Factory Automation

In order to design a high efficiency Wireless Electric Vehicle Charging (WEVC) system, the design of the different system components needs to be optimized, particularly the design of a high-coupling, misalignment-tolerant inductive link (IL), comprising primary and secondary charging coils. Different coil geometries can be utilized for the primary and the secondary sides, each with a set of advantages and drawbacks in terms of weight, cost, coupling at perfect alignment and coupling at lateral misalignments. In this work, a Finite Element Method (FEM)-based systematic approach for the design of double-D (DD) charging coils is presented in detail. In particular, this paper studies the effect of different coil parameters, namely the number of turns and the turn-to-turn spacing, on the coupling performance of the IL at perfect alignment and at ±200 mm lateral misalignment, given a set of space constraints. The proposed design is verified by an experimental prototype to validate the acc...

Reconfigurable manufacturing systems (RMS) and more specifically reconfigurable manufacturing automation systems (RMAS) represent a relatively recently evolved paradigm in industrial production, providing a low cost solution in the presence of product variety. In spite of the potential impact of this approach to industrial competitiveness, the literature still lacks a set of structured guidelines, derived not only from the theory but also from field studies, to promote its practical implementation in industry. In this paper some early results that contribute towards addressing this research gap are presented. A provisional set of practical guidelines is derived and compiled from four sources: a literature review; a structured questionnaire survey on the attitude of industry to RMAS based on 55 respondents from various sectors of the manufacturing industry; unstructured interviews with the survey respondents on the barriers to the implementation of RMAS; and lessons learned from thre...

In this study, a novel time-driven mathematical model for trust is developed considering human-multi-robot performance for a Human-robot Collaboration (HRC) framework. For this purpose, a model is developed to quantify human performance considering the effects of physical and cognitive constraints and factors such as muscle fatigue and recovery, muscle isometric force, human (cognitive and physical) workload and workloads due to the robots' mistakes, and task complexity. The performance of multi-robot in the HRC setting is modeled based upon the rate of task assignment and completion as well as the mistake probabilities of the individual robots. The human trust in HRC setting with single and multiple robots are modeled over different operation regions, namely unpredictable region, predictable region, dependable region, and faithful region. The relative performance difference between the human operator and the robot is used to analyze the effect on the human operator's trust in robots' operation. The developed model is simulated for a manufacturing workspace scenario considering different task complexities and involving multiple robots to complete shared tasks. The simulation results indicate that for a constant multi-robot performance in operation, the human operator's trust in robots' operation improves whenever the comparative performance of the robots improves with respect to the human operator performance. The impact of robot hypothetical learning capabilities on human trust in the same HRC setting is also analyzed. The results confirm that a hypothetical learning capability allows robots to reduce human workloads, which improves human performance. The simulation result analysis confirms that the human operator's trust in the multi-robot operation increases faster with the improvement of the multi-robot performance when the robots have a hypothetical learning capability. An empirical study was conducted involving a human operator and two collaborator robots with two different performance levels in a software-based HRC setting. The experimental results closely followed the pattern of the developed mathematical models when capturing human trust and performance in terms of human-multi-robot collaboration.

The purpose of this paper is to validate the real-time system in the Linux-RTAI/LXRT (Real Time Application Interface/Linux Real-time) environment, in the presence of hardware and software faults. Due to the simplicity of creating and injecting faults, the method of Software Implemented Fault Injection (SWIFI) is selected. With this mode of fault injection, a tested system can emulate real conditions, in which it is required to function. The Linux operating system was selected due to open source code and ease of manipulation of various parts. Verifications of some tests performed earlier by different authors, on various hardware and software platforms, have been made. The Linux operating system has been modified with an RTAI/LXRT patch in order to gain real-time system functionality. Subsequently, modification of the respective parts of the operating system was made to enable the injection of faults. After the injection of faults, several testing frames were selected to verify and v...

Technological advancements have led to the proliferation of wireless sensor networks (WSNs) in a wide variety of application domains. Many WSN applications are missioncritical, requiring continuous operation. However, WSN sensor nodes are often deployed in unattended and hostile environments making them more susceptible to failures than other systems. Nevertheless, in order to meet application requirements reliably, WSNs require fault tolerance mechanisms. To improve reliability in such systems, we propose a fault-tolerant (FT) sensor node model for such applications. We develop a Markov model of a triplex sensor node repairable system with independent repair facilities for characterizing WSN reliability and Mean Time to Failure (MTTF). Our model focuses on providing repair for faulty sensor nodes as an alternative to replacing them with spare sensors. Results show that our proposed model can result in an 18.47% MTTF increase over the triplex sensor node system with shared repair, a...

Industrial Wireless Sensor Networks (IWSN) are preferred over bulky wired networks in industrial monitoring and automation. These sensors are used to access locations, which are technically unreachable. The use of IWSN not only reduced the cost of automation systems but also played a significant role in alarm management by real time data transfer. ZigBee and WirelessHART are already deployed protocols for IWSN. ISA100.11a developed by International Society of Automation was specially designed for IWSN. The main features of this standard are low power consumption, real time fast data transfer, scalability, security, reliability, coexistence with other network architectures and robustness in harsh industrial environments. To achieve these features, these protocols use layer structure, which provides security, fast and reliable data transfer. IEEE 802.15.4 is used at its physical layer with variable data slots. This paper presents the results of the simulation of ISA100 done on Pymote ...

Factory of the future is emerging with the existence of new modeling and application tools that can both simulate and manage the whole production process in an autonomous, intelligent and interactive manner. Holonic modeling and its software correspondence agent oriented technology provides us with these tools. Especially the use of learning algorithms trying to optimize the behaviors of software agents

This article focuses on the modeling of two-wheel mobile robot with differential chassis, which is moving in the plane. According to the application, it can be modeled with different accuracy levels depending on structural limits and other physical impacts. Main goal of this article is to include the effects of friction into the mobile robot dynamics. Four basic models of friction are combined into generalized model, which is then implemented as single Simulink block and added to model of mobile robot. Experiments show behaviour of friction models and mobile robot with friction.