The operating cycle representation of road transport missions

Doktorsavhandling, 2023

The difficulties that conventionally road vehicles are facing in meeting regulation standards require ad-hoc solutions. Moreover, the impellent shift of paradigm towards full electrification and partial automation is posing great challenges to the automotive industry, which has set a zero-emissions target to be reached within a short time horizon. In this context, the energy performance of commercial vehicles may be dramatically improved if the characteristics of the transport application, that is, the intended usage, are known prior to prototype development and design selection. To tailor the vehicle's specifications, however, a representative description of the mission and the surroundings is needed.
Where many conventional approaches fail, the operating cycle format (OC) has revealed great potential in describing road operations in a way that is, to a large extent, independent of both vehicle and driver. More specifically, the framework consists of three levels of representation. The first, called the bird's-eye view, serves mainly as a classification tool and makes use of metrics and labels to completely characterise the overall application of a vehicle during its lifetime. The second description, the stochastic operating cycle (sOC), condenses the main properties of a road operation using elementary statistics. It is conceived as an intermediate representation with a higher resolution. Finally, the deterministic operating cycle (dOC) is the most detailed description of a transport mission and collects deterministic models to be used in simulations.
In previous studies, the OC format was demonstrated to work in theory, but some margins for improvement could still be identified. Furthermore, the benefits deriving from the use of the OC were explored only partially.
The first objective of this thesis consists in extending the OC representation to include stochastic models for weather, traffic, and mission properties, which were missing in the original formulation. The new models are built to be parsimonious and to facilitate parametrisation and implementation starting from real data. This enables reproducing and simulating realistic environments where a transport mission may take place, with a substantial gain in accuracy.
The second purpose of this work is to showcase how the OC concept can be used in practical applications concerning the design and sale phases. To this end, the relationships existing between the three levels of representation included in the format are formalised mathematically by exploiting the stochastic nature of the sOC, which acts as a bridge between the bird’s-eye view and the dOC. It is argued that the three descriptions can work synergically to support manufacturers in their internal processes of classification, optimal development and selection, and virtual testing of energy-efficient vehicles.