Development of Vision Stabilizing System for a Large-Scale Flapping-Wing Robotic Bird

Bio-inspired flapping-wing flying robots have huge application potential in military reconnaissance, environment exploring, disaster rescue and so on. Vision sensors are usually mounted to provide image information of targets. However, the position and attitude of this kind of robot changes drastically during flapping flight, resulting in more challenges for stable imaging. In this paper, a vision stabilizing system (also called stabilizer or camera gimble) is developed to supply stable imaging condition for a large-scale flapping wing robotic bird with 2.3m wingspan and 650g weight. Based on theoretical analyses and experiments, flight characteristics of the robot are first obtained. Then a 3-DOF stabilizer is designed to supply 2-DOF rotation and 1-DOF translation movement. The kinematics and dynamics equations are then derived to analyze the disturbance on the fuselage caused by the stabilizer. Furthermore, the key parameters of the stabilizer are determined according to the constraints on the flight capability. To deal with the interaction between the stabilizer and the fuselage, a coordinated control strategy is proposed and the onboard controller is developed to control the compounded system. Finally, the prototype of the stabilizer is assembled and integrated to a real robotic bird. Practical flight experiments are carried out and the results show that the developed stabilizer has good working performance.