CRITICAL SYSTEM AND ASSOCIATED MONITORING METHOD

• US 20160291586A1
• Filed: 11/19/2014
• Published: 10/06/2016
• Est. Priority Date: 11/19/2013
• Status: Active Application

• Current Assignee: Thales SA
• Original Assignee: Thales SA
• Inventors: BOBRINSKOY, Alexandre, GUERINEAU, Olivier, GATTI, Marc, BLUTEAU, Bruno, CAZAURANG, Franck
• Granted Patent: US 10,261,505 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G05B 23/0254 based on a quantitative model, e.g. mathematical relationships between inputs and outputs; functions: observer, Kalman filter, residual calculation, Neural Networks
• CPC Class Codes: G05B 9/03 with multiple-channel loop, i.e. redundant control systems

Abstract

A critical system comprises a control pathway comprising an actuation unit having a nonlinear behavior, that is able to be controlled by applying an input quantity and whose state is characterized by an output quantity. The behavior of the actuation unit being described by a flat nonlinear model, wherein the system comprises an estimation unit comprising a dynamic inversion linearization module calculating from the measured output quantity, the input quantity of the equivalent linear model; an estimation module estimating a flat output quantity from the input quantity of the equivalent linear model; and a computing module computing a residual based on the estimated flat output quantity and a measured flat output quantity, corresponding to the measured output quantity.

Claims

1. A critical system, in particular a critical flight system, including a control pathway comprising an actuation unit having a nonlinear behavior, that is able to be controlled by applying an input quantity and whose state is characterized by an output quantity measured by appropriate sensors, wherein the behavior of the actuation unit being described by a flat nonlinear model, for which there exists an equivalent linear model establishing a relation between an input quantity and a flat output quantity,

wherein the system comprises a monitoring pathway for the control pathway, having an estimation unit that includes comprising:

a dynamic inversion linearization module, calculating from the measured output quantity, the input quantity of the equivalent linear model;

a an estimation module for estimating a flat output quantity from the input quantity of the equivalent linear model, based on said equivalent linear model; and

a computing module for computing a residual based on the estimated flat output quantity and a measured flat output quantity, corresponding to the measured output quantity.

2. The system according to claim 1, wherein the estimating module implements a SKF observer.

3. The system according to claim 1, wherein the actuation unit comprises includes an induction motor.

4. The system according to claim 3, wherein the induction motor is of the hybrid stepping.

5. The system according to claim 4, wherein the input quantity of the equivalent linear model is:

6. The system according to claim 5, wherein the mechanical and electromagnetic equations of the behavior of the motor defining the equivalent linear model according to:

7. The system according to claim 1, wherein the actuation unit further comprising a control module generating, from a setpoint quantity, the input quantity of the actuation unit.

8. The system according to claim 1, wherein the monitoring pathway further having a diagnostic module using at least one residual as input and generating an inhibition signal of the control pathway.

9. The system according to claim 1, comprising:

a first control pathway associated with a first monitoring pathway, the latter generating first residuals;

a second control pathway associated with a second monitoring pathway, making the first control and monitoring pathways redundant, the second monitoring pathway generating second residuals,

wherein the system further comprising a shared diagnostic module inhibiting one and/or the other of the first and second control pathways, once a fault is detected, based on the first and second residuals.

10. A method for monitoring a critical system, in particular a critical flight system, including a control pathway comprising an actuation unit having a nonlinear behavior, which is able to be controlled by applying an input quantity and the state of which is characterized by an output quantity measured by appropriate sensors, wherein the behavior of the actuation unit of the system being described by a flat nonlinear model for which there is an equivalent linear model establishing a relation between an input quantity and a flat output quantity,

wherein the method comprises a step for linearization by dynamic inversion to calculate, from the measured output quantity, an input quantity of the equivalent linear model, and a step for estimating a flat output quantity of the equivalent linear system, from the calculated input quantity and using said equivalent linear model.

11. The method according to claim 10, comprising a step for calculating at least one residual by difference between the estimated flat output quantity and a measured flat output quantity, obtained from the measured output quantity, and a diagnostic step based on the comparison of the or each residual to a threshold value.