Methods and apparatus for state limiting in a control system

• US 8,965,538 B2
• Filed: 05/19/2010
• Issued: 02/24/2015
• Est. Priority Date: 05/19/2010
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Gadient, Ross J., Lavretsky, Eugene, Hyde, David C.
• Primary Examiner(s): Fennema, Robert
• Assistant Examiner(s): STEVENS, THOMAS H
• Application Number:
  US12/783,230
• Publication Number:
  US 20110288661A1
• Time in Patent Office: 1,742 Days
• Field of Search: 701/2, 701/13, 701/23, 701/48, 701/68, 701/91, 700/32, 700/33
• US Class Current: 700/32
• CPC Class Codes: G05B 13/04 involving the use of models or simulators
• CPC Class Codes: G05D 1/0066 for limitation of acceleration or stress

Abstract

A method for operating a controlled device. A feedback signal is received from a controlled device, the feedback signal indicating actual system dynamics of the controlled device. A predefined limit is applied to the actual system dynamics to create limited system dynamics. A modulation parameter is calculated by a processor based at least in part on the limited system dynamics and the actual system dynamics. Desired system dynamics for the controlled device are generated by the processor based at least in part on the modulation parameter and an external command.

Claims

1. A method for operating a controlled device, the method comprising:

receiving an external command that represents a desired system dynamics for the controlled device;

receiving a feedback signal from the controlled device, the feedback signal indicating actual system dynamics of the controlled device;

applying a predefined limit to the actual system dynamics to create limited system dynamics;

calculating, by a processor, a modulation parameter based at least in part on a predefined tolerance and a difference between the limited system dynamics and the actual system dynamics; and

generating, by the processor, the desired system dynamics for the controlled device based at least in part on the modulation parameter, wherein the modulation parameter enables a value of the external command to be approached gradually without exceeding the predefined limit at a particular rate, and wherein the particular rate is calculated based on the difference between the limited system dynamics and the actual system dynamics and a length of time corresponding to a magnitude of the predefined tolerance.

2. The method of claim 1, wherein the modulation parameter is calculated by applying a predefined function to the limited system dynamics, the actual system dynamics, the predefined limit, and a predefined tolerance.

3. The method of claim 1, wherein the controlled device is a vehicle associated with a plurality of states, the method further comprising generating desired system dynamics for each state of the plurality of states.

4. The method of claim 1, wherein generating the desired system dynamics comprises generating the desired system dynamics in real time.

5. The method of claim 1, further comprising generating a command signal for the controlled device based at least in part on the desired system dynamics.

6. The method of claim 1, wherein applying a predefined limit to the actual system dynamics comprises applying at least one predefined limit corresponding to an operating envelope of the controlled device.

7. The method of claim 6, wherein generating desired system dynamics for the controlled device comprises generating desired system dynamics within the at least one predefined limit.

8. The method of claim 6, further comprising generating a command signal for the controlled device based on the desired system dynamics, wherein the command signal enforces the at least one predefined limit.

9. A control system for a controlled device, the control system comprising:

a state limiter configured to;

receive a feedback signal indicating actual system dynamics of the controlled device; and

apply a predefined limit to the actual system dynamics to create limited system dynamics; and

a state limiting logic component coupled in communication with the state limiter and configured to;

calculate a modulation parameter based at least in part on a predefined tolerance and a difference between the limited system dynamics and the feedback signal, the modulation parameter indicating an adjustment to apply to desired system dynamics corresponding to an external command, wherein the adjustment enables a value of the external command to be approached gradually without exceeding the predefined limit at a particular rate, and wherein the particular rate is calculated based on the difference between the limited system dynamics and the actual system dynamics and a length of time corresponding to a magnitude of the predefined tolerance.

10. The control system of claim 9, wherein the state limiter is configured to apply a predefined limit representing a performance capability of the controlled device.

11. The control system of claim 9, further comprising a reference dynamics component coupled in communication with the state limiting logic component and configured to generate desired system dynamics based at least in part on the external command and the modulation parameter.

12. The control system of claim 11, wherein the state limiting logic component is further configured to calculate the modulation parameter such that the desired system dynamics generated by the reference dynamics component enforce the predefined limit.

13. The control system of claim 11, further comprising a controller coupled in communication with the reference dynamics component and configured to generate an input command for the controlled device based at least in part on the desired system dynamics.

14. The control system of claim 13, wherein the controller is configured to generate the input command based further on the feedback signal, wherein the input command is generated in real time.

15. The control system of claim 11, wherein the reference dynamics component is configured to receive the external command from a remote device.

16. The control system of claim 9, wherein the controlled device is associated with one or more states, the predefined limit comprises a plurality of limits corresponding to each state of the one or more states, and calculating a modulation parameter comprises calculating a modulation parameter corresponding to each state of the one or more states.

17. A control system for a vehicle associated with one or more states, the control system comprising:

a state limiter configured to;

receive a feedback signal indicating actual system dynamics corresponding to the one or more states; and

apply at least one predefined limit to the actual system dynamics to create limited system dynamics; and

a state limiting logic component coupled in communication with the state limiter and configured to;

calculate a modulation parameter based at least in part on a predefined tolerance and a difference between the limited system dynamics and the feedback signal, the modulation parameter indicating an adjustment to apply to desired system dynamics corresponding to an external command, wherein the modulation parameter enables a value of the external command to be approached gradually without exceeding the predefined limit at a particular rate, and wherein the particular rate is calculated based on the difference between the limited system dynamics and the actual system dynamics and a length of time corresponding to a magnitude of the predefined tolerance.