Intuitive Graphical Modeling and Testability Analysis
At the heart of the TEAMS system is the TEAMS-Model, a comprehensive multilevel data set describing the structure, behavior, interconnections, and failure modes of the system under test (SUT). The software used to design and generate this model is TEAMS-Designer, an intuitive graphical tool that gives test engineers the ability to diagram all inputs, outputs, fault conditions, events, dependencies, and tests for the SUT. By specifying cause-effect dependencies within the model, the TEAMS system can then compute and analyze all possible failure modes for the system. The model also links these potential failures to the system’s built-in tests, troubleshooting steps, and repair procedures. This same model gives maintenance engineers the ability to embed testability features directly into the system, thereby improve overall reliability and creating near-optimal diagnostic strategies.
TEAMS-Designer includes a complete set of diagramming and component description tools and runs as a Windows PC application. The software can be used on any electro-mechanical system and can model virtually any type of device, including electronic, mechanical, hydraulic, fluidic, pneumatic, and optical components. TEAMS-Designer can be used with standalone devices such as medical diagnostic equipment or can scale to handle large-scale systems with thousands of components.
The diagram below depicts a portion of the TEAMS model of a helicopter engine. Using the software’s multilevel hierarchy, users can drill down to reveal individual components within an element simply by clicking on the rectangle for the element. A complete set of properties such as the number of inputs and outputs, repair cost and time, and rectification cost and time can be assigned to each element. Note that in the example below, the line colors are color coded to represent different types of circuits or lines, i.e. electrical, fuel, hydraulics, coolant, etc.
Testability analysis is another important feature built into TEAMS-Designer. After a system is analyzed using TEAMS, the system’s testability shortcomings (e.g., uncovered faults, redundant tests, ambiguity groups and feedback loops) are marked directly on the function model. As part of QSI’s Design for Service approach, the tool also generates a set of testability recommendations (e.g., test-point placement and buffer placements to break feedback loops). TEAMS-Designer augments the testability analysis process by giving design engineers the ability to try different “what-if” scenarios and evaluate the testability characteristics of the design from multiple perspectives. Analysis options cover modules, repair options, I/O ports, optimization, system modes, unreliable tests, and technology.
Testability Analysis Options
Interfaces to Other CAE Tools
To extend the functionality of TEAMS and streamline the model design process, the TEAMS model can interface to other CAE tools. In its basic form, the TEAMS model captures the relationships between replaceable components and the observation/detection methods used to monitor those components. If an organization already has this type of data in a structured format or uses a modeling tool that generates these relationships, it is usually a simple matter to import the data/model into the TEAMS system. The system includes an XML import format and can also accommodate MATLAB/Simulink data. Contact QSI to discuss your needs in this area at greater length.