Control Component and Method For Determining an Adapted Master Value of a Master Axis

Abstract

A method for determining an adapted master value of a master axis, wherein a setpoint slave value for a slave axis is derivable from the adapted master value via a synchronism function and a drive on the slave axis is operated in synchronism with the master axis based on the setpoint slave value, where the adapted master value is determined based on a base master value of the master axis and a time difference of operative times of determinable events on the master axis and slave axis.

Claims

1. A method for determining an adapted master value of a master axis, the method comprising: operating a drive on a slave axis in synchronism with the master axis based on a setpoint slave value which is derivable from the adapted master value via a synchronism function; and determining the adapted master value based on a base master value of the master axis and a time difference of operative times of determinable events on the master axis and slave axis.

2. The method as claimed in claim 1, wherein the operative times refer to a system time which is common to the master axis and slave axis.

3. The method as claimed in claim 2, wherein the common system time of time systems of the master axis and the slave axis exists or is establishable based on a common clock time.

4. The method as claimed in claim 2, wherein a timestamp is assigned to at least one of (i) the base master value and (ii) the setpoint slave value in each case, and the timestamp relates to the common system time.

5. The method as claimed in claim 3, wherein a timestamp is assigned to at least one of (i) the base master value and (ii) the setpoint slave value in each case, and the timestamp relates to the common system time.

6. The method as claimed in claim 1, wherein an output of the master value on the master axis and an output of the setpoint slave value on the slave axis are determined as determinable events.

7. The method as claimed in claim 1, wherein an actual master value being reached on the master axis and an actual slave value being reached on the slave axis are determined as determinable events.

8. The method as claimed in claim 1, wherein the adapted master value is determined on at least one of (i) the slave axis and (ii) a proxy of the master axis in a system of the slave axis.

9. The method as claimed in claim 6, wherein an output of the master value on the master axis is determined on the slave axis or a proxy based on one of (i) an initial time and an output time of the master axis and (ii) an operative time of an event of the output of the master value.

10. The method as claimed in claim 7, wherein an actual master value being reached on the master axis is determined on the slave axis or a proxy based on one of (i) an initial time and an effective output time of the master axis and (ii) an operative time of an event of an actual position being reached on the master axis.

11. The method as claimed in claim 9, wherein one of (i) an initial time and an output time of the master value are provided on the slave axis or the proxy and (ii) the operative time of the event of the output of the master value is provided on the slave axis or the proxy.

12. The method as claimed in claim 11, wherein one of (i) the initial time and the output time of the master value are contained in a timestamp of the base master value or transmitted as data in a timestamp together with the base master value and (ii) the operative time of the event of the output of the master value is contained in a timestamp of the base master value or transmitted as data in a timestamp together with the base master value.

13. The method as claimed in claim 10, wherein one of (i) the initial time and the effective output time of the master axis are provided on the slave axis or the proxy and (ii) the operative time of the event of the actual position being reached on the master axis is provided on the slave axis or the proxy.

14. The method as claimed in claim 13, wherein one of (i) the initial time and the effective output time of the master axis are contained in a timestamp of the base master value or transmitted as data in a timestamp together with the base master value and (ii) the operative time of the event of the actual position being reached on the master axis is contained in a timestamp of the base master value or transmitted as data in a timestamp together with the base master value.

15. The method as claimed in claim 6, wherein the output of the setpoint slave value on the slave axis is determined based on an initial time associated with the calculation time comprising a next interpolation cycle boundary of the slave axis, and an output time for outputting the setpoint slave value.

16. The method as claimed in claim 9, wherein the output of the setpoint slave value on the slave axis is determined based on an initial time associated with the calculation time comprising a next interpolation cycle boundary of the slave axis, and an output time for outputting the setpoint slave value.

17. The method as claimed in claim 11, wherein the output of the setpoint slave value on the slave axis is determined based on an initial time associated with the calculation time comprising a next interpolation cycle boundary of the slave axis, and an output time for outputting the setpoint slave value.

18. The method as claimed in claim 12, wherein the output of the setpoint slave value on the slave axis is determined based on an initial time associated with the calculation time comprising a next interpolation cycle boundary of the slave axis, and an output time for outputting the setpoint slave value.

19. The method as claimed in claim 7, wherein the actual slave value being reached on the slave axis is determined based on an initial time associated with the calculation time comprising a next interpolation cycle boundary of the slave axis, and an effective output time of the slave axis.

20. The method as claimed in claim 10, wherein the actual slave value being reached on the slave axis is determined based on an initial time associated with the calculation time comprising a next interpolation cycle boundary of the slave axis, and an effective output time of the slave axis.

21. The method as claimed in claim 13, wherein the actual slave value being reached on the slave axis is determined based on an initial time associated with the calculation time comprising a next interpolation cycle boundary of the slave axis, and an effective output time of the slave axis.

22. The method as claimed in claim 14, wherein the actual slave value being reached on the slave axis is determined based on an initial time associated with the calculation time comprising a next interpolation cycle boundary of the slave axis, and an effective output time of the slave axis.

23. The method as claimed in claim 1, wherein the base master value and the adapted master value have a master value position or a master value position and a master value speed.

24. The method as claimed in claim 1, wherein the base master value associated with an initial time of the master axis is corrected by virtue of the adapted master value being determined at a time that, proceeding from the initial time of the master axis, is shifted by the time difference.

25. The method as claimed in claim 24, wherein the adapted master value for the time shifted by the time difference proceeding from the initial time of the master axis is extrapolated or interpolated proceeding from the base master value.

26. The method as claimed in claim 1, wherein the adapted master value is ascertained as a master value to be applied up to a next interpolation cycle boundary of an interpolation cycle of the slave axis.

27. The method as claimed in claim 1, wherein respective drives of one of (i) the slave axis and the master axis and (ii) the slave axis and a further slave axis of the master axis are operated in synchronism with one another.

28. A control component for controlling a drive of a slave axis (F) based on master values of a master axis, wherein the control component is configured to: operate a drive on a slave axis in synchronism with the master axis based on a setpoint slave value which is derivable from the adapted master value via a synchronism function; and determine the adapted master value based on a base master value of the master axis and a time difference of operative times of determinable events on the master axis and slave axis.

29. The control component as claimed in claim 28, wherein a control component for controlling a drive of the master axis has a separate embodiment and the control components communicate with one another via a bus connection.

30. The control component as claimed in claim 28, wherein the control component is simultaneously configured to control a drive of the master axis.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0069] With the aid of the figures, the invention will be explained in more detail below on the basis of exemplary embodiments, in which:

[0070] FIG. 1 shows an exemplary schematic illustration for elucidating relative temporal relationships of variables established for the calculation of an adapted master value in accordance with a first embodiment of the invention;

[0071] FIG. 2 shows an exemplary schematic illustration for elucidating relative temporal relationships of variables established for the calculation of an adapted master value in accordance with a second embodiment of the invention;

[0072] FIG. 3 shows an exemplary schematic illustration for elucidating relative temporal relationships of variables established for the calculation of an adapted master value in accordance with a third exemplary embodiment of the invention; and

[0073] FIG. 4 shows an exemplary schematic illustration of a method procedure for adapting the master value in accordance with a fourth embodiment of the invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0074] Functionally equivalent elements have been provided with the same reference sign in the figures, provided nothing else is specified.

[0075] FIG. 1 represents events and times of these events, which are used for determining an adapted master value in accordance with a first exemplary embodiment of the invention, in a time diagram. Here, the horizontal axis indicates a system time t, which is a common system time shared by a master axis L and the slave axis F. That is, the master axis L and slave axis F use a common system time t. By way of example, a first control component is provided for controlling the master axis L and a second control component is provided for controlling the slave axis F. The events that are related to one another in time are plotted in the upper half of the diagram for the master axis and in the lower half for the slave axis. A common system time t, to which calculations in the master axis L and in the slave axis F and to which the specification of setpoint values both systems relate, is available via a PROFINET-IRT communication within a bus segment.

[0076] A master value leading to an actual master value being assumed via the control component is output as setpoint master value by the master axis L at an initial time t0L. Consequently, the interpolator cycle clock boundary of the master axis lies at t0L, for which interpolator cycle clock boundary the setpoint value is calculated on the master axis. The latter is output over an output time T10L and, after a process time, it leads to the actual position on the master axis.

[0077] Consequently, the setpoint value is output at the time t10L. This time is the operative time t10L of the output of the setpoint value on the master axis.

[0078] The slave axis calculates the slave setpoint value at a subsequent interpolation cycle of the slave axis F. For an interpolation cycle boundary t0F of this interpolation cycle, the slave axis F predetermines, via a synchronism function, a setpoint slave value in relation to the base master value output by the master axis.

[0079] The interpolation cycle boundary t0F, at which the slave axis F calculates setpoint values, is shifted by an undefined time that emerges from the communication times and/or different interpolator cycle clock times.

[0080] The calculation of the operative time t10F of outputting the setpoint slave value is then implemented on the slave axis F.

[0081] Proceeding from the interpolation cycle boundary t0F, the effective time of the output of the setpoint slave value t10F can be ascertained by virtue of the known output time of the slave axis T10F being added. After this time interval of the output time of the slave axis T10F, the event, which is used for the master value adaptation in accordance with the first exemplary embodiment, has occurred on the slave axis. This operative time of the output of the setpoint slave value t10F is now compared in the uniform time system t to the operative time of the output of the setpoint master value t10L and, in particular, the difference between these two times is ascertained. This yields the time difference T10.

[0082] The sign of the result in this subtraction yields the shift of the master value on the time axis, either forward or backward in time.

[0083] The time difference T10 is now used to calculate an adapted master value that belongs to the time that has been shifted by the time difference T10 proceeding from the initial time t0L. This adapted master value is the master value that advantageously should be used by the slave axis in relation to its interpolation cycle boundary t0F for the synchronism function.

[0084] For the proposed method in accordance with the invention, the interpolation clocks on the master and slave axis are not necessarily matched to one another or synchronized or of equal length. On account of the reference to the common system time, the adaptation of the master value by the slave axis via the calculation step of the operative points of analogous events on the slave axis and master axis is not dependent on a known or ascertainable or fixed temporal reference of the respective interpolation cycles and their boundaries. This facilitates a precise synchronism, even for distributed synchronous operation with different interpolation cycles or interpolation cycles of the slave axis and the master axis that have an undetermined temporal relation with respect to one another.

[0085] FIG. 2 elucidates the adaptation of the master value in accordance with a second exemplary embodiment of the invention, which takes into account the respective actual positions being reached on the master axis and slave axis.

[0086] For an improved understanding, additional characteristic times and time intervals to be established for the second exemplary embodiment have also been plotted into the diagram of FIG. 1.

[0087] Following the time t10L, at which the base master value is output, the time interval T20L is plotted in the upper half of the diagram on the master axis, where the time interval elapses until the actual position was adopted on the master axis L. the operative time of reaching the actual position on the master axis is denoted by the sign t30L. An effective output time T30L until the actual position is adopted on the master axis after the interpolation cycle boundary of the master axis is therefore composed of, in particular, the output time of the master value T10L and the time interval T20L until the actual position is reached after the master value is output.

[0088] The value of the operative time of the actual position on the master axis t30L is ascertained by the slave axis from, for example, a frame of the master axis, or the slave axis calculates the value from specifications relating to the interpolation cycle boundaries of the master axis and setpoint output times or the effective output time of the actual values, which are or were provided either by the master axis directly or by a user.

[0089] Analogously, the operative time of the actual position being reached is ascertained for the setpoint value to be calculated in the current interpolation cycle for the next interpolation cycle boundary of the slave axis. To this end, for example, the effective output time T30F of the actual values is known on the slave axis. Proceeding from the interpolation cycle boundary t0F, which is known in the time system of the slave axis, the operative time of the actual position t30F being reached is thus ascertained. Here, the effective time of reaching the actual position t30F being calculated in a piecewise manner from the output time of the setpoint values T10F and a time interval T20F until the actual values are reached after the output of the setpoint values t10F is also conceivable in one embodiment of the method.

[0090] The temporal distance T30 of the two operative times of the intended values being reached at the respective axes t30L and t30F is subsequently used to adapt the master value. There is an extrapolation of the base master value on the slave axis in the first and in the second exemplary embodiment. Consequently, a master value following in time as adapted master value is used as master value that is optimized for the synchronism function.

[0091] The method for calculating the adapted master value consequently takes into account the communication times for the master value transmission and effective output times on the respective axes in the case of a distributed synchronous operation. The respective output times of the setpoint values or the effective output times until the actual values are reached can be caused by different interpolation cycle lengths or by respective times for providing the values in the servo or by required times in the drive until the output start or by setpoint value output delay times set on an axis or by setpoint value filter times in the setpoint value branch for adapting the dynamics or by different communication times of the axes to the drive or by an individually different process behavior of the axes in the case of a set feedforward control or without a feedforward control or by further adjustable times.

[0092] The base master values output by the master axis L can be adapted for further slave axis F (not illustrated). This can be implemented on the further slave axis F in the same way and independently of the adaptation of the slave axis F.

[0093] The further slave axis F can also ascertain the adapted master value therefor, provided the information about the master axis data are present. Consequently, the master value can be optimized individually for each slave axis F, F in a particularly advantageous manner, precisely in the case of a distributed synchronous operation with a plurality of slave axes and so, for example, the respective times of reaching the actual positions on the slave axes F coincide in comparison with the master axis L and the further slave axis F coincide in comparison with the master axis L, and hence also coincide with overall optimization. Here, the respective time difference that is ascertained for calculating the adapted master value may differ for the slave axis and a further slave axis F, i.e., may have a different length or temporal length or even a different sign, and so the adaptation of the master value for each slave axis can be implemented individually in each case, before it or in time. This means that the adapted master value can be adapted via an extrapolation or interpolation, particularly in a different manner for each slave axis. Here, the improved master value calculation on part of the slave axis and the flexibility in the case of a distributed synchronous operation with a plurality of slave axes becomes particularly clear.

[0094] Depending on the field of use of the synchronism function, extrapolations of the master values or interpolations of the master values tend to be expected. For applications that require a particularly high accuracy of the synchronism, the master axes operate with setpoint value output delays, for example, and consequently accept delays in order then to be able to apply an interpolation of the master value on the slave axes. The interpolation is supported by master values that have already been recorded, and so an output of a setpoint slave value can be implemented with a high accuracy, albeit with a delay. For applications such as for printing machines, for example, this is particularly advantageous.

[0095] In other applications, such as for packaging applications in which a short reaction time is required, a reduced accuracy on the slave axis, caused by an extrapolation of the master value, tends to be accepted for the benefit of a short reaction time.

[0096] In the comparison with the aid of FIG. 2, which contains both embodiments in the same diagram, the two exemplary embodiments show that, depending on the employed system and axes that should be operated in synchronism, deviations may again arise on the various axes up to the operative times of reaching the respective actual values t30L and t30F, even after the operative times of outputting the setpoint values at the respective axes t10L and t10F. Expressed differently, it is possible to see that it is not only the output times of the setpoint values T10L and T10F that deviate from one another, but also the time intervals T20L and T20F that elapse until the actual values are reached after the setpoint values have been output. Therefore, it may be particularly expedient in applications to set reaching the actual position on the respective axis as a relevant event for the purposes of forming the time difference. The output of the setpoint values can be used as a relevant event in applications in which, for example, the time intervals T20L and T20F for the master axis and the slave axis, which are initially of unequal length, can be actively compensated such that both take the same amount of time by way of delays in one of the axes.

[0097] FIG. 3 illustrates a time diagram for a third exemplary embodiment, in which the actual position on the master axis is reached later in time than the actual position being reached on the slave axis. The time difference T30 is likewise determined for such a case. This time difference T30 leads to the adaptation of the master value by interpolation. That is, the slave axis uses an adapted master value, which belongs to an earlier time than the base master value, to perform the synchronism function at the next interpolator cycle clock boundary.

[0098] FIG. 4 schematically shows a flowchart of the method steps to be performed on the slave axis in accordance with a fourth exemplary embodiment of the invention. By way of example, the operative time of the relevant event on the slave axis is calculated, as indicated in step S10. The latter is not already determined via the time of the interpolation cycle boundary but should be ascertained, as described above, by the addition of further time intervals. In a second step S20, the time of the relevant event on the master axis is calculated on part of the slave axis. This time of the operative time is known by way of the timestamp provided along with the base master value or by way of additional data in relation to the timestamp, should it not be directly contained in this timestamp. Method steps S10 and S20 can be performed in any order.

[0099] Subsequently, the time difference T10 or T30 is calculated, as indicated in step S30. This time difference will be ascertained (with reference to the reference signs of FIG. 2) based on the absolute time values t10L and t10F or t30L and T30F in the common time system t, with a reference time, such as a common interpolation cycle boundary of both axes in particular, not being required.

[0100] The master values are adapted in a fourth step S40. There is a conversion of the base master value, which belongs to the initial time t0L, to the master value that belongs to the time has been shifted by the time difference T10 or T30.

[0101] Thereupon, the fifth step S50 is still performed in a synchronism application. Here, the synchronism function is applied to the adapted master value to determine the best suited setpoint slave value that leads to a synchronism between the master axis and slave axis with a particularly good correspondence.

[0102] Thus. while there have been shown, described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the methods described and the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.