23． Car-body tilt control system for better ride comfort
- A control system was developed for tilting trains to mitigate motion sickness
- The new system can reduce the motion sickness dose value in sharp curves by 30% and be installed on existing tilting trains.
- It is proposed that the system can be installed on not only new trains but also existing tilting trains travelling through sections with successive sharp curves during their overhaul periods.
The car-body tilting mechanism with tilting bolsters and rollers, while it is more complex than the mechanism with air-spring systems, offers a larger tilt angle and optimal reactivity, and is designed for trains which require better ride comfort or that must pass through sections with successive sharp curves.
The tilt control system was designed to provide improved ride comfort and reduce motion sickness through (1) precise train positioning, (2) tilt patterns offering better ride comfort, and (3) optimal response pneumatic tilt actuators.
Table 1 compares the new mechanism with the existing system. Ride comfort is improved thanks to a “Tilt pattern” function which responds to curve radius, cant size and running speed, and produces successive predictions of the accelerations exerted on passengers in order to suppress the low frequency swaying action which causes motion sickness.
Results from test runs confirmed that compared to the existing system the new mechanism could reduce the motion sickness dose value (MSDV-y) by 30%, i.e. from a current average of 4.2m/s1.5 to 3.0 m/s1.5 with the new system (Fig 1).
It was also verified that if the tilt actuator could be applied then existing tilting dampers were no longer required.
Based on these findings, further developments were made to the device to incorporate features needed for the system to be installed on commercial trains, such as connectivity with monitoring equipment and failsafe performance (Fig. 2).