The Tactile Force Sensing of the Gripper Based on the Mode Interference Fiber Sensor

Robots can feel, weigh, and grasp objects based on tactile sensing, which is essential for object perception. Although tactile force-sensing technology has fully developed over recent decades, the sensitivity of tactile force-sensing is still low. In this article, a high-sensitivity optical force tactile sensor based on mode interference is presented to measure the tactile force of the gripper. The model between the tactile force and wavelength shift is established, and the formula of sensitivity for the presented tactile sensor is given. The experimental setup is designed and built to test the presented optical force tactile sensor. The experimental results show that the tactile force sensitivities are about 26.58 nm/N in the range of 0–3 N and about 6.53 nm/N in the range of 3–10 N, respectively. Compared with the existing tactile force fiber sensors, the designed optical sensor has a greater sensitivity and a wider range of tactile force without damaging the sensor.