Modular Design of Specialized Seating / Positioning Wheelchair for the Cerebral Palsied

• Main Authors: Chien-hong Lin, 林建宏
• Other Authors: Kao-Chi Chung
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/75478350673785229095

碩士 === 國立成功大學 === 醫學工程研究所 === 89 === In addition to medical and rehabilitative treatments, seating/positioning is important to the individual with central nervous deficits, particularly for moderate or severe cerebral palsied (CP) children. It has been reported statistically in Taiwan that 0.6 to 5.9 per 1,000 children are affected by CP. Proper seating and body support devices are useful in normalized muscle tone, decreasing the influence of pathological reflex and improving body stability and movement for preventing deformities, developmental delays and functional disabilities from their life span. This research purpose was to develop a modular design of specialized wheelchair (WC) and support systems for effectively customized fitting the individual’ seating/positioning needs, and for minimizing the product design and manufacturing cost. More specifically, this research was to: (1) develop and establish modular parameters of mechanical structure, mechanics and components for the design specification of specialized WC and body support system; (2) apply CAD/CAM and finite element method (FEM) for mechanical design, stress and strain analysis of structural and mechanic components, and manufacturing of modular products. The modular design of seating/positioning devices has been motivated from wide variations of age, body sizes, neuromuscular impairments and functional support needs for the CP population. The seat width and depth, backrest height and leg length, seat and back angles, and other components’ dimensions in linear and angular ranges need to be considered in the design of specialized WCs with foldable, anti-tip and braking functions. The design of body supports needs consider the size, shape and fitting location of head and trunk supports, H hardness and safety belts, abductor and tray. In Stage I, the main structural parameters of WC’ seat width and depth, backrest height and legrest length for modular design specifications were determined from Average Linkage and K-means methods of multivariable cluster analysis on the anthropometrics data measured and collected from 140 CP cases (ranging from 2 to 25 years old). The dimensional ranges of other components and body support systems were also statically determined from the subject’ database for modular design specifications. In Stage II, SolidWorks packages with constructive solid geometry of pipe, beam and shell components and triangular elements of FEM with strength analyses of maximum shear stress criterion were used for CAD design and stress-strain analysis of the structural and mechanic components and modular parts of the special wheelchair with A6061T6 aluminum alloy tubing and plate. In Stage III, CAM was used for the manufacturing and dies molding and assembly of the modular design products. The R&D has completed 3 prototype design modules of large, medium and small folding and reclining WCs equipped with anti-tip and brake devices for safety, the dimensional options include: 25.4, 31.8 and 41.4cm for WC width; 18, 21, 26, 31, 36, 41, 47, 51 and 56cm for both WC depth and backrest height; 15, 21, 27, 33, 39 and 44cm for legrest length; 5, 8 and 12 for seat angle; 75, 85 and 95mm in radius curve for head support; 40 and 65mm height for trunk support; and 60, 80 and 100mm width for abductor. All parts and components are easily inserted and removed adjustably to fit each individual needs. A seating/positioning protocol has been developed for clinical evaluation, measuring, prescription and fitting of the specialized WC and body supports. Fifty cases with severe cerebral palsy have been prescribed and fitted with their appropriate WCs and supports with the assembly of developed modular components according to their individuals’ needs. This pilot field testing of clinical application has demonstrated that the modular design of wheelchair and seating/positioning supports is useful to provide effective mobility aids, normalized muscle tone, body alignment and postural control , and to improved the influence of reflex, body coordination, balanced and movement, and functional abilities. The『Modular Design』seems to be highly applicable to satisfy widely varied seating/positioning needs for the CP, SCI, Strokes, TBI, MD and MS. In addition, the design and manufacturing process can be achieved with significantly minimized the product cost for wheelchair industries. Further clinical studies for application outcomes need to be investigated.