Sheng Jun, Desai Jaydev P
Department of Mechanical Engineering, University of Maryland, College Park, MD 20740 USA.
Smart Mater Struct. 2015 Aug 28;24(10). doi: 10.1088/0964-1726/24/10/105005.
This paper presents our work on design, modeling and characterization of a novel shape memory alloy (SMA) actuated torsion actuator for meso-scale robots. Development of a miniature torsion actuator is challenging, but it can enhance the agility and enlarge the workspace of meso-scale robots. This torsion actuator comprises of a pair of antagonistic SMA torsion springs, which bi-directionally actuate the actuator by Joule heating and natural cooling. First, the mechanical design of the torsion actuator is presented, followed by the fabrication of SMA torsion springs. Then, we present the constitutive model of the SMA torsion spring with an analysis of its strain change, and derive a quasi-static model with the Coulomb friction torque for this torsion actuator. Finally, a series of characterization experiments are conducted on the SMA torsion spring and the torsion actuator prototype to determine the values of all model parameters. This work shows that the properties of the SMA-actuated torsion actuator can be appropriately characterized by experiments and the actuator is feasible for robotics applications.
本文介绍了我们在用于中尺度机器人的新型形状记忆合金（SMA）驱动扭转致动器的设计、建模和特性研究方面的工作。开发微型扭转致动器具有挑战性，但它可以提高中尺度机器人的灵活性并扩大其工作空间。这种扭转致动器由一对对抗性的SMA扭转弹簧组成，通过焦耳加热和自然冷却双向驱动致动器。首先，介绍了扭转致动器的机械设计，随后是SMA扭转弹簧的制造。然后，我们给出了SMA扭转弹簧的本构模型并分析了其应变变化，并推导了该扭转致动器考虑库仑摩擦扭矩的准静态模型。最后，对SMA扭转弹簧和扭转致动器原型进行了一系列特性实验，以确定所有模型参数的值。这项工作表明，通过实验可以适当地表征SMA驱动扭转致动器的特性，并且该致动器在机器人应用中是可行的。
