Modelling and validation of a tracked vehicle for autonomous path tracking controller

The demand for autonomous technology in tracked vehicles is increasing, where path tracking controllers are vital. Developing stable and reliable in-track Direct Current (DC) motor controllers is essential for effective implementation. Therefore, this study presents a dynamic modelling and validation of a tracked vehicle, focusing on an in-depth analysis of the in-track DC motor system. To achieve this, three specific objectives were set: i) creating a dynamic vehicle model for path tracking control of an autonomous vehicle; ii) developing a motor model by analysing the speed characteristics of an in-track DC motor on a tracked vehicle; and iii) experimentally validating the proposed model against actual vehicle responses. The methodology begins with modelling and simulating the tracked vehicle in MATLAB/Simulink, followed by developing the DC motor model based on vehicle speed and turning radius during straight and cornering manoeuvres. Upon validating the motor model, an independent controller is developed for the DC motor on each side of tracked vehicle, incorporating all data from the characterization phase. The controller's effectiveness is validated by comparing the desired and actual response for DC motor model, motor controller, and vehicle model. With this, the Root-Mean-Square (RMS) of percentage difference is evaluated to quantify the validation between actual values and model predictions. The developed motor model agrees with the actual system with RMS of the percentage difference of 1.8% in vehicle speed during straight manoeuvring and 3.7% and 7.1% in turning radius for right and left cornering, respectively. The developed tracked vehicle model agrees with the actual setup, with 10.90% and 12.66% differences in terms of vehicle trajectory in X-Y coordinates for right and left cornering. With these findings, each objective has been achieved demonstrating the model’s suitability for path tracking controller development.