Rearward amplification is a problem of special concern for multiply articulated commercial vehicles. This paper has examined several types of dollies which alleviate this problem. A generalized model of the double trailer combination vehicle was presented. By adding special equations of constraint and /or special dolly tyre steering functions, the model can be modifie to represent vehicles incorporating several different types of dollies.In the case of simple drawbar dollies, the model decouples at the pintle hitch connection between the tractor semitrailer and the full trailer. The nature of the closed form solutions which have been obtained for such cases are discussed. The concept of the "steer point" is presented. This concept serves to clarify theinfluence which steering the tyre of the single drawbar dolly has on the dynamic performance of the vehicle. Useful close d form solutions have not been obtained for certain dolly types. Numerical results, derived from simulation, are presented for such cases.
Abstract