Failure Annotations - Wheel Node Controller

Both omission and value deviations are admitted for the outputs of the wheel node controller.

 

- As with the electronic pedal, in spite of the fail silent expected behavior of the local control unit, at the design stage at hand internal value failures are considered to be possible causes of output value deviations. Moreover, wrong value outputs can also be triggered by value deviation of the output of the leading bus or by the omission of that same output and value deviation of the output of the replica bus.

- Omission of both outputs can be caused by omission of both buses' outputs. Internal failures can also cause omission of the outputs. These failures may be related with component failure detection which results in the inhibition of the controller.

Like with the pedal unit, independent internal failures were considered for the causes of the deviations of each output. Each power converter reference may be calculated independently to avoid simultaneous failure of both braking devices, for example.

Table 4 - Failure Annotations - Wheel Node Controller
Output Deviation  Causes 
 Omission-Out1  Omission-In1 AND Omission-In2 OR OmissionFailure1
 Omission-Out2  Value-In1 OR Omission-In1 AND Value-In2 OR ValueFailure1
 Value-Out2  Omission-In1 AND Omission-In2 OR OmissionFailure2
Value-Out2 Value-In1 OR Omission-In1 AND Value-In2 OR ValueFailure2