Design and analysis of a concentrated-driven bionic-leg capable of omnidirectional legged locomotion based on 3-Dimensional dual-parallelogram-linkages

The Flexible, fast and lightweight leg mechanism is the key to improve legged robot's mobility, efficiency and adaptability on complex terrain. Inspired by the motion mechanism of legged animals, we report a concentrated-driven omnidirectional legged locomotion bionic leg - OmniLeg. All the motor actuators are centrally installed in the hip plate of the proposed leg to reduce the rotational inertia. Meanwhile, the special 3-Dimensional dual-parallelogram-linkages transmission mechanism enables it to have the ability of omnidirectional legged locomotion in 3-Dimensional space and makes the posture of leg's endpoint does not change with the motion of the leg mechanism which simplifying the motion control. In this paper, firstly the theoretical model, including mobility, kinematics model, inverse kinematics model, dimension parameters and workspace model, have been derived, analyzed and verified with the design and control of the real prototype. Next, to demonstrate the ability of omnidirectional legged locomotion intuitively, we manufacture a single-legged omnidirectional mobile robot and design a quadruped robot, and the simulation and experiment result illustrate that the design and analytical mode of OmniLeg is feasible and correct, which could be widely applied in the field of legged robot.