Visual Servoing of Robots using Estimated Image Features

Abstract

A major problem in a visual servo system arises because of longer sampling period of image processing as compared to that of manipulator control. This paper proposes a new visual servo system compensating the delay time of the image processing. To obtain an image feature of manipulators without delay time, variation of image feature during delay time is estimated by a Jacobian matrix from joint velocity to image feature. Moreover, a criterion function using the estimated image features is adopted so that manipulators can avoid obstacles using redundancy. Here, a strategy that enables less computational time and easy programming by using the Jacobian matrix is proposed. A feature based visual servo system without inner loop speed or position controller and 3D reconstruction is proposed. Here, the disturbance observer in joint space realizes acceleration control in image plane. The system utilizes the estimated image feature without delay in each manipulator control period. The proposed system is applied to trajectory control and obstacle avoidance using redundancy experimentally.