SYSTEM AND METHOD FOR DESIGN AND CONTROL OF ENGINEERING SYSTEMS UTILIZING COMPONENT-LEVEL DYNAMIC MATHEMATICAL MODEL

• US 20110077783A1
• Filed: 11/03/2008
• Published: 03/31/2011
• Est. Priority Date: 11/03/2008
• Status: Active Grant

• Current Assignee: Rtx Corporation
• Original Assignee: United Technologies Corporation (Rtx Corporation)
• Inventors: Lacour, Mark E., Karpman, Boris, Meisner, Richard P.
• Granted Patent: US 8,090,456 B2
• Time in Patent Office: Days
• US Class Current: 700/283
• CPC Class Codes: G05B 17/02 electric

Abstract

A control system comprises a controller for positioning an actuator in a working fluid flow and a model processor for directing the controller as a function of a model feedback. The model processor comprises an output module, a comparator and an estimator. The output module generates the model feedback as a function of a constraint, a model state and a model input describing fluid parameters measured along the working fluid flow. The comparator generates an error by comparing the model feedback to the model input. The estimator generates the constraint and the model state, such that the error is minimized.

Claims

1. A control system comprising:

an actuator for positioning a control device;

a control law for directing the actuator as a function of a model output, and

a closed-loop model processor for generating the model output, the closed-loop model processor comprising;

an open loop module for generating the model output as a function of a model state and a model input;

a corrector output module for generating a corrector output as a function of the model output;

a comparator for generating an error by comparing the corrector output to the model input; and

a model state estimator for generating the model state as a function of the error, such that the error is minimized.

2. The control system of claim 1, wherein the control device comprises a variable-position control surface positioned in a working fluid flow.

3. The control system of claim 2, wherein the model input describes a boundary flow condition at one of an inlet or an outlet of the working fluid flow.

4. The control system of claim 3, wherein the variable-position control surface comprises one of a variable-position vane surface or a variable-position nozzle surface positioned in the working fluid flow.

5. The control system of claim 1, wherein the model state estimator further generates the model state as a function of the error, such that a time derivative of the model state is minimized.

6. The control system of claim 1, wherein the actuator positions the control surface in order to control the model state.

7. The control system of claim 6, wherein the open loop module generates the model output as a further function of a constraint on the model state.

8. The control system of claim 7, wherein the constraint is based on flow continuity.

9. The control system of claim 8, wherein the model state describes a spool speed.

10. The control system of claim 9, wherein the spool speed has a response time greater than a cycle time of the closed-loop model processor.

11. The control system of claim 10, wherein a cycle time of the closed-loop model processor is 50 ms or less.

12. The control system of claim 1, wherein the closed-loop model processor is non-iterative, such that the open loop module, the corrector output module, the comparator and the model state estimator each utilize non-iterative functions to generate the model output, the corrector output, the error and the model state.

13. The control system of claim 12, wherein the closed-loop model processor is further non-linear, such that at least one of the open loop module, the corrector output module, the comparator and the model state estimator utilizes a non-linear function to generate at least one of the model output, the corrector output, the error and the model state.

14. A method for controlling flow through an apparatus, the method comprising:

sensing a boundary state describing the flow at a boundary of the apparatus;

controlling an actuator state as a function of a model feedback, wherein the actuator state describes a variable control surface positioned in the flow;

generating the model feedback as a function of the boundary state and the actuator state and a physical state of the apparatus;

correcting the model feedback for error based on the boundary state; and

estimating the physical state by minimizing the error, such that the flow is controlled.

15. The method of claim 14, wherein the boundary state describes the flow at one of an inlet boundary of the apparatus or an outlet boundary of the apparatus.

16. The method of claim 15, wherein the actuator state describes one of a variable vane position proximate the inlet boundary or a variable nozzle position proximate the outlet boundary.

17. The method of claim 14, wherein the physical state comprises a steady state of the apparatus, and wherein the steady state has a response time greater than a cycle time of the method.

18. The method of claim 17, further comprising minimizing a time rate of change of the physical state.

19. The method of claim 18, wherein the physical state comprises a rotational state.

20. The method of claim 18, wherein estimating the physical state is performed as a function a gain tensor designed to minimize the error and the time rate of change of the physical state.

21. The method of claim 20, wherein the gain tensor has a substantially triangular representation.

22. The method of claim 14, further comprising estimating a constraint state by minimizing the error, wherein the constraint state describes a flow continuity constraint on the physical state.

23. The method of claim 22, wherein generating the model feedback is performed as nonlinear, non-iterative function of the boundary state, the actuator state, the physical state and the constraint state.

24. The method of claim 22, wherein minimizing the error is performed as nonlinear, non-iterative function of the boundary state, the actuator state and the constraint state.

25. A system for controlling a rotational state of an apparatus, the system comprising:

a sensor for sensing a boundary state of the apparatus;

an actuator for changing a control state within the apparatus, in order to alter the boundary state;

a output module for generating an output vector as a function of an input vector and the rotational state, wherein the input vector describes the boundary state of the apparatus and the control state within the apparatus;

a comparator for generating an error vector by comparing the output vector to the input vector;

an estimator for estimating the rotational state by minimizing the error vector; and

a controller for controlling the actuator based on the output vector, such that the system controls the rotational state of the apparatus.

26. The system of claim 25, wherein the output module further generates a time derivative of the rotational state, and wherein the estimator further estimates the rotational state by minimizing the time derivative.

27. The system of claim 25, wherein the boundary state describes flow through the apparatus at one of an inlet boundary of the apparatus and an outlet boundary of the apparatus.

28. The system of claim 27, wherein the rotational state of the apparatus describes a spool speed for a gas turbine engine.

29. The system of claim 27, wherein the estimator further estimates a constraint vector that constrains the rotational state based on flow continuity, and wherein the output module generates the output vector as a further function of the constraint vector.

30. The system of claim 29, wherein the constraint vector describes the flow at an intermediate location between the inlet boundary and the outlet boundary.

31. The system of claim 30, wherein the estimator minimizes the error vector based on a tensor function of a gain matrix.

32. The system of claim 31, wherein the gain matrix has a substantially triangular form.

33. The system of claim 31, wherein the gain matrix is based on a control formulation in which the error vector is defined as a time derivative that is decoupled from the rotational state.

34. The system of claim 31, wherein the gain matrix is based on an observer formulation in which a time derivative of the constraint vector is zero.

35. The system of claim 31, wherein the output module generates the output vector as a nonlinear, non-iterative function of the input vector, the rotational state and the constraint vector, and wherein the estimator estimates the rotational state by minimizing the error vector based on a nonlinear, non-iterative function of the input vector and the constraint vector.