A study on the performance of NTS vehicle steering control system

NTS is an Automated Guideway Transit developed by Niigata Engineering Co., Ltd. in Japan. The performances of NTS vehicle steering control system which is so designed that the clearance between guide wheels and guide-wall is taken intentionally in order to reduce the lateral disturbance from guideway irregularities through guide wheels, is considered. The mathematical model of the lateral motion of the vehicle with the front steering linkage and the rear one connected together by some ingenious rod is derived, and the effects of some design parameters of the steering system on the lateral motion of the vehicle are predicted by making use of computer. The relevant lateral motion of the vehicle are observed after the action of an ideal disturbance force at the front edge of the vehicle-body for one second. It is found that though, in general, the clearance between guide wheels and guide-wall reduces the steering control stability and causes the oscillatory lateral motion, the connecting rod between the front steering linkage and the rear one restrain the oscillatory lateral motion, when the steering control gains of front and rear are chosen appropriately. The lateral motion of the vehicle without the connecting rod is always more oscillatory in any steering control gains because of the clearance. It is pointed out that connecting the front steering linkage with the rear one by some ingenious rod, NTS vehicle steering control system is so designed as to keep high stability in lateral motion even with the clearance between guide wheels and guide-wall.