TEWD-DFO: A Soft-Soil-Aware Driving Force Observer Using Terramechanics-Enhanced Wheel Dynamics for Planetary Rover

Abstract

Accurate driving force estimation is critical for ground vehicles operating in soft-soil terrains, where complex wheel-soil interactions involving sinkage and shear effects significantly affect vehicle mobility. Conventional Driving Force Observers (DFOs), initially developed for rigid road conditions, fail to account for these terrain-specific nonlinearities, leading to estimation offset and substantial errors. To overcome this limitation, this paper proposes a Terramechanics-Enhanced Wheel Dynamics (TEWD) model that explicitly integrates soil resistance derived from established wheel-soil interaction models. Based on the TEWD model, we develop a new driving force observer, termed TEWD-DFO, that estimates driving forces solely from internal vehicle signals without requiring additional external force sensors. The proposed method is validated through simulations conducted in the ProjectChrono environment under soft-soil conditions. Simulation results demonstrate that the TEWD-DFO significantly reduces estimation offsets and achieves robust driving force estimation performance, indicating its potential applicability in enhancing vehicle stability and control accuracy in realistic soft-soil scenarios. © 2025 IEEE.