Dynamic Characterization and Modeling of Flexure Based Planar Mechanism

Abstract

Abstract This paper investigates design, modeling and fabrication of a flexible five bar mechanism, which incorporates large deflecting flexure hinges attached to rigid links. This 3D printed flexible robotic mechanism is actuated by two servo motors and machine vision is used to obtain its tip position information. Detection of parts accomplished using color thresholding of a dynamic region of interest, while the position of detected elements is measured using the pinhole camera model. Under the assumption of non-small length flexures, where low aspect ratio is not satisfied, we adopt an initially curved pseudo rigid body approach to model each flexure as two rigid links that are pinned on top of each other using torsional springs, which capture the load-deflection behavior of the compliant flexures. Kinematic and dynamical equations are derived using both vector closure loop equations and Euler’s Laws of Motion. Adams simulation is performed by exporting the CAD model as a parasolid file, defining revolute joints and input motions and converting the rigid body to flexible. Mathematical model is validated using both the experimental data and Adams simulations.