Image based visual servoing using algebraic curves applied to shape alignment

Visual servoing schemes generally employ various image features (points, lines, moments etc.) in their control formulation. This paper presents a novel method for using boundary information in visual servoing. Object boundaries are modeled by algebraic equations and decomposed as a unique sum of product of lines. We propose that these lines can be used to extract useful features for visual servoing purposes. In this paper, intersection of these lines are used as point features in visual servoing. Simulations are performed with a 6 DOF Puma 560 robot using Matlab Robotics Toolbox for the alignment of a free-form object. Also, experiments are realized with a 2 DOF SCARA direct drive robot. Both simulation and experimental results are quite promising and show potential of our new method

Motion estimation of planar curves and their alignment using visual servoing

Motion estimation and vision based control have been steadily improving research areas recently. Visual motion estimation is the determination of underlying motion parameters by using image data. Visual servoing on the other hand refers to the closed loop control of robotic systems using vision. Solving these problems with objects that have simple geometric features, such as points and lines is rather easy. However, these problems may imply certain challenges when we deal with curved objects that lack such simple features. This thesis proposes novel vision based estimation and control techniques that use object boundary information. Object boundaries are represented by planar algebraic curves. Decomposition of algebraic curves are used to extract features for motion estimation and visual servoing. Motion estimation algorithm uses the parameters of line factors resulting from the decomposition of the curve whereas visual servoing method employs the intersections of lines. Motion estimation algorithm is verified with several simulations and experiments. Visual servoing algorithm developed for the arbitrary alignment of a planar object is tested both with simulations on a 6 DOF Puma 560 robot and experiments on a 2 DOF SCARA robot. Results are quite promising