Vertical Oscillating Platform
The Graybiel Lab constructed a vertical oscillating platform for a specific series of motion sickness experiments. The design was conceived by Dr. Simone Bortolami who also directed the construction. The platform can move up and down ± 0.85 meters at a frequency of 0.25 Hz, one complete cycle in five seconds. This is the key frequency produced by large ships that evoke motion sickness. With this intensity of stimulation, it has been found that 50 percent of subjects will vomit in one hour (O’Hanlon & McCauley, 1974).
The moving shuttle rides on linear bearing rails and is driven by a two-meter long ball screw and high-torque motor. The system was designed with a minimum safety factor of four on the weakest link (the ball screw to gearbox coupling) under the highest load conditions. An independent braking system is triggered by three automatic failure modes (one software and two hardware) and kill switches are accessible to the subject and experimenter. Both hardware safety loops were designed to OSHA standards.
The seat in which the subject rides is built for racing cars and cushions the subject in the unlikely event of shock. It has a five-point safety harness designed to withstand a 9g crash load. The highest g load under operational conditions will be just under 2g, at the point where the oscillator reverses from down to up motion.