A Hierarchical Path Tracking Method for High-speed Unmanned Tracked Vehicle

This paper proposes a hierarchical path tracking control framework divided into the upper controller and the lower controller for double motors independently driven unmanned high-speed tracked vehicle. The upper layer generates rolling speed command of the dual-side tracks using model predictive control. The Euler method, the second-order Runge-Kutta method and the revised fourth-order Runge-Kutta method are applied to compare the control performance in this layer. Meanwhile, to surmount control command execution delay, two compensatory methods based on control law in time domain are proposed. The lower controller translates the tracks speed command from the upper layer into motors torque according to the tracked vehicle dynamic model. Experiments show that the root-mean-square lateral error is 0.1176m and the root-mean-square heading error is 0.7552° when applying the second-order Runge-Kutta method that has the best tracking accuracy in straight off-road roads at 10m/s. Experiments also demonstrate that the control framework has good tracking performance in high-speed tracking straight path and low-speed tracking curved path. Results show the steady condition lateral error of 70km/h pavement tracking is less than 0.2m and 10km/h right-angled soft off-road road is less than 0.6m.