Derivation of error models incorporating slippage for a tracked vehicle coupled to a steerable trailer

This paper first presents a complete kinematic model and then presents kinematic model based error and offset models for tracked vehicles towing wheeled trailers or implements. In contrast to wheeled vehicles, the tracked vehicles have two tracks on either side of the vehicle. Steering is almost always through skid steer. They are fast becoming popular in agricultural fields due to excellent traction to weight ratio. As agricultural operations are progressing towards autonomous operations, it is important to develop models that can be used in developing controllers. In this paper kinematic models are used to develop two types of models one called the error model and the other called the offset model. They are developed for a system comprising a tracked vehicle towing a steerable wheeled trailer. The error model uses the errors in x, y and θ as the state variables of the model. The offset model uses the path offset and the alignment offset as state variables. Simulation results are presented to validate the error and offset models.