In this thesis is presented a novel approach to model, control, and planning the motion of
a nonholonomic wheeled mobile robot that applies stable pushes and pulls to a
nonholonomic cart (York mail trolley) in a loosely structured environment. The method is
based on grasping and ungrasping the nonholonomic cart, as a result, the robot changes its
kinematics properties. In consequence, two robot configurations are produced by the task
of grasping and ungrasping the load, they are: the single-robot configuration and the
robot-trolley configuration. Furthermore, in order to comply with the general planar
motion law of rigid bodies and the kinematic constraints imposed by the robot wheels for
each configuration, the robot has been provided with two motorized steerable wheels in
order to have a flexible platform able to adapt to these restrictions. [Continues.