Cooperation of human and machines in assembly lines
TL;DR: In this article, a survey about forms of human-machine cooperation in assembly and available technologies that support the cooperation is presented, including organizational and economic aspects of cooperative assembly including efficient component supply and logistics.
About: This article is published in CIRP Annals.The article was published on 2009-01-01. It has received 667 citations till now. The article focuses on the topics: Flexibility (engineering) & Robot.
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TL;DR: An extensive review on human–robot collaboration in industrial environment is provided, with specific focus on issues related to physical and cognitive interaction, and the commercially available solutions are presented.
632 citations
TL;DR: A review of the state of the art research in the areas of assembly system design, planning and operations in the presence of product variety is presented in this article, where methods for assembly representation, sequence generation and assembly line balancing are reviewed and summarized.
479 citations
TL;DR: The main purpose of this paper is to review the state-of-the-art on intermediate human–robot interfaces (bi-directional), robot control modalities, system stability, benchmarking and relevant use cases, and to extend views on the required future developments in the realm of human-robot collaboration.
Abstract: Recent technological advances in hardware design of the robotic platforms enabled the implementation of various control modalities for improved interactions with humans and unstructured environments. An important application area for the integration of robots with such advanced interaction capabilities is human---robot collaboration. This aspect represents high socio-economic impacts and maintains the sense of purpose of the involved people, as the robots do not completely replace the humans from the work process. The research community's recent surge of interest in this area has been devoted to the implementation of various methodologies to achieve intuitive and seamless human---robot-environment interactions by incorporating the collaborative partners' superior capabilities, e.g. human's cognitive and robot's physical power generation capacity. In fact, the main purpose of this paper is to review the state-of-the-art on intermediate human---robot interfaces (bi-directional), robot control modalities, system stability, benchmarking and relevant use cases, and to extend views on the required future developments in the realm of human---robot collaboration.
452 citations
Cites background from "Cooperation of human and machines i..."
...…2009,Evrard et al., 2009], object placing [Tsumugiwa et al., 2002a,Gams et al., 2014], object swinging [Donner and Buss, 2016a,Palunko et al., 2014], posture assistance [Ikemoto et al., 2012, Peternel and Babič, 2013], and industrial complex assembly processes [Krüger et al., 2009] (see also Fig....
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...…of physical human-robot interaction (see [De Santis et al., 2008, Murphy, 2004, Alami et al., 2006]), is defined when human(s), robot(s) and the environment come to contact with each other and form a tightly coupled dynamical system to accomplish a task [Bauer et al., 2008, Krüger et al., 2009]....
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Abstract: Although the concept of industrial cobots dates back to 1999, most present day hybrid human-machine assembly systems are merely weight compensators. Here, we present results on the development of a collaborative human-robot manufacturing cell for homokinetic joint assembly. The robot alternates active and passive behaviours during assembly, to lighten the burden on the operator in the first case, and to comply to his/her needs in the latter. Our approach can successfully manage direct physical contact between robot and human, and between robot and environment. Furthermore, it can be applied to standard position (and not torque) controlled robots, common in the industry. The approach is validated in a series of assembly experiments. The human workload is reduced, diminishing the risk of strain injuries. Besides, a complete risk analysis indicates that the proposed setup is compatible with the safety standards, and could be certified.
449 citations
Cites background from "Cooperation of human and machines i..."
...• In contrast with most existing human-machine manufacturing applications, where collision avoidance is guaranteed by a minimum security distance [2], our framework successfully manages direct physical contact between robot and human, and between robot and environment....
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...A thorough state-of-theart on human-machine cooperation in manufacturing lines is provided in [2]....
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...Although the welding assistance application targeted by these works also falls in the shared workplace paradigm evoked in [2], it differs from the one treated here, since the robot motion is driven by the human worker....
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...But as in the previously cited survey [2], the paper exposes the absence of high level human-robot collaboration, apart from “Intelligent Lift Assistants”....
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TL;DR: The progress made in robotics to emulate humans’ ability to grab, hold, and manipulate objects is reviewed, with a focus on designing humanlike hands capable of using tools.
Abstract: BACKGROUND Humans have a fantastic ability to manipulate objects of various shapes, sizes, and materials and can control the objects’ position in confined spaces with the advanced dexterity capabilities of our hands. Building machines inspired by human hands, with the functionality to autonomously pick up and manipulate objects, has always been an essential component of robotics. The first robot manipulators date back to the 1960s and are some of the first robotic devices ever constructed. In these early days, robotic manipulation consisted of carefully prescribed movement sequences that a robot would execute with no ability to adapt to a changing environment. As time passed, robots gradually gained the ability to automatically generate movement sequences, drawing on artificial intelligence and automated reasoning. Robots would stack boxes according to size, weight, and so forth, extending beyond geometric reasoning. This task also required robots to handle errors and uncertainty in sensing at run time, given that the slightest imprecision in the position and orientation of stacked boxes might cause the entire tower to topple. Methods from control theory also became instrumental for enabling robots to comply with the environment’s natural uncertainty by empowering them to adapt exerted forces upon contact. The ability to stably vary forces upon contact expanded robots’ manipulation repertoire to more-complex tasks, such as inserting pegs in holes or hammering. However, none of these actions truly demonstrated fine or in-hand manipulation capabilities, and they were commonly performed using simple two-fingered grippers. To enable multipurpose fine manipulation, roboticists focused their efforts on designing humanlike hands capable of using tools. Wielding a tool in-hand became a problem of its own, and a variety of advanced algorithms were developed to facilitate stable holding of objects and provide optimality guarantees. Because optimality was difficult to achieve in a stochastic environment, from the 1990s onward researchers aimed to increase the robustness of object manipulation at all levels. These efforts initiated the design of sensors and hardware for improved control of hand–object contacts. Studies that followed were focused on robust perception for coping with object occlusion and noisy measurements, as well as on adaptive control approaches to infer an object’s physical properties, so as to handle objects whose properties are unknown or change as a result of manipulation. ADVANCES Roboticists are still working to develop robots capable of sorting and packaging objects, chopping vegetables, and folding clothes in unstructured and dynamic environments. Robots used for modern manufacturing have accomplished some of these tasks in structured settings that still require fences between the robots and human operators to ensure safety. Ideally, robots should be able to work side by side with humans, offering their strength to carry heavy loads while presenting no danger. Over the past decade, robots have gained new levels of dexterity. This enhancement is due to breakthroughs in mechanics with sensors for perceiving touch along a robot’s body and new mechanics for soft actuation to offer natural compliance. Most notably, this development leverages the immense progress in machine learning to encapsulate models of uncertainty and support further advances in adaptive and robust control. Learning to manipulate in real-world settings is costly in terms of both time and hardware. To further elaborate on data-driven methods but avoid generating examples with real, physical systems, many researchers use simulation environments. Still, grasping and dexterous manipulation require a level of reality that existing simulators are not yet able to deliver—for example, in the case of modeling contacts for soft and deformable objects. Two roads are hence pursued: The first draws inspiration from the way humans acquire interaction skills and prompts robots to learn skills from observing humans performing complex manipulation. This allows robots to acquire manipulation capabilities in only a few trials. However, generalizing the acquired knowledge to apply to actions that differ from those previously demonstrated remains difficult. The second road constructs databases of real object manipulation, with the goal to better inform the simulators and generate examples that are as realistic as possible. Yet achieving realistic simulation of friction, material deformation, and other physical properties may not be possible anytime soon, and real experimental evaluation will be unavoidable for learning to manipulate highly deformable objects. OUTLOOK Despite many years of software and hardware development, achieving dexterous manipulation capabilities in robots remains an open problem—albeit an interesting one, given that it necessitates improved understanding of human grasping and manipulation techniques. We build robots to automate tasks but also to provide tools for humans to easily perform repetitive and dangerous tasks while avoiding harm. Achieving robust and flexible collaboration between humans and robots is hence the next major challenge. Fences that currently separate humans from robots will gradually disappear, and robots will start manipulating objects jointly with humans. To achieve this objective, robots must become smooth and trustable partners that interpret humans’ intentions and respond accordingly. Furthermore, robots must acquire a better understanding of how humans interact and must attain real-time adaptation capabilities. There is also a need to develop robots that are safe by design, with an emphasis on soft and lightweight structures as well as control and planning methodologies based on multisensory feedback.
371 citations
Cites background from "Cooperation of human and machines i..."
...Manipulating objects in interaction and collaboration with humans: Reality and challenges Human–robot collaboration in manufacturing setups has been deemed crucial for the industry (85, 86)....
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References
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TL;DR: The first systematic experimental evaluation of possible injuries during robot‐human crashes using standardized testing facilities is presented, and a consistent approach for using these sensors for manipulation in human environments is described.
Abstract: – The paper seeks to present a new generation of torque‐controlled light‐weight robots (LWR) developed at the Institute of Robotics and Mechatronics of the German Aerospace Center., – An integrated mechatronic design approach for LWR is presented. Owing to the partially unknown properties of the environment, robustness of planning and control with respect to environmental variations is crucial. Robustness is achieved in this context through sensor redundancy and passivity‐based control. In the DLR root concept, joint torque sensing plays a central role., – In order to act in unstructured environments and interact with humans, the robots have design features and control/software functionalities which distinguish them from classical robots, such as: load‐to‐weight ratio of 1:1, torque sensing in the joints, active vibration damping, sensitive collision detection, compliant control on joint and Cartesian level., – The DLR robots are excellent research platforms for experimentation of advanced robotics algorithms. Space and medical robotics are further areas for which these robots were designed and hopefully will be applied within the next years. Potential industrial application fields are the fast automatic assembly as well as manufacturing activities done in cooperation with humans (industrial robot assistant). The described functionalities are of course highly relevant also for the potentially huge market of service robotics. The LWR technology was transferred to KUKA Roboter GmbH, which will bring the first arms on the market in the near future., – This paper introduces a new type of LWR with torque sensing in each joint and describes a consistent approach for using these sensors for manipulation in human environments. To the best of one's knowledge, the first systematic experimental evaluation of possible injuries during robot‐human crashes using standardized testing facilities is presented.
585 citations
Book•
01 Jan 1991
TL;DR: In this paper, the authors present a detailed analysis of high-speed automatic insertion and insertion of parts for high speed feeding and orienting of a Vibratory-Bowl feeder.
Abstract: INTRODUCTION Historical Development of the Assembly Process Choice of Assembly Method Social Effects of Automation References AUTOMATIC ASSEMBLY TRANSFER SYSTEMS Continuous Transfer Intermittent Transfer Indexing Mechanisms Operator-Paced Free-Transfer Machine References AUTOMATIC FEEDING AND ORIENTING - VIBRATORY FEEDERS Mechanics of Vibratory Conveying Effect of Frequency Effect of Track Acceleration Effect of Vibration Angle Effect of Track Angle Effect of Coefficient of Friction Estimating the Mean Conveying Velocity Load Sensitivity Solutions to Load Sensitivity Spiral Elevators Balanced Feeders Orientation of Parts Typical Orienting System Effect of Active Orienting Devices on Feed Rate Analysis of Orienting Systems Performance of an Orienting Device Natural Resting Aspects of Parts for Automatic Handling Analysis of a Typical Orienting System Out-of-Bowl Tooling References AUTOMATIC FEEDING AND ORIENTING - MECHANICAL FEEDERS Reciprocating-Tube Hopper Feeder Centerboard Hopper Feeder Reciprocating-Fork Hopper Feeder External Gate Hopper Feeder Rotary-Disk Feeder Centrifugal Hopper Feeder Stationary-Hook Hopper Feeder Bladed-Wheel Hopper Feeder Tumbling-Barrel Hopper Feeder Rotary-Centerboard Hopper Feeder Magnetic-Disk Feeder Elevating Hopper Feeder Magnetic Elevating Hopper Feeder Magazines References FEED TRACKS, ESCAPEMENTS, PARTS-PLACEMENT MECHANISMS, AND ROBOTS Gravity Feed Tracks Powered Feed Tracks Escapements Parts-Placing Mechanisms Assembly Robots References PERFORMANCE AND ECONOMICS OF ASSEMBLY SYSTEMS Indexing Machines Free-Transfer Machines Basis for Economic Comparisons of Automation Equipment Comparison of Indexing and Free-Transfer Machines Economics of Robot Assembly References DESIGN FOR MANUAL ASSEMBLY Introduction Where Design for Assembly Fits in the Design Process General Design Guidelines for Manual Assembly Development of a Systematic DFA Analysis Method DFA Index Classification System for Manual Handling Classification System for Manual Insertion and Fastening Effect of Part Symmetry on Handling Time Effect of Part Thickness and Size on Handling Time Effect of Weight on Handling Time Parts Requiring Two Hands for Manipulation Effects of Combinations of Factors Threaded Fasteners Effects of Holding Down Problems with Manual Assembly Time Standards Application of the DFA Method Further General Design Guidelines References PRODUCT DESIGN FOR HIGH-SPEED AUTOMATIC ASSEMBLY AND ROBOT ASSEMBLY Introduction Design of Parts for High-Speed Feeding and Orienting Example Additional Feeding Difficulties High-Speed Automatic Insertion Example Analysis of an Assembly General Rules for Product Design for Automation Design of Parts for Feeding and Orienting Summary of Design Rules for High-Speed Automatic Assembly Product Design for Robot Assembly References PRINTED-CIRCUIT-BOARD ASSEMBLY Introduction Terminology Assembly Process for PCBs SMD Technology Estimation of PCB Assembly Costs Worksheet and Database for PCB Assembly Cost Analysis PCB Assembly - Equations and Data for Total Operation Cost Glossary of Terms References FEASIBILITY STUDY FOR ASSEMBLY AUTOMATION Machine Design Factors to Reduce Machine Downtime Due to Defective Parts Feasibility Study References Problems Appendix A: Simple Method for the Determination of the Coefficient of Dynamic Friction The Method Analysis Precision of the Method Discussion Reference Appendix B: Out-of-Phase Vibratory Conveyors Out-of-Phase Conveying Practical Applications Reference Appendix C: Laboratory Experiments Performance of a Vibratory-Bowl Feeder Performance of a Horizontal-Delivery Gravity Feed Track Conclusions Appendix D: Feeding and Orienting Techniques for Small Parts Coding System Feeding and Orienting Techniques Orienting Devices for Vibratory-Bowl Feeders Nonvibratory Feeders Nomenclature Index
368 citations
14 May 1989
TL;DR: In this paper, the authors explore the sources of and solutions to robot contact instability associated with force feedback, and suggest improved force control involving both mechanical design and compensator design, with non-colocated actuators and sensors.
Abstract: The authors explore the sources of and solutions to robot contact instability associated with force feedback. The behavior of several linear robot models is analyzed in terms of the properties of their admittances. Using the novel technique of passive physical equivalents, an explanation for the often-observed instability of a force-controlled robot contacting a stiff surface is offered, and it is shown that a fundamental limit exists to the efficacy of any force feedback controller implemented on a robot with noncolocated actuators and sensors. Suggestions for improved force control involving both mechanical design and compensator design are also presented. >
301 citations
27 Jun 2007
TL;DR: In this paper, the authors evaluated the potential injury risk emanating from the manipulator and evaluated several injury mechanisms and so-called Severity Indices with respect to their adaptability to physical human-robotic interaction.
Abstract: The light-weight robots developed at the German Aerospace Center (DLR) are characterized by their low inertial properties, torque sensing in each joint and a load to weight ratio similar to humans. These properties qualify them for applications requiring high mobility and direct interaction with human users or uncertain environments. An essential requirement for such a robot is that it must under no circumstances pose a threat to the human operator. To actually quantify the potential injury risk emanating from the manipulator, impact test were carried out using standard automobile crash-test facilities at the German Automobile Club ADAC. In our evaluation we focused on unexpected rigid frontal impacts, i.e. injuries caused by sharp edges are excluded. Several injury mechanisms and so called Severity Indices are evaluated and discussed with respect to their adaptability to physical human-robotic interaction.
254 citations
01 Jan 1996
TL;DR: In this article, the authors focus on the simplest possible cobot which has only a single joint (a steerable wheel) and two control modes of this "unicycle cobot" are developed in detail, termed virtual caster and virtual wall control.
Abstract: A “cobot” is a robotic device which manipulates objects in collaboration with a human operator. A cobot provides assistance to the human operator by setting up virtual surfaces which can be used to constrain and guide motion. While conventional servoactuated haptic displays may be used in this way also, an important distinction is that, while haptic displays are active devices which can supply energy to the human operator, cobots are intrinsically passive. This is because cobots do not use servos to implement constraint, but instead employ “steerable” nonholonomic joints. As a consequence of their passivity, cobots are potentially wellsuited to safety-critical tasks (e.g. surgery) or those which involve large interaction forces (e.g. automobile assembly). This paper focuses on the simplest possible cobot, which has only a single joint (a steerable wheel). Two control modes of this “unicycle cobot”, termed “virtual caster” and “virtual wall” control, are developed in detail. Experimental results are also presented.
232 citations