Patent ID: 6332107
Filing Date: 2001-12-18
Classification: B61L

Abstract:
A method of providing gradual increases or decreases in the speed of a following train that is traveling behind a leading train on a rail in a train system in order to eliminate cycles of braking and accelerating during an instance when the following train is closer than a minimum required separation distance (X.sub.min) to the leading train, the method comprising the steps of:repeatedly projecting the locations and speeds of the following train and the leading train after a delay time in the future;repeatedly estimating a train separation distance (X.sub.s) between the following train and the leading train based on the projected locations and speeds of the trains;repeatedly calculating the minimum required separation distance (X.sub.min) between the following train and the leading train based on the projected locations and speeds of the following train and the leading train, wherein the minimum required separation distance (X.sub.min) comprises a distance that ensures that cycles of braking and accelerating will not occur;repeatedly comparing the estimated train separation distance (X.sub.s) with the minimum required separation distance (X.sub.min);calculating the maximum worst case stopping distance (MaxWCSD) based on the projected locations and speeds of the following train and the leading train and based on the worst case stopping distance (WCSD) and the locations of the station stops; andreducing the speed and acceleration rate of the following train without braking when the train separation distance (X.sub.s) is less than the minimum required separation distance (X.sub.min) until the train separation distance (X.sub.s) is equal to or greater than the minimum required separation distance (X.sub.min);wherein the acceleration rate comprises ##EQU3##where V.sub.lead is the speed of the leading train, A.sub.lead is the acceleration of the leading train, dt is the time increment between successive commands, V.sub.rear is the speed of the following train, dSD/dx is the partial derivative of the MaxWCSD with respect to the location of the following train, and dSD/dv is the partial derivative of the MaxWCSD with respect to the speed of the following train.