A Modular Miniature 6-D Force Sensor Designed for Minimally Invasive Surgery

Force sensing is important in robot-assisted minimally invasive surgery (MIS), but it is still difficult to achieve both miniaturization and multidimensional perception at the same time. A modular design scheme of a miniature 6-D force sensor that can be integrated into an MIS robot is proposed. The force and moment applied on the sensor are converted into the signal response of the pressure-sensitive element, and the position of the pressure-sensitive element is located using flexible printed circuit board (FPCB), with which the wiring of signal circuits is simplified. The blind signal separation fast independent component analysis (FastICA) algorithm is used to decouple the output signal. The calibration experiment of the proposed sensor was carried out, and the calibration matrix was established. From the comparative experiment with commercial sensors, the accuracy, linearity, hysteresis, coupling error, and other performance of the proposed sensor are verified. The maximum coupling error is 2.8%, and the maximum stable measuring error is 3.9%. Analysis and experiments proved the rationality and scientificity of the sensor. This work opens up new ideas for the miniaturization, modularization, and integration of sensors for surgical robots.