Fault-Tolerant Control of Automated Guided Vehicle Under Centroid Variation

Aiming at stability and safety problems caused by the actuator failure of the automated guided vehicle under the condition of centroid position change. The four-wheel independent drive four-wheel independent steer (4WID/4WIS) AGV is studied for fault-tolerant control of single-wheel drive actuators under the centroid position variation condition. First, 3-DOF vehicle model, drive-wheel dynamics model, HSRI tire model, and the actuator loss of effectiveness model established. Second, a hierarchical controller is designed with an optimal input controller based on Model Predictive Control (MPC) theory of the upper layer, a desired yaw moment solver based on fuzzy theory of the middle layer, and a torque reconstruction controls distributor based on the control gain in the lower layer. Then, the AGV is simulated and analyzed in straight line and double line change conditions. The simulation results show that the yaw rate and the centroid sideslip angle can closely track the theoretical value. The difference between the theoretical value is kept within 5%. Finally, the 4WID/4WIS AGV prototype vehicle was developed and tested for straight-line and double-lane change condition. The difference between simulation and experiment was within 4%. The experimental results show that the designed controller is effective.