Real Time Computing
The signals from the various different measurement devices (motion capture cameras, force plates, etc.) are connected to a simulation host computer which monitors and controls all of the different simulation systems in real time (See figure above for a schematic). The information from these devices will then be used for several purposes. First, will be time-stamped and saved for post-experiment analysis. Second, it will be incorporated into reaction models which will be used to dictate the responses of the various interfaces, including, the motion platform, the treadmill, the visual display system and the audio cueing system. For instance, it order to create a fall scenario on the instrumented stairs, the reaction model might specify that as soon as a participant’s foot exerts a particular force on a particular step, the motion platform will then be accelerated rapidly. The expected latency of this process, from measurement system output to simulation system input is less than 25 ms and the simulation host computer shall operate at a frequency of at least 100 Hz.
