Driving Force Distribution and Control for Maneuverability and Stability of a 6WD Skid-Steering EUGV with Independent Drive Motors

Featured Application The paper proposes a hierarchical driving force distribution and control strategy for six-wheel drive (6WD) skid-steering electric unmanned ground vehicles (EUGVs) with independent drive motors to improve the vehicle maneuverability and stability. The proposed method can be applied to control the longitudinal velocity and yaw rate for distributed, independently driven electrical skid-steering vehicles, for instance, military vehicles, agricultural vehicles, and other special vehicles. In this paper, a hierarchical driving force distribution and control strategy for a six-wheel drive (6WD) skid-steering electric unmanned ground vehicle (EUGV) with independent drive motors is presented to improve the vehicle maneuverability and stability. The proposed hierarchical strategy is based on a nine-degrees-of-freedom (DOFs) dynamics model of 6WD skid-steering EUGV with a vehicle system dynamics model, wheel dynamics model, and tire model. In the proposed hierarchical strategy, the upper layer controller calculates the resultant driving force and yaw moment to control the vehicle motion states to track the desired ones by using the integral sliding mode control (ISMC) and proportion-integral-differential (PID) control methods. In the lower layer controllers, the driving force distribution method is adopted to allocate torques to the six motors. An objective function is proposed and composed of the longitudinal tire workload rates and weighting factors, considering the inequality constraints and equality constraints, which is solved by using the active set method. In order to evaluate the effectiveness of the proposed method, experiments with two types of scenarios were conducted. Comparative studies were also conducted with the other two methods used in the literature. The experimental results show that better performance can be achieved with the proposed control strategy in vehicle maneuverability and stability.

Automated summary

The paper proposes a hierarchical driving force distribution and control strategy for six-wheel drive skid-steering electric unmanned ground vehicles, utilizing a nine-degrees-of-freedom dynamics model and integral sliding mode control and PID control methods in the upper layer controller. The lower layer controllers adopt a driving force distribution method to allocate torques to the six motors, achieving better vehicle maneuverability and stability.