Safe Landing Analysis of a Quadrotor Aircraft With Two Legs

We proposed a multi-propeller multifunction aerial robot (MMAR) that is composed of a quadrotor with two legs. The legs can increase the function of the robot. We found that the legs can increase the safety region of the robot during the landing. To study the safety problem, the dynamics of MMAR interacting with environment should be solved. On the basis of the interaction dynamics, this paper investigates the velocity constraint for safe landing of MMAR. The investigation begins from the kinematics and dynamics of MMAR in flight mode. Then the impact dynamics of MMAR during landing is developed. Furthermore, the landing safety problem is formulated by a series of constraint equations which can give a safety region of the velocity during landing. The safety region can give the safe velocity of the aerial robot before landing. Finally, simulation examples are presented using the proposed methodology. In the examples, a detailed safety region of a simulated MMAR is constructed and shown.