Abstract:

The research and application of unmanned ground vehicles （UGVs） become more popular in both civilian and military fields. UGVs completely eliminate the human driving operating mechanisms， and adopt full X-by-wire control framework and distributed all-wheel independent drive/braking/steering techniques instead， with each wheel independently controlled to realize multi-steering modes and obtain high maneuver trajectory tracking ability which traditional vehicle cannot achieved. This paper aims to conduct a research on the all-wheel diagonal steering （vividly called crab walk steering） control of full X-by-wire controlled UGVs. Firstly， a stability robust control algorithm with a reconfigurable model is proposed， the robust control target and parameter perturbation dynamics model for diagonal maneuver are established， and a robust H₂/H_∞ stability controller is constructed to achieve a point-to-point yaw-less direct movement of UGVs. Then a decoupled control between body motion posture and movement trajectory is realized through comprehensive cooperated dynamics control， so significantly enhancing the trajectory tracking capability of UGVs in complex space. Finally， a test on a six-wheel UGV prototype is carried out to verify the control effects of the robust controller designed.

Key words: unmanned ground vehicles, all-wheel steering, diagonal maneuver, robust control