Centralized load decoupling of a rotational multi-axis force sensor for measuring wheel-terrain interaction forces

Abstract

For ensuring the safe mobility of off-road wheeled mobile robots (WMRs), the rotational multi-axis force sensor (RMFS) plays an important role in measuring the wheel-terrain interaction forces. However, the existing decoupling models cannot fully describe the coupling process of the RMFS when it is subjected to centralized loads, which is a common condition for off-road WMRs. A corrected decoupling model is proposed by taking elastic strains as the intermediate variable such that the coupling errors caused by centralized loads can be avoided. The proposed decoupling model replaces the original rotation matrix with a corrected matrix whose elements are odd harmonic functions. The calibration experiments indicate that the corrected model can reduce the variance of calibration error rate from 1.95% to 0.054% compared with another representative machine learning-based decoupling model. A set of simulation and physical tests also demonstrate that the decoupling model have good repeatability, accuracy and anti-vibration capability.