A Dual-Mode Twisted String Transmission system is an automatic transmission system using a twisted string.
This actuation system has two twisting modes (Speed Mode and Force Mode) with different radii of the twisted string, and the twisting mode can be changed automatically. Therefore, the actuator operates like an automatic transmission having two transmission ratios, and the robot finger can generate a large grasping force or fast motion depending on the twisting mode. In addition, a miniature tendon tension sensor is developed and embedded in the fingertip for automatic mode change and grasping force control.
 Y. J. Shin, H. J. Lee, K.-S. Kim, and S. Kim, "A robot finger design using a dual-mode twisting mechanism to achieve high-speed motion and large grasping force," Robotics, IEEE Transactions on, vol. 28, pp. 1398-1405, 2012.
 S. H. jeong, Y. J. Shin, K.-S. Kim, and S. Kim, "Dual-Mode Twisting Actuation Mechanism with an Active Clutch for Active Mode-Change and Simple Relaxation Process," in IEEE/RSJ International Conference on Intelligent Robots and Systems, 2015.
 S. H. Jeong, K.-S. Kim, and S. Kim, "Development of a Robotic Finger with an Active Dual-mode Twisting Actuation and a Miniature Tendon Tension Sensor," presented at the IEEE International Conference on Advanced and Intelligent Mechatronics, 2016.