Aerial manipulation aims at combining the versatility and the agility of some aerial platforms with the manipulation capabilities of robotic arms. This letter tries to collect the results reached by the research community so far within the field of aerial manipulation, especially from the technological and control point of view. A brief literature review of general aerial robotics and space manipulation is carried out as well.

/pdf/aerial-manipulation-a-literature-review-2gq2uh3t8a.pdf

Aerial Manipulation: A Literature Review

For agricultural applications, regularized smart-farming solutions are being considered, including the use of unmanned aerial vehicles (UAVs). The UAVs combine information and communication technologies, robots, artificial intelligence, big data, and the Internet of Things. The agricultural UAVs are highly capable, and their use has expanded across all areas of agriculture, including pesticide and fertilizer spraying, seed sowing, and growth assessment and mapping. Accordingly, the market for agricultural UAVs is expected to continue growing with the related technologies. In this study, we consider the latest trends and applications of leading technologies related to agricultural UAVs, control technologies, equipment, and development. We discuss the use of UAVs in real agricultural environments. Furthermore, the future development of the agricultural UAVs and their challenges are presented.

/pdf/unmanned-aerial-vehicles-in-agriculture-a-review-of-1ermmnz504.pdf

Unmanned Aerial Vehicles in Agriculture: A Review of Perspective of Platform, Control, and Applications

A survey on position-based routing protocols for Flying Ad hoc Networks (FANETs)

This paper describes a general passivity-based framework for the control of flexible joint robots. Recent results on torque, position, as well as impedance control of flexible joint robots are summarized, and the relations between the individual contributions are highlighted. It is shown that an inner torque feedback loop can be incorporated into a passivity-based analysis by interpreting torque feedback in terms of shaping of the motor inertia. This result, which implicitly was already included in earlier work on torque and position control, can also be used for the design of impedance controllers. For impedance control, furthermore, potential energy shaping is of special interest. It is shown how, based only on the motor angles, a potential function can be designed which simultaneously incorporates gravity compensation and a desired Cartesian stiffness relation for the link angles. All the presented controllers were experimentally evaluated on DLR lightweight robots and their performance and robustness shown with respect to uncertain model parameters. Experimental results with position controllers as well as an impact experiment are presented briefly, and an overview of several applications is given in which the controllers have been applied.

A Unified Passivity Based Control Framework for Position, Torque and Impedance Control of Flexible Joint Robots.

This article summarizes new aerial robotic manipulation technologies and methods-aerial robotic manipulators with dual arms and multidirectional thrusters-developed in the AEROARMS project for outdoor industrial inspection and maintenance (IaM).

/pdf/the-aeroarms-project-aerial-robots-with-advanced-46d7z50yuh.pdf

The AEROARMS Project: Aerial Robots with Advanced Manipulation Capabilities for Inspection and Maintenance

This paper presents a low weight (1.3 kg), human size dual arm system with compliant joints designed for aerial manipulation with a multirotor platform. Each arm provides four degrees of freedom (DOF) for end effector positioning in a kinematic configuration close to the human arm: shoulder pitch, roll and yaw, and elbow pitch. The aluminum frame structure of the arms has been designed with a double purpose: protecting the servo actuators against direct impacts and overloads, and allowing the integration of a compliant transmission mechanism with deflection measurement between the servo shaft and the output link Mechanical joint compliance increases safety in the physical interactions with the environment, removing also joint overloads typical in closed kinematic chain configurations. The dual arm system has been integrated in a hexarotor platform with a visual servoing system for object grasping, evaluating its performance first in a fixed base test bench and later in outdoor flight tests.

Anthropomorphic, compliant and lightweight dual arm system for aerial manipulation

This paper presents an anthropomorphic, compliant and lightweight dual arm manipulator designed and developed for aerial manipulation applications with multi-rotor platforms. Each arm provides four degrees of freedom in a human-like kinematic configuration for end effector positioning: shoulder pitch, roll and yaw, and elbow pitch. The dual arm, weighting 1.3 kg in total, employs smart servo actuators and a customized and carefully designed aluminum frame structure manufactured by laser cut. The proposed design reduces the manufacturing cost as no computer numerical control machined part is used. Mechanical joint compliance is provided in all the joints, introducing a compact spring-lever transmission mechanism between the servo shaft and the links, integrating a potentiometer for measuring the deflection of the joints. The servo actuators are partially or fully isolated against impacts and overloads thanks to the flange bearings attached to the frame structure that support the rotation of the links and the deflection of the joints. This simple mechanism increases the robustness of the arms and safety in the physical interactions between the aerial robot and the environment. The developed manipulator has been validated through different experiments in fixed base test-bench and in outdoor flight tests.

Design of an Anthropomorphic, Compliant, and Lightweight Dual Arm for Aerial Manipulation

This paper presents the design of a dual-arm aerial manipulator consisting of a multi-rotor platform with an ultra-lightweight (1.8 Kg) human-size dual arm prototype and its control system. Each arm provides three degrees of freedom (DOF) for positioning the end- effector, and two DOF for orientation. As most model-based controllers assume that joint torque feedback is available, a torque estimator for the arms is developed. Note that low cost servos used for building low weight manipulators do not provide any torque feedback or control capability. The redundant DOFs in the dual arm prototype are exploited for generating coordinated motions during contact-less phases in such a way that reaction torques can be partially canceled. Preliminary flight tests have been conducted in outdoors, evaluating the torque compensation capability in test-bench. The influence of the reaction torques exerted by the arms over the UAV controller is also analyzed in simulation.

/pdf/lightweight-and-human-size-dual-arm-aerial-manipulator-a2sm1ykuvj.pdf

Lightweight and human-size dual arm aerial manipulator

The proximity between the multirotor blades and the environmental obstacles restricts the application of aerial manipulators in inspection tasks due to the risk of impacts, the limitation in the reach of the arm, and the physical interactions. This paper presents a long reach aerial manipulator consisting of a hexarotor platform equipped with a 2-DOF compliant joint arm attached at the tip of a one-meter-length link in passive pendulum configuration. The arm integrates magnetic encoders for force/torque estimation-control based on joint deflection, a range sensor in the forearm link for measuring the distance to the contact point, and a camera for visual inspection. A 2-DOF wearable exoskeleton interface has been developed, allowing the teleoperation of the arm with visual feedback in a more intuitive way. The paper also covers the kinematics and dynamics of the aerial manipulator, including the dynamics of the flexible long reach link. The developed system has been evaluated in test-bench and in outdoor flight tests.

Lightweight and Compliant Long Reach Aerial Manipulator for Inspection Operations

This letter is devoted to benchmarks for aerial manipulation robots (drones equipped with robotic arms), which are demonstrating their potential to conduct tasks involving physical interactions with objects or the environment in high altitude workspaces, being a cost effective solution for example in inspection and maintenance operations. Thus, the letter deals with different methods and criteria to evaluate and compare the performance of aerial manipulators. This is not an easy task, taking into account the wide variety of designs, morphologies and implementations that can be found in recent works. In order to cope with this problem, this letter analyzes the capabilities and functionalities of several aerial manipulation prototypes (aerial platform + manipulator), identifying a set of relevant metrics and criteria. A number of benchmarks are defined to evaluate the performance of the aerial manipulator in terms of accuracy, execution time, manipulation capability, or impact response. Experimental results carried out with a compliant joint aerial manipulator in test-bench and in indoor-outdoor testbeds illustrate some of the benchmarks.

/pdf/benchmarks-for-aerial-manipulation-cwo8e7heb7.pdf

Alejandro Suarez

Papers

Anthropomorphic, compliant and lightweight dual arm system for aerial manipulation

Design of an Anthropomorphic, Compliant, and Lightweight Dual Arm for Aerial Manipulation

Lightweight and human-size dual arm aerial manipulator

Lightweight and Compliant Long Reach Aerial Manipulator for Inspection Operations

Benchmarks for Aerial Manipulation