Two-stage mechanism path synthesis using optimized control of a shadow robot: Case study of the eight-bar Jansen mechanism

Abstract

A novel methodology for the optimal path synthesis of mechanisms, particularly considering a high number of linkages and prescribed timing of the desired path, is presented in this paper. Such mechanisms are attracting increased interest in innovative fields such as surgical and rehabilitation robotics. The approach presented here is focused on optimizing the control effort of an equivalent "shadow robot" and utilizes a two-stage synthesis algorithm that shows promising capabilities. As a case study, the proposed approach is applied in the context of the popular eightbar Jansen mechanism. In the first stage, we explore a typical Jansen mechanism generating only the pure shape of a desired path, without considering its exact scale, orientation or position, and assuming a normalized path and mechanism. In the second stage, the normalized mechanism is resynthesized to match the non-shape relevant characteristics, i.e. scale, orientation, and position. Some numerical examples are also given to show the efficacy of the suggested method.