Modeling and analyses of a connected multi-car train system employing the inerter

This article develops the model of a connected multi-car train system and discusses the improvement of stability and performance by the inerter. The inerter is a genuine two-terminal element, whose reacting force is proportional to the relative acceleration across its terminals. First, we build a 31-degree-of-freedom full-train model by a multi-body package, called AutoSim, and show that its stability can be significantly improved by the inerter. Second, we derive a multi-car train model, by another multi-body package, called SimMechanics, and discuss the impacts of the number of connected cars on system stability: connecting cars tends to decrease the critical speed. Furthermore, we extend the discussion to performance and show that the connecting cars will increase the settling time, but has no influence on the passenger comfort. Finally, we apply network synthesis methods to realize a mechatronic network and conduct experimental verification. Based on the results, the inerter is deemed effective in improving the stability and performance of connected multi-car trains.