Affiliation:
1. Technische Universität München, Institute of Flight System Dynamics,
Germany
Abstract
<div>This work introduces a practical approach to external synchronization for flight
control computers (FCCs) deployed in a decentralized fashion. The internal
synchronization among the FCCs in distributed flight control systems needs to be
extended for specific applications, necessitating an urgent need for an external
synchronization mechanism. For instance, when the air data and attitude
reference system (ADAHRS) and the flight control computer (FCC) are not
synchronized, a dead time or time offset occurs between the time the ADAHRS
transmits data and the time the FCC begins executing its control functions,
which can impair flight control system performance or even cause system
instability, particularly for the system with incremental control approaches,
such as incremental nonlinear dynamic inversion (INDI). Therefore, an external
synchronization technique that does not rely on establishing a global view of
time that is accurately synchronized with an external reference device has been
proposed and implemented for distributed flight control systems. The findings of
the implemented system demonstrate that the suggested approach can synchronize
the distributed FCCs to an external reference device with high synchronization
precision and deal with varying clock drift rates.</div>