Design and Implementation of Actuator for the Swing Mechanism of Bio-mimosa Robot

仿生含羞草擺動機構之致動器設計與實現

張仲良(Chung-Liang Chang) ； 謝金龍(Jin-Long Shie)

《中國機械工程學刊》 34卷2期 (2013/04) Pp. 137-142

摘要

可塑性形狀金屬近幾年來已廣泛應用於工業與醫學領域，該技術藉由特定合金製程，利用特殊加工方式來完成合金形狀塑造以及記憶的能力。本文旨在利用鎳鈦合金熱收縮的特性，應用於仿生含羞草的擺動機構，擬設計具有可改變形狀金屬型態的線性控制致動器。首先，將加工後的可塑性形狀金屬置入於所製作之葉片矽膠材質之中，其次利用脈寬調變的方法驅動並控制可塑性形狀金屬擺動幅度，最後推算出其含羞草葉尖的擺動位移量，同時，我們透過熱像儀觀察不同電壓下可塑性形狀金屬所產生的溫度值變化量，並藉由分析所獲得的數據資料充當仿生含羞草機構與微控制器輸出電流量的參考，以便獲得最佳擺動品質。本文所提技術，期望可運用於微型仿生機械人系統以及生物醫學領域。

並列摘要

Shape memory alloy (SMA) has been widely used in industrial and medical fields in recent years. Through specific alloying processes, metals are shaped with memory capacity. For the present study, we used SMA to create a swing mechanism in a bionic mimosa robot. The mechanism design and a pulse width modulation (PWM) control method were adopted to drive the SMA. Meanwhile, the optical sensor can detect the status of the environment, which allows the leaves of the robot to contract when necessary. The heat shrinkage characteristics of nickel-titanium (Ni-Ti) alloy were used in the swing mechanism of the bionic mimosa. The Ni-Ti alloy is intended for the design of a linear control actuator capable of changing the shape of the metal type. First, the processed SMA was placed into the polydimethylsiloxane (PDMS) material of the leaf. Then, the actuator that controls the swing mechanism was designed. A PWM technique was utilized to drive and control the SMA. Finally, the tip shift was calculated through experimental results. Meanwhile, a thermal imager was adopted to analyze the temperature generated by SMA under different voltages. The values of tip shift obtained through analysis serve as reference for bionic mimosa mechanisms and output electric current of microcontroller in order to obtain the best swing quality. The proposed method can be applied to future biomimetic micro-robot systems, as well as to greenhouse systems.

並列關鍵字

bio-robot ； actuator ； PWM ； shape memory alloy