RT Journal T1 A Stiffness Adjustment Mechanism Based on Negative Work for High-efficient Propulsion of Robotic Fish A1 Dong Xu, Haining Zeng, Xiang Peng, Ziqing Zhao, Jingmeng Liu* PB Journal of Bionic Engineering FD 2018-03-10 YR 2018 JF Journal of Bionic Engineering JO Journal of Bionic Engineering VO 15 IS 2 SP 270 DO https://doi.org/10.1007/s42235-018-0021-0 K1 robotic fish;propulsion efficiency;negative work;stiffness adjustment LK {http://jbe.jlu.edu.cn/EN/article/article_613.shtml}