On March 31, 2020, the student Artur Tozzi de Cantuaria Gama presented his master’s thesis entitled “Development of a supervisory controller with state machines applied to commercial vehicles with a hydraulic-pneumatic hybridization system”, in Florianópolis, SC. The work is a continuation of the study initiated in the doctoral thesis of Rafael Rivelino da Silva Bravo, which discusses a proposal for a hydraulic-pneumatic hybridization for large commercial vehicles.
The focus of the dissertation is on the implementation of a supervisory controller responsible for deciding on the use and operation of the system, opting for regenerative braking through the loading of hydraulic accumulators, production of compressed air for the air reservoirs or assistance in accelerating the vehicle after an energy recovery period. The supervisory control system uses statecharts, an expansion of the theory of state machines, to identify the states of the vehicle during operation and activate the different modes of operation of the regenerative system. The mathematical model allows the definition of different speed and slope profiles to assess the performance of the hybrid vehicle and compare it with the conventional one. The results show that it is possible to achieve improvements in energy use at the end of a working cycle, producing more useful energy from the fuel consumption, and confirm the applicability of the system, especially in situations of frequent deceleration and downhill traffic.
This was also one of the first defenses in the laboratory carried out entirely through videoconference, following the guidelines from UFSC due to the coronavirus pandemic.
