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標題: | 從坐到站的重力平衡裝置設計 Design of a Gravity-Balance Device for Sit to Stand Assistance |
作者: | 蔡易宸 Yi-Chen Tsai |
指導教授: | 陳達仁 Dar-Zen Chen |
關鍵字: | 外骨骼,靜平衡,平面機構,彈簧配置,質量重心,肌電訊號, Exoskeleton,Static balance,Planar mechanism,Spring configuration,Center of gravity,Electromyography, |
出版年 : | 2023 |
學位: | 碩士 |
摘要: | 本文提出一種輔助人體從坐到站的重力平衡裝置設計。該設計將人體肢段與外骨骼視為一組閉迴路裝置,且裝置自由度與人體肢段相同。裝置將大腿、小腿及腳掌作為人體肢段,並以腳掌為地桿,而人體與外骨骼關節皆視為旋轉接頭。透過人體肢段的安排及排除多餘迴路等條件下,得到可行的二自由度二迴路七桿八接頭裝置。此裝置使用彈簧達到重力平衡,並以最少彈簧數進行彈簧配置設計。
裝置藉由健康人體的參數與肢段於坐到站時的角度變化進行外骨骼設計。先是對一名健康人體進行坐到站的動作分析,並記錄大腿和小腿於過程中的角度變化。因矢狀面上重心與安全區的關係可作為人體傾倒的評估標準,因此進一步計算人體於動作中的重心與安全區的關係。當人體穿戴外骨骼時,目標則是使裝置重心(COGH+E)比未穿戴時(COGH) 更快進入安全區且使重心保持於內。 由於外骨骼不產生任何可完全旋轉的桿件,因此藉由Grashof’s準則訂定幾何條件,使裝置不產生可完全旋轉的關節。並利用牛頓法進行迭代求解外骨骼的角度變化。選擇一組滿足幾何條件的外骨骼尺寸,透過敏感度測試方法(OAT)進行外骨骼尺寸優化,並藉由迭代誤差、重心進入安全區域的時間及最終重心的位置等條件,得到符合目標的最佳外骨骼尺寸設計。 將裝置的尺寸設計進行坐到站時的動作模擬,並將彈簧配置進行靜平衡的能量驗證。透過原型機設計與量測受試者坐到站時有無穿戴外骨骼的肌電訊號,進而分析裝置對肌肉的收縮影響。量測肌電訊號時,同時對裝置進行動作分析,分析其重心和安全區的關係。其中,原型機為了滿足彈簧拉伸量的需求,選用二根氣彈簧及二根拉伸彈簧。肌電訊號則選擇股直肌(RF)、股二頭肌(BF)、腓腸肌(GAS)和脛骨前肌(TA)作為量測。 This paper presents a design for a gravity balance device aimed at assisting the human body in the transition from a seated to a standing position (STS). The design treats the human limbs and the exoskeleton as a closed-loop system, with the device having the same mobility as human limbs. The device considers the thigh, calf, and foot as human limbs, with the foot as the ground link. Additionally, both the human body and the exoskeleton joints are treated as revolute joints. Through arranging the human limbs and eliminating redundant loops, a feasible device with two DOF, two loops, seven links, and eight joints is obtained. This device uses springs to achieve gravity balance, and the spring configuration is designed with a minimum number of springs. The device's design is based on parameters of a healthy human body and the angles of the limbs during the STS process. Initially, motion analysis is conducted on a healthy human body to record the angles of the thigh and calf during the STS process. The relationship between the center of gravity of the human limbs (COGH) and the safe zone on the sagittal plane is calculated and analyzed, serving as an evaluation standard for preventing human body tipping. The objective is to ensure that with the exoskeleton, the overall center of gravity (COGH+E) enters the safe zone faster than without it (COGH) and remains within the safe zone. To design the exoskeleton, geometric conditions based on Grashof's criterion are established to prevent complete rotation of any links. The angles of the exoskeleton with human limb movements are iteratively solved using Newton's method. A set of exoskeleton dimensions satisfying the geometric conditions is selected, and optimization of the exoskeleton dimensions is performed using the sensitivity analysis method (OAT). Optimization criteria include iterative error, time for COG to enter the safe zone, and final COG position to achieve the desired exoskeleton dimensions. The dimensional design of the device is simulated for the STS transition, and the spring configuration design is subjected to energy verification through static balance analysis. A prototype is developed, and electromyographic signals (EMG) from participants are measured during the sit-to-stand transition, both with and without the exoskeleton, to analyze the device's impact on muscle contractions. Additionally, motion analysis of the device is performed to verify its relationship with the center of gravity and the safe zone. The prototype utilizes two gas springs and two tension springs to meet spring elongation requirements. EMG signals from the rectus femoris (RF), biceps femoris (BF), gastrocnemius (GAS), and tibialis anterior (TA) muscles are selected for measurement. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/91130 |
DOI: | 10.6342/NTU202304287 |
全文授權: | 同意授權(限校園內公開) |
顯示於系所單位: | 機械工程學系 |
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