Software for Analyzing Valve-Actuator

A computer program assists engineers in analyzing data on the performances of actuators of fuel and oxidizer valves in the main engines of the space shuttle. The program could be adapted to similar use in other settings in which, as in the space shuttle, valve actuators are instrumented to provide data on commanded versus actual actuator positions. The program acquires such data during a specified diagnostic procedure in which valves are opened and closed. The program processes the data and generates several indications of performance, including trend plots, delta command minus actual positions plots, ramp-rate plots, error-from-command plots, and the means and standard deviations of the plotted quantities. The advantage afforded by the program is that it gives more information than does a simple pass/fail testing criterion. By looking at engineering performance profiles generated by this program during tests performed at different times, the engineers can identify valves that are about to fail in time to replace them.