Difficulty and complexity definitions for assembly task allocation and assignment in human–robot collaborations: A review

This paper presents a literature review on the different aspects of task allocation and assignment problems in human–robot collaboration (HRC) tasks in industrial assembly environments. In future advanced industrial environments, robots and humans are expected to share the same workspace and collaborate to efficiently achieve shared goals. Difficulty- and complexity-aware HRC assembly is necessary for human-centric manufacturing, which is a goal of Industry 5.0. Therefore, the objective of this study is to clarify the definitions of difficulty and complexity used to encourage effective collaboration between humans and robots to leverage the adaptability of humans and the autonomy of robots. To achieve this goal, a systematic review of the following relevant databases for computer science was performed: IEEE Xplore, ScienceDirect, SpringerLink, ACM Digital Library, and ASME Digital Collection. The results extracted from 74 peer-reviewed research articles published until July 2022 were summarized and categorized into four taxonomies for 145 difficulty and complexity definitions from the perspectives of (1) definition-use objectives, (2) evaluation objectives, (3) evaluation factors, and (4) evaluation variables. Next, existing definitions were primarily classified according to the following two criteria to identify potential future studies on the formulation of new definitions for human-centric manufacturing: (1) agent specificity and (2) common aspects in manual and robotic assemblies.     

Robots assembling machines: learning from the World Robot Summit 2018 Assembly Challenge

ABSTRACT

The Industrial Assembly Challenge at the World Robot Summit was held in 2018 to showcase the state-of-the-art of autonomous manufacturing systems. The challenge included various tasks, such as bin picking, kitting, and assembly of standard industrial parts into 2D and 3D assemblies. Some of the tasks were only revealed at the competition itself, representing the challenge of ‘level 5’ automation, i.e. programming and setting up an autonomous assembly system in less than one day. We conducted a survey among the teams that participated in the challenge and investigated aspects such as team composition, development costs, system setups as well as the teams' strategies and approaches. An analysis of the survey results reveals that the competitors have been in two camps: those constructing conventional robotic work cells with off-the-shelf tools, and teams who mostly relied on custom-made end effectors and novel software approaches in combination with collaborative robots. While both camps performed reasonably well, the winning team chose a middle ground in between, combining the efficiency of established play-back programming with the autonomy gained by CAD-based object detection and force control for assembly operations.     

Analysis of autonomous cooperative assembly using coordination schemes by heterogeneous robots using a control basis approach

Robotic technology is quickly evolving allowing robots to perform more complex tasks in less structured environments with more flexibility and autonomy. Heterogeneous multi-robot teams are more common as the specialized abilities of individual robots are used in concert to achieve tasks more effectively and efficiently. An important area of research is the use of robot teams to perform modular assemblies. To this end, this paper analyzed the relative performance of two robots with different morphologies and attributes in performing an assembly task autonomously under different coordination schemes using force sensing through a control basis approach. A rigid, point-to-point manipulator and a dual-armed pneumatically actuated humanoid robot performed the assembly of parts under a traditional “push-hold” coordination scheme and a human-mimicked “push-push” scheme. The study revealed that the scheme with higher level of cooperation—the “push-push” scheme—performed assemblies faster and more reliably, lowering the likelihood of stiction phenomena, jamming, and wedging. The study also revealed that in “push-hold” schemes industrial robots are better pushers and compliant robots are better holders. The results of our study affirm the use of heterogeneous robots to perform hard-to-do assemblies and also encourage humans to function as holder’s when working in concert with a robot assistant for insertion tasks.     

服务机器人技术研究现状与发展趋势

服务机器人技术经过近30年的发展,在机械、信息、材料、控制、医学等多学科交叉方面取得了重要的成果,本文结合作者在机器人领域的相关工作,在分析国内外关于服务机器人发展研究现状的基础上,就服务机器人目前涉及的仿生材料与结构、自重构机器人、复杂环境下机器人动力学问题、智能认知与感知、网络化交互及微纳系统等关键技术的研究进展做简要的综述,并概要展望了其发展趋势.希望能够在把握国际服务机器人前沿技术发展动态的同时,为培育我国服务机器人产业提供相关理论、方法及技术.     

Robotic Assembly Processes as a Driver in Architectural Design

Over the last couple of years industrial robots have increasingly gained the interest of architects and designers. Robotics in architecture and construction has mainly been looked at from an engineering perspective during the latter half of the twentieth century, with the main purpose of automating the building process. Today the focus has turned towards realizing non-standardized designs and developing custom fabrication processes. However, the specific characteristics of the robot, which distinguish it from common computer numerically controlled machines, are often overlooked. Industrial robots are universal fabrication machines that lend themselves especially well to assembly tasks. Applied to architecture this resolves to the ability to control and manipulate the building process. As such, applying industrial robots emphasizes construction as an integral part of architectural design. Moreover, designing and manipulating robotic assembly processes can become a driver in architectural design. The potential of such an approach is discussed on the basis of several design experiments that illustrate that by applying such methods, form is not derived from computation or geometry, but from a physical process.     

Artificial intelligence and robotic assembly

Traditionally, most industrial robots are programmed by teaching. The emergence of robot-level programming languages has improved the programmer's ability to describe and modify the robot moves. However, commercially available robot-level programming languages still fall short of the robot user's need to program complex tasks, and consequently, are not widely used in industry. There is an increasing need for integrating sensors feedback into the robot system to provide better perception and for improving the capacity of the robot to reason and make decisions intelligently in real time.The role of artificial intelligence in programming and controlling robots is discussed. Available robot programming systems including robot-level, object-level, and task-level languages are reviewed. The importance of developing intelligent robots in broadening the scope of flexible automation and opening the door to new robotic applications in space, under water and in harsh environments is outlined. The current development and implementation of programming and control systems for intelligent robots, at McMaster University, are explained. A number of research issues are discussed such as (1) automatic task planning, (2) knowledge representation and use, (3) world modeling, (4) reasoning in automatic assembly planning, and (5) vision monitoring of actions. Examples of geometric, functional, and handling reasoning, as they apply to assembly, are provided. The systems described in this paper are being implemented in the center for flexible manufacturing research and development. Several pieces of hardware are used, including a six-axis articulated robot, a grey-level vision system with a multi-camera, Micro VAX II, and a variety of graphics monitors. The languages available for software development include Common LISP, C, OPS5, VAL II, PASCAL, and FORTRAN 77. The domain of application is currently focused on mechanical assembly.     

How to include User eXperience in the design of Human-Robot Interaction

In recent years Human-Robot Collaboration (HRC) has become a strategic research field, considering the emergent need for common collaborative execution of manufacturing tasks, shared between humans and robots within the modern factories. However, the majority of the research focuses on the technological aspects and enabling technologies, mainly directing to the robotic side, and usually neglecting the human factors. This work deals with including the needs of the humans interacting with robots in the design in human-robot interaction (HRI). In particular, the paper proposes a user experience (UX)-oriented structured method to investigate the human-robot dialogue to map the interaction with robots during the execution of shared tasks, and to finally elicit the requirements for the design of valuable HRI. The research adopted the proposed method to an industrial case focused on assembly operations supported by collaborative robots and AGVs (Automated Guided Vehicles). A multidisciplinary team was created to map the HRI for the specific case with the final aim to define the requirements for the design of the system interfaces. The novelty of the proposed approach is the inclusion of typically interaction design tools focusing in the analysis of the UX into the design of the system components, without merely focusing on the technological issues. Experimental results highlighted the validity of the proposed method to identify the interaction needs and to drive the interface design.     

A manufacturing hand

In unmanned Flexible Manufacturing Cells, robots can be used for loading machines, inspection activities, and assembly operations. What kind of robotic end-effector should be built for such tasks? The human hand has evolved to be a general purpose manipulator that adapts to the richness of our daily lives but, in doing so, it is not particularly suited to manufacturing operations. Here, we rely heavily on special tools, fixtures, and protective layers. This paper describes the initial development of a hand specifically for manufacturing work. This has involved the manufacture of an instrumented wrist with an adjustable remote center of compliance, and the design of fingers for gripping. Object shapes have also been analysed in order to provide for a stable static grip. Importantly, these studies of the physical aspects of prehension have been matched to tasks. The research has considered a range of industrial operations and specified the level of end-effector control needed. This work is leading to some design guides for robotic end-effectors which, it is hoped, will be of use to industrial designers.     

Autonomous industrial assembly using force,torque, and RGB-D sensing

ABSTRACT

We present algorithms and results for a robotic manipulation system that was designed to be easily programable and adaptable to various tasks common to industrial setting, which is inspired by the Industrial Assembly Challenge at the 2018 World Robotics Summit in Tokyo. This challenge included assembly of standard, commercially available industrial parts into 2D and 3D assemblies. We demonstrate three tasks that can be classified into ‘peg-in-hole’ and ‘hole-on-peg’ tasks and identify two canonical algorithms: spiral-based search and tilting insertion. Both algorithms use hand-coded thresholds in the force and torque domains to detect critical points in the assembly. After briefly summarizing the state of the art in research, we describe the strategy and approach utilized by the tested system, how it's design bears on its performance, statistics on 20 experimental trials for each task, lessons learned during the development of the system, and open research challenges that still remain.     

Hard material small-batch industrial machining robot

Hard materials can be cost effectively machined with standard industrial robots by enhancing current state-of-the-art technologies. It is demonstrated that even hard metals with specific robotics-optimised novel hard-metal tools can be machined by standard industrial robots with an improved position-control approach and enhanced compliance-control functions. It also shows that the novel strategies to compensate for elastic robot errors, based on models and advanced control, as well as the utilisation of new affordable sensors and human-machine interfaces, can considerably improve the robot performance and applicability of robots in machining tasks. In conjunction with the development of safe robots for human-robot collaboration and cooperation, the results of this paper provide a solid background for establishing industrial robots for industrial-machining applications in both small- and medium-size enterprises and large industry. The planned short-term and long-term exploitation of the results should significantly increase the future robot usage in the machining operations.     

关节型工业机器人轨迹规划研究综述

关节型工业机器人凭借其良好的灵活性和高效率的工作模式被广泛地应用于现代工业自动化生产之中,例如搬运、码垛、焊接、切割等。轨迹规划是工业机器人运动控制的基础研究领域,决定着其作业效率和运动性能。工业机器人的轨迹规划是指综合考虑作业需求和机器人性能,在笛卡尔空间或关节空间内得出指导机器人末端执行器运动的轨迹。阐述了工业机器人轨迹规划的概念及其分类,就各个领域的轨迹规划算法进行了全面综述,包括基本轨迹规划和最优轨迹规划,指出了各类轨迹规划算法中所存在的问题和未来的发展方向。     

Application of robots in assembly automation

The development of flexible assembly is closely related to the introduction of robots in assembly automation. If has long been recognized that automatic parts assembly by robots is one of the most delicate and most difficult tasks in industrial robotics. This task involves two control problems, trajectory planning for the whole automatic assembly process and reduction of the reaction forces appearing between the parts being assembled. This paper addresses both aspects of this control task. The strategical control level for the manipulation of robots and various approaches to trajectory planning tasks in assembly processes are discussed. A new approach to the determination of the strategical control level, including various models (geometric, kinematic and dynamic) for manipulation robots, is briefly described.The last and most delicate phase of the assembly process is parts mating, which is rather like inserting a peg in a hole. In order to reduce the reaction forces appearing between the parts being assembled, force feedback control is applied. The experimental results of the industrial robot insertion process with force feedback are also presented in the paper.     

Introduction to the special issue on Advances in intelligent nonlinear control for robotic systems

In the last two decades, robotic systems have achieved wide applications in every aspect of human society, including industrial manufacturing, automotive production, medical devices, and social lives. With the     

Human–robot interaction in industrial collaborative robotics: a literature review of the decade 2008–2017

ABSTRACT

Currently, a large number of industrial robots have been deployed to replace or assist humans to perform various repetitive and dangerous manufacturing tasks. However, based on current technological capabilities, such robotics field is rapidly evolving so that humans are not only sharing the same workspace with robots, but also are using robots as useful assistants. Consequently, due to this new type of emerging robotic systems, industrial collaborative robots or cobots, human and robot co-workers have been able to work side-by-side as collaborators to accomplish tasks in industrial environments. Therefore, new human–robot interaction systems have been developed for such systems to be able to utilize the capabilities of both humans and robots. Accordingly, this article presents a literature review of major recent works on human–robot interactions in industrial collaborative robots, conducted during the last decade (between 2008 and 2017). Additionally, the article proposes a tentative classification of the content of these works into several categories and sub-categories. Finally, this paper addresses some challenges of industrial collaborative robotics and explores future research issues.     

Developing a limb repositioning robotic interface for persons with severe physical disabilities

Limb repositioning is necessary for individuals with severe physical disabilities to sustain muscle strength and prevent pressure sores. As robotic technologies become ubiquitous, these tools offer promise to support the repositioning process. However, research has yet to focus on ways in which individuals with severe physical disabilities can control robots for these tasks. This paper presents a study that examines the needs and attitudes of potential users with physical disabilities to control a robotic aid for limb repositioning. Subjects expressed interest in using brain–computer interface (BCI) and speech recognition technologies for purposes of executing robotic tasks. The performance of four subjects controlling arm movements on an avatar through the keyboard, mouse, BCI, and Dragon NaturallySpeaking speech recognition was evaluated. Although BCI and speech technologies may limit physical fatigue, more challenges were faced using BCI and speech conditions compared to the keyboard and mouse. This research promotes accessibility into mainstream robotic technologies and represents the first step in the development of a robotic prototype using a BCI and speech recognition technologies for limb repositioning.     

机器人感知与控制关键技术及其智能制造应用

智能机器人在服务国家重大需求,引领国民经济发展和保障国防安全中起到重要作用,被誉为“制造业皇冠顶端的明珠”.随着新一轮工业革命的到来,世界主要工业国家都开始加快机器人技术的战略部署.而智能机器人作为智能制造的重要载体,在深入实施制造强国战略,推动制造业的高端化、智能化、绿色化过程中将发挥重要作用.本文从智能机器人的感知与控制等关键技术的视角出发,重点阐述了机器人的三维环境感知、点云配准、位姿估计、任务规划、多机协同、柔顺控制、视觉伺服等共性关键技术的国内外发展现状.然后,以复杂曲面机器人三维测量、复杂部件机器人打磨、机器人力控智装配等机器人智能制造系统为例,阐述了机器人的智能制造的应用关键技术,并介绍了工程机械智能化无人工厂、无菌化机器人制药生产线等典型案例.最后探讨了智能制造机器人的发展趋势和所面临的挑战.     

The multiple-robot assembly plan problem

In previous research, we defined, classified, and solved the robotic assembly plan problem for a single assembly robot. In this paper, we formulate this problem for the case of multiple, cooperating assembly robots. The problem now includes the allocation of assembly tasks among multiple robots.     

CAMPOUT: a control architecture for tightly coupled coordination of multirobot systems for planetary surface exploration

Exploration of high risk terrain areas such as cliff faces and site construction operations by autonomous robotic systems on Mars requires a control architecture that is able to autonomously adapt to uncertainties in knowledge of the environment. We report on the development of a software/hardware framework for cooperating multiple robots performing such tightly coordinated tasks. This work builds on our earlier research into autonomous planetary rovers and robot arms. Here, we seek to closely coordinate the mobility and manipulation of multiple robots to perform examples of a cliff traverse for science data acquisition, and site construction operations including grasping, hoisting, and transport of extended objects such as large array sensors over natural, unpredictable terrain. In support of this work we have developed an enabling distributed control architecture called control architecture for multirobot planetary outposts (CAMPOUT) wherein integrated multirobot mobility and control mechanisms are derived as group compositions and coordination of more basic behaviors under a task-level multiagent planner. CAMPOUT includes the necessary group behaviors and communication mechanisms for coordinated/cooperative control of heterogeneous robotic platforms. In this paper, we describe CAMPOUT, and its application to ongoing physical experiments with multirobot systems at the Jet Propulsion Laboratory in Pasadena, CA, for exploration of cliff faces and deployment of extended payloads.     

Tolerance dataset: mating process of plug-in cable connectors for wire harness assembly tasks

In this research, we studied the mating tolerance of various plug-in cable connectors and provide a mating tolerance dataset of 70 different connectors. This dataset will be highly advantageous to industries for wire harness assembly tasks using robots. Understanding the mating tolerance is crucial for automating the mating process because it is closely related to the control specifications of a robotic manipulator. Our system uses a 2-finger Robotiq adaptive gripper attached to a 6 degree-of-freedom industrial robot (ABB Robotics) to test the mating process of wire harness assembly tasks. In addition, we use 70 types of wire harness connectors with different numbers of pins widths, lengths, and thicknesses, and various shapes, to test the mating tolerance. The results indicate that the connector mating tolerance of our dataset is more generous than the repeatability of conventional industrial manipulators, and further demonstrate the suitability of the position control methods to wire harness assembly tasks.

     

可穿戴式下肢外骨骼康复机器人研究进展

对于脊髓损伤、脑损伤等因素导致下肢运动障碍的患者,利用下肢外骨骼康复机器人可在患者损伤早期进行精准康复,并在康复过程中优化康复策略。本文详细对比了下肢外骨骼康复机器人相比于传统康复方法的优势,并结合国内外研究现状阐述了不同外骨骼机器人的设备特点及应用场景,详细分析了机器人的驱动方式、控制系统以及训练模式等关键技术。最后,着重探讨了下肢外骨骼康复机器人未来发展所面对的挑战,并针对机械结构优化、驱动算法优化、康复流程智能化、基于虚拟现实技术的应用场景优化及康复效果评估等5方面提出了可行的探讨,对下肢外骨骼康复机器人未来的技术发展趋势作出可行分析。