MPC fault-tolerant flight control case study: flight 1862

TLDR: In this paper, the authors demonstrate that the fatal crash of El Al Flight 1862 might have been avoided by using MPC-based fault-tolerant control, and demonstrate that it is possible to reconfigure the controller so that the aircraft is flown successfully down to ground level, without entering the condition in which it was lost.

About: This article is published in IFAC Proceedings Volumes.The article was published on 2003-06-01 and is currently open access. It has received 212 citations till now. The article focuses on the topics: Model predictive control & Control theory.

Figures

Fig. 1. MPC Fault-Tolerant Controller

Fig. 4. Lateral Pilot Inputs; Solid: Working Aircraft, Dashed: Failed Aircraft

Fig. 3. Lateral Tracking Performance; Solid: Working Aircraft, Dashed: Failed Aircraft

Fig. 2. Actuator Positions; Solid: Working Aircraft, Dashed: Failed Aircraft

Frequently asked questions

Q1. What are the contributions in this paper?

The authors demonstrate that the fatal crash of El Al Flight 1862 might have been avoided by using MPC-based fault-tolerant control. The authors assume in this paper that an FDI function delivers information about actuator damage, and about changes to aerodynamic coefficients in the failed condition. 

Q2. What are the future works in this paper?

Secondly, they did not consider the possibility that the wing ’ s aerodynamic performance might have changed as a result of damage. Knowing how much information about behaviour is needed for effective control, and how quickly that information can be acquired, are topics on which very little is known at present, and which deserve further study. 

Q3. What is the definition of ‘active fault tolerance’?

In this survey ‘robust control’ is included in the category of ‘passive fault-tolerance’, whereas both adaptive control and reconfigurable control are considered to be included in ‘active fault-tolerance’. 

Q4. What is the possibility of fault-tolerant control?

The possibility of fault-tolerant control arises only if there is, in some sense, enough redundancy in the system being controlled to allow the effects ofa fault to be in some way circumvented. 

Q5. What is the main purpose of the MPC controller?

As stated above, MPC is a good framework for fault-tolerant control, as many kinds of aircraft failures can be handled online in an adaptive fashion via modifications to the internal model. 

Q6. Why are the lateral channels shown in Figure 2?

Due to space constraints, only the lateral channels are shown here, although the model and controller have six degrees of freedom, and control of this asymmetric aircraft requires coordination between the lateral and longitudinal controls. 

Q7. How long did the crew stay in the air?

Despite this failure, the crew continued flying for almost 15 minutes, giving considerable time for identification of the failure and for the online design of a new controller. 

Q8. What is the definition of fault-tolerant control?

In their view ‘fault-tolerant’ control certainly considers the possibility of structural changes in the plant being controlled (including changes in dynamic behaviour, changes in available actuators, and changes in available sensors), as well as the possibility that control objectives may need to be changed.