Human-State-Aware Controller for a Tethered Aerial Robot Guiding a Human by Physical Interaction

Abstract

With the rapid development of Aerial Physical Interaction, the possibility to have aerial robots physically interacting with humans is attracting a growing interest. In one of our previous works [1], we considered one of the first systems in which a human is physically connected to an aerial vehicle by a cable. There, we developed a compliant controller that allows the robot to pull the human toward a desired position using forces only as an indirect communication-channel. However, this controller is based on the robot-state only, which makes the system not adaptable to the human behavior, and in particular to their walking speed. This reduces the effectiveness and comfort of the guidance when the human is still far from the desired point. In this paper, we formally analyze the problem and propose a human-state-aware controller that includes a human's velocity feedback. We theoretically prove and experimentally show that this method provides a more consistent guiding force which enhances the guiding experience.

Design, Modeling, and Control of AVOCADO: A Multimodal Aerial-Tethered Robot for Tree Canopy Exploration

“…Drone applications with taut tethers include perching [28]- [30], take-off and landing on sloped terrain [31] or human interaction [32]. Contrary to slack tethers, an interaction force along the link arises for taut tethers, changing the dynamics of the aerial robot.…”

“…While steering the robot using the thrusters, we are spooling or unspooling the tether to extend the reach of the robot. Previous aerial robots exploiting tethers have a fixed tether length [28], [30]- [32], [35], slack tethers while unspooling [28], [29] and/or are not flying with the tether in tension [29]. Thruster-equipped CDPR and ACTR address interaction tasks with high load conditions, requiring a complex system with multiple robots and/or multiple tethers for stable operation [34], [36].…”

Design of Dynamics Invariant LSTM for Touch Based Human–UAV Interaction Detection

“…In this analogy, the mass corresponds to the UAV, the first set of spring-damper corresponds to the closed loop UAV system, and the second set of spring-damper corresponds to the dynamics of the human arm. Human dynamics have been modelled as a spring-mass damper system in the literature [34]. The force exerted by the human is F h .…”

“…Very recently, new applications emerged focusing on a direct interaction between a human and UAV. For example, the authors in [4] present a system where a human is physically connected to a UAV, and where the UAV physically pulls the human towards a desired position, unknown to the human. Similarly, the authors in [5] present a framework to safely operate an aerial manipulator interacting with a human.…”

Static Hovering Realization for Multirotor Aerial Vehicles with Tiltable Propellers

“…These platforms have seen an increase in their actuation abilities from the first presented designs [1] demonstrating the ability to achieve static hovering, to modern platforms able to apply independent forces and moments [2] in all directions, or achieve omnidirectinal flight [3,4]. This increase in abilities allowed new applications to emerge that were previously not possible with fixed wing Unmanned Aerial Vehicles (UAV)s [5], most notably, Aerial Physical Interaction [6,7] and Human Robot Interaction [8].…”