One of the significant trends in smart manufacturing is the idea of industrial digitalization, which is enabled through the use of new information technologies, such as the Internet of Things, big ...data, cloud computing, and artificial intelligence. However, manufacturing industries can only be achieved by combining the physical manufacturing world and digital world, to realize a series of smart manufacturing activities, such as active perception, real-time interaction, automatic processing, intelligent control, and real-time optimization, etc. In this paper, a digital twin-driven approach combines with agent-based decision-making for real-time optimization of motion planning in robotic cellular is proposed, with optimizing the physical and virtual layer at the manufacturing facility. Accordingly, an architecture of the digital twin-driven facility is design, and its operational mechanisms and implementation methods are explained in detail. Moreover, qualitative analysis and a quantitative comparison based on a real robotic cell are provided. Several key findings and observations are generated relating to managerial implications, which are valuable for various users to make manufacturing decisions under the digital twin-driven environment.
Robotic cell scheduling has received considerable attention from researchers. Several existing review papers have presented then-existing studies on robotic cell scheduling and related fields from ...different perspectives. Since the latest review, numerous new results have emerged, contributing significant advancements in recent years. Furthermore, certain features of these problems have not been appropriately addressed. This paper aims to provide an up-to-date review and present our particular perspectives to address recent publications on scheduling robotic cells with fixed processing times or time windows. First, we identify various characteristics of robotic cell scheduling and explain their impact on the structure and complexity. Based on these characteristics, the related robotic cell scheduling studies are classified and compared in various dimensions. Second, we present complexity results, along with both exact and approximation solution techniques, for the robotic cell scheduling problem with time windows or fixed processing times. These results are presented in tabular forms to visually reveal the relationships between different problem configurations and their respective solution approaches. Finally, we discern emerging trends in the realm of robotic cell scheduling research, subsequently indicating prospective directions for future investigations.
•Review of scheduling robotic cells with fixed processing times or time windows.•Various characteristics of different problems are identified and analyzed.•Solution approaches of scheduling with processing time windows are reviewed.•Complexity results of scheduling with fixed processing times are reviewed.•Potential future research directions are outlined and discussed.
The manufacturing landscape is rapidly evolving, being characterized by the emergence of Industry 5.0, leading to a growing recognition of the importance of a human-centered, sustainable and ...resilient approach. In response to these needs, collaborative robotics has emerged as a promising solution to enhance flexibility in industrial operations, while ensuring a higher level of safety. Cobots enable human-robot collaboration without the need for physical barriers, reduce the footprint of the robotic station, and foster a closer working relationship between humans and machines.
This article focuses on an application of collaborative robotics in end-of-line industrial operations, specifically in the unloading of products from an automatic machine. By managing repetitive tasks, such as placing the trays near the end of the line of the automatic machine, waiting for them to be filled, and placing them on a trolley, which will then be moved by the human operator, the robot significantly improves efficiency. The proposed solution involves alternating the placement of trays in two rack trolleys, allowing the worker to replace the full trolleys with empty ones at his own timing. The paper examines the potential advantages of using a human-centric approach that emphasizes operator empowerment and human oversight: the collaborative robotic cell and the automation implemented free the workers from the low value-added operations and allow them to oversee and manage multiple machines simultaneously, thus enhancing productivity. The approach behind this proposal is to keep robotic tasks simple, easily reprogrammable and modular, while empowering the human operator to engage in supervision, decision-making, and problem-solving tasks. This collaboration allows the operator to assume a supervisory role, organizing production based on identified needs, and elevating their involvement to production line management tasks.
•We present a new robotic disassembly cell based on two cobots and a human operator.•Human-robot interaction was realised using force (touch) and positional control.•Active compliance control was ...utilised to achieve complex disassembly HRC tasks.•A case study has demonstrated the successful application of the proposed cell.
Disassembly is the first operation in the remanufacture, repair and recycling of products that have reached the end of their service life. Both productivity and flexibility should be considered when using robots to carry out disassembly due to the complexities associated with the products returned for remanufacturing. Human-robot collaboration is a flexible semi-automated approach to mitigate against the effects of uncertainties in the frequency, quantity and quality of those End-of-Life (EoL) products.
This paper presents a new experimental robotic disassembly cell comprising two collaborative robots and a human operator. The robots and the operator can work safely in tandem for individual, parallel or common disassembly tasks in a shared workspace. Active compliance control is employed by the collaborative robots to achieve complex disassembly tasks and safe human-robot interaction. The human operator communicates with the robots using a new method based on touch sensing combined with position control. The paper first provides a short literature review of robotic disassembly and human-robot collaboration focusing on disassembly. It then describes the collaborative disassembly demonstration cell. Finally, the paper details a case study highlighting the capabilities of the cell. The case study shows that the automation of complex disassembly tasks is feasible and has the potential to release people from tedious and repetitive work.
•Considering a dynamic scheduling problem in a U-shaped job shop robotic cell.•Devising a mixed-integer linear programming model and three speed-up constraints.•Proposing a novel Constraint ...Programming model for the considered problem.•Analyzing the impact of critical parameters’ values and model presumption.
Display omitted
This paper investigates a dynamic scheduling problem within a job shop robotic cell, wherein multiple robotic arms are responsible for material handling in a U-shaped arrangement. Each robotic arm has access to specific workstations based on their distance in the cell layout. Therefore, a part may need to be exchanged between several robots according to its process plan. For this purpose, intermediate buffers are positioned between each pair of consecutive robots. Due to the dynamic nature of the problem, new jobs arrive at unpredictable times, which in turn necessitates rescheduling taking the system’s current state into account. To tackle this problem, firstly, a Mixed-Integer Linear Programming (MILP) model is devised. Secondly, three distinct Speed-up Constraints (SCs) derived from the problem’s inherent characteristics are designed and implemented to accelerate the MILP model’s solving procedure. Afterward, the problem is formulated using Constraint Programming (CP) approach. The performance of the CP model and the MILP model in presence of all possible combinations of the SCs are evaluated and compared through solving various random instances. Next, an analysis is performed on the buffers’ pick-up criterion and how it is affected by the problem’s size. Besides, the impact of changes in the robots’ speed on the productivity of the cell is assessed. Finally, the extent to which the rescheduling priority affects the output of the model is studied.
In this paper, we develop a Digital Twin (DT) for a cell with a robotic arm serving seven stations and assisted by a human operator. The lack of reliable predictions of human behaviours requires ...constant monitoring of the cell in order not to affect the degree of context-awareness, autonomy, and adaptability of a DT. This monitoring is carried out through a real-time simulation and optimization algorithm, which continuously produces near-optimal decisions for machines and efficient recommendations for human operators. The proposed approach is tested in a large computational campaign based on real-world data. The results show that the behaviour of the operator scarcely affects the performance of the cell at least in the considered settings.
•An autonomous adaptive context-aware Digital Twin for a robotic cell with operator.•The Digital Twin is a closed loop framework with simulator database and optimization.•A real-time algorithm to plan robot’s movement and operator’s suggestions.•Tests with real data show feasibility of the approach and influence of the parameters.
Robotic cell scheduling problem with batch-processing machines (RCSP-BMs) needs to determine the processing sequence and the transferring sequence simultaneously. The buffer size before and after the ...batch-processing machines has a big influence on the scheduling solution. A big amount of energy is always consumed by batch-processing machines. Hybrid flow shop scheduling has been proven NP-hard, and the features of the batch-processing machines in a flow shop make the hybrid flow shop scheduling more difficult. This study proposes a multiobjective differential evolution (DE) algorithm to address these issues. First, a mathematical optimization model is formulated for the RCSP-BMs to minimize makespan and energy consumption of the batch-processing machines. Second, the multiobjective DE algorithm (MODE) is developed. A green scheduling algorithm is designed to decode the individuals to balance the makespan and energy consumption. A local search method is also presented to help the searching escape from the local optimum. Finally, experiments are carried out, and the results show that the MODE can solve the robotic cell scheduling problem with batch-processing machines effectively and efficiently. Note to Practitioners -This study focuses on the robotic cell scheduling problem with batch-processing machines (RCSP-BMs) and discusses the influence of the buffer sizes and different batching methods on scheduling. In this study, we propose a green scheduling algorithm and a multiobjective differential evolution algorithm to optimize the makespan and the energy consumption of the batch-processing machines simultaneously. In future research, we will address more complicated situations, such as many-objective optimization and many-robot scheduling.
