Investigation of FBG Accelerometers and Load Sensors for Vibration Analysis and Slip Detection in Robotic Manipulators

This paper presents an investigation of the viability of Fiber Bragg Grating (FBG) accelerometers and load sensors for two diagnostic tasks in robotics: vibration analysis of industrial manipulators and slip detection in robotic grippers. The study synthesizes experimental results from two independent experiments, focusing on the use of optical sensors in place of traditional electromechanical devices such as MEMS accelerometers and resistive strain gauges. The experiments were performed on an ABB industrial robot with a parallel robotic gripper equipped with embedded optical fibers. Under the conditions tested, the optical chains provided good sensitivity and detected dynamic events such as slip onset and contact or movement-induced vibrations. Compared with the conventional chains recorded alongside them, the fiber-optic accelerometers delivered cleaner vibration spectra (SNR 36.7 dB against 13.7 dB), while the FBG load sensors measured gripping forces with a lower noise floor and less mains-band interference, although the force lost before a slip alarm favored the FBG chain only in the experiment carried out with brass. Obtained with a single specimen of each sensor type and a limited set of grasped objects, these findings indicate that optical sensing is a viable alternative for robotic diagnostics, but it comes at the cost of higher price and complexity.