本研究利用拓樸最佳化及幾何最佳化方法來設計等力輸出撓性機構，此機構可在不同的位移輸入條件下，在輸出端維持等力輸出，且不需要額外加裝感測器進行輸出力量控制，此機構可做為自動化過程中的被動式定力控制裝置或是過載保護裝置使用。在等力輸出撓性機構拓樸最佳化理論部分，包含了幾何非線性與材料非線性假設，並使用非線性有限元素法進行分析，本研究使用移動漸近線方法(Method of Moving Asymptotes)來更新設計變數，並在拓樸最佳化流程中加入投射方法，可有效降低灰階元素數量。由於拓樸最佳化結果中的低密度超彈性體元素對於輸出端之輸出特性具有一定影響，但卻不易實際製作，故本研究在拓樸最佳化的低密度區加入彈簧來取代超彈性體之影響，並對此設計進行進一步的幾何最佳化設計。在幾何最佳化理論部份，本研究使用布穀鳥搜尋演算法來更新等力輸出撓性機構之幾何外形。本研究並使用3D列印軟性材料來實際製作等力輸出撓性機構，實驗結果顯示本研究所設計的等力輸出撓性機構於3mm~6mm的位移輸入區間內，具有等力輸出之效果。此外，本研究並將此等力撓性機構安裝於國產電動夾爪上，設計成一個被動式等力輸出撓性夾爪，並將其安裝於國產SCARA機械手臂上進行夾取試驗。根據實驗結果，此設計可以等力夾取不同外形尺寸之脆弱目標物。本設計為一套低成本的被動式等力輸出裝置，可對定位精度不高的自動化系統提供定力輸出與過載保護。

This study presents an optimal design procedure including topology and geometry optimization methods to design a compliant constant-force mechanism. The compliant constant-force mechanism can generate a nearly constant output force over a range of input displacements without the need of additional sensors for output force control. The numerical optimization problem is treated as an error minimization problem between output and objective forces. Both material and geometric nonlinearities are considered in topology and geometry optimization steps. The method of moving asymptotes is used to update design variables, and a Heaviside based projection method is used to reduce gray elements in topology optimization. Although the element stiffness for grey and void elements after topology optimization are quite small comparing to solid elements, their existence also contributes to the output force characteristic of the synthesized mechanisms. As these low-stiffness elements are not easy to manufacture in physical prototype, a helical compression spring is introduced in the topology optimized constant-force mechanism to account for the effect of low-stiffness elements, and an additional geometry optimization step is utilized to identify the spring constant as well as to fine tune the geometric parameters based on cuckoo search algorithm. The optimized constant-force mechanism is prototyped by 3D printing of thermoplastic elastomer. The results show that the proposed design can generate a nearly constant output force in the input displacement range of 3 to 6mm. The developed constant-force mechanism is installed on a robot arm with an electric gripper for robotic picking and placing application. Test results show the design can be used in handling of size-varied fragile objects. The developed compliant constant-force mechanism is a low-cost design which can be used to provide passive force control and overload protection for automation systems with low positioning accuracy.

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