Observer-based Controller Design for Oscillation Damping of a Novel Suspended Underactuated Aerial Platform

In this work, we present a novel actuation strategy for a suspended aerial platform. By utilizing an underactuation approach, we demonstrate the successful oscillation damping of the proposed platform, modeled as a spherical double pendulum. A state estimator is designed in order to obtain the deflection angles of the platform, which uses only onboard IMU measurements. The state estimator is an extended Kalman filter (EKF) with intermittent measurements obtained at different frequencies. An optimal state feedback controller and a PD+ controller are designed in order to dampen the oscillations of the platform in the joint space and task space respectively. The proposed underactuated platform is found to be more energy-efficient than an omnidirectional platform and requires fewer actuators. The effectiveness of our proposed system is validated using both simulations and experimental studies.

I. Introduction

Aerial robotic manipulation is a modern field of research that involves manipulation performed using a flying base [1]. In recent years, this field of aerial robotic manipulation has evolved significantly and has been utilized in numerous applications related to aerial inspection, construction, and load transportation [1]–[5]. Research on aerial manipulation is often centered around an unmanned aerial vehicle (UAV) integrated with a robotic arm. In [6], [7], a fully actuated UAV is mounted with a 3 degrees of freedom (DoF) robotic arm in order to perform collaborative human-handover tasks. An impedance-based grasping task was demonstrated in [8] using a UAV fitted with a 7-DoF Kuka robotic arm.