Active Interaction Force Control for Contact-Based Inspection With a Fully Actuated Aerial Vehicle
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.
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TL;DR: In this paper , an image-based impedance control strategy for force tracking of an unmanned aerial manipulator (UAM) is presented, where the relationship between the camera motion and the image features is derived.
Abstract: In this paper, an image-based impedance control strategy for force tracking of an unmanned aerial manipulator (UAM) is presented. Firstly, image features with nice decoupling characteristics are designed and the relationship between the camera motion and the image features is derived. Then, a two-stage strategy is proposed to achieve force tracking of the UAM on a planar object in an arbitrary pose. The first stage drives the end-effector perpendicular to the object’s planer surface by pure visual servoing. To achieve force tracking under the visual guidance, an adaptive visual impedance control method which adjusts the target stiffness according to the force tracking error and the visual feature error is proposed in the second stage. The closed-loop system is proved asymptotically stable by means of Lyapunov analysis. Further, the stability in free flight phase of the stage two is also analyzed and ensured. Finally, experiments were carried out including a whiteboard cleaning task in different poses. The experimental results illustrate the validity and effectiveness of the proposed approach. Note to Practitioners—This work is motivated by the contact force tracking problem of an unmanned aerial manipulator (UAM) without the position measurement. In recent years, impedance control is widely used in force tracking problems. However, position measurement is needed both for the robot and the object in most studies. To generate desired force under visual guidance, image-based visual servoing is combined with a novel impedance controller with variable stiffness. The idea is intuitive. For a human in contact with a wall, the contact force is controlled by adjusting his arm stiffness, which means the stiffness is adapted to the difference between the desired and actual contact force. Furthermore, the stiffness is also adapted to the visual tracking error, removing the assumption that no tracking error is in the inner loop of the impedance controller in the previous works. The proposed strategy is a promising solution for real applications and is validated by a board cleaning experiment in this paper.
14 citations
04 Aug 2021
TL;DR: In this paper, an aerial manipulation platform consisting of a parallel 3-DOF manipulator mounted to an omnidirectional tilt-rotor aerial vehicle is presented, where the manipulator is coupled to the base pose controller with a dynamic compensation term.
Abstract: To address the challenge of precise, dynamic and versatile aerial manipulation, we present an aerial manipulation platform consisting of a parallel 3-DOF manipulator mounted to an omnidirectional tilt-rotor aerial vehicle. The general modeling of a parallel manipulator on an omnidirectional floating base is presented, which motivates the optimization and detailed design of the aerial manipulator parameters and components. Inverse kinematic control of the manipulator is coupled to the omnidirectional base pose controller with a dynamic compensation term, going beyond common decoupled approaches. This presents a baseline for the control of redundant omnidirectional aerial manipulators. Experimental flights show the advantages of an active manipulator vs. a fixed arm for disturbance rejection and end effector tracking performance, as well as the practical limitations of the dynamic compensation term for fast end effector trajectories. The results motivate future studies for precise and dynamic aerial manipulation.
14 citations
TL;DR: This work introduces an over-actuated multirotor deploying a dry-coupled ultrasonic wheel probe as a novel means of wall thickness mapping and quantitatively defined the multi-modal operational confidence bounds of the system.
Abstract: Unmanned Aerial Vehicles (UAVs) are seeing increasing adoption to automated remote and in situ inspection of industrial assets, removing the need for hazardous manned access. Aerial manipulator architectures supporting pose-decoupled exertion of force and torque would further enable UAV deployment of contact-based transducers for sub-surface structural health assessment. Herein, for the first time, we introduce an over-actuated multirotor deploying a dry-coupled ultrasonic wheel probe as a novel means of wall thickness mapping. Using bi-axial tilting propellers in a unique tricopter layout, this system performs direct thrust vectoring for efficient omnidirectional flight and application of interaction forces. In laboratory testing we demonstrate stable and repeatable probe deployment in a variety of representative asset inspection operations. We obtain a mean absolute error in measured thickness of under 0.10 mm when measuring an aluminum sample with varying wall thickness. This is maintained over repeated exit and re-entry of surface contact, and when the sample is mounted vertically or on the underside of a 45° overhang. Furthermore, when rolling the probe dynamically across the sample surface in an area scanning modality, a mean absolute error in wall thickness below 0.28 mm is recorded. Multi-modal operational confidence bounds of the system are thereby quantitatively defined.
11 citations
Cites methods from "Active Interaction Force Control fo..."
...Building on previous work [32], using a hexacopter layout with 12 vectored propellers Bodie et al [33], [34] generate 6 DoF pose-decoupled force and torque....
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01 Oct 2021
TL;DR: In this paper, an aerial manipulation robot is used to install clip-type bird flight diversters on power lines, consisting of a multi-rotor platform equipped with a high force linear actuator and a clamp mechanism that holds the device until it is exerted on the cable.
Abstract: This paper presents an aerial manipulation robot intended to conduct the installation of clip-type bird diverters on power lines, consisting of a multirotor platform equipped with a high force linear actuator and a clamp mechanism that holds the device until it is exerted on the cable. The installation mechanism has been specifically designed for a particular model of bird flight diverter that is extensively employed on the Spanish power grid. The paper analyzes the risks involved in this operation and describes the approach followed in the validation of the aerial robot, from the installation in indoor testbed, to representative outdoor scenario, and preliminary flight tests on a 15 kV power line to identify possible malfunctions on the platform due to the electrostatic discharge.
9 citations
References
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TL;DR: A new conceptually simple approach to controlling compliant motions of a robot manipulator that combines force and torque information with positional data to satisfy simultaneous position and force trajectory constraints specified in a convenient task related coordinate system is presented.
Abstract: A new conceptually simple approach to controlling compliant motions of a robot manipulator is presented. The 'hybrid' technique described combines force and torque information with positional data to satisfy simultaneous position and force trajectory constraints specified in a convenient task related coordinate system. Analysis, simulation, and experiments are used to evaluate the controller's ability to execute trajectories using feedback from a force sensing wrist and from position sensors found in the manipulator joints. The results show that the method achieves stable, accurate control of force and position trajectories for a variety of test conditions.
2,991 citations
"Active Interaction Force Control fo..." refers background in this paper
...Methods for direct force control of fixed-base manipulators are well established [23], [24], typically switching controller modes when contact is detected....
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01 Feb 1987
TL;DR: A framework for the analysis and control of manipulator systems with respect to the dynamic behavior of their end-effectors is developed, and the unified approach for motion and force control is developed.
Abstract: A framework for the analysis and control of manipulator systems with respect to the dynamic behavior of their end-effectors is developed. First, issues related to the description of end-effector tasks that involve constrained motion and active force control are discussed. The fundamentals of the operational space formulation are then presented, and the unified approach for motion and force control is developed. The extension of this formulation to redundant manipulator systems is also presented, constructing the end-effector equations of motion and describing their behavior with respect to joint forces. These results are used in the development of a new and systematic approach for dealing with the problems arising at kinematic singularities. At a singular configuration, the manipulator is treated as a mechanism that is redundant with respect to the motion of the end-effector in the subspace of operational space orthogonal to the singular direction.
2,849 citations
"Active Interaction Force Control fo..." refers background in this paper
...Methods for direct force control of fixed-base manipulators are well established [23], [24], typically switching controller modes when contact is detected....
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26 Jun 2006
TL;DR: A spatially adaptive multiscale algorithm whose time and space complexities are proportional to the size of the reconstructed model, and which reduces to a well conditioned sparse linear system.
Abstract: We show that surface reconstruction from oriented points can be cast as a spatial Poisson problem. This Poisson formulation considers all the points at once, without resorting to heuristic spatial partitioning or blending, and is therefore highly resilient to data noise. Unlike radial basis function schemes, our Poisson approach allows a hierarchy of locally supported basis functions, and therefore the solution reduces to a well conditioned sparse linear system. We describe a spatially adaptive multiscale algorithm whose time and space complexities are proportional to the size of the reconstructed model. Experimenting with publicly available scan data, we demonstrate reconstruction of surfaces with greater detail than previously achievable.
2,712 citations
"Active Interaction Force Control fo..." refers methods in this paper
...We use the TOF camera to obtain a point cloud of the surface to interact with, which is then converted to a triangular mesh with face and vertex normals by using Poisson surface reconstruction [32]....
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Book•
23 Feb 2004
TL;DR: In this article, the authors focus on the chloride and carbonation induced corrosion of steel in concrete and present transport mechanisms and electrochemical concepts for preventative measures, condition assessment and repair techniques.
Abstract: Reinforced concrete has been developed and applied extensively in the 20th century. It combines the good compressive strength of concrete with the high tensile strength of steel and has proven to be successful in terms of structural performance and durability. However, there are instances of premature failure of reinforced concrete and prestressed concrete components due to corrosion of the reinforcing steel with very high economic implications of such damage. This book focuses on the chloride and carbonation induced corrosion of steel in concrete, presenting transport mechanisms and electrochemical concepts. Other types of corrosion of steel and degradation of concrete are also treated. The main emphasis lies on design and execution aspects related to durability of new and existing structures. New methods and materials for preventative measures, condition assessment and repair techniques are discussed. This makes this book an invaluable reference for any engineer and materials scientist involved in research and practice of corrosion protection, rehabilitation and maintenance of reinforced concrete structures and components. Owners, designers and contractors will profit by this updated state of the art. © 2013 Wiley-VCH Verlag GmbH & Co. KGaA.
769 citations
01 Apr 2016
TL;DR: This work presents a method of jointly optimizing polynomial path segments in an unconstrained quadratic program that is numerically stable for high-order polynomials and large numbers of segments, and is easily formulated for efficient sparse computation.
Abstract: We explore the challenges of planning trajectories for quadrotors through cluttered indoor environments. We extend the existing work on polynomial trajectory generation by presenting a method of jointly optimizing polynomial path segments in an unconstrained quadratic program that is numerically stable for high-order polynomials and large numbers of segments, and is easily formulated for efficient sparse computation. We also present a technique for automatically selecting the amount of time allocated to each segment, and hence the quadrotor speeds along the path, as a function of a single parameter determining aggressiveness, subject to actuator constraints. The use of polynomial trajectories, coupled with the differentially flat representation of the quadrotor, eliminates the need for computationally intensive sampling and simulation in the high dimensional state space of the vehicle during motion planning. Our approach generates high-quality trajecrtories much faster than purely sampling-based optimal kinodynamic planning methods, but sacrifices the guarantee of asymptotic convergence to the global optimum that those methods provide. We demonstrate the performance of our algorithm by efficiently generating trajectories through challenging indoor spaces and successfully traversing them at speeds up to 8 m/s. A demonstration of our algorithm and flight performance is available at: http://groups.csail.mit.edu/rrg/quad_polynomial_trajectory_planning.
578 citations
"Active Interaction Force Control fo..." refers methods in this paper
...Recent research in fully actuated MAVs begins to reach this goal....
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...[17] K. Bodie, Z. Taylor, M. Kamel, and R. Siegwart, “Towards efficient full pose omnidirectionality with overactuated MAVs,” in Proc....
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...Several fully actuated MAVs have further performed contact inspection tasks of industrial structures [3], [21], but direct (closed-loop) force control has only been demonstrated very recently [22]....
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...Fully actuated MAVs are now entering the aerial robotics curriculum [14], with the ability to control force and torque in six-DOFs without compromising system stability....
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...I. INTRODUCTION THE demand for industrial contact inspection with aerialrobots has been growing rapidly in recent years, coinciding with the development of fully actuated micro aerial vehicles (MAVs) for aerial interaction [1]–[5]....
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