Haptic-Based Bilateral Teleoperation of Aerial Manipulator for Extracting Wedged Object with Compensation of Human Reaction Time

TL;DR

This work tackles the challenge of wedged object extraction by a UAM under human reaction time constraints. It introduces a haptic-based bilateral teleoperation framework using a $4$-DOF haptic device and a two-phase flight (nominal and recovery) with an extraction detection mechanism and post extraction trajectory generation. An admittance-type controller for the haptic device and a disturbance-observer controller for the UAM, together with Kalman-based extraction detection and minimum-snap recovery trajectories, enable fast and stable recovery after extraction. Experimental plug-pulling tests show reduced position overshoot and quicker return to the initial state, highlighting the practical impact for safe and robust aerial manipulation in hazardous environments; future work includes hybrid or model predictive control and enhanced feedback modalities.

Abstract

Bilateral teleoperation of an aerial manipulator facilitates the execution of industrial missions thanks to the combination of the aerial platform's maneuverability and the ability to conduct complex tasks with human supervision. Heretofore, research on such operations has focused on flying without any physical interaction or exerting a pushing force on a contact surface that does not involve abrupt changes in the interaction force. In this paper, we propose a human reaction time compensating haptic-based bilateral teleoperation strategy for an aerial manipulator extracting a wedged object from a static structure (i.e., plug-pulling), which incurs an abrupt decrease in the interaction force and causes additional difficulty for an aerial platform. A haptic device composed of a 4-degree-of-freedom robotic arm and a gripper is made for the teleoperation of aerial wedged object-extracting tasks, and a haptic-based teleoperation method to execute the aerial manipulator by the haptic device is introduced. We detect the extraction of the object by the estimation of the external force exerted on the aerial manipulator and generate reference trajectories for both the aerial manipulator and the haptic device after the extraction. As an example of the extraction of a wedged object, we conduct comparative plug-pulling experiments with a quadrotor-based aerial manipulator. The results validate that the proposed bilateral teleoperation method reduces the overshoot in the aerial manipulator's position and ensures fast recovery to its initial position after extracting the wedged object.

Figures (7)

• Figure 1: Illustration of the haptic-based bilateral teleoperation of a UAM (remote environment) extracting a wedged object from a static structure with a haptic device (local environment).
• Figure 2: Illustration of the robotic arm that is used for our haptic device. Key coordinate frames are also depicted.
• Figure 3: Illustration of the UAM with the key coordinate frames.
• Figure 4: Diagram including the teleoperation method during nominal flight (blue lines) and reference trajectory generation methods for the haptic device and the UAM during recovery flight (red lines).
• Figure 5: (a) UAM utilized for our plug-pulling experiments. (b) Structure of the electric socket.