Examining the simulation-to-reality gap of a wheel loader digging in deformable terrain
Aoshima K, and Servin M. Examining the simulation-to-reality gap of a wheel loader digging in deformable terrain. Multibody System Dynamics (2024). doi.org/10.1007/s11044-024-10005-5, arxiv:2310.05765 [pdf]
We investigate how well a physics-based simulator can replicate a real wheel loader performing bucket filling in a pile of soil. The comparison is made using field test time series of the vehicle motion and actuation forces, loaded mass, and total work. The vehicle was modeled as a rigid multibody system with frictional contacts, driveline, and linear actuators. For the soil, we tested discrete element models of different resolutions, with and without multiscale acceleration. The spatio-temporal resolution ranged between 50-400 mm and 2-500 ms, and the computational speed was between 1/10,000 to 5 times faster than real- time. The simulation-to-reality gap was found to be around 10% and exhibited a weak dependence on the level of fidelity, e.g., compatible with real-time simulation. Furthermore, the sensitivity of an optimized force feedback controller under transfer between different simulation domains was investigated. The domain bias was observed to cause a performance reduction of 5% despite the domain gap being about 15%.

Simulators of different level of fidelity for sim2real transfer.

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UMIT Research Lab, Digital Physics