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Patrick Pfändler

Bio: Patrick Pfändler is an academic researcher from ETH Zurich. The author has contributed to research in topics: Free flight & Corrosion. The author has an hindex of 4, co-authored 6 publications receiving 62 citations.

Papers
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Proceedings ArticleDOI
TL;DR: An omnidirectional aerial manipulation platform for robust and responsive interaction with unstructured environments, toward the goal of contact-based inspection, equipped with a rigidly mounted end-effector and an impedance controller with selective apparent inertia.
Abstract: This paper presents an omnidirectional aerial manipulation platform for robust and responsive interaction with unstructured environments, toward the goal of contact-based inspection. The fully actuated tilt-rotor aerial system is equipped with a rigidly mounted end-effector, and is able to exert a 6 degree of freedom force and torque, decoupling the system's translational and rotational dynamics, and enabling precise interaction with the environment while maintaining stability. An impedance controller with selective apparent inertia is formulated to permit compliance in certain degrees of freedom while achieving precise trajectory tracking and disturbance rejection in others. Experiments demonstrate disturbance rejection, push-and-slide interaction, and on-board state estimation with depth servoing to interact with local surfaces. The system is also validated as a tool for contact-based non-destructive testing of concrete infrastructure.

61 citations

Journal ArticleDOI
TL;DR: A variable axis-selective impedance control is presented which integrates direct force control for intentional interaction, using feedback from an on-board force sensor, and is validated as a tool for nondestructive testing of concrete infrastructure.
Abstract: This article presents and validates active interaction force control and planning for fully actuated and omnidirectional aerial manipulation platforms, with the goal of aerial contact inspection in unstructured environments. We present a variable axis-selective impedance control which integrates direct force control for intentional interaction, using feedback from an on-board force sensor. The control approach aims to reject disturbances in free flight, while handling unintentional interaction and actively controlling desired interaction forces. A fully actuated and omnidirectional tilt-rotor aerial system is used to show capabilities of the control and planning methods. Experiments demonstrate disturbance rejection, push-and-slide interaction, and force-controlled interaction in different flight orientations. The system is validated as a tool for nondestructive testing of concrete infrastructure, and statistical results of interaction control performance are presented and discussed.

48 citations

Journal ArticleDOI
TL;DR: In this article, a variable axis-selective impedance control is proposed to reject disturbances in free flight, while handling unintentional interaction, and actively controlling desired interaction forces using feedback from an on-board force sensor.
Abstract: This paper presents and validates active interaction force control and planning for fully actuated and omnidirectional aerial manipulation platforms, with the goal of aerial contact inspection in unstructured environments. We present a variable axis-selective impedance control which integrates direct force control for intentional interaction, using feedback from an on-board force sensor. The control approach aims to reject disturbances in free flight, while handling unintentional interaction, and actively controlling desired interaction forces. A fully actuated and omnidirectional tilt-rotor aerial system is used to show capabilities of the control and planning methods. Experiments demonstrate disturbance rejection, push-and-slide interaction, and force controlled interaction in different flight orientations. The system is validated as a tool for non-destructive testing of concrete infrastructure, and statistical results of

35 citations

Proceedings ArticleDOI
22 Jun 2019
TL;DR: In this article, an omnidirectional aerial manipulation platform for robust and responsive interaction with unstructured environments, toward the goal of contact-based inspection, is presented, which is equipped with a rigidly mounted end-effector, and is able to exert a 6 degree of freedom force and torque, decoupling the system's translational and rotational dynamics, enabling precise interaction with the environment while maintaining stability.
Abstract: This paper presents an omnidirectional aerial manipulation platform for robust and responsive interaction with unstructured environments, toward the goal of contact-based inspection. The fully actuated tilt-rotor aerial system is equipped with a rigidly mounted end-effector, and is able to exert a 6 degree of freedom force and torque, decoupling the system's translational and rotational dynamics, and enabling precise interaction with the environment while maintaining stability. An impedance controller with selective apparent inertia is formulated to permit compliance in certain degrees of freedom while achieving precise trajectory tracking and disturbance rejection in others. Experiments demonstrate disturbance rejection, push-and-slide interaction, and on-board state estimation with depth servoing to interact with local surfaces. The system is also validated as a tool for contact-based non-destructive testing of concrete infrastructure.

25 citations

DOI
01 Aug 2019
TL;DR: A flying robot equipped with electrochemical sensors to detect corrosion was developed and first flight tests demonstrate that electrochemical steel potentials and electrical concrete resistance can be successfully measured by the robot and are comparable to measurements taken conventionally.
Abstract: A main challenge in the coming decades will be the assessment of our ageing infrastructure and their repair. Automating corrosion assessments by means of inspection robots will help to lower the costs of routine inspections. In order to apply well-proven non-destructive test methods to structures a physical contact to the surface is often essential. Establishing physical contact with a drone to the structure requires high stability and ideally full 6 degrees of freedom, force and torque tracking to be robust in the field. Here, in an interdisciplinary collaboration, such a flying robot equipped with electrochemical sensors to detect corrosion was developed. First flight tests with the electrochemical sensor on a laboratory sample demonstrate that electrochemical steel potentials and electrical concrete resistance can be successfully measured by the robot and are comparable to measurements taken conventionally.

9 citations


Cited by
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Journal Article
TL;DR: In this paper, the authors examined the reactions of various concretes on steel reinforcement and concluded that the most significant influences on the corrosion of prestressing wire in concrete are: the presence of chloride, presence of nitrates, the composition of concrete, the degree of carbonation of the concrete; concrete compaction and chlorides and sulphates should be used as far as possible when steel is embedded.
Abstract: The author details the reactions of various concretes on steel reinforcement. Although portland cements, slag cements and high alumina cements are all hydraulic binders, each possess special properties which are examined. The discussion of causes and methods of preventing the corrosion of steel reinforcement covers such aspects as galvanised steel reinforcement, effects of concrete composition, corrosion of steel reinforcments in concrete and prestressed reinforcement. It is concluded that the most significant influences on the corrosion of prestressing wire in concrete are: the presence of chloride; the presence of nitrates; the composition of the concrete; the degree of carbonation of the concrete; concrete compaction and, chlorides and sulphates should be used as far as possible when steel is embedded. (TRRL)

621 citations

Journal ArticleDOI
TL;DR: In this paper , the evolution and current trends in aerial robotic manipulation, comprising helicopters, conventional underactuated multirotors, and multidirectional thrust platforms equipped with a wide variety of robotic manipulators capable of physically interacting with the environment, are analyzed.
Abstract: This article analyzes the evolution and current trends in aerial robotic manipulation, comprising helicopters, conventional underactuated multirotors, and multidirectional thrust platforms equipped with a wide variety of robotic manipulators capable of physically interacting with the environment. It also covers cooperative aerial manipulation and interconnected actuated multibody designs. The review is completed with developments in teleoperation, perception, and planning. Finally, a new generation of aerial robotic manipulators is presented with our vision of the future.

65 citations

Journal ArticleDOI
TL;DR: A variable axis-selective impedance control is presented which integrates direct force control for intentional interaction, using feedback from an on-board force sensor, and is validated as a tool for nondestructive testing of concrete infrastructure.
Abstract: This article presents and validates active interaction force control and planning for fully actuated and omnidirectional aerial manipulation platforms, with the goal of aerial contact inspection in unstructured environments. We present a variable axis-selective impedance control which integrates direct force control for intentional interaction, using feedback from an on-board force sensor. The control approach aims to reject disturbances in free flight, while handling unintentional interaction and actively controlling desired interaction forces. A fully actuated and omnidirectional tilt-rotor aerial system is used to show capabilities of the control and planning methods. Experiments demonstrate disturbance rejection, push-and-slide interaction, and force-controlled interaction in different flight orientations. The system is validated as a tool for nondestructive testing of concrete infrastructure, and statistical results of interaction control performance are presented and discussed.

48 citations

Journal ArticleDOI
TL;DR: In this article, a variable axis-selective impedance control is proposed to reject disturbances in free flight, while handling unintentional interaction, and actively controlling desired interaction forces using feedback from an on-board force sensor.
Abstract: This paper presents and validates active interaction force control and planning for fully actuated and omnidirectional aerial manipulation platforms, with the goal of aerial contact inspection in unstructured environments. We present a variable axis-selective impedance control which integrates direct force control for intentional interaction, using feedback from an on-board force sensor. The control approach aims to reject disturbances in free flight, while handling unintentional interaction, and actively controlling desired interaction forces. A fully actuated and omnidirectional tilt-rotor aerial system is used to show capabilities of the control and planning methods. Experiments demonstrate disturbance rejection, push-and-slide interaction, and force controlled interaction in different flight orientations. The system is validated as a tool for non-destructive testing of concrete infrastructure, and statistical results of

35 citations