Collaborative robots (cobots) are robots that are designed to collaborate with humans in an open workspace. In contrast to industrial robots in an enclosed environment, cobots need additional ...mechanisms to assure humans’ safety in collaborations. It is especially true when a cobot is used in manufacturing environment; since the workload or moving mass is usually large enough to hurt human when a contact occurs. In this article, we are interested in understanding the existing studies on cobots, and especially, the safety requirements, and the methods and challenges of safety assurance. The state of the art of safety assurance of cobots is discussed at the aspects of key functional requirements (FRs), collaboration variants, standardizations, and safety mechanisms. The identified technological bottlenecks are (1) acquiring, processing, and fusing diversified data for risk classification, (2) effectively updating the control to avoid any interference in a real-time mode, (3) developing new technologies for the improvement of HMI performances, especially, workloads and speeds, and (4) reducing the overall cost of safety assurance features. To promote cobots in manufacturing applications, the future researches are expected for (1) the systematic theory and methods to design and build cobots with the integration of ergonomic structures, sensing, real-time controls, and human-robot interfaces, (2) intuitive programming, task-driven programming, and skill-based programming which incorporate the risk management and the evaluations of biomechanical load and stopping distance, and (3) advanced instrumentations and algorithms for effective sensing, processing, and fusing of diversified data, and machine learning for high-level complexity and uncertainty. The needs of the safety assurance of integrated robotic systems are specially discussed with two development examples.
Warehouse logistics plays an increasingly important role in the activities of enterprises and modern society in general. Warehouses are used both by manufacturing enterprises to store raw materials, ...materials and products ready for shipment, and by trading companies that store finished products there. The optimality of the work of industrial enterprises, the speed of turnover in trading companies, as well as the level of customer satisfaction depend on the efficiency of warehouse management. To organize an effective business, you need to be able to properly manage resources, flows and means. The main element of warehouse logistics is a warehouse, the purpose of which in modern conditions is no longer the storage of goods, it is transformed into a transshipment point for the provision of modern services of cross-docking, assembly, consolidation, sorting, labeling of goods in order to minimize the costs of transportation and storage of goods and reducing delivery time. This article analyzes modern warehouse logistics management mechanisms and examines its main types. It was determined that the growth of the consumer society and the rapid development of electronic commerce require innovative solutions to ensure higher warehousing efficiency. The world and Ukrainian market of warehouse services and its growth rates were also analyzed. The impact of digital transformation on requirements for warehouse logistics management is determined. On the basis of the research carried out, directions for the development of warehouse logistics in the modern world were identified.
Collaborative robots are a promising alternative to traditional haptic displays due to their expansive workspaces, ability to generate substantial forces, and cost-effectiveness. However, they have ...higher levels of friction compared to conventional haptic displays, which negatively impact the precise movement and accuracy of haptic feedback, potentially causing operator fatigue. This article proposes a novel model-free, energy-based approach for estimating and compensating the friction coefficient. Our approach calculates the time-varying impact of frictional forces during an energy cycle, defined as the period between two consecutive zero crossings of the system's kinetic energy, based on the energy dissipated by friction. This approach directly estimates the friction coefficients, based on the chosen friction model, without requiring any prior system model information or tuning parameters. The effectiveness of our approach is demonstrated through single and multi-degree-of-freedom human interaction experiments using a Franka Emika Panda robot. The results indicate that the proposed approach outperforms state-of-the-art friction compensation methods.
In this paper, the socio-economic problems facing the construction industry in Japan are presented, including the COVID19 pandemic, an aging population, aging infrastructure, and severe natural ...disasters, and a project to tackle the problem is introduced. This project, called 'Collaborative robots for adaptation of diverse environments and innovation of infrastructure construction,' is a sub-project of the Moonshot project organized by the Cabinet Office in Japan. The key approach to proceeding with this project is an 'open design' for robotics. Based on this approach, three aspects of the research plans are introduced: (1) robots that flexibly adapt to the environment, (2) Many-modal AI for environment evaluation, and (3) Physical AI and dynamic collaboration of multi-robots.
For collaborative robots, the ability to accurately predict the actuator torques required to realize the desired task is highly important. This will improve and guarantee the safety, motion and force ...control performance, and smooth lead-through programming experience. Thus, this paper presents the investigation towards comprehensive modeling and identification of nonlinear joint dynamics for collaborative robots. The proposed joint dynamics model and identification describes the most dominant dynamic characteristics of robot joints that comprise strain-wave transmissions, such as nonlinear friction, nonlinear stiffness, hysteresis, and kinematic error. Position-dependent backlash characteristics is observed and quantified using our proposed identification method and the Generalized Maxwell-Slip friction model is extended to describe the observed phenomena. The developed dynamic modeling and identification procedures provides insightful guidance for the design and model-based control of collaborative robots.
•The dependency of friction on velocity, load, and temperature is considered.•Experiments on the UR5e robot reveal backlash to depend on angular position.•Backlash phenomenon is described accurately by extending the GMS friction model.•A polynomial law for the GMS model improves accuracy of linear identification.
•We review safety assurance methods for collaborative robot systems described in ISO 15066.•We evaluate orientation of design safeguards to hazard analysis and risk assessment.•We propose a framework ...for aligning design safeguards to risk assessment.
Close interactions with a human operator are an important safety concern for collaborative robot systems. For safety assurance, robot integrators are required to demonstrate that they have taken steps to identify potential hazards, which may be embedded in collaborative tasks, or embedded within the collaborative workspace. Consequently, design safeguards are developed to mitigate unintended contact, which may be hazardous to the human co-worker, while performing cooperative or collaborative tasks. The ISO 15066 standard proposes guidelines, which designers, integrators, and users need to consider when embedding passive and active safeguards on the robot system, or while designing collaborative workspaces. Importantly, the standard premises such safeguards on structured hazard analysis and risk assessment processes. However, from studies in literature, it is often unclear how designers, integrators or users can orient design safeguards to outcomes of hazard analysis and risk assessment. Often it is unclear which steps designers need to follow, or which methods they can use to analyze hazards and assess risks, which may occur when robot systems and human co-worker perform collaborative/cooperative manufacturing tasks. Consequently, verifying the sufficiency of design safeguards to mitigate hazardous interactions in a manufacturing cell is challenging. This article reviews requirements for safety assurance of collaborative robot systems discussed in the recent ISO 15066 standard for collaborative robots and how such safeguards are realized in studies discussed in literature. The review explores gaps and propose a framework based on the ISO 31000 for orienting design safeguards for collaborative robots to outcomes of hazard analysis and risk assessment.
Backdrivable joint actuators are critical to enhancing the human–robot interaction performance of collaborative robots. A Planetary Gear Train (PGT) with a high reduction ratio and high bidirectional ...transmission efficiencies is a promising gear reducer candidate for joint actuators. However, a conventional PGT normally has a large backlash resulting in low transmission accuracy and an uncontrollable dead zone, which hinders the applications in joint actuators. Utilizing the unique structural characteristic of the 3K-type PGT that its carrier is not participated in the torque transmission, a novel flexure-based carrier with the adjustable preload and stiffness is proposed to significantly reduce backlash. To study the effects of the proposed carrier on the backlash of the 3K-type PGT, a kinetostatic model and a modified backlash model are formulated. Simulation results indicate that the carrier reduces backlash effectively, and the step dead zone caused by backlash is transformed into a low stiffness zone. The effectiveness of the proposed carrier is further verified by experimental results such that the backlash of the prototype is reduced from 10.97 arcmin to 0.47 arcmin significantly.
•A 3K PGT with a high accuracy and a high backdrivability is proposed for Cobots.•A novel flexure-based anti-backlash carrier is proposed to improve the accuracy.•A kinetostatic model is built to analyze the effects of carrier on the backlash.•Prototypes are fabricated to verify the effectiveness of the proposed carrier.
Following ethnographic studies of Danish companies, this article examines how small- and medium-sized companies are implementing cobots into their manufacturing systems and considers how this is ...changing the practices of technicians and operators alike. It considers how this changes human values and has ethical consequences for the companies involved. By presenting a range of dilemmas arising during emergent processes, it raises questions about the extent to which ethics can be regulated and predetermined in processes of robot implementation and the resulting reconfiguration of work.
•Wire harnesses are used in several industrial sectors.•Handling of flexible materials it is very complex in automation.•Spot taping process of wire harnesses is performed manually.•The proposed ...collaborative robotic approach improves cycle time and ergonomics.
Wire harnesses are used in several industrial sectors such as automotive, white goods, toys, or electrical and mechanical engineering. One of the key tasks of the process is to assemble and secure harnesses with a taping pistol in several spots to group single wires and make the final harness with all the required ramifications. The proposed method tries to advance the state of the art and enhance the current process, which is being performed manually, by adding robotic arms in a custom cell that collaborates with the human worker. The robotic solution of the proposal will perform all the spot tapings of the process, while the worker performs only the positioning of the cable. It reduces the processing time of the task and allows workers to work on two harnesses at the same time. The results of the present proposal will have a positive impact on companies dedicated to the production of wiring and the sectors to which they supply their products. The solution will also impact on the ergonomic conditions of workers through an innovative work environment that removes the most tedious and repetitive tasks of the operator.
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