Mathematical modelling of operating cycles for road vehicles
Licentiate thesis, 2021
Difficulties that commercial vehicles are facing in meeting regulation standards require ad-hoc solutions. Emissions can be dramatically lowered if the characteristics of the transport application are known in advance. To tailor the vehicle's specification towards the use-case, however, a representative description of the mission, together with the surroundings, is needed.
Where many conventional approaches fail, the operating cycle format (OC) has shown promising results in describing road operations in a way which is completely 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 degree of accuracy. Finally, the deterministic operating cycle (dOC) is the most detailed description of a transport mission, and collects deterministic models to be used in simulation.
In previous studies, the OC format was demonstrated to work in theory, but some margins for improvement could still be identified. Furthermore, the utility and benefits deriving from the use of the OC in concrete situations was explored only partially.
The main objective of this thesis consists in extending the OC representation to include stochastic models for weather and traffic, which were missing in the original formulation. The new models are built to be parsimonious and to allow ease of parametrisation and implementation starting from real data. This enables to reproduce and simulate realistic environments where a transport mission can 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 involving real customers. A case study is presented to exemplify the advantages connected with the use of the OC description in product selection, prospecting a potential reduction of fuel consumption and emission of about 10%.
Where many conventional approaches fail, the operating cycle format (OC) has shown promising results in describing road operations in a way which is completely 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 degree of accuracy. Finally, the deterministic operating cycle (dOC) is the most detailed description of a transport mission, and collects deterministic models to be used in simulation.
In previous studies, the OC format was demonstrated to work in theory, but some margins for improvement could still be identified. Furthermore, the utility and benefits deriving from the use of the OC in concrete situations was explored only partially.
The main objective of this thesis consists in extending the OC representation to include stochastic models for weather and traffic, which were missing in the original formulation. The new models are built to be parsimonious and to allow ease of parametrisation and implementation starting from real data. This enables to reproduce and simulate realistic environments where a transport mission can 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 involving real customers. A case study is presented to exemplify the advantages connected with the use of the OC description in product selection, prospecting a potential reduction of fuel consumption and emission of about 10%.
energy estimation
transport application
operating cycle
autoregressive models
road mission
stochastic models
Author
Luigi Romano
Chalmers, Mechanics and Maritime Sciences (M2), Vehicle Engineering and Autonomous Systems
Subject Categories
Aerospace Engineering
Transport Systems and Logistics
Vehicle Engineering
Publisher
Chalmers