Small-Time Local Controllability of a Differential Drive Robot with a Limited Sensor for Landmark-Based Navigation

This work studies the interaction of the nonholonomic and visibility constraints of a robot to maintain visibility of a landmark. The robot is a differential drive system (nonholonomic robot) and has a sensor with limited capabilities (limited field of view). In this research, we want to determine whether or not a robot can always maintain visibility of a landmark during the execution of a path between any two locations. We present two kinematic models. First, a robot with 3 controls, where the controls correspond to the two wheels velocities plus one independent controlled sensor. Second, a model with only 2 controls, which controls both the wheels and the sensor rotation. We show that our system (with 3 or 2 controls) is small-time local controllable.