Fiber optic conformal embedded six-dimensional force sensing grasper and its in-situ calibration method

Fiber Bragg grating (FBG) six-dimentional force/torque sensors was used in surgical robots to sense forces interacting with human tissues. However, due to the narrow space and the susceptibility to the water environment of the body in laparoscopic surgery, it is challenging to integrate the existing sensors with the surgical grasper. Therefore, in order to realize the force in-situ sensing between the surgical forceps and tissues, this paper proposes a Fiber optic conformal embedded sixdimensional force sensing grasper with a Stewart-like elastomer structure, which effectively avoids the interference of the water environment on the FBG through the inner cavity structure. Considering the measurement error caused by the state change before and after the installation of the grasper and the nonlinear characteristics caused by the processing error, the in-situ calibration method is proposed. Finally, the full-scale root mean square error of the designed 6-dimensional force/ torque is controlled within 4% by combining with ELM nonlinear decoupling. These results validate the effectiveness of the designed fiber optic conformal embedded six-dimensional force sensing grasper.