BAE Systems PLC
Control systems and methods

Abstract:

A control system (200) using fixed point computation avoids overflow conditions by limiting the internal quantities ensuring that contributing calculations from various parts of the control loop never add up to an overflow. Various parts of a control loop e.g. proportional terms can be prioritised over other parts, e.g. integral and differential terms and ensuring that the overall total resulting when the separate terms are summed together never exceeds the maximum or minimum imposed limits. Variable limit calculator circuits (211,219) revise the limits according to the output of the higher priority control path(s). The revised limits cascade down through each contributor, eventually allowing the lowest priority control path the smallest authority. The control system may be applied to control of a drive motor (111) for an aircraft inceptor (103).