The Effects of Reference-Command Preview on the Strategies that Humans Use in Command-Following Tasks

This thesis presents results from an experiment in which 22 human subjects each interact with a dynamic system 40 times over a one-week period. For each interaction, a subject performs a command-following task, where the reference command is the same for all 22 subjects but different on each trial. The subjects are divided into 2 groups of 11 subjects. One group performs the command-following task without reference-command preview. The other group is provided with 1-s preview of the reference command. The experimental results are used to examine the effects of reference-command preview. For the group with 1-s reference-command preview, the average identified feedforward time delay is approximately 26 ms over the last ten trials, whereas the average identified feedforward time delay is approximately 284 ms over the last ten trials for the group without preview. For the group with preview, the average identified feedforward controller approximates the inverse dynamics of the system with which the subjects interact better after 40 trials than on the first trial. In contrast, for the group without preview, the average identified feedforward controller does not approximate the inverse dynamics of the system better after 40 trials