Development of a tendon-driven finger with single pulley-type TDT sensors

This paper discusses a design for a robotic finger with the capability of joint torque sensing. The finger joint torque around a drive pulley is proportional to the tension difference on both ends of the pulley. Using a coupling mechanism between tendons, this tension difference can be measured directly, without sensing individual tendon-tensions. The tension differential type torque sensor (TDT sensor) is based on this idea. With a single body of small size and fewer signal lines, the TDT sensor has several advantages in comparison with the conventional approach that obtains the torque by attaching tension sensors at both ends of the drive pulley and feeding sensor signals to a differential circuit