A Stable and Transparent Framework for Adaptive Shared Control of Robots

In mixed-initiative haptic shared control of robots, humans and automatic control system work in parallel. The commands to the robot are a weighted sum of forces from these two agents. This thesis develops control methods to improve the force feedback performance for mixed-initiative shared teleoperation and to adapt the control authority between human and automatic control system in a stable manner even in the presence of communication delays. All methods are validated on real robotic hardware

Time Domain Control for Passive Variable Motion and Force Scaling in Delayed Teleoperation

Scaling of motion and forces has always been of high relevance in teleoperation setups since it allows the adaptation of workspaces of master and slave devices or to increase precision. Teleoperation setups are often affected by a delay in the communication channel. Most state of the art control approaches that guarantee stability despite delay are based on the passivity criterion which is highly restrictive to standard scaling methods. This paper proposes different time domain control concepts that regulate the motion or force scaling based on the energy flow in delayed teleoperation systems. The approach focuses on setups with motion down-scaling and is applicable to variable motion and impedance scaling. The scaling control is integrated in a state of the art time delay control concept and its performance is analyzed in experiments

Passive Compliance Control of Aerial Manipulators

This paper presents a passive compliance control for aerial manipulators to achieve stable environmental interactions. The main challenge is the absence of actuation along body-planar directions of the aerial vehicle which might be required during the interaction to preserve passivity. The controller proposed in this paper guarantees passivity of the manipulator through a proper choice of end-effector coordinates, and that of vehicle fuselage is guaranteed by exploiting time domain passivity technique. Simulation studies validate the proposed approach.Comment: IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) 201

A Compliant Partitioned Shared Control Strategy for an Orbital Robot

In this letter, a novel partitioned shared controller is proposed, which exploits a fully-actuated orbital robot to perform a primary end-effector task involving environmental interactions. This task is remotely performed using a bilateral teleoperation controller, while a secondary task is automatically controlled in situ for operational safety in a partitioned manner. In particular, the proposed method is derived as a modified 4-Channel teleoperation architecture. The orbital robot’s momentum and shape (joints) dynamics are exploited to benefit the controller design. Asymptotic stability and finite-gain L2-stability are proved in the absence and presence of external interactions, respectively. Furthermore, the proposed method is validated experimentally on a hardware-in-the-loop facility

KONTUR-2: Force-feedback Teleoperation from the International Space Station

This paper presents a new robot controller for space telerobotics missions specially designed to meet the requirements of KONTUR-2, a German & Russian telerobotics mission that addressed scientific and technological questions for future planetary explorations. In KONTUR-2, Earth and ISS have been used as a test-bed to evaluate and demonstrate a new technology for real-time telemanipulation from space. During the August 2015' experiments campaign, a cosmonaut teleoperated a robot manipulator located in Germany, using a force-feedback joystick from the Russian segment of the International Space Station (ISS). The focus of the paper is on the design and performance of the bilateral controller between ISS joystick and Earth robot. The controller is based on a 4-Channels architecture in which stability is guaranteed through passivity and the Time Delay Power Network (TDPN) concept. We show how the proposed approach successfully fulfills mission requirements, specially those related to system operation through space links and internet channels, involving time delays and data losses of different nature

An Energy-Based Approach for the Multi-Rate Control of a Manipulator on an Actuated Base

In this paper we address the problem of controlling a robotic system mounted on an actuated floating base for space applications. In particular, we investigate the stability issues due to the low rate of the base control unit. We propose a passivity-based stabilizing controller based on the time domain passivity approach. The controller uses a variable damper regulated by a designed energy observer. The effectiveness of the proposed strategy is validated on a base-manipulator multibody simulation

Virtual Reality via Object Pose Estimation and Active Learning:Realizing Telepresence Robots with Aerial Manipulation Capabilities

This paper presents a novel telepresence system for advancing aerial manipulation indynamic and unstructured environments. The proposed system not only features a haptic device, but also a virtual reality (VR) interface that provides real-time 3D displays of the robot’s workspace as well as a haptic guidance to its remotely located operator. To realize this, multiple sensors, namely, a LiDAR, cameras, and IMUs are utilized. For processing of the acquired sensory data, pose estimation pipelines are devised for industrial objects of both known and unknown geometries. We further propose an active learning pipeline in order to increase the sample efficiency of a pipeline component that relies on a Deep Neural Network (DNN) based object detector. All these algorithms jointly address various challenges encountered during the execution of perception tasks in industrial scenarios. In the experiments, exhaustive ablation studies are provided to validate the proposed pipelines. Method-ologically, these results commonly suggest how an awareness of the algorithms’ own failures and uncertainty (“introspection”) can be used to tackle the encountered problems. Moreover, outdoor experiments are conducted to evaluate the effectiveness of the overall system in enhancing aerial manipulation capabilities. In particular, with flight campaigns over days and nights, from spring to winter, and with different users and locations, we demonstrate over 70 robust executions of pick-and-place, force application and peg-in-hole tasks with the DLR cable-Suspended Aerial Manipulator (SAM). As a result, we show the viability of the proposed system in future industrial applications

Hierarchical Control of Redundant Aerial Manipulators with Enhanced Field of View

Providing the operator with a good view of the remote site is of paramount importance in aerial telemanipulation. In light of that, this paper proposes the application of a hierarchical control framework in order to tackle the problem of adjusting the field of view of an on-board camera as a secondary task. The proposed approach ensures that the flying base, and consequently the camera, can be steered in order to provide a distant operator with a desired field of view without disturbing the end-effector pose. The approach is focused on aerial manipulators with torque-controlled arms, like the DLR Suspended Aerial Manipulator (SAM), while allowing the base to be directly torque-controlled or, alternatively, through an inner-loop velocity controller. Quantitative, qualitative, and real-scenario experimental validation is carried out using the SAM and confirms the need for such an approach and its efficacy in achieving decoupled field-of-view control

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

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 (I&M). Our report deals with the control systems, including the control of the interaction forces and the compliance the teleoperation, which uses passivity to tackle the tradeoff between stability and performance the perception methods for localization, mapping, and inspection the planning methods, including a new control-aware approach for aerial manipulation. Finally, we describe a novel industrial platform with multidirectional thrusters and a new arm design to increase the robustness in industrial contact inspections. In addition, the lessons learned in applying the platform to outdoor aerial manipulation for I&M are pointed out