Investigation of Various Tracking Rules in Platoons of Unmodeled Loads and Saturated Drives

This paper is devoted to the analysis and adaptive control of a platoon of vehicles that behaves like a virtual train. It is supposed that the first vehicle plays leading role while the other members have local controllers trained for keeping a safe tracking distance between themselves and the preceding one. In the model investigated the connection between the vehicles acts like an elastic spring without "reaction forces", i.e the (n + 1)th member's motion is influenced by that of the nth member but the members do not affect the motion of the preceding ones. It is supposed that the leading vehicle can freely move, and the aim is to guarantee smooth motion for the last cart of the platoon that may be followed by a participant of the road communication whose driving comfort has to be kept in mind. The carts are modeled as rigid bodies while their loads are represented by masses connected to their carts by elastic springs of dynamic friction. It is shown that the simple semi-mechanistic connection between the carts can result in instable motion due to the resonance in the interaction between the loads and the carts. This effect can be eliminated if the acceleration of the preceding cart is also taken into account in the motion of the actual one. Furthermore, if an adaptive controller of lucid geometric interpretation akin to Soft Computing Solutions is also applied the last cart can trace the nominal trajectory with very good precision.