Synergy-based Knee Angle Estimation on Stairs and Slopes for A Powered Transfemoral Prosthesis. - Lifen Mo; Fei Gao; Yiou Sun; Zhipeng Tang; Jing Jie; Zhenhua Song; Wei-Hsin Liao; Fengyan Liang; Ming Yin (EMBC, 2024)