本研究提出一套多重材料撓性機構拓樸最佳化方法與一個複合目標函數，並將此方法應用於自適性撓性夾爪之設計。藉由3D列印填充密度與等效材料性質之關係，能以一般低成本的FDM(fused deposition modeling) 3D列印設備製造出一體成型且近似雙材料效能之自適性撓性夾爪。在拓樸最佳化方面，本研究於濾化演算法中加入臨界投影法以減少灰階元素，再利用穩健性拓樸最佳化之概念改寫問題方程式，避免撓性機構出現單一節點連接之結構。本研究另外提出一個可用於雙輸出自適性撓性夾爪設計之複合目標函數，此目標函數結合交互位能與應變能，以交互位能描述第一輸出端(夾取面末端)傳遞位移之能力，而應變能則描述第二輸出端(夾取面中點)承受反作用力之能力，使夾爪具備適應目標物外形之自適性。本研究並對3D列印之軟性材料TPE(thermoplastic elastomer)進行拉伸試驗，測試TPE於不同填充密度下之應力應變關係，獲得其線彈性與超彈性材料模型。本研究提出一個多重材料撓性機構設計流程，此方法能設計出具備較佳目標函數之雙材料撓性機構，也將此方法應用於反向機構、夾鉗機構與自適性撓性夾爪之設計。本研究最終挑選出一組單材料(填充密度50%)與雙材料(填充密度30%與100%)之自適性撓性夾爪進行試作驗證，測試夾爪之輸入力量、輸出位移與自適性，並將其安裝於六軸機械手臂進行實物夾取。實驗結果顯示兩種設計皆具備良好之自適性，能夾取不同尺寸、形狀與易損傷之目標物，包含雞蛋、番茄與玻璃杯等物品。相較於單材料設計夾爪，雙材料設計夾爪末端之輸出位移平均可提升7.59%，且驅動所需之輸入力量平均可減少41.55%。本研究利用不同3D列印填充密度所製作的近似雙材料效能之自適性撓性夾爪，其最大負載重量為2.4kg，在達成自適性夾取的情況下能夾取尺寸小於80mm之未知目標物。

This study presents a multi-material topology optimization method and a multi-criteria ob-jective function for design of an adaptive compliant gripper. Based on the fact that different infill densities in 3D printing leads to prototypes with different equivalent mechanical properties, a multi-material design can be approximated by varying the values of infill den-sities in 3D printing of a prototype, which enables the multi-material designs can be proto-typed using general low-cost FDM (fused deposition modeling) 3D printing machines. The compliant gripper is prototyped by 3D printing using thermoplastic elastomer (TPE); the relations between infill densities and mechanical properties (including linear elastic and hyperelastic material parameters) of the 3D printed TPE are identified based on tensile test results. The optimal designs of bi-material compliant mechanisms including inverter mech-anism, crunching mechanism, and adaptive compliant gripper are presented using the pro-posed method, which can lead to better objective function values than their original sin-gle-material designs. In addition, one bi-material gripper design (with infill densities of 30 and 100%), and one single-material gripper design (with an infill density of 50%) are pro-totyped then installed on a six-axis industrial robot to perform grasping tests. Experimental results show both designs can be used in adaptive grasping of size-varied delicate objects including egg, tomato, and glass cups. The bi-material gripper design can yield a larger output displacement at the fingertip (7.59% in average) with a smaller input force (41.55% in average) comparing to the single-material gripper design. The identified maximum pay-load of the prototyped bi-material gripper is 2.4kg, whereas the maximum allowable object size for a successful adaptive grasping is 80mm.

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