Closed-Loop Behavior of an Autonomous Helicopter Equipped with a Robotic Arm for Aerial Manipulation Tasks

This paper is devoted to the control of aerial robots interacting physically with objects in the environment and with other aerial robots. The paper presents a controller for the particular case of a small‐scaled autonomous helicopter equipped with a robotic arm for aerial manipulation. Two types of influences are imposed on the helicopter from a manipulator: coherent and non ‐ coherent influence. In the former case, the forces and torques imposed on the helicopter by the manipulator change with frequencies close to those of the helicopter movement. The paper shows that even small interaction forces imposed on the fuselage periodically in proper phase could yield to low frequency instabilities and oscillations, so called phase circle

Accepted for publication in the Journal of Robotic Systems. On the Kinematics of Multiple Manipulator Space Free-Flyers and their Computation

Abstract. In this paper, two basic approaches for kinematics modelling of multiple manipulator Space Free-Flying Robots (SFFRs) are developed. In the barycentric vector approach, the center of mass of the whole system is taken as a representative point for the system’s translational motion, and a set of body-fixed vectors which reflect both geometric configuration and mass distribution of the system are used. On the other hand, the direct path method relies on taking a point on the base body (preferably its center of mass) as the representative point for the system’s translational motion. The consequences of using each of the two approaches in deriving dynamics equations and in control design of SFFRs are discussed. It is revealed that the direct path method is a more appropriate approach for modelling multiple arm systems, in the presence of external forces/torques (i.e. free-flying mode). A fourteen degree-of-freedom space free-flying system is considered as a benchmark system and a quantitative comparison between the two approaches is presented. The results show that the direct path method requires significantly less computations for position and velocity analyses. 1 I