Visual tracking and control of a moving overhead crane load

The trial stereovision is manufactured which is a non-contact sensor and tried to control the overhead crane by visual feedback. The stereovision has four degree of freedom for tracking and gazing with two cameras. The three-dimensional position of the crane load is provided with image data of two cameras, the focus distance, and four-vision drive angles and is used for crane control. The desired angles to control the stereovision is obtained using inverse kinematics that a point of intersection of two camera optical axes seems to always accord with the crane load center. On the other hand, in the overhead crane, positioning and vibration suppression of the crane load are controlled, using three-dimensional position of the crane load measured by the stereovision. The overhead crane load is transported by the simultaneous traveling, traversing and hoisting motions of the trolley and swings with the vibrating amplitude and its direction. Therefore the dynamic overhead crane model has five degree of freedom. Variable feedback digital gains of the trolley to control the crane load are pursued in consideration of the rope length change. Experimental results of the positioning and swing control of the crane load and tracking of the stereovision in case of the load transportation with up and down hoisting are reported, and the possibility of zoom lens activity is described. The experimental results of overhead crane control by visual feedback show that the control system was effective