Method and apparatus for controlling a physical unit in an automation system
View Patent ↗A method for controlling a physical unit, involving: cyclically generating a plurality of controlling outputs, wherein the plurality of controlling outputs is provided in a redundant manner; applying a selected one of the controlling outputs to the physical unit; checking if at least the selected controlling output is correct; and selecting one of the control units whose controlling output was checked as correct to apply its controlling output to the physical unit ( 2 ) in a subsequent cycle, wherein the applying the selected one of the controlling outputs to the physical unit is performed before or during the step of checking.
1. A method for controlling a physical unit, the method comprising:
cyclically generating a plurality of controlling outputs, wherein the plurality of controlling outputs is provided in a redundant manner;
applying a selected controlling output of the controlling outputs to the physical unit;
checking if at least the selected controlling output is correct; and
selecting a selected control unit whose controlling output was checked as correct to apply its controlling output to the physical unit in a subsequent cycle,
wherein the applying is performed before the step of checking, and in case the selected control unit has generated an invalid output, the selected control unit is replaced by another control unit before the next controlling cycle.
2. The method of claim 1 , wherein the checking is performed as a plurality, majority, or likelihood voting.
3. The method of claim 1 , wherein the checking includes checking among all controlling outputs which of the controlling outputs are correct.
4. The method of claim 3 , wherein the selecting is performed using:
a priority scheme;
a random scheme; or
a scheme wherein a number of changes of the selected controlling output is minimized.
5. The method of claim 1 , wherein, if the controlling outputs are generated successively, the selected controlling output that is checked as correct and is generated first in one cycle is selected.
6. The method of claim 1 , wherein, if a predetermined default value is recognized in one or more of the controlling outputs, a respective controlling output is checked as incorrect.
7. An apparatus for selecting one of a number of control units to be used for controlling a physical system, the number of control units redundantly providing controlling outputs, the apparatus comprising:
a voting unit, which is configured:
to allow a previously selected control unit to apply its controlling output, as a previously selected controlling output, to the physical system;
to check if at least the previously selected controlling output is correct;
to select one of the controlling outputs checked as correct;
to provide the controlling output of a selected one of the control units for applying to the physical unit in a subsequent cycle; and
to allow a previously selected controlling output to be applied to the physical system before the next controlling cycle and before it is checked, if the previously selected controlling output is correct.
8. An automation system, comprising:
a plurality of control units configured to generate redundant controlling outputs;
an apparatus for selecting one of the plurality of control units to be used for controlling a physical system, the plurality of control units redundantly providing controlling outputs, the apparatus comprising:
a voting unit, which is configured:
to allow a previously selected control unit to apply its controlling output, as a previously selected controlling output, to the physical system;
to check if at least the previously selected controlling output is correct;
to select one of the controlling outputs checked as correct;
to provide the controlling output of a selected one of the plurality of control units for applying to the physical unit in a subsequent cycle; and
to allow a previously selected controlling output to be applied to the physical system before the next controlling cycle and before it is checked, if the previously selected controlling output is correct; and
the physical system.
9. The automation system of claim 8 , further comprising:
a multiplexer configured to select one of the controlling outputs of the control units to be applied to the physical system.
10. The method of claim 1 , wherein the checking is performed as a plurality voting.
11. The method of claim 1 , wherein the checking is performed as a majority voting.
12. The method of claim 1 , wherein the checking is performed as a likelihood voting.
13. The method of claim 2 , wherein the checking includes checking among all controlling outputs which of the controlling outputs are correct.
14. The method of claim 4 , wherein the selecting is performed using the priority scheme.
15. The method of claim 4 , wherein the selecting is performed using the scheme wherein a number of changes of the selected controlling output is minimized.
16. The method of claim 4 , wherein the selecting is performed using the random scheme.