Design, Optimization and Evaluation of a New Cylinder Attachment Geometry to Improve the Hopping Height of the Bionic One-Legged Robot

Due to the high power-to-weight ratio and robustness, hydraulic cylinders are widely used in actuation area of legged robot systems. Most these applications focused on motion stability, gait planning, impedance control. However, energy efficiency robotic system is also a very important point be considered. Hopping locomotion requires fast extension tibia leg at end take-off phase, which causes continuous increment cylinder velocity under normally direct attachment geometry (DAG) cylinder. This leads flow requirement, large pressure drop, low efficiency. Therefore, we propose four-bar mechanism (FMAG) improve by refining relationship between joint angle displacement trend. The kinematic dynamic models bionic one-legged built calculate hopping process during phase. Based established models, design parameters both DAG FMAG optimized maximize height, respectively. experiments conducted verify effectiveness new geometry. experimental results show that phase increases 14.8% FMAG.