High Sensitive Force Sensing Based on the Optical Fiber Coupling Loss

In the present paper, an innovative miniaturized optical force sensor is introduced for use in medical devices such as minimally invasive robotic-surgery instruments. The sensing principle of the sensor relies on light transmission in optical fibers. Although the sensor is designed for use in surgical systems, it can be used in various other applications due to its novel features. The novelty of the sensor lies in offering four features in a single miniaturized package using a simple optical-based sensing principle. These four features are the high accuracy/resolution, the magnetic resonance compatibility, the electrical passivity, and the absence of drift in the measurement of continuous static force. The proposed sensor was micromachined using microsystems technology and tested. The sensor measures 18 mm, 4 mm, and 1 mm in length, width, and thickness, respectively. The sensor was calibrated and its performance under both static and dynamic loading conditions was investigated. The experimental test results demonstrate a 0.00–2.00 N force range with an rms error of approximately 2% of the force range. Its resolution is 0.02 N. The characteristics of the sensor such as its size, its measurement range, and its sensitivity are also easily tunable.