Dynamics modelling and predictive control for 6-DOF rotorcraft aerial manipulator system

Abstract

Rotorcraft aerial manipulator (RAM) is a new concept of aerial robots with arms, and it changes the traditional searching rotorcraft unmanned aerial vehicles (RUAVs) into operating aerial robots. The additional six degree-of-freedom (DOF) manipulator makes RUAV more flexible to accomplish 'touching' tasks. However, the relative force and torque disturbance, which cannot be eliminated completely in the controller, between the 6-DOF manipulator and the aerial robot, makes the operation precision of the end-effector too poor to accomplish the 'touching' missions. In this research, the overall dynamics model is firstly developed based on dynamic disturbance analysis between the RUAV and the joint 6 DOF robotic arm. Based on the proposed model, to compensate for the disturbance from relative dynamics with rotor system's control delay, a predictive controller is designed to minimise the errors of positions and attitudes of the end-effector. At last, different control strategies are compared in simulated insertion tasks, and the simulation results show the effectiveness of the proposed overall dynamic model and the proposed control strategies in precise air-operation.