Adaptive control system having hedge unit and related apparatus and methods

• US 7,218,973 B2
• Filed: 06/23/2003
• Issued: 05/15/2007
• Est. Priority Date: 04/25/2000
• Status: Expired due to Term

• Current Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Original Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Inventors: Calise, Anthony J., Johnson, Eric Norman
• Primary Examiner(s): PHAM, THOMAS K
• Application Number:
  US10/602,458
• Publication Number:
  US 20040088059A1
• Time in Patent Office: 1,422 Days
• Field of Search: 700/28, 700/29, 700/30, 700/31, 700/32, 700/47, 700/48, 700/173, 701/58, 701/59, 701/60, 701/63, 701/38
• US Class Current: 700/28
• CPC Class Codes: G05B 13/027 using neural networks only
• CPC Class Codes: G05B 13/04 involving the use of models or simulators
• CPC Class Codes: G05B 13/041 in which a variable is automatically adjusted to optimise the performance

Abstract

The invention includes an adaptive control system used to control a plant. The adaptive control system includes a hedge unit that receives at least one control signal and a plant state signal. The hedge unit generates a hedge signal based on the control signal, the plant state signal, and a hedge model including a first model having one or more characteristics to which the adaptive control system is not to adapt, and a second model not having the characteristic(s) to which the adaptive control system is not to adapt. The hedge signal is used in the adaptive control system to remove the effect of the characteristic from a signal supplied to an adaptation law unit of the adaptive control system so that the adaptive control system does not adapt to the characteristic in controlling the plant.

Claims

1. A method comprising the step of:

a) generating a hedge signal with an adaptive control system to avoid adaptation to at least one characteristic of the adaptive control system, the characteristic having an effect to which adaptation would be detrimental to control of a plant with the adaptive control system.

2. A method as claimed in claim 1 further comprising the steps of:

b) modifying a commanded state signal with the hedge signal; and

c) generating a reference model state signal based on the commanded state signal modified with the hedge signal in the step (b).

3. A method as claimed in claim 2 further comprising the step of:

d) generating a tracking error signal based on the reference model state signal and a plant state signal; and

e) generating an adaptive control signal based on the tracking error signal to adapt control response of the adaptive control system.

4. A method as claimed in claim 1 wherein the plant is an aircraft and/or spacecraft.

5. A method as claimed in claim 1 wherein the plant is an automobile.

6. A method as claimed in claim 1 wherein the plant is an unmanned vehicle.

7. A method as claimed in claim 1 wherein the characteristic pertains to a control limit of the actuator used to control the plant.

8. A method as claimed in claim 7 wherein the control limit pertains to actuator end points.

9. A method as claimed in claim 7 wherein the control limit pertains to actuator dynamics.

10. A method as claimed in claim 7 wherein the control limit pertains to a rate limit of the actuator.

11. A method as claimed in claim 7 wherein the control limit pertains to quantization effects associated with the actuator.

12. A method as claimed in claim 1 wherein the characteristic relates to a control limit of the sensor.

13. A method as claimed in claim 1 wherein the control limit relates to a speed at which the sensor can sense a state of the plant.

14. In an adaptive control system for controlling a plant, a hedge unit coupled to receive at least one control signal and a plant state signal, the hedge unit generating a hedge signal based on the control signal, the plant state signal, and a hedge model including a first model having a characteristic of the adaptive control system to which the adaptive control system is not to adapt, and a second model not having the characteristic to which the adaptive control system is not to adapt, the hedge signal used in the adaptive control system to remove an effect of the characteristic from a signal supplied to an adaptation law unit of the adaptive control system so that the adaptive control system does not adapt to the characteristic in controlling the plant, the characteristic having an effect to which adaptation would be detrimental to control of a plant with the adaptive control system.

15. An adaptive control system as claimed in claim 14 wherein the characteristic pertains to a control limit of the actuator used to control the plant.

16. An adaptive control system as claimed in claim 14 wherein the control limit pertains to actuator end points.

17. An adaptive control system as claimed in claim 14 wherein the control limit pertains to actuator dynamics.

18. An adaptive control system as claimed in claim 14 wherein the control limit pertains to a rate limit of the actuator.

19. An adaptive control system as claimed in claim 14 wherein the control limit pertains to quantization effects associated with the actuator.

20. An adaptive control system as claimed in claim 14 wherein the plant is an aircraft and/or spacecraft.

21. An adaptive control system as claimed in claim 14 wherein the plant is an automobile.

22. An adaptive control system as claimed in claim 14 wherein the plant is an unmanned vehicle positioned remotely from an operator.

23. A system as claimed in claim 14 wherein the characteristic relates to a control limit of the sensor.

24. A system as claimed in claim 23 wherein the control limit relates to a speed at which the sensor can sense a state of the plant.