Control of an electro-hydraulic manipulator by vision system using central point of a marker estimated via Kalman Filter

Abstract

In the paper, the vision system for control a electro-hydraulic manipulator is presented. The authors have proposed a Kalman Filter (KF) to estimate a central position of markers. Two different methods of initial estimation of markers position are used. First one is based on central point of marker’s mass. Second refers to a circle fitting method of binary object. These two methods theoretically give the same position of a central point of given marker, however, in case of image distortion results will have different errors. This can occur when operator is holding marker in a hand, and cover some parts of it. Therefore it is important to develop new robust method for marker tracking. Authors proposed Kalman Filter to estimate central point of a marker by making a fusion of information provided by two initial estimation methods. The conducted research proved that KF reduces totalmanipulator’s control error even in situation where 30% of marker area is invisible.