An industry 4.0-enabled low cost predictive maintenance approach for SMEs: a use case applied to a CNC turning centre

This paper outlines the base concepts, materials and methods used to develop an Industry 4.0 architecture focused on predictive maintenance, while relying on low-cost principles to be affordable by Small Manufacturing Enterprises. The result of this research work was a low-cost, easy-to-develop cyber-physical system architecture that measures the temperature and vibration variables of a machining process in a Haas CNC turning centre, while storing such data in the cloud where Recursive Partitioning and Regression Tree model technique is run for predicting the rejection of machined parts based on a quality threshold. Machining quality is predicted based on temperature and/or vibration machining data and evaluated against average surface roughness of each machined part, demonstrating promising predictive accuracy

Wire Harness Assembly Process Supported by a Collaborative Robot: A Case Study Focus on Ergonomics

Products and assets are becoming increasingly “smart”, e.g., mechatronic, electronic, or cyber-physical. In the lack of fully reliable wireless solutions, extensive wiring and wire bundling into wire harnesses are needed. This has manufacturing implications, leading to increasingly complex wire harness assembly processes, where numerous components, connectors, and cables are assembled, connecting critical and non-critical electric and electronic systems in smart products and assets. Thus, wire harnesses demand is rapidly rising in most industries, requiring human or robotic work. Often, required work tasks are repetitive and physically demanding, while still needing people for quality reasons. An attractive solution would therefore be humans collaborating with robots. Unfortunately, there are very few scientific studies on automation solutions using collaborative robots (cobots) for wire harness assembly process tasks to increase process productivity and improve work ergonomics. Furthermore, wire harness assembly process tasks are presently carried out 90% manually in this industry, causing serious ergonomic problems for assembly workers who perform such tasks daily. The challenge is reducing the ergonomic risks currently present in many established wire harness assembly processes while improving production time and quality. This paper presents an early prototype and simulation to integrate a cobot into a wire harness assembly process, primarily for work ergonomic improvements. The use of a cobot is specifically proposed to reduce ergonomic risks for wire harness assembly workers. Two methodologies: RULA and JSI were used to evaluate the ergonomics of the task of cable tie collocation. The real-world case study results illustrate the validation of a cobot which significantly reduced non-ergonomic postures in the task of placing cable ties in the wire harnesses assembly process studied. An ergonomic analysis without the cobot (the actual process) was conducted, based on RULA and JSI methodologies, presenting the highest possible scores in both evaluations, which calls for urgent changes in the current wire harness assembly process task studied. Then, the same analysis was performed with the cobot, obtaining significant reductions in the ergonomic risks of the task at hand to acceptable values

Adaptive control optimization in micro-milling of hardened steels-evaluation of optimization approaches

Nowadays, the miniaturization of many consumer products is extending the use of micro-milling operations with high-quality requirements. However, the impacts of cutting-tool wear on part dimensions, form and surface integrity are not negligible and part quality assurance for a minimum production cost is a challenging task. In fact, industrial practices usually set conservative cutting parameters and early cutting replacement policies in order to minimize the impact of cutting-tool wear on part quality. Although these practices may ensure part integrity, the production cost is far away to be minimized, especially in highly tool-consuming operations like mold and die micro-manufacturing. In this paper, an adaptive control optimization (ACO) system is proposed to estimate cutting-tool wear in terms of part quality and adapt the cutting conditions accordingly in order to minimize the production cost, ensuring quality specifications in hardened steel micro-parts. The ACO system is based on: (1) a monitoring sensor system composed of a dynamometer, (2) an estimation module with Artificial Neural Networks models, (3) an optimization module with evolutionary optimization algorithms, and (4) a CNC interface module. In order to operate in a nearly real-time basis and facilitate the implementation of the ACO system, different evolutionary optimization algorithms are evaluated such as particle swarm optimization (PSO), genetic algorithms (GA), and simulated annealing (SA) in terms of accuracy, precision, and robustness. The results for a given micro-milling operation showed that PSO algorithm performs better than GA and SA algorithms under computing time constraints. Furthermore, the implementation of the final ACO system reported a decrease in the production cost of 12.3 and 29 % in comparison with conservative and high-production strategies, respectively

A Wrapper Component-Based Methodology for Integrating Distributed Robotics Systems

Building an intelligent robot system has been an extensive research area. There are many advances in components needed to construct a robotic system, such as vision systems, sensory systems, and planning systems among others. Integration of these components represents a big challenge for robot designers, because each component comes from different vendors and they run with different interfaces or under different operating systems. This will be even more difficult if the overall system development has to deal with environmental uncertainties or changing conditions. In these cases, new tools and equipments are necessary to adapt the initial configuration to the new changing requirements. Each added component increases the complexity of integration due to the interconnection required with the previous components. This thesis research presents a novel approach to solve the integration problem using the concepts of distributed framework and distributed computing systems. We named this methodology DWC (Divide-Wrap-Connect). This methodology is based on the mechanisms used by standard middleware software to provide transparency and porta- bility among different operating systems and languages. The idea is to define software modules named Wrapper Components, which are object-oriented modules that create an abstract interface for a specific class of hardware or software components. These modules are the components of a bigger system. Basic steps in this methodology are: a) Divide, b) Wrap and c) Connect. The creation of Wrapper Components is the core activity of the second step (b) but its design is af- fected by the first and third step of this methodology. We provide some basic definitions in order to clarify the scope of different design alternatives. Furthermore, we present how using standard mechanisms from distributed computing such as Event services and Naming services, the third step (c) is improved. We tested our approach by solving an experimental classical AI problem, block-world problem. The intelligent functions are object recognition, environment recognition, planning, tracking capabilities, tasks control and robot arm control. These functions were developed into several components and a coordinator module. This coordinator modules interacts with the user and the other components in order to solve the block- world problem. The construction of the system was done in an incremental way showing the benefits of this methodology

A cost-benefit analysis for a wire harness assembly workstation: Manual vs. collaborative workstation

A fundamental competitiveness factor in the wire harness manufacturing industry is the economic aspect. A collaborative robot automation project could be very innovative, but the manufacturer will not invest in the project if it does not produce clear financial returns. The cost-benefit analysis of changing from a manual to a collaborative (human-robot) assembly process of wire harnesses is something that has not been deeply studied in the literature. Therefore, a cost-benefit analysis is proposed to determine if a collaborative assembly process is financially viable in the wire harness manufacturing industry. A case study is presented to verify and validate the analysis proposed. This case study focuses on the cable tie collocation task within a wire harness assembly process. The proposed cost-benefit analysis shows that the country where the analysis is made has great relevance in the financial viability of changing from a manual to a collaborative assembly process due to the workers’ salaries