Exploring aerial perching and grasping with dual symmetric manipulators and compliant end-effectors

Inspired by talon of a predator bird, this paper presents a quadrotor with two 2- Degree of Freedoms (DOFs) compliant manipulators which could mimic bird perching and grasping. The symmetric configuration of the manipulators causes minimum shift in center of gravity and a minimum disturbance to the angular momentum of the platform during grasping and perching maneuvers. Thus, the dynamics of the manipulator is independent to that of the platform. Moreover, a compliant end-effector is introduced to decouple the dynamics of the unmanned aerial vehicles from the force interaction with the environment or target objects. Therefore, aerial manipulation problem is significantly simplified due to the minimum amount of disturbance among components. In addition, the manipulators could function as the landing gear, which allows larger work envelope, weight saving and less landing impact. It also has the potential to achieve a bird-like “perch and watch” to increase the endurance of unmanned aerial vehicles in missions that involve extended endurance.