On-Board Arm

In this paper we present a new methodology to achieve vision-based control using a mobile manipulator to reach a required three-dimensional target position and orientation. Examples of mobile ma-nipulators include standard forklifts and backhoes, which have a fixed manipulator mounted on a mobile platform. The overall objec-tive of this methodology is to apply the nonholonomic degrees of free-dom represented by two independently driven wheels together with the holonomic dexterity of the on-board arm in order to bring about a desired positioning objective for the arm. Mobile Camera-Space Manipulation and an extended Kalman filter are implemented to use a minimum number of holonomic and nonholonomic degrees of free-dom as required for the end member of the on-board arm to achieve a target position and orientation. We present this vision-based method to control mobile manipulators as an alternative to methods such as visual servoing and calibration (i.e., stereo approaches). This new approach only requires a minimum number of holonomic degrees of freedom to achieve the required three-dimensional positioning by taking full advantage of the nonholonomic degrees of freedom. Ex-perimentally, the method shows itself to be robust to errors in the nominal kinematics and the optics models, as demonstrated by the experimental tests. KEY WORDS—mobile manipulators, mobile robots, ma-chine vision, Kalman filter, camera space manipulation 1