Vision-based online vibration estimation of the in-vessel inspection flexible robot with short-time Fourier transformation

• Published in: Fusion engineering and design Vol. 98-99; pp. 1683 - 1687
• Main Authors: Wang, Hesheng, Chen, Weidong, Xu, Lifei, He, Tao
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2015
• Subjects: Cameras; Computer vision; Environmental extremism; Estimates; Flexible arms; Flexible manipulators; Fourier transformation; Robots; STFT; Tokamak devices; Vibration; Vibration-estimation; Flexible arms; Computer vision; STFT; Vibration-estimation
• ISSN: 0920-3796; 1873-7196
• DOI: 10.1016/j.fusengdes.2015.06.181

•Vision-based online vibration estimation method for a flexible arm is proposed.•The vibration signal is obtained by image processing in unknown environments.•Vibration parameters are estimated by short-time Fourier transformation. The vibration should be suppressed if it happens during the motion of a flexible robot or under the influence of external disturbance caused by its structural features and material properties, because the vibration may affect the positioning accuracy and image quality. In Tokamak environment, we need to get the real-time vibration information on vibration suppression of robotic arm, however, some sensors are not allowed in the extreme Tokamak environment. This paper proposed a vision-based method for online vibration estimation of a flexible manipulator, which is achieved by utilizing the environment image information from the end-effector camera to estimate its vibration. Short-time Fourier Transformation with adaptive window length method is used to estimate vibration parameters of non-stationary vibration signals. Experiments with one-link flexible manipulator equipped with camera are carried out to validate the feasibility of this method in this paper.