1,085 research outputs found
UAV/UGV Autonomous Cooperation: UAV Assists UGV to Climb a Cliff by Attaching a Tether
This paper proposes a novel cooperative system for an Unmanned Aerial Vehicle
(UAV) and an Unmanned Ground Vehicle (UGV) which utilizes the UAV not only as a
flying sensor but also as a tether attachment device. Two robots are connected
with a tether, allowing the UAV to anchor the tether to a structure located at
the top of a steep terrain, impossible to reach for UGVs. Thus, enhancing the
poor traversability of the UGV by not only providing a wider range of scanning
and mapping from the air, but also by allowing the UGV to climb steep terrains
with the winding of the tether. In addition, we present an autonomous framework
for the collaborative navigation and tether attachment in an unknown
environment. The UAV employs visual inertial navigation with 3D voxel mapping
and obstacle avoidance planning. The UGV makes use of the voxel map and
generates an elevation map to execute path planning based on a traversability
analysis. Furthermore, we compared the pros and cons of possible methods for
the tether anchoring from multiple points of view. To increase the probability
of successful anchoring, we evaluated the anchoring strategy with an
experiment. Finally, the feasibility and capability of our proposed system were
demonstrated by an autonomous mission experiment in the field with an obstacle
and a cliff.Comment: 7 pages, 8 figures, accepted to 2019 International Conference on
Robotics & Automation. Video: https://youtu.be/UzTT8Ckjz1
Human Motion Trajectory Prediction: A Survey
With growing numbers of intelligent autonomous systems in human environments,
the ability of such systems to perceive, understand and anticipate human
behavior becomes increasingly important. Specifically, predicting future
positions of dynamic agents and planning considering such predictions are key
tasks for self-driving vehicles, service robots and advanced surveillance
systems. This paper provides a survey of human motion trajectory prediction. We
review, analyze and structure a large selection of work from different
communities and propose a taxonomy that categorizes existing methods based on
the motion modeling approach and level of contextual information used. We
provide an overview of the existing datasets and performance metrics. We
discuss limitations of the state of the art and outline directions for further
research.Comment: Submitted to the International Journal of Robotics Research (IJRR),
37 page
Workflow-Net Based Cooperative Multi-Agent Systems
Workflow-nets are mathematical frameworks that are used to formally describe, model and implement workflows. First, we propose critical section workflow nets (abbreviated WFCSnet). This framework allows feedbacks in workflow systems while ensuring the soundness of the workflow. Feedback is generally not recommended in workflow systems as they threaten the soundness of the system. The proposed WFCSnet allows safe feedback and limits the maximum number of activities per workflow as required. A theorem for soundness of WFCSnet is presented. Serializability, Separability, Quasi-liveness and CS-Properties of WFCSnet are examined and some theorems and lemmas are proposed to mathematically formalize them. In this thesis, we define some formal constructs that we then build upon. We define the smallest formal sub-workflow that we call a unit. We propose some mathematical characteristics for the unit and show how it can be used. We study similarities between units and whether two units can be used interchangeably or not. We then use composites out of simple units to build more complex constructs and we study their properties. We define the concept of cooperation and propose a mathematical definition of the concept. We discuss the concept of task coverage and how it affects cooperation. We claim that task coverage is necessary for any task to be achieved and therefore, a necessity for cooperation. We use mathematical methods to determine the task coverage and the candidate cooperative partners based on their capabilities that can contribute to the desired task. Workflow-net based cooperative behaviour among agents is proposed. First, we propose a cooperative algebra, which takes the desired objective of cooperation as a plan and then transforms this plan into a workflow-net structure describing dependencies and concurrency among sub-workflow elements constituting the overall plan. Our proposed cooperative algebra converts the plan into a set of matrices that model the cooperative workflow among agents. We then propose a cooperative framework with operators that assign tasks to agents based on their capabilities to achieve the required task
Automated sequence and motion planning for robotic spatial extrusion of 3D trusses
While robotic spatial extrusion has demonstrated a new and efficient means to
fabricate 3D truss structures in architectural scale, a major challenge remains
in automatically planning extrusion sequence and robotic motion for trusses
with unconstrained topologies. This paper presents the first attempt in the
field to rigorously formulate the extrusion sequence and motion planning (SAMP)
problem, using a CSP encoding. Furthermore, this research proposes a new
hierarchical planning framework to solve the extrusion SAMP problems that
usually have a long planning horizon and 3D configuration complexity. By
decoupling sequence and motion planning, the planning framework is able to
efficiently solve the extrusion sequence, end-effector poses, joint
configurations, and transition trajectories for spatial trusses with
nonstandard topologies. This paper also presents the first detailed computation
data to reveal the runtime bottleneck on solving SAMP problems, which provides
insight and comparing baseline for future algorithmic development. Together
with the algorithmic results, this paper also presents an open-source and
modularized software implementation called Choreo that is machine-agnostic. To
demonstrate the power of this algorithmic framework, three case studies,
including real fabrication and simulation results, are presented.Comment: 24 pages, 16 figure
Robotic Automation of Turning Machines in Fenceless Production: A Planning Toolset for Economic-based Selection Optimization between Collaborative and Classical Industrial Robots
Ursprünglich wurden Industrieroboter hauptsächlich hinter Schutzzäunen betrieben, um den Sicherheitsanforderungen gerecht zu werden. Mit der Flexibilisierung der Produktion wurden diese scharfen Trennbereiche zunehmend aufgeweicht und externe Sicherheitstechnik, wie Abstandssensoren, genutzt, um Industrieroboter schutzzaunlos zu betreiben. Ausgehend vom Gedanken dieser Koexistenz bzw. Kooperation wurde die Sicherheitssensorik in den Roboter integriert, um eine wirkliche Kollaboration zu ermöglichen. Diese sogenannten kollaborierenden Roboter, oder Cobots, eröffnen neue Applikationsfelder und füllen somit die bestehenden Automatisierungslücken. Doch welche Automatisierungsvariante ist aus wirtschaftlichen Gesichtspunkten die geeignetste? Bisherige Forschung untersucht zum Großteil isoliert eine der beiden Technologien, ohne
dabei einen Systemvergleich hinsichtlich technologischer Spezifika und Wirtschaftlichkeit anzustellen. Daher widmet sich diese Dissertation einer Methodik zum wirtschaftlichen Vergleich von kollaborierenden Robotern und Industrierobotern in schutzzaunlosen Maschinenbeladungssystemen. Besonderer Fokus liegt dabei auf dem Herausarbeiten der technischen Faktoren, die die Wirtschaftlichkeit maßgeblich beeinflussen, um ein Systemverständnis der wirtschaftlichen Struktur beider Robotertechnologievarianten zu erhalten. Zur Untersuchung werden die Inhalte eines solchen Planungsvorhabens beschrieben, kategorisiert, systematisiert und modularisiert. Auf wirtschaftlicher Seite wird ein geeignetes Optimierungsmodell vorgestellt, während auf technischer Seite vor allem die Machbarkeit hinsichtlich Greifbarkeit, Layoutplanung, Robotergeschwindigkeiten und Zykluszeitbestimmung untersucht wird. Mit deduktiven, simulativen, empirischen und statistischen Methoden wird das Systemverhalten für die einzelnen Planungsinhalte analysiert, um die Gesamtwirtschaftlichkeit mit einem Minimum an Investment,- Produktions,- und Zykluszeitinformationen a priori vorhersagen zu können. Es wird gezeigt, dass durch einen Reverse Engineering Ansatz die notwendigen Planungsdaten, im Sinne von Layoutkomposition, Robotergeschwindigkeiten und Taktzeiten, mithilfe von Frontloading zu Planungsbeginn zur Verfügung gestellt werden können. Dabei dient der Kapitalwert als wirtschaftliche Bewertungsgrundlage, dessen Abhängigkeit vom Mensch-Roboter-Interaktionsgrad in einem Vorteilhaftigkeitsdiagramm für die einzelnen Technologiealternativen dargestellt werden kann. Wirtschaftlich fundierte Entscheidungen können somit auf quantitiativer Basis getroffen werden.:1. Introduction 25
1.1 Research Domain 25
1.2 Research Niche 26
1.3 Research Structure 28
2. State of the Art and Research 31
2.1 Turning Machines and Machine Tending 31
2.1.1 Tooling Machine Market Trends and Machine Tending Systems 31
2.1.2 Workpiece System 34
2.1.3 Machine System 36
2.1.4 Logistics System 39
2.1.5 Handling System 41
2.2 Robotics 43
2.2.1 Robot Installation Development and Application Fields 43
2.2.2 Fenceless Industrial and Collaborative Robots 48
2.2.3 Robot Grippers 55
2.3 Planning and Evaluation Methods 56
2.3.1 Planning of General and Manual Workstations 56
2.3.2 Cell Planning for Fully Automated and Hybrid Robot Systems 59
2.3.3 Robot Safety Planning 61
2.3.4 Economic Evaluation Methods 70
2.4 Synthesis - State of the Art and Research 71
3. Solution Approach 77
3.1 Need for Research and General Solution Approach 77
3.2 Use Case Delineation and Planning Focus 80
3.3 Economic Module – Solution Approach 86
3.4 Gripper Feasibility Module – Solution Approach 89
3.5 Rough Layout Discretization Model – Solution Approach 94
3.6 Cycle Time Estimation Module – Solution Approach 97
3.7 Collaborative Speed Estimation Module – Solution Approach 103
3.7.1 General Approach 103
3.7.2 Case 1: Quasi-static Contact with Hand 107
3.7.3 Case 2: Transient Contact with Hand 109
3.7.4 Case 3: Transient Contact with Shoulder 111
3.8 Synthesis – Solution Approach 114
4. Module Development 117
4.1 Economic Module – Module Development 117
4.1.1 General Approach 117
4.1.2 Calculation Scheme for Manual Operation 117
4.1.3 Calculation Scheme for Collaborative Robots 118
4.1.4 Calculation Scheme for Industrial Robots 120
4.2 Gripper Feasibility Module – Module Development 121
4.3 Rough Layout Discretization Module – Module Development 122
4.3.1 General Approach 122
4.3.2 Two-Dimensional Layout Pattern 123
4.3.3 Three-Dimensional Layout Pattern 125
4.4 Cycle Time Estimation Module – Module Development 126
4.4.1 General Approach 126
4.4.2 Reachability Study 127
4.4.3 Simulation Results 128
4.5 Collaborative Speed Estimation Module – Module Development 135
4.5.1 General Approach 135
4.5.2 Case 1: Quasi-static Contact with Hand 135
4.5.3 Case 2: Transient Contact with Hand 143
4.5.4 Case 3: Transient Contact with Shoulder 145
4.6 Synthesis – Module Development 149
5. Practical Verification 155
5.1 Use Case Overview 155
5.2 Gripper Feasibility 155
5.3 Layout Discretization 156
5.4 Collaborative Speed Estimation 157
5.5 Cycle Time Estimation 158
5.6 Economic Evaluation 160
5.7 Synthesis – Practical Verification 161
6. Results and Conclusions 165
6.1 Scientific Findings and Results 165
6.2 Critical Appraisal and Outlook 173Initially, industrial robots were mainly operated behind safety fences to account for the safety requirements. With production flexibilization, these sharp separation areas have been increasingly softened by utilizing external safety devices, such as distance sensors, to operate industrial robots fenceless. Based on this idea of coexistence or cooperation, safety technology has been integrated into the robot to enable true collaboration. These collaborative robots, or cobots, open up new application fields and fill the existing automation gap. But which automation variant is most suitable from an economic perspective? Present research dealt primarily isolated with one technology without comparing these systems regarding technological and economic specifics. Therefore, this doctoral thesis pursues a methodology to economically compare collaborative and industrial
robots in fenceless machine tending systems. A particular focus lies on distilling the technical factors that mainly influence the profitability to receive a system understanding of the economic structure of both robot technology variants. For examination, the contents of such a planning scheme are described, categorized, systematized, and modularized. A suitable optimization model is presented on the economic side, while the feasibility regarding gripping, layout planning, robot velocities, and cycle time determination is assessed on the technical side. With deductive, simulative, empirical, and statistical methods, the system behavior of the single planning entities is analyzed to predict the overall profitability a priori with a minimum of investment,- production,- and cycle time information. It is demonstrated that the necessary planning data, in terms of layout composition, robot velocities, and cycle times, can be frontloaded to the project’s beginning with a reverse engineering approach. The net present value serves as the target figure, whose dependency on the human-robot interaction grade can be illustrated in an advantageousness diagram for the individual technical alternatives. Consequently, sound economic decisions can be made on a quantitative basis.:1. Introduction 25
1.1 Research Domain 25
1.2 Research Niche 26
1.3 Research Structure 28
2. State of the Art and Research 31
2.1 Turning Machines and Machine Tending 31
2.1.1 Tooling Machine Market Trends and Machine Tending Systems 31
2.1.2 Workpiece System 34
2.1.3 Machine System 36
2.1.4 Logistics System 39
2.1.5 Handling System 41
2.2 Robotics 43
2.2.1 Robot Installation Development and Application Fields 43
2.2.2 Fenceless Industrial and Collaborative Robots 48
2.2.3 Robot Grippers 55
2.3 Planning and Evaluation Methods 56
2.3.1 Planning of General and Manual Workstations 56
2.3.2 Cell Planning for Fully Automated and Hybrid Robot Systems 59
2.3.3 Robot Safety Planning 61
2.3.4 Economic Evaluation Methods 70
2.4 Synthesis - State of the Art and Research 71
3. Solution Approach 77
3.1 Need for Research and General Solution Approach 77
3.2 Use Case Delineation and Planning Focus 80
3.3 Economic Module – Solution Approach 86
3.4 Gripper Feasibility Module – Solution Approach 89
3.5 Rough Layout Discretization Model – Solution Approach 94
3.6 Cycle Time Estimation Module – Solution Approach 97
3.7 Collaborative Speed Estimation Module – Solution Approach 103
3.7.1 General Approach 103
3.7.2 Case 1: Quasi-static Contact with Hand 107
3.7.3 Case 2: Transient Contact with Hand 109
3.7.4 Case 3: Transient Contact with Shoulder 111
3.8 Synthesis – Solution Approach 114
4. Module Development 117
4.1 Economic Module – Module Development 117
4.1.1 General Approach 117
4.1.2 Calculation Scheme for Manual Operation 117
4.1.3 Calculation Scheme for Collaborative Robots 118
4.1.4 Calculation Scheme for Industrial Robots 120
4.2 Gripper Feasibility Module – Module Development 121
4.3 Rough Layout Discretization Module – Module Development 122
4.3.1 General Approach 122
4.3.2 Two-Dimensional Layout Pattern 123
4.3.3 Three-Dimensional Layout Pattern 125
4.4 Cycle Time Estimation Module – Module Development 126
4.4.1 General Approach 126
4.4.2 Reachability Study 127
4.4.3 Simulation Results 128
4.5 Collaborative Speed Estimation Module – Module Development 135
4.5.1 General Approach 135
4.5.2 Case 1: Quasi-static Contact with Hand 135
4.5.3 Case 2: Transient Contact with Hand 143
4.5.4 Case 3: Transient Contact with Shoulder 145
4.6 Synthesis – Module Development 149
5. Practical Verification 155
5.1 Use Case Overview 155
5.2 Gripper Feasibility 155
5.3 Layout Discretization 156
5.4 Collaborative Speed Estimation 157
5.5 Cycle Time Estimation 158
5.6 Economic Evaluation 160
5.7 Synthesis – Practical Verification 161
6. Results and Conclusions 165
6.1 Scientific Findings and Results 165
6.2 Critical Appraisal and Outlook 17
Robotic Wireless Sensor Networks
In this chapter, we present a literature survey of an emerging, cutting-edge,
and multi-disciplinary field of research at the intersection of Robotics and
Wireless Sensor Networks (WSN) which we refer to as Robotic Wireless Sensor
Networks (RWSN). We define a RWSN as an autonomous networked multi-robot system
that aims to achieve certain sensing goals while meeting and maintaining
certain communication performance requirements, through cooperative control,
learning and adaptation. While both of the component areas, i.e., Robotics and
WSN, are very well-known and well-explored, there exist a whole set of new
opportunities and research directions at the intersection of these two fields
which are relatively or even completely unexplored. One such example would be
the use of a set of robotic routers to set up a temporary communication path
between a sender and a receiver that uses the controlled mobility to the
advantage of packet routing. We find that there exist only a limited number of
articles to be directly categorized as RWSN related works whereas there exist a
range of articles in the robotics and the WSN literature that are also relevant
to this new field of research. To connect the dots, we first identify the core
problems and research trends related to RWSN such as connectivity,
localization, routing, and robust flow of information. Next, we classify the
existing research on RWSN as well as the relevant state-of-the-arts from
robotics and WSN community according to the problems and trends identified in
the first step. Lastly, we analyze what is missing in the existing literature,
and identify topics that require more research attention in the future
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