Energy management in Pontryagin's framework for hybrid tractors during agricultural operations

Heavy-duty and agricultural hybrid electric vehicles arise new challenges in the design of energy management strategies (EMSs) with respect to traditional urban vehicles. Indeed, variegate driving-cycles, typical of traditional vehicles, are not a standard for heavy-duty ones. In such a scenario, and, in particular, when considering machining/agricultural operations, driving-cycles become very long and repetitive. Indeed, the vehicle works for hours around a specific constant operating point, during agricultural operations or heavy-duty machining. In this paper, we proposed a specific EMS for this scenario, derived by verifying the validity of the Potryagin's minimum principle (PMP) equations, that are necessary to claim optimality. Finally, the proposed EMS is evaluated considering real agricultural driving-cycles, showing performance close to the global optimal solution computed a-posteriori.