Advanced 2-DOF Counterbalance Mechanism Based on Gear Units and Springs to Minimize Required Torques of Robot Arm. - Hwi-Su Kim; Jongwoo Park 002; Myeongsu Bae; Dong Il Park 001; Chanhun Park; Hyunmin Do; Tae-Yong Choi; Doo-Hyeong Kim; Jin Ho Kyung (IEEE Robotics Autom. Lett., 2022)