Temperature Independent Triaxial Force and Torque Sensor for Minimally Invasive Interventions

In this article, a triaxial force and torque sensor is developed and its response is evaluated. The sensor is designed for minimally invasive interventions. The fabrication method of the sensing structure is 3-D printing and the material used is a biocompatible acrylic plastic. Optical fibers are used as sensing elements in this sensor and the working principle is based on the Bragg wavelength shift of Bragg gratings. The response of the sensor is highly linear along all axes of measurement with the range of working around 0.7 N. The sensor has a high resolution of force and torque measurement which are 0.05 N and 0.1 Nmm, respectively. Experiments show that the sensor can accurately measure the applied force in a dynamic environment. Experiments are conducted to evaluate the thermal response of the sensor. The results show that the sensor can measure all components of the applied forces and torques to the surgery instruments without temperature cross-sensitivity.