one another by means of chains of command being controlled; each of the latter usually exists as in Figure 1 of the drawings is shown schematically from:

a reading in front of device 1 for the order of magnitude, a drive motor 2 with a connected control device 3 (a lead screw or other device) for the movable member to be brought into position 4,
a control body 5,
a differential 6.

The differential shows at each instant the difference between that of the control organ read dimension and the dimension set by the reading device. This information is now used for the drive of the motor or its control is used, either directly by a mechanical one Method or indirectly by an electrical, electronic, hydraulic, pneumatic or a other procedure.

In addition, these devices must comply with the following two for automatic adjustments Satisfy demands:

One must be able to bring the movable organ into its position by a movement in a positive or in a negative sense, i.e. if X _{0 means} the starting position and X ₁ the commanded position, then the dimension A ^ _{1 can be} greater or less than that Dimension X be ₀ ;
it is necessary to take into account mechanical play in the control members of an order of magnitude equal to or greater than that required for positioning precision. It is necessary that the movement of the definitive approach to the commanded dimension always takes place in the same sense, so that the game can be taken into account by a constant correction factor.

One adjustment method commonly used to achieve this result is to operate after two different cycles, shown in FIG. 2, depending on whether X _{1 is} greater or less than X ₀ .

In the event that X _{1 is} greater than X ₀ : Approach at high speed F ₁ up to a dimension X ₁ ',

for automatic positioning
of a mechanical organ

Applicant:

Directed by Nationale des Usines Renault,
Billancourt, Seine (France)

Representative: Dipl.-Ing. CH. Huss, patent attorney,
Garmisch-Partenkirchen, Rathausstr. 14th

Claimed priority:
France from October 22, 1958 and June 16, 1959

which is a little smaller than X ₁ , transition to a low speed F ₂ (so that the lead when the stop command arrives is less than the required accuracy) and stop at X ₁ .

In the event that X _{1 is} less than X ₀ : approaching at high speed and exceeding dimension X ₁ , stopping at dimension X ₁ "which is less than X ₁ , then transitioning to a low speed and changing it up to Stop at X ₁ .

It is sufficient to consider the dimensional differences (X ₁ -X ₁ ') and

(X ₁ -X ₁ ") taking into account the lead of the

"Select the machine from speed F ₁ when the stop command is issued.

This method is sometimes perfected by using three successive and decreasing speeds of approach - V ₁ , V ₂ and F ₃ (Fig. 3) - which allows time to be saved by using the preceding dimensional difference (X ₁ -X ₁ ') or (X ₁ -X ₁ "), because the lead due to the inertia is less when the stop command is issued from the speed F ₂ than the lead due to the inertia when the stop command is issued from the speed F ₁ but does not change anything in the principle which consists in commanding the changes in motion as soon as the movable organ is a certain distance away from it

009 550/259

3 4

has reached its final location, expressed through a meaning processed, in other words, it is a

fixed number in the machine's work program. Work cycle provided with at least one rapid

Another method, also used, is approximation until the readings agree

is shown in Fig. 4, is that one of the weighty digits when this match a command to change the speed was 5 not there from the start, and at least with

tied with a command to change the loading a slow final approach, always im

direction of movement is given each time the same sense and with that required for the

movable organ has reached the exact position. Accuracy suitable speed, up to

Due to the inertia of the organs, the readings of the remaining,

exceeding the measure (in dashed lines io less weighty digits.

shown, but the extent of this overshooting Obviously it is necessary that the sub is the lower the lower the speed. Settlement between two consecutive readers So you only need to provide the working cycle so that it is in the interpretation of the overall the last approximation to the lowest result, taking into account the accuracy of the speed in the desired sense, 15 readings of both can give no doubt. Acts to get to the goal safely. it is, for example, dividing disks through a

The aim of the present invention is to provide a gear transmission that is geared down and under which starting for positioning, in which the assumption that one reads off the dimension in the decimal system movements like a combination that previously wanted, then one becomes a conversion ratio of written movements appear. It will be interesting to use 20 1: 100 if you are certain a hundred Invention, however, through certain simplifications, estimate one turn without ambiguity in the control device. To be able to understand that well.

one must follow the principle of reading the respective When applying to a lathe has the Er position of the movable organ and its fixation is a further improvement in the presentation consider in the differential. 25 working cycle of the positioning described here

The activity of the latter organ consists in an aim, characterized by a sub-subtraction or at least in a comparison process of separation, which is determined by the reading disc of the of the read-off measure to the commanded measure, less important digits, if the where the appearance of a final result of zero third displayed code number is equal to zero or one, Equivalent to a command to stop 30 is the movable organ until it reaches the enddes The motor is moved slowly, if necessary with a change in the valid position, while, Direction of movement. if the third digit is zero or one

This mode of operation can be divided according to a numerical one, the movable organ is the normal

or by an analogy procedure, the speed is maintained until the comparator indicates

the. As far as the two proceedings are concerned, it has come to a position which is based on the

What differs is the fact that the former with the last-mentioned graduated disk is ten divisions ahead

Quantities expressed in individual units of the final position,

works, the latter with continuously changing quantities. This greater complexity of the program

The accuracy required for positioning avoids excessive loss of time

speed is almost always of this order of magnitude, 40 and poor working of the tool

with regard to those for whom the position is reported - as a result of excessively long, extended working hours

the organs (dividing discs, electric potentiometers, low speed.

Selsyns or single-phase autosynchronizers, straight- The following are examples of the work cycles

linear divisions, etc.) that one necessarily uses the inventive method of positioning

must have several organs under 45 and an example of a control device for the automatic

are squat like a clockwork, matic positioning for the purpose of explaining the

where the reduction ratio is equal to a power Invention, reference being made to the drawings

of 10 is. A decimal system is used, of which Figures 1 to 4 are already used

from the whole a display of the position were mentioned.

50 Fig. 5 schematically illustrates a three

the number of code numbers is formed. phased work cycle of the Po-

However, this results in great difficulties in positioning, namely for the two cases where the

namely: starting size smaller or larger than the commanded one

The construction of the differential organ is * ZZ. ¹ '. . ,. , ". .

the more complicated and more expensive, the larger ⁵⁵ *>, ⁶ 'igt an auto- schematically

the number of code digits is what it is at the same time matic control device for the implementation

to process haf && _this p _OS itioration process;

very difficult problems arise. FIG. 7 explains another in a schematic manner

Coverage of the details of the various _c work cycles of the positioning according to the invention

Readers on which through the lower ^{6o hl} J the two cases where the initial ^{size is smaller}

Settling device are coupled to one another. or greater than the commanded measure;

^ö ° rr p _X g_ g corresponds to a variant within the framework of the

For the sake of a remarkable simplification of the last-mentioned working cycle;

Differential, the present invention is aimed precisely at Fig. 9 is the schematic of the work described a way of working for positioning, 6g for example when used on a lathe, the first which the information of the different reading cases accordingly, d. H. if the third digit devices sequentially and not simultaneously equal to zero or one;

used by the differential organ one after the other Fig. 10 is the scheme of the same working cycle,

is switched to this reader, although it is for the second case where the third code number

Code digits in the order of their decreasing 70 is other than zero or one.

5 6

According to the operating mode described above, the working cycle according to FIG. 5 is presented in a concrete manner

a working cycle like that of FIG. 5 can be used.

choose where, in a first period, the approach takes place in this example, the moving member bringing into the position to at high speed V ₁ in the required position is the table 7 of a positive or negative work by placing 5 machine tools that are in a plane after the both by the differential alone the most important characteristic coordinate axes X and Y are movable, whereby the number of the least reduced reading organ compares the table along these axes by two lead screws in order to stop at a value and to command the corresponding nuts, which is immediately next to the of the commanded one is taken. It is to be assumed that the measure lies, in this example the table is in its position with an accuracy of a lower order of magnitude. from Vio mm is to be brought, whereby the table is assumed, for example, that the commanded stroke in the X-axis as well as in the F-axis is a stroke dimension of 487.1, and that the organs for each 1 m, so that one has to read the position from two disks with 100 parts each using four code numbers.

deleted (the second, therefore, to the first in the 15

ratio of 1: 100 reduced), then positioning is limited to the coordinate axis X ,

Stop signal when the reduced pulley has the same value as the positioning according to the F-axis

47 indicates. is accomplished.

Obviously, it is necessary that the leading screw X, which is driven by a motor 8 with three of the machine at the stop signal sufficiently low 20 different speeds in decreasing Pveihe

so that the disc is driven at the stopped - V ₁ , V ₂ and V ₃ - works to-

always shows the same value. together with a position reading device from the

In a second period, the differential is on both discs 9 and 10 with perforations that follow

the details of the second reading organ are coded according to a linear number system, each

first, so with the next lower reduction 25 disc has a hundred such holes that one

switched. It should be remembered here that it can be read from the photocells 11 on which

its final position to be brought movable organ the light falls through the perforations,

is then in such a starting position, the identification marks for the positioning are in

that the approximation is still punched in a paper strip 12 in a similar way in a positive sense

must be done, and that one must necessarily be the 30 and be in the same way through the photocells

Position must appear, which the zero of the 13 read off.

second reading organ, since the previous- The information of the photocells for the commands or going stopping on the unit of the first reading- the order of magnitude and those of the photocell organs was controlled, which is lower than the value for the respective position are mutually commanded . 35 compared by an electronic arithmetic unit 14, in this second period the motor drives the which via a device 15 both the rotary machine at the speed V ₂ , and controls the direction as well as the speed of the motor. Stop is commanded at the first reading. Assuming, for example, that the correspondence position commanded after passing through 487.1, then the electronic computer will enter zero. Furthermore, if a fairly large 40 14 is switched to the command and position cells, speed V _{2 is} selected in order to make a noticeable difference which correspond to the two largest digits. If this can be caused by exceeding, in a third period the motor changes the direction of movement at high speed V ₁ period (e.g. 50 mm / sec), then the computer commands the foal, namely at speed V ₃ to the stop when the position of the cells on the disc 10 to reach the desired position. Show 45 of the high digits 47. The advance of the one must also be noted here that it is no longer necessary from the table, due to the inertia, from the second period onwards, the order of magnitude of 4 mm.

Determine the direction of movement, which is a new one. Assuming a dimension of less than 470.0,

Difficulty would arise for the positions in then the stop takes place at around 474.0. Is this

near zero, if there is an advance due to a mass 50 starting dimension higher than 479.9, then the

inertia occurs. The stop signal is sufficient, given at around 476.0. But if the starting point

If the direction of movement changes and lies between 470.0 and 479.9, the elec-

the speed if they match. tronencomputer soon match, and this

The speeds V ₁ , V ₂ , V ₃ etc. form a first period is then omitted.

decreasing series and can inevitably be coupled with one another. To the command and position cells for the course, a similar work cycle would be switched on in the two lowest digits; it should then insist that the stopping in the first period is no longer detected, but only in the case of overcommanding, where the digits of meaning coincide with a zero. The engine runs with the other compares, namely for the value unit, the 60 of the mean speed V ₂ (10 mm / sec. For example) in the positive sense that of the commanded measure (increasing measure). The electron is, during the other periods identical to the computer, is triggered first and foremost if the ones just given remain, however with the reverse disk 9 is set to zero and shows the reversed direction of movement. attunement on when the table does not reach the position (48) 7.1 as one of the scope of the invention 65 in any way; he then gives the command for the restrictive example is a possible hold, which occurs as a result of the advance at approximately (48) 8.0 guide form of a device for implementation.

of the positioning method according to the invention In a third period, the electron

shown schematically in FIG. 6. On the basic calculator a reversal of the movement in the down-

In this application form, the speed V ₃ set above (0.5 mm / sec, for example) can be used, see above

that the final stop as a result of the new agreement with an exceedance of the chosen one Dimension takes place, which is less than the required accuracy of 0.1 mm.

According to the method according to the invention for positioning, however, one can also use a working cycle, as shown in FIGS. 7 and 8, where the approach takes place at the high speed V _x , in the required positive or negative sense Differential alone compares the high indicators which correspond to the least squat reading organ; this time the engine is then commanded to stop if tied.

For example, if one continues to assume that the commanded measure is 487.1 and that the reading organs for the position consist of two discs with 100 partial marks each (the second being the first in the ratio of 1: 100 is reduced), then the stop is commanded when the reduced disc shows the value 48.

In a second period, the differential is reduced to the information given in the second and compared to the first Reading organ switched.

In this second period the motor runs in such a way that it moves the table of the machine at the speed V ₂ , namely in the required direction (depending on whether, when the first stop is made, the moving member stopped on the other or this side of the desired line); stopping is then ordered when the readings match.

The working cycle then takes place in a different way, depending on the direction of the previous stop Move:

When approaching at speed V _2, as here in the positive sense (FIG. 7), nothing special is provided before the transition to the third period.

If the approach has taken place in the opposite direction at the speed V ₀ (FIG. 8), then before the transition to the third period a reverse stroke is commanded towards the measure towards at the same speed V ₂ , with a stop if the readings match.

This peculiarity is necessary because the definitive approximation with the very slow speed V ₃ must take place in a certain sense during the third period in order to be able to compensate for the mechanical play in the power transmission, as already explained above.

As before, this working cycle comes to a. Application form for the execution, as already explained in FIG. 6, that is to say for the positioning of the table 7 of the machine along the coordinate axis X, the commanded dimension initially being assumed to be 487.1.

In the first period, the electronic computer 14 is then switched to the command and the position cells, which correspond to the two highest digits, the speed of the motor corresponding to a high speed (for example V ₁ = 50 mm / sec). The electronic computer commands a stop when the position cells 48 indicate. The lead of the table as a result of the moment of inertia or the inertia amounts to about 6g 4 mm. Assuming a level below 480.0, it will stop at around 484.0. If the initial dimension is greater than 489.9, it will stop at around 486.0. If, however, the initial measurement is between 480.0 and 489.9, the electronic computer will immediately show a match, which means that the first period is no longer applicable.

In the second period the electronic computer is switched to the command and position cells, which correspond to the two lowest digits.

The electronic computer then has to determine and store the sign of the first shift at speed V _2; then he only has to determine the agreement when the dimension line is exceeded.

In the present case, the definitive measure (48) 7.1 is always greater than the measure of the first stop of the machine (at around 484.0 or 486.0). The electronic computer registers the sign +, which controls the sequence of operations.

The motor then runs at a speed V ₂ (z. B. 10 mm / sec accordingly) in the positive sense, and the electronic computer indicates a match when the dimension (48) 7.1 is exceeded, whereby it commands the stop, which as a result of the advance takes place here at around (48) 8.0.

In a third period, the electronic computer then commands a change in the direction of movement at the reduced speed V ₃ (e.g. 0.5 mm / sec), so that the final stop at the new correspondence occurs when the dimension line is exceeded, which is less than the required accuracy of 0.1 mm.

As already indicated earlier, there is a variant of this work cycle, depending on the sense of the approach with the speed V _2. For example, if the commanded amount were equal to 481.1 (Fig. 8) then the first period would be the same as before, while the second period would be different.

In this case, the definitive dimension (48) 1.1 is always smaller than the dimension when the machine was first stopped (for example at 484.0 or 486.0;. The electronic computer registers as the symbol - ,. Which is the sequence of operations controls in a second period, namely:

A displacement at the speed V ₂ in the negative sense, with the stop being commanded if they agree and with a corresponding lead;

a shift at the speed V ₂ in the positive sense, with a stop command in the event of a match and a corresponding lead.

Finally, a third period with the speed V ₃ and final application to the dimension line is provided, just as before.

In the case of applying the method to a lathe (FIGS. 9 and 10), the operations are winding in the following order:

1. Rapid approximation until the two largest indicators on the strip coincide with the number on the encoder disc of the large digits, one unit less than the previous ones two digits is formed.

So far, nothing has been compared to that already procedure described changed.

The special case of the lathe, however, whose bodies slowly shift (leading as a result the inertia when the engine is switched off is generally only very low), allows a more precise Positioning by means of the single encoder disc for the large numbers, which in this case has a division in thousandths of a revolution. An additional reading section allows consumption

gen of the movable organ in the highest tenth of the unit of length, which is divided by a hundredth of a revolution is pictured.

Example: The final dimension is 48 / 0.3. The first stop occurs between 47 / 9.0 and 48 / 0.0.

2. The comparator is this time once on the strip, which has advanced in such a way that it both low code numbers (in the above case 03), on the other hand to the code disk switched with the lower numbers.

There can be two cases here:

a) The third digit is zero or one (Fig. 9). The moving body has the very low speed V ₂ , so that the leading when switched off! Motor is less than the accuracy required by the machine. Stop is commanded when the comparator indicates agreement.

This is the case in the previous example, where 03 is the lower two digits. That the definitive level then amounts to exactly 480.3.

b) The third digit is neither zero nor one (Fig. 10). The movable body starts running at the normal speed V _x until the comparator indicates its arrival at a point which is ten sub-marks of the disk with the lower digits before the final position. New stop.

The movable body has recently been moving at the very low speed V ₂ to the final extent.

Example: The final dimension is 486.3. First stop between 479.0 and 480.0 (pass at speed V _x - disk with large digits);

second stop, commanded at 485.3 (pass at speed V _x - disk with lower digits); third and final stop at 486.3 (run at speed V ₂ - disk with lower digits).

Claims (4)

Claims: 45 1. A method for the automatic positioning of a mechanical organ with the help of a control device including a differential organ which on the one hand cooperates with reading devices for commands or order of magnitude, on the other hand with reading devices of the respective position in order to control a predetermined work sequence for positioning, characterized in that for the purpose Simplification of the differential organ the same is switched one after the other to the different reading devices, so that their codes are processed separately, in the order of their decreasing importance, so the working cycle at least a rapid approximation to the correspondence of the readings of the high digits, if such is not was there from the beginning, and includes at least one final slow approximation, the latter always in the same sense as the former and at a speed appropriate to the accuracy required, bi s to match the readings of the remaining, lower or less significant digits. 2. The method of positioning according to claim 1, characterized by a work cycle with an approach phase at high speed until the readings match for a group of weighty digits immediately next to a unit with reference to that of the commanded position, the permissible excess after agreement is less than the value or the size of the aforementioned unit, a further, slower approximation phase until the readings agree for the remaining group of less important digits, this approximation preferably with a permissible exceedance takes place with the subsequent phase of the final application the dimension line, when the direction of movement is changed and at a speed that is suitable for the Assuming the commanded position is appropriate. 3. The method of positioning according to claim 1, characterized by a work cycle with an approach phase at high speed until the readings match for a group of weighty digits identical to that of the commanded position, another Approach phase at lower speed until the readings for the remaining group of less weighty numbers when registering the sense of approximation and possible doubling so that this rapprochement always ends in the same sense, whereby this approximation, preferably with a permissible excess, takes place with a subsequent final application to the intended dimension line when changing the direction of movement and with a speed suitable for taking up the commanded posture. 4. The method for automatic positioning according to claim 1 in its application to a mechanical part of a lathe, characterized by an additional discrimination, which comes into operation when the encoder disc with the less important digits intervenes, in such a way, that if the third of the four indicators displayed is zero or one, the one to be positioned Organ is slowly moved until the desired final position is reached, while, if the third digit is neither zero nor one, the moving organ is at its normal speed resumes until the comparator indicates that it is in a position the ten partial marks of the code disc with the less important digits before the final one Position lies. 1 sheet of drawings © 009 550/259 7.60