Tendon-sheath actuation mechanisms can provide compact and lightweight tendon routing. However, torque control of a tendon-sheath actuation system is challenging because of variable friction with respect to the sheath configuration. Model-based feedforward friction compensation algorithms have been developed to accurately deliver desired torque, but it is difficult to apply such algorithms to multi-degrees of freedom (DOFs) systems because of changes in sheath configurations that in turn alter the base tension and friction parameters. In this article, we develop a series elastic tendon-sheath actuation mechanism that allows feedforward torque control in multi-DOFs systems. The mechanism features series elastic elements on the motor side to reduce base tension changes and enable accurate input torque control. Friction is compensated by a feedforward controller with a modeled friction parameter to transmit desired torque to the distal joint under varying sheath configurations. The performance of the proposed series elastic tendon-sheath actuation mechanism is demonstrated in experiments using a control interface for a tele-operation system.

中文翻译：

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弹性弹性腱鞘驱动机构的转矩控制

肌腱护套致动机构可以提供紧凑而轻便的肌腱布线。然而，由于相对于护套构造的可变摩擦，腱-鞘致动系统的转矩控制是有挑战性的。已经开发了基于模型的前馈摩擦补偿算法来精确地传递所需的扭矩，但是由于护套结构的变化进而改变了基础张力和摩擦参数，因此很难将这种算法应用于多自由度（DOF）系统。在本文中，我们开发了一系列弹性的肌腱-护套致动机构，该机构允许在多自由度系统中进行前馈转矩控制。该机构在电动机侧具有一系列弹性元件，可减少基本张力变化并实现精确的输入转矩控制。前馈控制器通过建模的摩擦参数补偿摩擦，从而在各种护套配置下将所需的扭矩传递到远端关节。在远程操作系统的控制界面上，通过实验证明了所提出的系列弹性腱-护套致动机构的性能。