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Welcome To Advanced Technology Associates’ Demonstration Of An Adaptable Prototype and Test System For Aerospace Control Software Development. Throughout this demonstration use the right and left arrow keys to forward or rewind respectively.
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Welcome To Advanced Technology Associates’ Demonstration Of An Adaptable Prototype and Test System For Aerospace Control Software Development Throughout this demonstration use the right and left arrow keys to forward or rewind respectively. Advanced Technology Associates, Inc. (ATA) is a leading-edge aerospace software and technology firm that provides both product and service solutions to the aerospace industry. Advanced Technology Associates, Inc. (303) 948-7980 www.atacolorado.com
Objective Demonstrate how LabVIEW and the ATA Aerospace Toolkit combine to create a prototype and test platform that adapts as the project life-cycle changes. Iterate/ Reuse Prototype Test
Prototype And Test System High-Level Architecture Typically engineers use a variety of environments for development of algorithms. Whatever environment is used it should be easily integrated into other environments. Typically, as GN&C laws are defined, they are coded and tested in an iterative process characterized by the following high-level diagram. Each component should be designed to be highly modular, to maximize code reuse. The components of the prototype and test system are shown below. A 6 DOF simulation of the mission is configured. The chosen simulation platform should be flexible and provide easy reconfiguration to allow for mission changes A model of the IMU is developed. The modules are then integrated. In the case of software-in-the-lopp, this may be as simple as integrating code modules, or in the case of hardware, could be physically connecting the modules and working out communication protocols. Simulated Vehicle (6 DOF using ATA Aerospace Toolkit) GN&C (system under development) IMU model Advanced Technology Associates, Inc. (303) 948-7980 www.atacolorado.com
LabVIEW and the ATA Aerospace Toolkit as a Platform for Prototyping and Test To create a prototype and test system that truly adapts from one project phase to the next, the system needs to have 5 characteristics.
Be Extensible LabVIEW provides open connectivity with other environments including C, Ada, and Mathscript, to name only a few. Extensible platforms save vast amounts of time. They allow developers to develop code modules in the best language suited to the task and then easily integrate the modules into the prototype system. LabVIEW
• Be Modular • Be Real-Time Capable • Be Hardware Friendly The PXI is just one solution from National Instruments which provides high-performance operation with a modular design, making it an excellent platform for aerospace prototype and test applications. The PXI combines a PC platform with modular I/O and is an excellent host for running real-time applications LabVIEW, with the LabVIEW Real-Time Module offers a high level development environment , with a highly deterministic operating system. National Instruments solutions come complete with drivers and allow easy integration with diverse I/O including (analog, digital, a wide range of data buses and more).
Be Capable of High-Fidelity Simulation The ATA Aerospace Toolkit for LabVIEW extends the LabVIEW graphical development environment. It gives the user all the functionality needed to build high-fidelity simulations of spacecraft and air vehicle flight. The simulation can be easily deployed to any National Instruments host and can operate in real-time mode. Deploy the simulation to a PXI or other National Instruments real-time capable system for test Place functions on the panel and wire them together to create sophisticated, high-fidelity simulations of spacecraft or air vehicle flight in minutes. Select functions such as Compute Acceleration Due to Drag from the ATA Aerospace Toolkit palette in LabVIEW
The ATA Aerospace Toolkit for LabVIEW has 11 comprehensive libraries with over 140 functions.
This simulation uses the CartesianToKepler function to convert the position and velocity vectors from a Cartesian representation to Kepler elements for display. Kepler elements are often much easier for humans to interpret. Creating a high-fidelity simulation requires the use of multiple time scales and formats. In this simulation UTC is used for input. The function ExactTimeUTCtoUTC Date is used to convert from the UTC format to a date format (yyyy,mm,dd.ddd…) for computational purposes. In vehicle simulation it is sometimes convenient to use different attitude representations to perform different calculations. In this simulation the QuaternionToDCM function converts a quaternion used to represent a vehicle attitude to a direction cosine matrix (DCM) In any 3 degree of freedom simulation it is necessary to propagate the state vector over a given time interval In this simulation the ECItoLLH function is used to convert an Earth Centered Earth Fixed coordinate frame to a Latitude, Longitude, Altitude representation This code snippet is part of the 3 degree of freedom example included with the ATA Aerospace Toolkit. It demonstrates the depth of functionality in the ATA Aerospace Toolkit. In this example the DCM is then converted to an Eigen Axis/Angle representation for display. The Orbit Library contains many functions for performing orbit alanalysis including Time of Flight, Line of Sight, Anomaly conversions, Flight Path Angle and Orbital Elements and Conversions, including Kepler, Cartesian and Geoditic. The Coordinate Frame Library in the ATA Aerospace Toolkit contains 9 coordinate frames, including ECI, North East Down, True of Date, Mean of Date and a high-fidelity frame called ECI J2000 The Toolkit contains a comprehensive time library with conversion between all the necessary time formats and scales for high-fidelity simulation The Aerospace Toolkit has a full suite of integrators and an orbit propagator featuring a Runge Kutta 4/5 Adaptive Step Size Integrator with the ability to select between three gravity models (Spherical, J2 and Vinit J6)and the capability to model atmospheric drag. The ATA Aerospace Toolkit has an extensive Math Analysis Library that contains functions for quaternion manipulation, matrix exponential computation, linear/inverse linear interpolation and Jacobi matrix diagnalization. The Math Analysis Library includes attitude parameterizations such as Quaternions, Euler angles, Eigen Axis/Angle and Direction Cosine Matrix.
Typical Test Project Lifecycle Development and test of GN&C systems can be viewed as a three stage process. Advanced Technology Associates, Inc. (303) 948-7980 www.atacolorado.com
SIL Setup Simulated Vehicle (6 DOF with ATA Aerospace Toolkit) GN&C Algorithm (system under test) IMU model During the SIL phase all modules may reside within a single environment such as a desktop PC. SIL Test Note, the use of blue in these diagrams indicates software. As the system is adapted some of these components will be replaced with hardware. The system is characterized and control algorithms are developed. Algorithms are tested against a mission simulation. All components are modeled with software. This process supports rapid prototyping At this phase of development the mission simulation may not be fully refined and does not necessarily need to operate in real-time. Any number of development environments may be used for developing the GN&C algorithms including LabVIEW, MATRIXx, MATLAB, Simulink, C, Ada, which all have the ability to be called from LabVIEW. The SIL Test setup is ideal for rapid proto-typing. Allowing for quick and inexpensive testing of control algorithms. Advanced Technology Associates, Inc. (303) 948-7980 www.atacolorado.com
PIL Setup Simulated Vehicle (6 DOF model using ATA Aerospace Toolkit) GN&C Control Board (system under test) IMU Model During the PIL all flight hardware, except the controller, is still simulated with software. The same 6 DoF model used during the GN&C algorithm development is again used for PIL testing. The vehicle simulation is transferred to a PXI or other platform running a real-time OS. The control code has been embedded on the target and the controller is placed In-The-Loop. Physical connection is made between the controller and the platforms hosting the Simulated Vehicle and the IMU Model. Note that red denotes hardware or embedded software. PIL Test Control software has been developed and is embedded on the selected target; the controller is tested In-The-Loop, with the same simulated vehicle, operating in a real-time environment in accordance with mission parameters. This allows the engineer to verify that the controller operates according with mission specifications. The output of the IMU is physically cabled to the controller and the output of the controller is connected to the real-time system. This verifies that the GN&C control board operates in real-time and within mission parameters. The mission simulation built with the ATA Aerospace Toolkit is modified as needed and deployed to the PXI to operate in real-time. Advanced Technology Associates, Inc. (303) 948-7980 www.atacolorado.com
HIL Setup Simulated Vehicle (6 DOF model using ATA Aerospace Toolkit) GN&C Control Board (system under test) IMU Flight Hardware The 6 DoF simulation runs in real-time on a PXI or other system. The mission simulation is further refined as needed, to accommodate project changes. HIL Test Additional flight hardware is brought into the loop to fully test the capability of the controller GN&C controller has been verified. The controller has been verified and is now ready for a system test. The system test will consist of the GN&C controller operating in a closed loop with the IMU. These components will “fly” in a high-fidelity simulation in accordance with mission parameters. Some tests can only be performed once (such as the firing of a rocket motor). In such cases there are great advantages to using a modular, adapting test system for development. Using such a process ensures that components and connections are verified in a system that is as like the environment of the final test as possible, prior to the final test event. HIL Testing is an expensive and time consuming proposition. As much work and testing as possible should be done before reaching this stage of development. Setting up an efficient SIL and PIL system will allow developers to work out problems before integration, lowering cost and reducing risk. Advanced Technology Associates, Inc. (303) 948-7980 www.atacolorado.com
Summary • A good prototype and test system will be capable of adapting to meet the project life-cycle requirements. • The ATA Aerospace Toolkit extends the LabVIEW graphical development environment, allowing the user to build high-fidelity spacecraft and air vehicle simulations for prototyping and test. • LabVIEW, the modular National Instruments platforms (like the PXI) and the ATA Aerospace Toolkit combine to provide an excellent integrated solution for control software prototyping and test. Advanced Technology Associates, Inc. (303) 948-7980 www.atacolorado.com
Want to Know More? • Learn more about the ATA Aerospace Toolkit. www.atacolorado.com/aerospace_toolkit.htm • Download the ATA Aerospace Toolkit and try it free for 30 days. www.atacolorado.com/downloads.htm • Learn more about National Instruments’ LabVIEW graphical development environment or other embedded design and test solutions. www.ni.com