ZONA Aeroelastic Model Simulator (ZAMS)
The ZONA Aeroelastic Model Simulator (ZAMS) is an ActiveX control developed to run under the IADS real-time and post-test display and analysis software developed by Symvionics, Inc.† ZAMS is used to display the aeroelastic response (i.e., motion) of an aircraft during flight test or during playback of recorded flight test data. ZAMS can provide flight test engineers within the mission control room the ability to rapidly visualize, in a near real time capacity, aircraft structural oscillations when the aircraft is excited by:
Based on aircraft accelerometer responses obtained in IADS during flight test, ZAMS uses these accelerometer responses to compute/display the aeroelastic deformation of the structure. A few seconds of flight test data are buffered by ZAMS to perform the required computations. ZAMS includes options such as display of pitch/roll rigid body motions, amplification of computed displacements, display of control surface motions, zero-displacement "node-line" tracking to characterize the type of aeroelastic motion, as well as sensor information plots to visually verify the adequacy of the computed sensor displacements.
How Does ZAMS Fit Into IADS?
The aircraft, to be flight tested, is instrumented with accelerometers on areas of interest (e.g., wings, stores, nacelles, horizontal/vertical tails, etc.) These accelerometer responses along with flight control information, such as control surface deflections, Mach Number, Altitude, etc., is sent via telemetery to a ground receiving station. This information is processed through a data server that is connected to numerous workstations located, typically, in a mission flight control room. The IADS client desktop software executes on these workstations and can be tailored by the flight test engineers to display the flight test data within controls provided in IADS (strip charts, data displays, cross plots, etc.) ZAMS can be added within any IADS client desktop display to allow the flight test engineers to visualize the aeroelastic response of the aircraft in flight. Multiple ZAMS controls can be added to a single desktop display or multiple displays allowing for more than one 3D view of the response. Zero-displacement nodal lines can also be displayed on the model to help identify or categorize the type of aeroelastic response that is observed.
The following figure shows the basic role of IADS and ZAMS' relation within this envornment.
What Input is Required by ZAMS?
The input to ZAMS is shown in the figure at right within the dashed green line. Two ASCII text files, that are read in a single time when starting the ZAMS tool, are needed to display a 3D model and perform the simulation within ZAMS. The first is the ZAMS' IADS Data File that stores the matrices used by ZAMS. The second is the configuration file that defines the IADS parameters containing telemetry response data to be used by ZAMS.
The ZAMS IADS Data File
ZONA has developed two methods that can be used to generate the ZAMS IADS Data File. The first method, for those who already have the ZAERO Software System, is to activate the new Solution Sequence that exists in ZAERO (SOL -3) along with an IADS bulk data card to define the accelerometers/components within the structural model. This feature is available in ZAERO version 8.3 and higher. This makes the process of setting up a ZAMS IADS Data File a very simple task for ZAERO users who already have ZAERO models set up (i.e., in that you only need to add an IADS card to your existing input deck). The second method is to use the GENZAMS software that was specifically developed by ZONA to generate the ZAMS IADS Data File. The GENZAMS program supports the same Executive Control and Spline Modules of ZAERO but implements the use of Nastran CQUAD4/CTRIA3 elements to define the surface panel model to be displayed in ZAMS. This difference allows the user using GENZAMS to create higher fidelity geometry models than that of ZAERO which uses the CAERO7/BODY7 macroelements. Note that when you purchase ZAMS, GENZAMS and its accompanying documentation (User's Manual) are included in your purchase.
The ZAMS IADS Data File contains matrices stored in Nastran's OUTPUT4 format. These include the geometry [GEOXYZ], the natural frequencies of the structural model modal analysis [FREQ], the sensor-to-Q matrix least squares matrix [SENTOQ], the modal matrix ar the ZAMS model grid points [PHIC], and the control surface matrix [CNTLC] used by ZAMS to compute control surface panel deflections.
The ZAMS Configuration File
The ZAMS Configuration File is used to relate the IADS parameter names to ZAMS data; such as, accelerometers (sensor) corresponding to which structural model grids, control surface responses to be applied to which ZAMS model control surfaces, and so on. The file is set up in sections that all begin with a [BEGIN...] tag and end with an [END...] tag. Some of these sections include:
[BEGIN ACCELEROMETER DATA]
specifies the IADS parameter accelerometer information as they relate to the ZAERO or GENZAMS IADS input and correlates the sensor location structural model grids and degrees-of-freedom (component number) to the IADS parameter names.
[BEGIN CONTROL SURFACE DATA]
Specifies IADS parameter control surface information as the relate to the ZAERO or GENZAMS IADS input (i.e., control surfaces defined via the SURFSET bulk data card) and correlates the control surface deflections to the corresponding IADS parameter values.
[BEGIN AIR DATA]
Specifies the IADS parameter Air Data to correlate rigid body pitch and roll angles to the rigid body motion display of the model in ZAMS.
[BEGIN SIMULATION TIME]
Specifies the simulation time (in seconds) of IADS data to be buffered for ZAMS to compute the vehicle displacements. Integration and high-band pass filtering is applied by ZAMS on this "buffered" data.
[BEGIN HIGH PASS CUTOFF FREQUENCY]
Specifies the high-pass filtering cut-off frequency to be used by ZAMS to help remove noise from the accelerometer signals.
Scale (or conversion) factors can also be specified in the Configuration File allowing for complete control over the telemetry data that is received in ZAMS from IADS.
Sample IADS Display using ZAMS Display of an F-16 Typical LCO Configuration
ZAMS is available for single computer licensing.