One-and two-axis compensatory control tasks were performed both with and without motion inputs. Additional tests were made in which the motion input, compared with the visual input, was reduced in scale. L i t t l e o r no difference in error measurements was observed in the single-axis-motion/no-motion tests. However, a decrease in normalized tracking error and an increase in the closed-loop system frequency were observed when motion was added to the two-axis tests. In the tests with reduced motion scale, the normalized tracking error remained constant for full, 1/2, and 1/4 motion scaling but increased with a further reduction in motion scaling. In general, the results show that motion may o r may not be an aid in controlling a compensatory tracking task, depending on the difficulty of the task and on the requirements of the mission. Also it is shown that for cases in which motion is beneficial, it is not always necessary to supply full-scale motion cues.

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Pilot response in a multi-task simulation, which consisted of a primary control task combined with one or two secondary or side control tasks, was investigated. A general description of the response characteristics of each of these tasks was obtained and this information was used to determine the work-load requirements of the tasks. Two different control tasks were used as the primary control task, either a fixed-base simulation of a lunar letdown or a simplified multi-loop tracking task which was similar to the end portion of the lunar letdown. The simplified tracking task was used in lieu of the more complicated lunar letdown because it could be represented and reproduced analytically. The secondary or side tasks consisted of a system failures task and a motor response task. The system failures task was incorporated from those systems present in a vehicle known as the Mercury Procedures Trainer. The motor response task was similar to that presented by the late Dr. Fitts of the University of Michigan. The task consisted of using a pencil-like device to make impacts on two separated, restricted columns. An evaluation of the pilot's capability in controlling the multi-task simulation and a determination of the inter-task correlation was made. It was shown that either of the two side tasks produced similar effects on the primary task. Quality measurements were made of all three tasks in all possible combinations. The degradation of each, when in the combined task tests, was then correlated to the other task(s) of the same test. A simple relationship was found by which one could predict the time required of a human operator to perform the particular task(s) in question. This relationship could be used to determine the workloading qualities of the tasks when performed either alone or combined. An analytical representation for the degraded pilot response in the multi-loop tracking task was also obtained.

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