Difficulty in preventing rollover accidents of marine containers derives from various load conditions of cargoes inside the containers. Heavier cargoes are widely regarded as presenting greater danger of rollover accidents. However, this presupposition is severely misleading because lighter cargoes having a higher center of gravity such as machinery with an upper mass can also cause rollover accidents. Rollover accidents are explainable fundamentally as follows. The center of gravity of a truck loading a marine container conflicts with the centrifugal force in cornering. A truck is unstable, causing a rollover accident when the moment originating from the centrifugal force exceeds that originating from the force of gravity. Such a truck might cause a rollover accident at a lower driving speed when the center of gravity is positioned higher. The question is therefore how to find the center of gravity of trucks with marine containers. Conditions of cargoes inside the containers differ greatly. Moreover, it is practically impossible to calculate those conditions by measuring all cargoes piece-by-piece in a container unless the time and cost to do so are unlimited. Without knowing what is inside a container, there is no way to detect the center of gravity after a truck starts moving. An important invention by the second author of this paper was produced to solve that difficulty. Detection of the Three Dimensional Center of Gravity (D3DCG) can ascertain the position of the center of gravity while trucks are moving. Soon after starting to move, vertical and rolling motions are measured onboard the trucks in half a minute. Then D3DCG is activated, instantly assessing the position of the center of gravity. D3DCG assumes that the center of gravity causes unique motions depending on its position on the truck. Therefore there is no need to know what is inside the container. This paper first demonstrated the precision of D3DCG running an experiment by which a truck scale model was used. It was driven by remote control. Results of positions of the center of gravity delivered from D3DCG were compared to those obtained using ordinary piece-by-piece calculations. Secondly, this paper assessed examples of D3DCG installed on an actual truck loading real marine containers. Results proved that D3DCG is valuable for real-time detection of the center of gravity when driving. This achievement will greatly contribute to the prevention of rollover accidents.
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