Kikuchi Takehito, Ikeda Asaka, Matsushita Rino, Abe Isao
Faculty of Science and Technology, Oita University, Oita 870-1192, Japan.
Graduate School of Engineering, Oita University, Oita 870-1192, Japan.
Micromachines (Basel). 2024 Sep 25;15(10):1184. doi: 10.3390/mi15101184.
Magnetorheological fluids (MRFs) are functional fluids that exhibit rapid and reproducible rheological responses to external magnetic fields. An MRF has been utilized to develop a haptic device with precise haptic feedback for teleoperative surgical systems. To achieve this, we developed several types of compact MRF clutches for haptics (H-MRCs) and integrated them into a twin-driven MRF actuator (TD-MRA). The first TD-MRA prototype was successfully used to generate fine haptic feedback for operators. However, undesirable torque ripples were observed due to shaft misalignment and the low rigidity of the structure. Additionally, the detailed torque control performance was not evaluated from both static and dynamic current inputs. The objective of this study is to develop a second prototype to reduce torque ripple by improving the structure and evaluating its static and dynamic torque performance. Torque performance was measured using both constant and stepwise current inputs. The coefficient of variance of the torque was successfully reduced by half due to the structural redesign. Although the time constants of the H-MRC were less than 10 ms, those of the TD-MRA were less than 20 ms under all conditions. To address the slower downward output response, we implemented an improved input method, which successfully halved the response time.
磁流变液（MRF）是一种功能流体，能对外部磁场表现出快速且可重复的流变响应。一种磁流变液已被用于开发一种用于远程手术系统的具有精确触觉反馈的触觉设备。为实现这一目标，我们开发了几种用于触觉的紧凑型磁流变液离合器（H-MRC），并将它们集成到一个双驱动磁流变液致动器（TD-MRA）中。首个TD-MRA原型成功用于为操作人员产生精细的触觉反馈。然而，由于轴不对中和结构刚度低，观察到了不期望出现的转矩脉动。此外，未从静态和动态电流输入两方面评估详细的转矩控制性能。本研究的目的是开发第二个原型，通过改进结构并评估其静态和动态转矩性能来减少转矩脉动。使用恒定电流输入和逐步电流输入测量转矩性能。由于结构重新设计，转矩的方差系数成功降低了一半。尽管H-MRC的时间常数小于10毫秒，但在所有条件下TD-MRA的时间常数均小于20毫秒。为解决向下的输出响应较慢的问题，我们实施了一种改进的输入方法，该方法成功将响应时间减半。
