Examining the relationship between perturbation kinematics and motion induced interruptions in simulated marine environments

Abstract

The purpose of this doctoral dissertation was to attempt to gain a better understanding of when an operator working in a moving environment will experience a motion induced interruption (MII) or execute a motion induced correction (MICs). This was accomplished through a series of experiments and subsequent data analyses which attempted to describe the differences between MIIs and MICs, and define and characterize the postural stability limits of these events when persons are performing standing and manual materials handling tasks. From the results of these experiments it was found that MIIs and MICs are distinctly different phenomena which differ in occurrence, duration and platform kinematics at the time of event initiation. These change-in-support events may also occur well before the theoretical physics-based stability limits have been reached. It was also found that e initiation of these events cannot be predicted solely upon platform perturbation kinematics. Other factors, such as task characteristics and participant experience, may also affect response choice. Therefore, MIIs or MICs cannot be characterized as a last resort event, used only once all other strategies have been exhausted. Since these events may not be a last resource to maintain balance their occurrence may not necessarily suggest greater postural instability than fixed support alternatives and be a good measure of ship operability. Future examination of effects of change-in-support responses such as MIIs or MICs in offshore environments the resultant outcome of the MIC should be examined on a case-by-case basis, and include analysis of ship operability as well as the acute and cumulative injury caused by the performance of the event.