Relative-pose optimisation for robust and nonlinear control of unmanned aerial manipulators

Abstract

Recently, the complexity of control systems for autonomous Aerial Manipulators (AMs), i.e. Unmanned Aerial Vehicle (UAV) + Robot Manipulator (RM), is growing faster as per our demand of being able to perform more and more complex tasks. In the present work, we go a step forward adding an optimiser to the actual (nonlinear) control strategy, in order to comply with high-level control demands related to safety, accuracy and efficiency of the operational task. The actual strategy combined robust controllers with separate referencesfor both aerial vehicle and robot manipulator-optimising their shared priorities. Here, we demand the controller to meet an additional feed-forward action, so that the a priori free degree of freedom of the UAV relative-pose reference is optimised in real time according to the aforementioned requirements. In particular, the influence of the UAV relative-pose reference on the capabilities of the AM has been thoroughly analysed, demonstrating among others the benefits of a correct configuration to meet such high-level requirements, while reducing the End-Effector (EE) error, preventing unstability of hazardous situations and increasing the energetic efficiency of the whole system. A complete analysis of realistic simulations on a benchmark AM is reported.

Command-Filtered Backstepping Redesign for Aerial Manipulators Under Aerodynamic and Operational Disturbances

“…As was previously studied in [13] and [7], the aerodynamic effects, and especially its vertical component, do have an important impact on the whole AM dynamics. In those works, both propulsive and flight aerodynamics effects were presented, highlighting the importance of a correct modelling in order to obtain a realistic and faithful simulation responding as expected in a real AM.…”

“…Aerial Manipulators (AMs) are Unmanned Aerial Vehicle (UAVs) with mounted Robot Manipulators (RMs) Different AMs with multi-joint arms have been presented in [1,2] and [3]. For a detailed literature review on platforms and control systems of UAVs and RMs we refer interested readers to recent author's work and references therein in [4,5,6] and [7]. In fact, interaction capabilities have been demonstrated under the framework provided by ARCAS project [8].…”

Static Sensitivity of the Aerial Load Transport by Two Rotocopter Unmanned Aerial Vehicles

“…Here we neglect the process of connecting the load to the UAVs. That may be the mooring of cargo while the UAVs are on land, but also the grasping of cargo by the UAVs' manipulators during their hovering [10].…”

“…Left condition in (10) assures that both UAVs carry the load, while right condition excludes configurations, which are symmetrical for interchange of indices 1 and 2. For convenience, we consider the geometry to be known if d and h are determined.…”