Constraint-Based Cooperative Control of Multiple Aerial Manipulators for Handling an Unknown

This paper presents the planning and control synthesis of cooperative aerial manipulators to carry an unknown object together. The online parameter estimation algorithm is designed to estimate the unknown physical parameters of the common payload such as mass and moment of inertia, without the need of multiaxis force/torque sensors. Based on the augmented adaptive sliding mode controller with the estimated physical parameters, the desired trajectory of each aerial manipulator is generated to track the desired trajectory of corresponding end effector. In order to carry an unknown object safely considering the actuation limit of the hexacopter, we use the task priority to satisfy the unilateral constraints determined by the allowable flight envelope. To validate our approach, the experimental result on a successful transportation by using multiple custom-made aerial manipulators is shown. This result suggests that the proposed approach can be utilized for safe cooperative aerial transportation.