Model Based Design Framework Development of a Hybrid Supervisory Controller for a P4 Parallel Hybrid Vehicle

Abstract

The expected rise in the number of ECUs in an automotive based development environment, poses additional efficiency risk on developer time and code complexity. This thesis examines the design and validation of a Hybrid Supervisory Controller, developed for the University of Waterloo Alternative Fuels Team’s (UWAFT) retrofitted P4 parallel Chevrolet Blazer, in the EcoCAR Mobility Challenge competition.

The controller, component models and I/O interaction layers are developed in a MathWorks Simulink environment. The framework discussed, is built to incorporate automation via a custom developed -Model-Configurator tool. Component models, and functional sub-systems are converted to masked library blocks within Simulink, that are populated via an object-oriented class in the MATLAB environment. This opens the possibility for custom environment data population, swapping of data for models while retaining underlying physics and setting up for SIL/HIL requirements testing without explicit/contemporary interaction with the Simulink environment. The advantages of this approach are discussed, along with explanation accompanying the software framework.

The HSC incorporates interaction models of 9 stock vehicle, and on-board GM ECUs. The model spans full chassis longitudinal, and powertrain components. The functional controller incorporates 4 powertrain control layers - fault detection, vehicle state control, torque strategy and component level execution layers. The test environment switching time is reduced by >50%, and 86 controls requirements are tested over the course of 3 years.

The test vehicle is tested at the Canadian Technical Center McLaughlin Advanced Technology Track (CTC MATT) where a non-standard drive cycle is used due to limitations posed by the COVID-19 pandemic. The vehicle robustly sustains a 91-minute city/highway drive, with a 24% improvement in fuel economy compared to stock. The vehicle however is short of its VTS targets which are attributed to the lack of engine start/stop functionality, and a thermally constrained battery pack. Those remain major design shortcomings and immediate powertrain improvements are proposed, and efficacy of a well-organized model are discussed.