Design and kinematics of a biologically-inspired leg for a six-legged walking machine

Legged locomotion is a fascinating form of motion. Almost all legged robotic systems are biologically-inspired by some kind of role model. The stick insect and cockroach are two of the most popular role models in the field of six-legged walking robots. Although, their legs have at least four degrees of freedom, most robotic systems, which are biologically-inspired by these insects, come along with only three joints in each leg. In this paper we will present a new leg design with four degrees of freedom for the six-legged walking machine LAURON. This enlarges the workspace of our leg significantly compared to previous leg generations and makes it very similar to the leg of the stick insect. With the additional rotational fourth joint the kinematic structure becomes redundant. The inverse kinematics for this redundant structure is solved in a very efficient way by benefiting from the orientational redundancy.