ABSTRACT
This Chapter describes the development and assessment of control strategies for autonomous flight. It is now assumed that the problem concerning local optic-flow detection is solved (Chap. 5) and we thus move on to the question of how these signals can be combined in order to steer a flying robot. This Chapter focuses on spatial combinations of optic-flow signals and integration of gyroscopic information so as to obtain safe behaviours: to remain airborne while avoiding collisions. Since the problem is not that trivial, at least not from an experimental point of view, we proceed step by step. First, the problem of collision avoidance is considered as a 2D steering problem assuming the use of only the rudder of the aircraft while altitude is controlled manually through a joystick connected to the elevator of the airplane. Then, the problem of controlling the altitude is tackled by using ventral optic-flow signals. By merging lateral steering and altitude control, we hope to obtain a fully autonomous system. It turns out, however, that the merging of these two control strategies is far from straightforward. Therefore, the last Section proposes a slightly different approach in which we consider both the walls and the ground as obstacles that must be avoided without distinction. This approach ultimately leads to a fully autonomous system capable of full 3D collision avoidance.
