隨著高齡化現象的普遍，社會的勞動力減少，醫療需求、長照服務則日漸增加。輪椅床作為可在住家及醫療場所使用之個人行動輔具，功能為協助行動不便者之坐立與平躺的姿態轉換。現有的輪椅床產品若為電力驅動，則重量重且價格昂貴；而手動式輪椅床通常為多自由度因此操作較為複雜。
本研究提出一新型輪椅床設計，藉由單一自由度以簡化操作步驟，並透過靜力平衡機構設計達成操作的省力效果。分析現有的專利及文獻了解現有輪椅床構造特性，並透過創意性機構設計(Creative Mechanism Design)與靜力平衡圖譜產生56種具六桿七接頭、一自由度之椅背與腳靠可連動之輪椅床機構，並以幾何約束編程(Geometric Constraint Programming)進行機構尺寸設計，利用向量迴路分析運動角度約束的誤差為正負1度。其次，利用Solidworks建立3D模型，並利用Adams分析系統位能與計算結果最大誤差為0.67%。其後，藉由原型機製作與實驗，驗證此創新輪椅床設計的運動與省力效果。透過實驗得知縮小版本與原尺寸的兩種原型機均可達成設計之運動特性，並可在任意位置下維持靜止。此外經由拉力計量測，原尺寸原型機平均省力效果約為58%。

With the prevailing phenomenon of population aging and the decrease in the labor force, the demand for healthcare and long-term care services has been increasing. Wheelchair beds are personal mobility aids used in homes and medical facilities to assist individuals with limited mobility in transitioning between sitting and lying positions. Existing wheelchair bed products that are powered by electricity tend to be heavy and expensive, while manual wheelchair beds typically have multiple degrees of freedom, making the operation more complex.
This study proposes a novel wheelchair bed design that simplifies the operation steps by utilizing a single degree-of-freedom mechanism and achieves labor-saving effects through the statically balanced design. An analysis of existing patents and literature is conducted to understand the structural characteristics of existing wheelchair beds. Using Creative Mechanism Design Methodology with the atlas of statically balanced mechanisms, 56 feasible mechanisms with six links, seven joints, and one degree of freedom are generated to interconnect the backrest and footrest of the wheelchair bed. Geometric Constraint Programming is applied for mechanism dimensional design, ensuring motion angle constraints with an error of ±1 degree using vector loop analysis. Subsequently, 3D models are created using Solidworks, and the Adams analysis system is utilized to verify the potential energy. In comparison to the theoretical and simulated results, the maximum error of the energy is 0.67%. Furthermore, the motion and labor-saving effects of this innovative wheelchair bed design are validated through prototype testing. Experimental results indicate that both the scaled-down and full-size prototypes achieve the desired motion characteristics and can maintain stability in any position. Additionally, measurements using a tension gauge demonstrate an average labor-saving effect of 58% for the full-size prototype.

[1] Y. Y. Lin and C. S. Huang, "Aging in Taiwan: Building a Society for Active Aging and Aging in Place," The Gerontologist, vol. 56, no. 2, pp. 176-183, 2016.
[2] L. B. Victor Gaigbe-Togbe, Danan Gu,Thomas Spoorenberg,Lubov Zeifman. "World Population Prospects 2022: Summary of Results." United Nations. https://www.un.org/development/desa/pd/sites/www.un.org.development.desa.pd/files/wpp2022_summary_of_results.pdf (accessed Apr 15, 2023).
[3] 中華民國國家發展委員會. "人口推估." https://www.ndc.gov.tw/Content_List.aspx?n=81ECE65E0F82773F (accessed Jun 11, 2023).
[4] ISO. "ISO 9999:2011 Assisitive products for persons with disability - Classification and terminology." https://www.iso.org/standard/50982.html (accessed Apr 17, 2023).
[5] 衛生福利部社會及家庭署多功能輔具資源整合推廣中心. "認識CNS 15390." https://newrepat.sfaa.gov.tw/home/cns15390 (accessed Apr 17, 2023).
[6] 名一生物科技股份有限公司. "三合一移位床 氣墊床型 YM2000A." https://www.yofa-tech.com/products_detail/96 (accessed Mar 28, 2023).
[7] SolidFocus. "多功能居家接便輪椅床." http://www.solidfocus.com.tw/zh-TW/product/standup-bed_AS-1000.html#!prettyPhoto (accessed Apr 17, 2023).
[8] Karma康揚. "水平椅501." https://www.karma.com.tw/featured_item/km-5001 (accessed Mar 28, 2023).
[9] J. H. Duncan, "Convertible bed and chair," United States Patent, US1584994A, 1926.
[10] J. D. Lilley, "Convertible bed and chair," United States Patent, US2034985A, 1936.
[11] B. R. F. Macdonald, "Convertible hospital bed-chair," United States Patent, US3239853A, 1966.
[12] S.J.Piazza, "Bed-wheelchair," United States Patent, US3284126A, 1966.
[13] E. J. Etal, "Adjustable wheelchair device," United States Patent, US3379450A, 1968.
[14] T. A. Trkla, "All purpose wheelchair," United States Patent, US4949408A, 1990.
[15] T. Shohei, K. Hideo, N. Tohru, and U. Ryuichi, "Movable bed," United States Patent, US9004508 B2, 2015.
[16] R. M. Zerhusen and A. Vaidyanathan, "Patient support apparatus adaptable to multiple modes of transport," United States Patent, US2019/0350780 A1, 2019.
[17] 邱仕融, "具移床功能之輔具設計," 碩士論文, 機械與機電工程學系, 國立中山大學, 2014.
[18] 林祐丞, "創新輪椅床機構設計與分析," 碩士論文, 機械工程系, 國立臺灣科技大學, 2020.
[19] M. J. French and M. B. Widden, "The spring-and-lever balancing mechanism, George Carwardine and the Anglepoise lamp," Proceedings of the Institution of Mechanical Engineers Part C-Journal of Mechanical Engineering Science, vol. 214, no. 3, pp. 501-508, 2000.
[20] G. Carwardine, "Equipoising mechanism," United States Patent, US2090439A, 1937.
[21] 張鎬宇, "扭力彈簧式螢幕支架之靜平衡機構設計," 碩士論文, 機械工程系, 國立臺灣科技大學, 2022.
[22] 余承翰, "具可變負載自動調節之靜力平衡支架機構設計," 碩士論文, 機械工程系, 國立臺灣科技大學, 2021.
[23] S. K. Banala, S. K. Agrawal, A. Fattah, K. Rudolph, and J. P. Scholz, "A gravity balancing leg orthosis for robotic rehabilitation," IEEE International Conference on Robotics and Automation, New Orleans, LA, USA, 2004.
[24] A. Fattah, S. K. Agrawal, G. Catlin, and J. Hammnett, "Design of a Passive Gravity-Balanced Assistive Device for Sit-to-Stand Tasks," Journal of Mechanical Design, vol. 128, no. 5, pp. 1122-1129, 2006.
[25] K. Hain, "Der Federausgleich von Lasten," Grundlagen der Landtechnik : Verfahren, Konstruktion, Wirtschaft ; Organ d. VDI-Fachgruppe Landtechnik, vol. 2, no. 3, pp. 38-50, 1952.
[26] R. H. Nathan, "A Constant Force Generation Mechanism," Journal of Mechanisms, Transmissions, and Automation in Design, vol. 107, no. 4, pp. 508-512, 1985.
[27] D. A. Streit and B. J. Gilmore, "Perfect Spring Equilibrators for Rotatable Bodies," Journal of Mechanisms, Transmissions, and Automation in Design, vol. 111, no. 4, pp. 451-458, 1989.
[28] S. Hirose, T. Ishii, and A. Haishi, "Float arm V: hyper-redundant manipulator with wire-driven weight-compensation mechanism," 2003 IEEE International Conference on Robotics and Automation, Taipei, Taiwan, vol. 1, pp. 368-373, 2003.
[29] W. D. van Dorsser, R. Barents, B. M. Wisse, and J. L. Herder, "Gravity-Balanced Arm Support With Energy-Free Adjustment," Journal of Medical Devices, vol. 1, no. 2, pp. 151-158, 2007.
[30] Y. L. Chu and C. H. Kuo, "A Single-Degree-of-Freedom Self-Regulated Gravity Balancer for Adjustable Payload," Journal of Mechanisms and Robotics, vol. 9, no. 2, pp. 021006 1-8, 2017.
[31] W. H. Chiang and D. Z. Chen, "Design of planar variable-payload balanced articulated manipulators with actuated linear ground-adjacent adjustment," Mechanism and Machine Theory, vol. 109, pp. 296-312, 2017.
[32] H. N. Nguyen and W. B. Shieh, On the Design of the Gravity Balancer Using Scotch Yoke Derivative Mechanism. Netherlands: Springer Netherlands, 2018, pp. 13-25.
[33] J. L. Herder, "Energy-free Systems. Theory, conception and design of statically," PhD thesis, Department of Precision and Microsystems Engineering, Delft University of Technology, Netherlands, 2001.
[34] 顏鴻森, 機械裝置的創意性設計. 東華書局, 2013.
[35] P. Y. Lin, W. B. Shieh, and D. Z. Chen, "Design of perfectly statically balanced one-DOF planar linkages with revolute joints only," Journal of Mechanical Design, vol. 131, no. 5, pp. 051004 1-9, 2009.
[36] A. G. Erdman and G. N. Sandor, Mechanism design analysis and synthesis. New Jersey: Prentice-Hall, Inc., 1997.
[37] H. Zhou and E. H. M. Cheung, "Adjustable four-bar linkages for multi-phase motion generation," Mechanism and Machine Theory, vol. 39, no. 3, pp. 261-279, 2004.
[38] P. Wisanu, S. Suwin, P. Natee, and B. Sujin, "Synthesis of four-bar linkage motion generation using optimization algorithms," Advances in Computational Design, vol. 4, no. 3, pp. 197-210, 2019.
[39] E. C. Kinzel, J. P. Schmiedeler, and G. R. Pennock, "Kinematic Synthesis for Finitely Separated Positions Using Geometric Constraint Programming," Journal of Mechanical Design, vol. 128, no. 5, pp. 1070-1079, 2005.
[40] J. P. Schmiedeler, B. C. Clark, E. C. Kinzel, and G. R. Pennock, "Kinematic Synthesis for Infinitesimally and Multiply Separated Positions Using Geometric Constraint Programming," Journal of Mechanical Design, vol. 136, no. 3, pp. 034503 1-7, 2014.
[41] R. H. Krishnan, V. Devanandh, A. K. Brahma, and S. Pugazhenthi, "Estimation of mass moment of inertia of human body, when bending forward, for the design of a self-transfer robotic facility," Journal of Engineering Science and Technology, vol. 11, no. 2, pp. 166-176, 2016.