A New Method for Calibrating a Six-DOF Joint Force/Torque Sensor

One of the main senses that humans use to interact with their environment is the sense of touch and this is currently the major aim of many research projects of robots in varied forms. The measurement of the multi-dimension interactive force between the human hand and interaction device such as hand-controllers, joysticks, limb rehabilitation devices, etc., becomes important components. Encoders are installed in each joint for position-sensing feedbacks while tactile sensors are often installed at the fingertip of a hand to detect contacts [1][2][3][4]. There have been varied sensor structures, one of which is shown in Fig. 1 [5]. The method of structure design used in Song’s research [5] is for a 4-degree-of-freedom (DOF) force/torque sensor. The resulted error is larger than 1%. Although it is better than the error from commercial 6-DOF force/torque sensors, the error of 1% is still unsatisfactory for some applications, especially for precision robots.