Doublet input for system identification. The doublet is a multi step maneuver for system identification. Two modes are implemented, the 0,1,-1,0 maneuver (which correspond to one period of a squared sine wave oscillation, and the “so-called” 3-2-1-1 maneuver. The module is used by including the module in the airframe file and adding the following line to the <command_laws> section: <call fun=”sys_id_doublet_add_values(autopilot_get_motors_on(),FALSE,values)”/> You can pick the axes to apply doublets to by setting the SYS_ID_DOUBLET_AXES variable with the COMMAND_XXX variables where XXX are the actuators defined in the <commands> section of your airframe. Remeber to deactivate the control input when the system identification input is running using (can be checked using the sys_id_wave_running() function) Then, the GCS exposes the settings for the doublet. - 3-2-1-1 setting is to execute the 3-2-1-1 doublet maneuver when active. Otherwise, the normal 1-1 doublet maneuver will be executed. - The Doublet axis settings is the index (0-based) of the axis to choose within the SYS_ID_DOUBLET_AXES variable specified. In the default, this means i.e. 0 means roll doublet. - Amplitude is the amplitude of the doublet - Length_s is the length in seconds of the doublet. The lenght of each doublet step depends on the active mode and on the doublet lenght. - Extra_waiting_time_s is the length in second of the waiting time with zero input after the doublet maneuver is over. Start the doublet by checking the Active box in the “Activate doublet”. Stop the doublet by checking the Inactive box in the same input setting.

Section SYS_ID







Which axes the doublet is applied to (specify as array with {})



If false, the doublet does not run and values are not added



0= normal, 1=half, 2=the 3-2-1-1 doublet