Developments in or relating to system prognostics

• US 20090281683A1
• Filed: 03/27/2009
• Published: 11/12/2009
• 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: Walker, David, Self, Kristian A., Radmore, Geoffrey
• Granted Patent: US 8,103,392 B2
• Time in Patent Office: Days
• 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 the system-level effect of a fault detected in a system during an operating period, the method comprising:

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

using a processor to automatically generate a corresponding set of alternative reversionary action plans for mitigating said system-level effect during the remainder of the operating period, 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 an objective; and

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

2. A method according to claim 1, wherein the decision-making authority comprises a processor having a predetermined remit of delegated autonomy for determining a 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 the residual capability of one or more of the 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 the residual capability for each subsystem in said group.

5. A method according to claim 1, wherein prognosis of the residual capability of a system or subsystem includes determining a time scale for the 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 the confidence in the determined time-scale.

7. A method according to claim 1, wherein the number of alternative reversionary action plans generated is a function of the 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.