de Oliveira, E. and de Oliveira e Souza, M., "An Investigation on Techniques for Accurate Phase or Time Synchronization in Reconfigurable Control Systems," SAE Technical Paper 2012-36-0398, 2012, doi:10.4271/2012-36-0398.
Current systems such as: satellites, aircrafts, automobiles, turbines, power controls and traffic controls are becoming increasingly complex and/or highly integrated as prescribed by the SAE-ARP-4754 Standard. Such systems and their control systems use many modes of operation and many forms of redundancy to achieve high levels of performance and high levels of reliability under changing environments and phases of their lifecycle. The environment disturbances, environment variability, plant non-linear dynamics, plant wear, plant faults, or the non-symmetric plant operation may cause de-synchronization in phase or time among: 1) simultaneous units in the same normal mode of operation; 2) successive units in successive normal modes of operation; 3) main and spare units from normal to faulty modes of operation. So, techniques to reduce those causes or their effects are becoming important aspects to consider in the design of such systems. This paper presents an investigation on techniques for accurate phase or time synchronization in reconfigurable control systems. It is based on the review of the literature, discussion and simulation of some techniques used in a reconfigurable aerospace control system which require phase or time synchronization among simultaneous rotor units in the same normal mode of operation due to environment variability. The preliminary results of such investigation shows that the techniques used: 1) can reduce the phase skew between operational modes of control; 2) can contribute to high levels of performance and reliability of reconfigurable control of aerospace, automotive and power systems.