• Corpus ID: 13286032

Conceptual Design Selection of Manual Wheelchair for Elderly by Analytical Hierarchy Process ( AHP ) Method : A Case Study

@inproceedings{Ahmad2017ConceptualDS,
  title={Conceptual Design Selection of Manual Wheelchair for Elderly by Analytical Hierarchy Process ( AHP ) Method : A Case Study},
  author={Mohd Nazri Ahmad and N. A. Maidin and M. H. Ab. Rahman and M. H. Osman},
  year={2017}
}

• Mohd Nazri Ahmad, N. A. Maidin, +1 author M. H. Osman
• Published 2017
• Business

The purpose of this study is to select the best design concept of manual wheelchair for elderly. The plight of the elderly people is often overlooked and not given attention by the public. A study has been carried out to identify the problems that encountered by elderlies during transferring from or into a wheelchair besides, to improve the design of the existing wheelchair that will reduce physical fatigue and enhance independence or ability among elderly. The case study was done at Old Folks Home, Rumah Seri Kenangan Cheng, Melaka. A new design of manual wheelchair that designated special for elderlies is developed and fabricated. Therefore, in developing the best design of wheelchair, an approach so called Analytical Hierarchy Process (AHP) method is applied in this study. There are five design concepts have developed which are D1, D2, D3, D4 and D5. Through the application of AHP the result shows the best design concept is D5 with the highest value, which is 0.275 (27.5%). Hence, the AHP approach is able to help design engineer to evaluate the various design concept in effectively at the conceptual design stage. Keyword: AHP, Design selection, Decision making, Manual wheelchair, Elderly. INTRODUCTION Wheelchairs are the most efficient devices dedicated to these patients, offering them the ability to lead a normal life by allowing them to perform most of their daily activities [6]. Reza et al. [4] has reports that by comparing the following binarysub-criteria and the main criteria to rank each using six types of marine tourism using the Analytic Hierarchy Process (AHP) were implemented in terms of consistency and rhythmic with the Caspian Sea and Gilan province conditions. Fuzzy analytical hierarchy process (FAHP) is widely used in multi-criteria decision making (MCDM) under uncertain environments. Many works have been proposed. However, the existing methods are complex and time consuming [2]. The Analytic Hierarchy Process (AHP) is an advanced technique that supports decision makers in structuring complex decisions, quantifying intangible factors and evaluating choices in multi-objective decision situations. AHP is essentially a theory of measurement and decision making developed by Saaty [7], when he was at the Wharton School of the Universaity of Pennsylvania. The problem of limitations in higher order prioritization matrices in analysis by tools such as the Seven Management and Planning Tools (7 MP) can be obviated by using the AHP. AHP helps prioritize complex architectural and design issues in the software development process. The AHP provides a framework for solving complex and unstructured problems through a systematic logical analysis. This analysis involves the following four principles: a) structuring of a hierarchy, b) prioritizing through pair-wise comparisons, c) synthesizing of pair-wise comparison to obtain a priority vector, and d) checking for consistency of the preference judgements. The AHP first principle is the structuring of a hierarchy. A hierarchy decomposes a problem into individual independent elements and is a fundamental concept of the AHP [3]. According to Saaty [5], a hierarchy is “an abstraction of the structure of a system to study the functional interactions of its components and their impacts on the entire system”. Structuring a hierarchy requires a unique process that involves the following steps: a) the decision makers must identify the elements of the problem, b) the decision maker must group these elements into homogeneous sets, and c) these homogeneous sets must be arranged into different levels or tiers [8]. The AHP methods will be optimized by combining with Design for Assembly (DFA) method to gain the best result to be market. The improvement of product design by using the Boothroyd Dewhurst DFA method is able to produce significant results upon product assembly time and assembly cost [10]. Selecting the right design concepts at the conceptual design stage in product development process is a crucial decision. According to Xu et al. [9], implementing appropriate evaluation and decision tool should be considered at the conceptual design stage that involves many complex decisionmaking tasks. One of the useful tools that can be employed at the conceptual design stage is Analytical Hierarchy Process (AHP). The AHP is a powerful and flexible weighted scoring International Journal of Applied Engineering Research ISSN 0973-4562 Volume 12, Number 17 (2017) pp. 6710-6719 © Research India Publications. http://www.ripublication.com 6711 decision making process to help people set priorities and make the best decision. Generally, there are six stages in product development process. One of them is conceptual design. It consists of three processes namely concept generation, concept evaluation and concept development. The aim of this study is to select the best design concept of manual wheelchair for elderly then will optimize in term of cost, performance, safety and maintenance by using the AHP method. METHODOLOGY A case study was conducted at Rumah Seri Kenangan Cheng, Melaka. Data were obtained from a total of 50 respondents among the elderly and attendant staff there. Observations have also been made to look at the problems faced by them while using a wheelchair to perform daily activities. In a conceptual design stage, several sketch ideas are generated based on the specifications of the customer requirement. This idea will be selected among the best in the next concept selection method. The characteristic of wheelchairs on each sketch is different and it can be combined with one idea with another idea. Fig. 1 shows the observation on situation while using the current manual wheelchair by the elderly. This observation required to ensure that the improvement can be done on new design of wheelchair. Besides that, this method can perform as a guideline to get an idea to redesign the current wheelchair. Conceptual design Several sketch ideas are generated based on the specifications of the customer requirement as in Fig. 2. These ideas will be selected among the best in the next concept selection method. The characteristic of wheelchairs on each sketch is different and it can also be combined with one idea with another idea. Table 1 shows the characteristic of each design concept of manual wheelchair. Figure 1: The observation on problem encountered by elderly during transfer process from wheelchair to bed Table 1: Functional of conceptual design Design 1 Design 2 Design 3 Design 4 Design 5  hydraulic jack for lifting mechanism  Armrest can be fliped  footrest can be flip.  Horizontal scissors structure  gas spring for lifting mechanism  Armrest can be detachable.  Footrest can be sliding in  Vertical scissors structure.  Gear jack as lifting mechanism  Armrest can be swing away  Footrest can be flip in.  Vertical scissors structure.  Jack for lifting mechanism.  Armrest can be swing away.  Jack position has a slot.  Standard fixed footrest.  Gear jack for lifting mechanism  Armrest can be swing away.