Steerability of Articulated Multi-Tracked Vehicles by Flexed Posture Moving on Slippery Surface

Serpentine tracked robots - i.e., articulated multi-tracked vehicles - are designed to move on rough terrains and used for a variety of purposes, including search and rescue operations, planetary exploration and environmental investigations. The steerability of such vehicles depends on its posture and interaction between the vehicle and the ground. In previous research, kinematic models with slip information were derived for articulated multi-tracked vehicles. Such kinematic models, however, do not allow for the slippage of the vehicle that occurs when moving at a high speed or on a slippery surface. In this paper, we derive a dynamic model on which the frictional force is acting between the track shoes of each track of the vehicle and the ground for the slippery conditions. The frictional model neglecting static friction is given by a formula for the friction coefficient function proposed in the field of Teramechanics in order to mainly analyze slip behavior. The model is also used to analyze the steering properties, or steerability of the vehicles.