Eliminate Motion Sickness on Tilting Trains
By Victoria Hennemann
Scientists at Mount Sinai School of Medicine have studied and concluded that motion sickness on titling trains cane be eliminated. In order to achieve this, the driver must adjust the timing as they enter and leave the curves. The study they conducted showed that if the car tilts at the beginning of the curb instead of while they are making the turns, then their was no motion sickness.
Researchers placed angular velocity and lateral accelerations (acceleration that tends to push a vehicle sideways) sensors on the front car of the seven-car train. They also placed this on the heads of the passengers. The experiments were conducted early September to late October of 2009. Over the span of three months the researches used control modes to study the levels of motion sickness that 200 passengers may or may not experience. The passengers sat in the front car because it was reported by SBB that the motion sickness sensations were the greatest when passengers rode in the front car compared to other cars. The distance from the front to the back of the train was 150 m long and it took about 5 minutes to transverse. The train took two round trips from Winterthur to Gossau in the morning and 2 in the afternoon. So there were a total of eight rides each day. It took between 22-25 minutes per each trip and was followed by a 15-30 minute rest.
The study showed that the passengers had no motion sickness in the untitled mode, which means later acceleration did not influence motion sickness in any way in this experiment. The negative affect of the lateral acceleration was that the train ran more slowly. The train had the same speed in the reactive and predictive moods, however the passenger comfort was better when the researches used the predictive mode which allowed the train to tilt just at the onset of the curves.
Can this relate to Cars?
Motion sickness is believed to be caused by the conflict between sensory information and the past experiences. This is referred to as the sensory conflict hypothesis. Many scientist have studied motion sickness in cars, trains, ships etc. Similar to the trains many scientists have been working on various experiments in cars that could help reduce motion sickness. One of these theories is called the head-tilt strategy. Hiroyuki Konno, Satoru Sujisawa, Takahiro Wada, Shun'chi Doi created a posture control device that would make passengers tilt their head to the side like drivers do when driving. Initial timing of the device is determined by the steering wheel operation and has to be synchronized with the timing of the lateral acceleration. Their results showed that the device did reduce motion sickness.
Work Cited
Cohen, Bernard, et al. “Motion Sickness on Tilting Trains .” The Journal of the Federation of
American Societies for Experimental Biology, National Center for Biotechnology Information, 25
Nov. 2011, www.ncbi.nlm.nih.gov/pmc/articles/PMC3205836/.
Konno, Hiroyuki, et al. “Analysis of Motion Sensations of Car Drivers and Its Application to Posture
Control Devices.”Analysis of Motion Sensations of Car Drivers and Its Application to Posture
Control Devices, 18 Sept. 2011, pp. 192–197., hr.ci.ritsumei.ac.jp/wp-
content/uploads/2015/07/2_2011_SICE_H_Konnno_Kagawa-uIEEE.pdf. IEEE
Scientists at Mount Sinai School of Medicine have studied and concluded that motion sickness on titling trains cane be eliminated. In order to achieve this, the driver must adjust the timing as they enter and leave the curves. The study they conducted showed that if the car tilts at the beginning of the curb instead of while they are making the turns, then their was no motion sickness.
How It Works
When a train enters a curve their sensors on the front wheels signal to the remaining cars when they should begin their tilt to make the turn. Since the other cars react based on the first car, their is a delay for the other cars while making the turn. As a result, the cars tilt slowly. The researchers that conducted this study found that the slow rise in the velocity of the tilt during the curve combined with the centrifugal force produced by the turn caused the motion sickness. However, using a global positioning system (GPS) the tilts occurred earlier and were faster, which eliminated the motion sickness.Who's responsible?
The Schweizerische Bundeshanen (SBB), is the train system in Switzerland requested the study. They want to maximize the trains speed but also provide comfort for the passengers. Since trains are utilized to compensate for the centripetal acceleration during turns, they can run faster. However, this is what leads to motion sickness. So the SBB invested 3.2 billion Swiss francs for trains to utilize the technology that was created from these experiments.
The Study
Researchers placed angular velocity and lateral accelerations (acceleration that tends to push a vehicle sideways) sensors on the front car of the seven-car train. They also placed this on the heads of the passengers. The experiments were conducted early September to late October of 2009. Over the span of three months the researches used control modes to study the levels of motion sickness that 200 passengers may or may not experience. The passengers sat in the front car because it was reported by SBB that the motion sickness sensations were the greatest when passengers rode in the front car compared to other cars. The distance from the front to the back of the train was 150 m long and it took about 5 minutes to transverse. The train took two round trips from Winterthur to Gossau in the morning and 2 in the afternoon. So there were a total of eight rides each day. It took between 22-25 minutes per each trip and was followed by a 15-30 minute rest.
Picture1. Train (SBB-RABDe 500) which was similar to one used in experiments
On each test day 20 normal and 20 motion sickness-susceptible subjects came to Winterthur to participate in the experiments. The passengers would fill out a survey every 10 minutes to their level of motion sickness. The train had basic utilities such as restroom, and had refreshments for the passengers.
The tilt system consisted of angular velocity sensors, lateral acceleration sensors, a processor control model, and an electromechanical actuators. The cars made two angular movements which consisted of a turn in the horizontal plane, and a turn inwards towards the center of the turn. They used a untitled mode, a reactive mode based on the information of the front wheel seat, and the predictive mode which was based of the information from the GPS.
The track itself was 42.5 km long and had 58 total turns. The turns consisted of an initial transition curve, a circular arc, and a terminal transition curve. During the turns the track curvature changed from zero degrees to a constant value then back. The approximate radius of the turns was 400 m. The speed of the train was 120 km/h.
The tilt system consisted of angular velocity sensors, lateral acceleration sensors, a processor control model, and an electromechanical actuators. The cars made two angular movements which consisted of a turn in the horizontal plane, and a turn inwards towards the center of the turn. They used a untitled mode, a reactive mode based on the information of the front wheel seat, and the predictive mode which was based of the information from the GPS.
The track itself was 42.5 km long and had 58 total turns. The turns consisted of an initial transition curve, a circular arc, and a terminal transition curve. During the turns the track curvature changed from zero degrees to a constant value then back. The approximate radius of the turns was 400 m. The speed of the train was 120 km/h.
The Results
Figure 1. Increase in nausea scores after 30-min rides in the train
Can this relate to Cars?
Motion sickness is believed to be caused by the conflict between sensory information and the past experiences. This is referred to as the sensory conflict hypothesis. Many scientist have studied motion sickness in cars, trains, ships etc. Similar to the trains many scientists have been working on various experiments in cars that could help reduce motion sickness. One of these theories is called the head-tilt strategy. Hiroyuki Konno, Satoru Sujisawa, Takahiro Wada, Shun'chi Doi created a posture control device that would make passengers tilt their head to the side like drivers do when driving. Initial timing of the device is determined by the steering wheel operation and has to be synchronized with the timing of the lateral acceleration. Their results showed that the device did reduce motion sickness.
Picture 2. Control Model
Analysis
What is so interesting about these two experiments is that they connect human health and comfort to physics. Physics effects everyday life and in this case affects the comfort of many passengers. In fact, the velocity during the curve and the relationship between this and the centrifugal force causes the motion sickness. In the study with the trains the solution to this was creating a system that would stop the delay in the turning so the car would ease into the turn more. This would reduce the motion sickness. In the car experiment instead of focusing on the car itself and how the car made the turn, they created something that would effect the passenger. This also reduced motion sickness.
Work Cited
Cohen, Bernard, et al. “Motion Sickness on Tilting Trains .” The Journal of the Federation of
American Societies for Experimental Biology, National Center for Biotechnology Information, 25
Nov. 2011, www.ncbi.nlm.nih.gov/pmc/articles/PMC3205836/.
Konno, Hiroyuki, et al. “Analysis of Motion Sensations of Car Drivers and Its Application to Posture
Control Devices.”Analysis of Motion Sensations of Car Drivers and Its Application to Posture
Control Devices, 18 Sept. 2011, pp. 192–197., hr.ci.ritsumei.ac.jp/wp-
content/uploads/2015/07/2_2011_SICE_H_Konnno_Kagawa-uIEEE.pdf. IEEE
“New Study Shows How to Eliminate Motion Sickness on Tilting Trains .” Phys.org, Science X Network, 4 Aug. 2011.
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