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A Multistage Controller with Smooth Switching for Autonomous Pallet Picking

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review


Original languageEnglish
Title of host publicationIEEE International Conference on Robotics and Automation
Place of PublicationStockholm, Sweden
Number of pages8
ISBN (Electronic)978-1-4673-8025-6
Publication statusPublished - 19 May 2016
Publication typeA4 Article in a conference publication
EventIEEE International Conference on Robotics and Automation -
Duration: 1 Jan 19001 Jan 2000

Publication series

ISSN (Print)2152-4092


ConferenceIEEE International Conference on Robotics and Automation


This paper addresses the problem of pallet picking by an Articulated-Frame-Steering (AFS) hydraulic machine. We propose a macro-micro visual mobile manipulation architecture, where a smooth switching logic navigates the robot to pick an object. The state space is divided into several regions depending on the accuracy of the vision and robot's degrees of freedom. The control architecture benefits from the following phenomena: at distance, when the location of the object of interest is detected, its orientation may not be reliably estimated; at some closer distances, orientations also become available; and because pallets are wide with small height, yaw angle estimation are more accurate than pitch is. The switching logic is devised to control the corresponding degree of freedom of the mobile manipulator in each region. Moreover, in different regions, we employ different coordinate frames, namely an earth-fixed frame or an object-local frame, which is more natural for the problem in that region. We show that the architecture accomplishes the following: 1) it eliminates the need for replanning as the accuracy of pose estimation improves; and 2) it provides the mobile base with a longer corridor to steer toward the pallet and align its heading. We also incorporate a robust, accurate solution based on fiducial markers for object manipulation in unstructured outdoor environments and unfavourable weather conditions, which relies solely on a monocular camera for pallet detection.


  • visual servoing, Mobile manipulators, Vision-based method, navigation

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