Park Shinsuk, Lim Hokjin, Kim Byeong-sang, Song Jae-bok
Dept. of Mechanical Engineering, Korea University, Anam-dong, Sungbuk-gu, Seoul, Korea.
Med Image Comput Comput Assist Interv. 2006;9(Pt 1):570-7. doi: 10.1007/11866565_70.
This paper introduces a novel mechanism for surgical robotic systems to generate human arm-like compliant motion. The mechanism is based on the idea of the equilibrium point control hypothesis which claims that multi-joint limb movements are achieved by shifting the limbs' equilibrium positions defined by neuromuscular activity. The equilibrium point control can be implemented on a robot manipulator by installing two actuators at each joint of the manipulator, one to control the joint position, and the other to control the joint stiffness. This double-actuator mechanism allows us to arbitrarily manipulate the stiffness (or impedance) of a robotic manipulator as well as its position. Also, the force at the end-effector can be estimated based on joint stiffness and joint angle changes without using force transducers. A two-link manipulator and a three-link manipulator with the double-actuator units have been developed, and experiments and simulation results show the potential of the proposed approach. By creating the human arm-like behavior, this mechanism can improve the performance of robot manipulators to execute stable and safe movement in surgical environments by using a simple control scheme.
本文介绍了一种用于手术机器人系统生成类人手臂柔顺运动的新型机制。该机制基于平衡点控制假设的理念，该假设认为多关节肢体运动是通过改变由神经肌肉活动定义的肢体平衡点来实现的。通过在机器人操纵器的每个关节处安装两个执行器，一个用于控制关节位置，另一个用于控制关节刚度，平衡点控制可以在机器人操纵器上实现。这种双执行器机制使我们能够任意操纵机器人操纵器的刚度（或阻抗）及其位置。此外，无需使用力传感器，就可以根据关节刚度和关节角度变化来估计末端执行器处的力。已经开发了具有双执行器单元的双连杆操纵器和三连杆操纵器，实验和仿真结果表明了该方法的潜力。通过创建类人手臂行为，该机制可以通过使用简单的控制方案来提高机器人操纵器在手术环境中执行稳定和安全运动的性能。
