Pose Control of Mobile Robots for Vision-Guided Material Grasping

• Main Authors: Mau-Hsiung Hsu, 許貿雄
• Other Authors: Tsing-Iuan Tsay
• Format: Others
• Language: en_US
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/60648860197434949207

碩士 === 國立成功大學 === 機械工程學系碩博士班 === 90 === Abstract Mobile robots frequently replace humans in handling and transporting wafer carriers in semiconductor production lines. The constructed mobile robot is primarily composed of a mobile base, a robot manipulator, and a visual system. This flexible material transfer system can save the expense of human resources, as well as provide reliable and efficient transportation and handling. During pick-and-place operations between a predefined station and the mobile robot, position and orientation errors of the mobile base are inevitably caused by the guidance control system. Thus, this study employs the eye-in-hand vision system to provide visual information for controlling the manipulator of the mobile robot to grasp accurately stationary material. This work further presents a position-based look-and-move, task encoding control strategy for eye-in-hand vision architecture, that maintains all target features in the camera’s field of view throughout the visual guiding. Moreover, the manipulator can quickly approach the material and precisely position the end-effector in the desired pose. Numerous techniques are required for implementing such a task, including image enhancement, edge detection, corner and centroid detection, camera model calibration method, robotic hand/eye calibration method, using a camera with controlled zoom and focus, and task encoding scheme. Finally, these technologies are experimentally applied to realize a manipulator that can quickly approach a target object and precisely position its end-effector in the desired relative pose to the object, independently of where the target object is located on a station. Specific experimental demonstrations include grasping the target object with different locations on the station and grasping the target object tilted by different angles to the station.