A Novel Power-Split Hybrid Electric Architecture for Off-Road Tracked Vehicles: Design and Performance Evaluation.

Tracked off-road vehicles operate at low speeds with high tractive effort and frequent skid-steer maneuvers, conditions that push torque and power demand to extremes and exacerbate powertrain efficiency losses. Electrification can improve energy conversion and mobility for such duty cycles. This paper introduces a novel power-split hybrid electric architecture for a tracked vehicle and benchmarks it against three designs: a conventional mechanical driveline, a series hybrid, and a P2 parallel hybrid. To enable fair, architecture-agnostic comparisons, a supervisory controller based on Stochastic Dynamic Programming (SDP) schedules engine operation and power flow across all layouts under representative off-road scenarios, including skid-steer events, with varying terrain and power-demand profiles. Results show higher energy conversion efficiency (lower fuel use) for the proposed power-split architecture, followed by the parallel, then series, and lastly conventional configuration across missions. Beyond efficiency, the proposed architecture offers packaging and robustness advantages: compared with the P2 parallel it eliminates transmission and steering hydraulics, yielding a more compact driveline and compared with the series hybrid it enables smaller traction motors and a smaller battery pack for the same missions. Finally, by allowing the machines to operate below base speed for longer, it extends burst-mode operation without sustained field weakening, thereby reducing demagnetization risk. Study analyzes the reason behind these trends and discusses packaging considerations. DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. OPSEC10035.