Terrain model-based anticipative control for articulated vehicles with low bandwidth actuators

Mobile robots and vehicles with active articulated elements are well suited to drive on irregular and rough terrain because they are able to adjust their center of mass and decrease the risk of tip over or other accidents. The articulated mechanism, however, is usually constrained by the actuator´s bandwidth, making it difficult for the vehicle to compensate for abrupt changes in terrain profile. In this paper we propose a terrain model-based control method to improve stability when traversing terrains with varying slopes, depressions, and rises. A model predictive control approach takes into account actuator bandwidth to anticipate interactions with the terrain and control the articulated elements to prevent tipping over. The method is applied to an autonomous orchard platform where workers stand while conducting production tasks on the trees, adjusting the platform height and increasing its stability. The feasibility is illustrated via numerical simulations performed with the MD Adams/Car software and Matlab, with both artificial and natural terrain data. Challenging yet realistic terrain profiles are considered to demonstrate the control effectiveness in preventing the platform from tipping over and therefore improving the workers´ and the vehicle´s safety.