Speed Control of Remotely Operated Multi-Wheel Motor-Driven Vehicles for Unpaved Roads and Obstacles

This paper describes the speed control of a remotely operated multi-wheel motor-driven electric vehicle that can be effectively utilized not only on paved roads but also on unpaved roads or obstacles. The proposed speed control algorithm consists of an upper-level control module and two lower-level control modules. The upper-level module generates acceleration commands and the weighting factor, allowing the tractive and braking forces to intersect smoothly. Two lower-level modules generate motor torque and hydraulic brake commands, respectively. This speed controller tracks the speed commands of each axle to reduce wheel slip on unpaved roads. In addition, it uses the pitch angle of the vehicle body for mobility on slopes or obstacles. The disturbance observer is also applied to the lower-level control modules for robustness against modeling errors and frequently changing road conditions. Finally, the proposed speed control algorithm is applied to a simulation model and a six-wheel motor-driven prototype vehicle used for military purposes. Its effectiveness is verified through various scenarios, including unpaved roads and obstacles.