The development of a mobile manipulator imaging system for bridge crack inspection

A mobile manipulator imaging system is developed for the automation of bridge crack inspection. During bridge safety inspections, an eyesight inspection is made for preliminary evaluation and screening before a more precise inspection. The inspection for cracks is an important part of the preliminary evaluation. Currently, the inspectors must stand on the platform of a bridge inspection vehicle or a temporarily erected scaffolding to examine the underside of a bridge. However, such a procedure is risky. To help automate the bridge crack inspection process, we installed two CCD cameras and a four-axis manipulator system on a mobile vehicle. The parallel cameras are used to detect cracks. The manipulator system is equipped with binocular Charge Coupled Devices (CCD) for examining structures that may not be accessible to the eye. The system also reduces the danger of accidents to the human inspectors. The manipulator system consists of four arms. Balance weights are placed at the ends of Arms 2 and 4, respectively, to maintain the center of gravity during operation. Mechanically, Arms 2 and 4 can revolve smoothly. Experiments indicated that the system could be useful for bridge crack inspections.