Developments in or relating to system prognostics

• US 8,103,392 B2
• Filed: 03/27/2009
• Issued: 01/24/2012
• Est. Priority Date: 05/12/2008
• Status: Active Grant

• Current Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Inventors: Self, Kristian A., Radmore, Geoffrey, Walker, David
• Primary Examiner(s): Dickson, Paul N
• Assistant Examiner(s): FRISBY, KEITH J
• Application Number:
  US12/382,984
• Publication Number:
  US 20090281683A1
• Time in Patent Office: 1,033 Days
• Field of Search: 701/34, 701/29, 701/31, 701/3, 701/39, 701/40, 701/11, 701/12, 701/62, 701/63, 701/92, 701/97, 701/98, 701/106, 701/107, 701/36, 701/1, 714/2, 714/26, 702/185, 702/35
• US Class Current: 701/3
• CPC Class Codes: G05B 23/0262 Confirmation of fault detection, e.g. extra checks to confirm that a failure has indeed occurred
• CPC Class Codes: G05B 23/0291 Switching into safety or degraded mode, e.g. protection and supervision after failure

Abstract

A method of mitigating the system-level effect of a fault detected in a vehicle system during a vehicle mission, the method comprising: using a processor to automatically prognose the system-level effect of said fault in terms of the residual capability of the vehicle system during the remainder of the mission, on the basis of predetermined stored data; using a processor to automatically generate a corresponding set of alternative reversionary or investigative action plans for mitigating said system-level effect during the remainder of the vehicle mission, on the basis of said prognosis; submitting the set of alternative reversionary action plans to a decision-making authority for determination by the decision-making authority of a preferred one of the reversionary action plans suitable for achieving a mission objective; and using a control unit, operably connected to the vehicle system, to implement the preferred reversionary action plan in accordance with said determination.

Claims

1. A method of mitigating a system-level effect of a fault detected in a system during an operating period, the method comprising:

using a controller to automatically prognose the system-level effect of said fault in terms of a residual capability of the system during a remainder of the operating period based on predetermined stored data;

using the controller to automatically generate a corresponding set of alternative reversionary action plans for mitigating said system-level effect during the remainder of the operating period based on said prognosis, wherein each reversionary action plan includes a first projected outcome if a current setting for a mitigation parameter is not adjusted, a proposed adjustment to the current setting for the mitigation parameter and a time frame for reaching the first projected outcome;

submitting the set of alternative reversionary action plans to a decision-making authority for determination by the decision-making authority of a preferred one of the reversionary action plans suitable for achieving an objective; and

using the controller, operably connected to the system, to implement a preferred reversionary action plan in accordance with said determination.

2. A method according to claim 1, wherein the decision-making authority comprises the controller having a predetermined remit of delegated autonomy for determining the preferred reversionary action plan.

3. A method according to claim 1, wherein the system comprises one or more subsystems and the system level-effect of the fault is determined as a function of a residual capability of the one or more subsystems.

4. A method according to claim 3, wherein the system encompasses one or more compensatory groups of subsystems and the system-level effect of the fault is determined as a function of a residual capability for each subsystem in said one or more compensatory groups of subsystems.

5. A method according to claim 1, wherein prognosis of the residual capability of the system or subsystem includes determining a time scale for a severity of the fault to escalate to a threshold severity for that system or subsystem respectively.

6. A method according to claim 5, wherein the prognosis further includes estimating a confidence in the determined time scale.

7. A method according to claim 1, wherein a number of the alternative reversionary action plans generated is a function of a differential system-level severity with respect to one or more mitigation parameters.

8. A method according to claim 1, wherein said automatic prognosis of the system-level effect of said fault comprises implementing a fault detection analysis loop for resolving identification of the fault.

9. A method according to claim 1, wherein the system is a vehicle system, the operating period is a vehicle mission and the objective is a mission objective.

10. A method according to claim 9, wherein the decision-making authority comprises a pilot of the vehicle.

11. A method according to claim 10, wherein the pilot is an autopilot.

12. A method according to claim 9, wherein the vehicle is an aircraft.

13. A control-system configured for carrying out the method according to claim 1.

14. A method according to claim 1, wherein each reversionary action plan further includes a current system-level criticality, a second projected outcome if the current setting for the mitigation parameter is adjusted as proposed and a time frame for reaching the second projected outcome.