Preemptive Interventions for Carsickness Mitigation and Their Effects on Passenger Task Performance

Abstract

The objective of this thesis is to investigate methods to mitigate carsickness using preemptive interventions and their effects on passengers performing tasks. The solution strategy behind this research was to recreate this anticipation and preemption for an autonomous vehicle passenger using mechatronic hardware and software. This research proposed two strategies to mitigate motion sickness in car passengers performing tasks. The first strategy was to use preemptive sensory stimuli (haptic) to inform the passenger of upcoming vehicle motion. The second strategy was to use preemptive motion of a tilting seat to move the passenger in anticipation of upcoming vehicle motion.

There are four key contributions of this thesis. First, a refined model of motion sickness in vehicle passengers was developed. The proposed model integrated visual and vestibular sensory 6 degree of freedom (DoF) motion signals in an enhanced architecture to predict motion sickness. This model’s prediction was compared to experimentally measured motion sickness data from motion simulators as well as on-road vehicle testing, yielding accurate results in both cases.

Second, an experimental vehicle platform (based on a Ram ProMaster Van) was developed to evaluate the efficacy of motion sickness mitigation systems in realistic driving conditions. The vehicle was suitably modified to include instrumentation such as inertial measurement units, sEMG, cameras, GPS, and other sensors to monitor the response of the passenger to vehicle motion, and to track the motion of the vehicle itself. A driving path on the Mcity track was designed to recreate realistic driving conditions in a safe and controlled environment to ensure high repeatability. Over 200 drives, the mean peak lateral position error was less than 2x the width of the vehicle.

Third, a human participant’s experiment using a preemptively triggered haptic active passenger stimulation (h-APS) system was conducted. In addition, the experiment included a non-driving related task (NDRT). The experiment consisted of three test conditions. Over thirty participants were recruited as part of this IRB approved study. Twenty-four participants completed their participation in the study. The experimental results demonstrated that the h-APS can reduce motion sickness while having no negative effects on the passenger’s task performance ability. The data indicated a 15% reduction in the rate of motion sickness accumulation when the haptic stimulation system was operational, even when the participant was performing a NDRT. Also, 75% of the participants indicated a positive preference for the haptic stimuli system.

Fourth, a human participant’s experiment using a preemptively triggered tip-tilt active seat system (AST) was conducted. Over forty participants were recruited as part of this IRB approved study. In addition, this experiment also included a NDRT that was designed to mimic cognitive burdens associated with everyday tasks. Twenty-nine participants completed their participation in the study. The data indicated that across all participants, the tilting seat system reduced the rate of motion sickness accumulation by 10%. Also, when the data was further assessed by gender, the data indicated a 50% reduction in the rate of motion sickness accumulation for the male participants but had no effect on the motion sickness response of female participants. The results also showed that the AST had no negative effects on the passenger’s task performance ability. This is the first research of its kind to demonstrate the efficacy of mitigation systems when triggered precisely and preemptively, under realistic driving conditions.