PDF(Pubmed)
Abstract：
This paper presents the design, control and evaluation of a novel robotic finger actuated by shape memory alloy (SMA) tubes which intrinsically afford an internal conduit for fluidic cooling. The SMA tubes are thennomechanically programmed to flex the robotic finger when Joule heated. A superelastic SMA plate provides a spring return motion to extend the finger when cooling liquid is pumped through the internal channel of the SMA tube actuators. The mechanical design and nonlinear force controller are presented for this unique robotic finger. Sinusoidal and step response experiments demonstrate excellent error minimization when operated below the bandwidth which was empirically determined to be 6 rad s-1. Disturbance rejection experiments are also performed to demonstrate the potential to minimize externally applied forces. This method of internal liquid cooling of Joule heated SMA tubes simultaneously increases the system bandwidth and expands the potential uses of SMA actuators for robotic applications. The results show that this novel robotic finger is capable of precise force control and has a high strength to weight ratio. The finger can apply a force of 4.35 N and has a mass of 30 g. Implementing this design into wearable prosthetic devices could enable lightweight, high strength applications previously not achievable.
摘要：
本文介绍了设计,控制和评估由形状记忆合金（SMA）管驱动的新型机器人手指，该形状记忆合金管本质上提供了用于流体冷却的内部导管。SMA管被机械编程为在焦耳加热时弯曲机器人手指。超弹性SMA板提供弹簧复位运动,以在冷却液被泵送通过SMA管致动器的内部通道时延伸指状物。针对这种独特的机器人手指，提出了机械设计和非线性力控制器。正弦和阶跃响应实验表明，当在经验确定为6rads-1的带宽以下操作时，误差可达到出色的最小化。还进行了干扰抑制实验以证明最小化外部施加的力的潜力。这种焦耳加热SMA管的内部液体冷却方法同时增加了系统带宽并扩展了用于机器人应用的SMA致动器的潜在用途。结果表明，这种新颖的机器人手指能够精确控制力，并且具有很高的强度重量比。手指可以施加4.35N的力，并且质量为30g。将这种设计实施到可穿戴的假肢设备中可以实现轻量化，以前无法实现的高强度应用。
