초록 ▼

In a triplex redundant digital control system, one of three computer units is selected for controlling a digital flight control system by using fault scoring and selection logic circuitry that responds to discrete signals produced by the computer units that represent both self-test and cross-test in

In a triplex redundant digital control system, one of three computer units is selected for controlling a digital flight control system by using fault scoring and selection logic circuitry that responds to discrete signals produced by the computer units that represent both self-test and cross-test information on the health of the three available units. The self-test and cross-test discrete information signals are received and processed by the selection logic circuit in accordance with a fault-scoring scheme in which the self-test scores are accorded different and, in particular, greater weight than the cross-test scores and a computer unit exhibiting the lowest combined self- and cross-test fault score is selected as the computer in control. The circuitry also includes memory devices for storing the fault scores associated with previous fault conditions so that a previously unfailed computer unit is selected over a previously failed but currently healthy computer. The memory devices are cleared whenever all three computer modules have scored a fault condition of equal weight such that transient failures do not cause permanent disablement of a computer unit, rather the temporarily faulty unit is allowed to recover and to be brought back on line if needed. To minimize switching, the selection logic causes a new selection only if a computer unit with a lower fault score is available. For simplicity and reliability, the fault scoring and selection logic functions of the circuitry are performed by read-only memories (ROMs) and the memory function is implemented by resettable latches.

대표청구항 ▼

A fault scoring and selection circuit for selectively enabling at least one of a plurality of redundant control units to govern the operation of controlled equipment in which the redundant control units are each of the type having both self-testing and cross-testing capabilities respectively produci

A fault scoring and selection circuit for selectively enabling at least one of a plurality of redundant control units to govern the operation of controlled equipment in which the redundant control units are each of the type having both self-testing and cross-testing capabilities respectively producing self-test and cross-test fault signals, said circuit comprising: fault-scoring logic circuit means including means for receiving self-test and cross-test fault signals from each of said control units, and means assigning predetermined scoring weights, certain of which are different, to said self-test fault signals and cross-test fault signals, and means for combining these weighted fault signals to produce combined fault score signals representing the health of each of said control units; and selection logic circuit means for receiving said fault score signals, and for converting said fault score signals into a selection output signal that selects at least one of said control units having the lowest available fault score as determined by said fault score signals.