Torque-Based Center-of-Mass Estimation and Rollover-Aware Motion Planning for Heavy Omnidirectional Mobile Robots

Abstract

Eccentric payloads redistribute wheel loads and change the forces and moments required to maneuver heavy mobile robots. This study combines torque-based center-of-mass (CoM) estimation with global and local motion planning. During aligned, quasi-static creep, normalized wheel torques give a planar CoM estimate under calibrated rolling-resistance assumptions. An acceleration-based extension for CoM height remains unvalidated on hardware. The global planner adds a direction-selective turning penalty, while the DWB-style local planner uses an operational rollover-index constraint and a preview speed limit. Tests on a 2000 kg platform with a 500 kg payload recovered the reference quadrant at all four asymmetric placements using forward–reverse creep. Combined-CoM discrepancies were 20–75 mm at three placements and 265 mm at the front-left placement. In fixed-placement simulations with nominal offsets, local planning reduced the peak index by 40.3% on average, and the combined global and local planners by 44.7%, without violating the selected bound. A reduced-multibody replay retained a 39.7% mean peak reduction at the nominal contact stiffness but produced brief violations at three placements. With a recovery policy that keeps the constraint active during normal candidate selection, 40 randomized scenarios had no violations; with hardware-informed error scales, ten exceeded the bound. Estimation accuracy and physical validation remain limitations.