Research on virtual Ackerman steering model based navigation system for tracked vehicles

•An autonomous driving system for a low-cost tracked orchard vehicle is established.•Cubic spline interpolation smoothen RTK-GNSS position based path point sequencen.•Virtual Ackerman steering model and forward-steering PWM-based vehicle control method.•Feedback control algorithm based on pole assignment enables path-tracking control. A state feedback navigation control system based on a virtual Ackerman steering model is proposed in this study to address the problems of the poor smoothness of steering control and low control accuracy of tracked vehicles. The proposed system uses a real-time dynamic positioning global navigation satellite system. Furthermore, it incorporates cubic spline interpolation to smoothen a predetermined path. In addition, a path-tracking control method based on pole assignment, virtual Ackerman steering control model of a single-cylinder diesel-engine-powered tracked vehicle, and forward-steering proportional control method based on the principle of pulse-width modulation were designed. Simulations and field experiments were performed to test the application of the proposed system. The experimental results indicated that the absolute average and standard deviation of the path waypoint interval decreased from 0.227 and 0.348 m to 0.018 and 0.015 m, respectively. In 5- and 6-m-radius-circular and straight-line path-tracking simulations, the average error in path tracking was less than 0.002 m. For path tracking in an orchard environment, the average tracking error and standard error deviation between tree rows were 0.051 and 0.084 m, respectively. These results indicate that the proposed control system enable significantly stable control of single-cylinder diesel-engine-powered tracked vehicles, and its control accuracy meets the operational objectives of tracked vehicles.