## The autopilot subsystem Actuator & cable dynamics

The autopilot subsystem Actuator & cable dynamics contains the dynamics of the actuators and cables for the ailerons, elevator, and rudder channels. It is used by the systems APILOT1, APILOT2, and APILOT3 and by the systems PAH, RAH, and PAHRAH.

In the case of the 'Beaver' aircraft, these dynamics have been modeled as linear state-space blocks with state matrices Aail, Bail, Cail, Dail, Aelv, Belv, Celv, Delv, and Arud, Brud, Crud, and Drud. These matrices must be loaded into the Matlab workspace before starting a simulation of the autopilot models.

The initialization utilities APINIT, and PRAHINIT contain a menu option to load these matrices into the workspace (both utilities use the subroutine ACTRLOAD when the user presses the button 'Load state-space actuator/cable models'). The model-data will then be extracted from the files FCS35.DAT, FCS45.DAT, or FCS55.DAT. The three datafiles contain state matrices for the airspeeds V = 35 m/s, V = 45 m/s, and V = 55 m/s, respectively. Choose the set which best fits your desired flight-condition; in general the data for V = 45 m/s (FCS45.DAT) will yield good results.
Note that all signals between the control laws and the block Actuator and cable dynamics have been expressed in Volts, whereas the outputs of the block Actuator and cable dynamics represent changes in elevator-deflection, aileron-deflection, and rudder-deflection, respectively. Consequently, the latter signals have been measured in [rad].