Motor Redundancy in a Model Rig

Part of my background reading for my Final Year Project FYP has lead me to a paper byMuenchhof, Beck, Isermann titled Fault Tolerant Actuators and Drive Structures, Fault Detection Principles and Applications within this paper its discusses fault tolerance along with fault detection methods.

The main objective of my project for me is to make a system that can accept a fault without a change in performance. This system would be implemented in a very critical system ie. and aeroplane or nuclear power plant. The actuators or motors in my system could be used for a valve in a pipe or wing flaps so it is really just an exercise to show one of the ways of producing a fault tolerant system.

The current arrangement of my system is to have two motors running constantly, if one should fail the system will continue with degraded performance.

I have been looking at redundancy within a system and it involves having back up parts that are activated when a fault is detected. In my system I could power one of the motors and have the other as a stand by. I could model a simple control system that will used a speed sensor to detect a 'lock up' type fault. This fault would trigger the other motor to start running the system.

The added advantages are simple the system would undergo no drop in performance should a fault occur, fault detection would be simple as a warning lamp or fault code could be integrated into the back up motor.

The obvious drawbacks are the differential arrangement gearing down the motor, and if the same motors are  used it can lead to the common cause faults occurring in both. The fault be caused by adverse conditions like water or vibration that both of the motors would have to operate in.

I will look into similar spec motors that have different mounting or housing to prevent the common fault possibility.

I am yet to draw up a preliminary control system, I will probably do this under close guidance from my tutor as he is an expert in this field.

I have also started reading Blanke, Kinnaert, Lunze and Starowiecki Diagnosis and Fault Tolerant Control.