隨著工業自動化的進步與機器人領域的發展，夾具廣泛應用於生產線上之抓取、裝配與拆卸等用途，如何有效且精確地達成夾持力調控是門重要的課題。目前自動化工廠中多使用電動式夾具，配合力量感測器提供力量回授資訊以控制夾持力，然而此項做法增加了夾具系統的複雜度與使用成本。為避免於夾持過程中破壞脆弱物體且達到力量調控之目標，本論文延伸零勁度機構的概念，設計一新型可調被動式力量控制機構裝置於夾具上，取代精密控制之主動式力量控制系統，除了達到降低成本、提升可靠度與簡化機構外，同時於機構操作區間中提供可調之定夾持力輸出。
有別於電動式夾具利用力量感測器與控制系統進行夾持力控制，考量工業生產線上工作速度與夾具使用成本的要求，將力量控制機構裝置於氣動式夾具組成氣動式力量控制夾具，具有以下優點：(1)氣動式夾具工作速度快，且成本大幅低於電動式夾具；(2)利用力量控制機構取代力量感測器的使用，進一步降低夾具使用成本，同時達到精確調控夾持力的功能，而被動式機構的設計也提升了系統可靠度。本論文利用正負勁度疊加的方式設計零勁度機構，採用特殊設計之平面彈簧有效地提升空間運用性與減少零件數目，使機構尺寸具有微小化的優點；此外，建立彈簧數學模型，對參數進行最佳化設計，使得輸出夾持力波動小，具有力量穩定的特性；並針對夾持力調控設計調整機構，增加輸出夾持力範圍。最後，將理論分析結果輔以模擬軟體驗證其合理性，並加工製造力量控制機構實體進行實驗驗證其夾持力調控之可行性，期許設計之新型力量控制機構能提供工業夾具於穩定抓取物體和力量調控與之解決方案。

Controlling the gripping force on objects has been a challenging task for industrial grippers. Its realization often requires an electric gripper with embedded force sensors and control feedback. This approach is costly and introduces extra complexity for grippers. To avoid damage while handling fragile objects, this paper presents a novel force regulation mechanism(FRM) to be installed on grippers. Without using additional sensors and control, the FRM can passively produce an adjustable contact force between the jaws and objects of variable sizes. Apart from electric gripper with embedded force sensors and control feedback while considering speed and cost, the merits of pneumatic gripper with FRM are as follows: (1) faster gripping speed and lower cost in comparison with electric gripper; (2) using FRM rather than force sensors can further reduce cost and achieve accurate force regulation at the same time, in addition, its passive design has high reliability. This approach offers a more attractive solution in terms of cost, gripping speed and complexity.

In the paper, the design concept and simulation results are presented and discussed. Instead of using coil springs, special planar springs are designed to realize FRM in a compact space and reduce installation complexity. Spring parametric model are developed to evaluate the effect of key design parameters, use optimal deisgn method to reduce force variation so that fragile objects can be manipulated steadily without causing damage. An adjustment mechanism are introduced to achieve wide range of gripping force. A prototype of a gripper with the proposed FRM is illustrated to demonstrate the effectiveness and accuracy of force regulation. The results clearly show that pneumatic grippers with FRM not only combine the merits of accurate force regulation from electric counterpart, but also have characteristcs from its own, e.g. low cost, fast gripping speed and high reliability. This novel mechanism is expected to serve as a reliable alternative for industrial object manipulation.

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