隨著少子化及人口老化等社會問題日趨嚴重，人們對於機器人的需求逐漸增長，因此該如何讓高剛性的機器人與人類和平共存是目前科學家們致力於研究的議題。機器人通常以致動器作為其動力來源，而在眾多的致動器中，「可變剛性致動器」(Variable stiffness actuator，VSA)由於具有順應性、力矩感測及可變剛性的能力，適用於人機互動相關的應用，因此在近年來逐漸受到重視。「機械式可調順應性與可控平衡位置致動器」(Mechanically Adjustable Compliance and Controllable Equilibrium Position Actuator，MACCEPA)為一種常見的VSA，其內部具有一條彈簧及兩顆馬達，能以相對簡易的設計使兩顆馬達分別進行力量控制及剛性控制；但其具有無法連續旋轉以及可變剛性範圍狹小等缺點，導致其應用範圍受到侷限。本研究以MACCEPA為基礎進行改良，克服上述兩項缺陷開發出功能更加完備的VSA。本研究同時亦對所開發的VSA進行力矩估測公式推導，並以修正係數來彌補機構誤差所導致的估測誤差，且藉由力矩感測器驗證推導公式的準確性，而VSA內部的彈簧之剛性與力矩曲線分布的關係則可作為彈簧選用的依據。最後本研究將所開發的VSA應用於簡化版的飛躍抓枝機器人，探討VSA能否增加其著陸穩定性。我們將實驗分為不同著陸策略與不同釋放高度進行，實驗結果證實藉由虛擬阻尼控制並設定適當的剛性及虛擬阻尼係數可使VSA有效吸收機器人著陸時產生的衝擊，減少彈跳及搖晃的現象，因此未來可將此VSA應用於飛躍抓枝機器人提升其著陸成功機率。

With the growing social problems such as declining birthrate and population aging, the demand for robots is increasing day by day. Therefore, how to make high-stiffness robots safely interacted with humans is a popular research topic nowadays. Among many robot actuators, "Variable Stiffness Actuator" (VSA) have the capability of torque sensing and stiffness variation, which is very suitable for the applications related to human-robot interaction. As a matter of fact, VSA has gradually drawn much attention in recent years. MACCEPA (Mechanically Adjustable Compliance and Controllable Equilibrium Position Actuator) is a common VSA including a spring and two motors, in which torque control and stiffness control can be performed separately by these two motors with a relatively simple design, but it is incapable of continuous rotation and lack of wide stiffness modulation, limiting the use in practical applications. In view of this, this study aims to overcome the above two issues in order to develop a more versatile VSA based on the principle of MACCEPA design. In addition, this study also derives the torque estimation equation for the developed VSA and proposes a correction factor to compensate the estimating error caused by the assembling inaccuracy, where the effectiveness of equation is verified by using a torque sensor. The relationship between spring constant and torque curve distribution is also discussed, which can be used as a guideline for spring selection. We finally apply the developed VSA to a simplified version of ricochetal brachiating robot and discuss whether the VSA can improve its landing stability. We set up two experiments associated with different landing strategies and releasing heights. The experimental results show that by using virtual damper control with an appropriate stiffness selection, we can let the VSA effectively reduce the landing impact as well as the bouncing and shaking effect. In the future the VSA and developed control methods could be integrated to the design and control of ricochetal brachiating robots to increase the success rate of landing.

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