Object-Based Visual Servoing for Autonomous Mobile Manipulators

Abstract

This paper proposes an object based vision (O-BV) system to implement visual servoing for autonomous mobile manipulators using two charge-coupled device (CCD) cameras. Conventional stereo vision (C-SV) system estimates the depth based on the disparity between two camera images for the same object. However, the disparity is not an effective cue for a small disparity at a long distance. To resolve this problem, in the proposed O-BV system, the individual camera tracks the object independently, and the angles of the two cameras are used to estimate the distance to the object. This depth estimation technique is applied for an autonomous mobile robot to approach to a target object precisely. The O-BV system is experimentally compared to the C-SV system in terms of computing time and depth estimation accuracy. Also the two cameras which are attached on the top of the autonomous mobile manipulator have been utilized for the mobile manipulator to approach to a target object precisely through the visual servoing. Through the experiments, it is demonstrated that the fast and precise depth estimation is a critical factor for the successful visual servoing.