Rizauddin Ramli

Genetically optimised disassembly sequence for automotive component reuse

Environmental sustainability through end-of-life recovery has become the main items of contest in the automotive industries. Component reuse as one of the product recovery strategy is now gaining importance in view of its impact on the environment. Disassembly as one of the determinant factors for reuse is a very important and difficult process in life cycle engineering. To enable reuse, a certain level of disassembly of each component is necessary so that parts of the products that have arrived at their end-of life can be easily taken apart. Improvements to the disassembly process of products can be achieved at two levels: in the design phase, making choices that favours the ease of disassembly of the constructional system (design for disassembly) and planning at best and optimising the disassembly sequence (disassembly sequence planning). Hence, finding an optimal disassembly sequence is important to increase the reusability of the product. This paper presents the development work on an optimisation model for disassembly sequence using the genetic algorithms (GA) approach. GA is chosen to solve this optimisation model due to its capability in solving many large and complex optimisation problems compared with other heuristic methods. The fitness function of the GA in this study is dependent on the increment in disassembly time. Comparison of results using different combinatorial operators and tests with different probability factors are shown. This paper will present and discuss the disassembly sequence of an engine block, as a case example which achieves the minimum disassembly time.

Genetic algorithm for buffer size and work station capacity in serial-parallel production lines

Recently, many production lines that have complicated structures such as parallel, reworks, feed-forward, etc., have become widely used in high-volume industries. Among them, the serial-parallel production line (S-PPL) is one of the more common production styles in many modern industries. One of the methods used for studying the S-PPL design is through a genetic algorithm (GA). One of the important jobs in using a GA is how to express a chromosome. In this study, we attempt to find the nearest optimal design of a S-PPL that will maximize production efficiency by optimizing the following three decision variables: buffer size between each pair of work stations, machine numbers in each of the work stations, and machine types. In order to do this we present a new GA-simulation-based method to find the nearest optimal design for our proposed S-PPL. For efficient use of a GA, our GA methodology is based on a technique that is called the gene family arrangement method (GFAM), which arranges the genes inside individuals. An application example shows that after a number of operations based on the proposed simulator, the nearest optimal design of a S-PPL can be found.

Adaptive decentralized coordinated control of multiple robot arms

Abstract This paper presents an adaptive decentralized coordinated control method for multiple robot arms grasping a common object. In the proposed controller, the dynamic parameters of both object and robot arms are estImated adaptively. The desired motions of the robot arms are generated by an estimated object reference model and each robot controller works independently as hybrid adaptive controller. The asymtotic stability of position and internal force of the object is proven by the Lyapunov-Like Lemma. Expenmental result for the two robot arms grasping a common object is shown.

Integrated Set Parts Supply system in a mixed-model assembly line

The mixed-model assembly line (MMAL) is a type of assembly line in which a variety of product models are assembled on the same line. The use of highly variant parts on the assembly line need to be considered carefully to enable satisfactory material flow control and allow for smooth production. To increase the quality of parts supply and parts assembly in MMAL, Toyota has introduced an innovation system known as Set Parts Supply (SPS). In this paper, we investigate the parts supply issues in SPS implementation using a case study in the automotive industry. The linkage of parts supply strategies with Manufacturing Execution System (MES) is introduced to improve the SPS implementation which are (i) synchronized parts supply, (ii) e-kanban system and (iii) Synchronized Supply Sheet. From the research findings, the integration with MES has contributed to the Just In Time in parts supply at the supermarket area and assembly line.

Buffer size decision for Flexible Transfer Line with Rework Paths using Genetic Algorithm

The buffer size decision for the flexible transfer line (FTL) gains more and more importance because of growing FTL complexity and production costs. The buffer size in front of the bay of machines in the FTL is still one of the major optimization problems faced by production engineers. In this paper, we attempt to find the near optimal buffer size for flexible transfer line with rework paths (FTLRP) that achieves the best throughput of the FTLRP. A genetic algorithm (GA) was applied to find buffer size of FTLRP. For the performance evaluation of the FTL, a novel aggregation technique proposed by Jingshan (2004), is used to find the throughput of the FTLRP at a given buffer size. In order to achieve the efficient use of the GA, multiple vectors distribution method (MVDM) is used for the genes arrangement. An application example was developed and after a number of operations based on GA, the sizes of all buffers for the FTLRP could be found

Factors related to supply chain network members in SMEs

Purpose – The purpose of this paper is to give a clear picture of the evidence for small and medium enterprises of what the key factors are affecting the performance of supply chain members (SCMs) and their impact. Design/methodology/approach – The authors conducted a survey of small and medium automotive enterprises. After a comprehensive search of the literature on effective factors requirements of supply chain actors (supplier, manufacturer, inventory, distribution, and information flow) 23 factors were identified, and collected data were analysed using SPSS software. Findings – The results show that among the 23 factors, the inventory level is the most significant factor for inventory with the highest percentage (91 per cent). This is followed by productivity to fill the order (88 per cent) and lead time of manufacturing (86 per cent) for manufacturer, and transportation flexibility (84 per cent) for distribution section. Research limitations/implications – Study limitation was that only the companies...

Decentralized Adaptive Coordinated Control of Multiple Robot Arms for Constrained Tasks

This paper presents a distributed adaptive coordinated control of multiple robot arms grasping a common object that is constrained by known environment. The cases of rigid contact and rolling contact are analyzed. In the proposed controller, the dynamic parameters of both object and robot arms are estimated adaptively. The desired motions of the robot arms are generated by an estimated object reference model. The asymptotic stability of motion is proven by the Lyapunov-like Lemma. An experiment involving two robot arms handling a common object constrained by a cylindrical plane is shown.

Real-time control of decentralised autonomous flexible manufacturing systems by using memory and oblivion

This paper describes a method that uses memory to determine a priority ranking for competing hypotheses. The aim is to increase the reasoning efficiency of a system which controls Automatic Guided Vehicles (AGVs) in Autonomous Decentralised Flexible Manufacturing Systems (AD-FMSs). The system includes memory data of past production conditions and AGV actions. Using these memory data, the system reorders hypotheses by giving the highest priority ranking to the hypothesis that is most likely to be true. The system was applied to an AD-FMS constructed on a computer. The results showed that this reasoning system reduced the number of hypothesis replacements.

Design and development of lower limb exoskeletons: A survey

Abstract Research into the development of the lower limb exoskeleton (LLE) has been on-going since the 1960s. Although this field has long been explored, the technological progress has been very slow. Many exoskeletons were stopped in their tracks toward commercialization at the research stage itself. Therefore, this paper is aimed at systematically reviewing the design and development of multiple joint LLEs. The discussion focuses on the application of LLEs for augmentation, muscle weakness or gait recovery and rehabilitation. Details of aspects such as the control strategy, actuator, safety and design, including compactness, noise, heavy structural weight, cost, mimicking of natural walking, and power sources, will be discussed. Finally, issues concerning the design and development of LLEs will also be presented.

Impediments of Collaborative Relationships in Automotive SMEs in Malaysia

The interests of various economies in improving and expanding the growth of small and medium enterprises (SMEs) have thrived for a few years, particularly in the automotive sector. Although there are several supporting programs, SMEs face a large number of issues in their operation and performance. One of the successful techniques towards achieving collaborative relationships and problem solving in SMEs is through supply chain integration. Many enterprises have realized the benefits of integration among supply chain members. Supply chain management has become an effective strategy for boosting competitiveness. However, there are a few reasons that put off automobile SMEs from completely performing supply chain management. This study combines literature and findings of a questionnaire analysis to urge facts and knowledge regarding the importance of supply chain management and challenges of automotive SMEs in enhancing their collaborative relationships and effectiveness through SCM. In addition, this study observed that top management, work culture and attitudes of staffs and technologies being traded are among the significant impediments to well-integrated relationship between SMEs. Finally, the study concludes that SMEs need to fully adopt SCM to meet potential advantages and control their performance.