Bi-mobile planar mechanisms for robotics obtained through inverse modelling

Abstract

Bi-mobile planar mechanisms are commonly used in various fields of robotics. By adding additional degrees of mobility (rotation and/or translation) to the basis, multi-mobile systems for manipulators or pedipulators (legs) found in various fields are obtained. The paper aims to highlight these mechanisms using bi-mobile planar kinematic linkages described in the classical literature of mechanism theory [1‒5,16,17,23,25] in which the basis and the effector are nominated by inverse modelling [8‒12,13,15]. The effector extremity of such mechanism may describe any trajectory in its field. This is equivalent to introduce a pair with two constrains which determines the structure to have zero degree of mobility, its inverse structural model could have only passive modular groups. All basis-effector solutions for planar bi-mobile mechanisms obtained from linkages with five degrees of mobility and two and three independent contours are mentioned. The mechanism mobility is given by two active kinematic pairs suitably placed in the same chain [8‒15]. The structural algorithm included in the paper offers the possibility to create various optimal solution for bi-mobile mechanisms. At the same time, the base-effector structural solutions mentioned in the paper are useful in designing these systems, and can be used to verify or adopt appropriate solutions.