MTS also claims system performance is more repeatable over time. The control system is also different than traditional crash simulators. Instead of a closed-loop control system, the MTS system uses an open loop control system to improve the response. The company can do this because it has a model of the system, which lets it set the system parameters, calculate the valve positions, and then predict the simulator performance. If the performance does not meet specifications, engineers can loop through the process until it meets specs.
System software gives the user a great deal of control over the test.
For example, the software includes a waveform editor, which allows a user to easily enter the waveform for a test. Once a user has defined a waveform, the software calculates an expected waveform, taking into account what the simulator can actually do. If the discrepancy is too great, the user can re-define the waveform. On Thursday, I attended the Accelerated Testing Research technical session. This session was an all-day affair with ten papers covering various aspects of accelerated testing.