An operator-controlled crack-sealing machine was developed and tested at the Advanced Highway Maintenance and Construction Technology (AHMCT) Research Center at the University of California, Davis. The machine, integrated onto a single truck, provides ease of operation and a simple, automated method of sealing random pavement cracks. The operator provides the machine its tasks and is the decision maker; the machine automatically performs the repetitive and dangerous tasks of mapping pavement cracks, creating seal paths for the robot, and sealing the cracks. The operator communicates with the machine through a simple user interface adjacent to the driver. This operator control approach drastically reduces the machine's control complexity relative to fully automated crack-sealing machines. To be able to seal cracks within a full lane without intruding into adjacent lanes, a telescoping long-reach robotic arm was developed that can position the sealing head mounted to its end in a large 3.7- x 4-m (12- x 13-ft) workspace, within 0.4 mm (1/64 in.) at a traverse speed up to 1 m/s (3 ft/s). A special sealant applicator that deploys a pressurized reservoir was developed to allow high-speed and automated sealing operations. A 100-Mbps fast Ethernet and 10-Mbps wireless control network allows for distributed real-time motion control, input/output control, and machine vision. A fully object-oriented, multithreaded Internet-based software architecture allows reliable and efficient system integration and provides an interactive and responsive user interface for feature-rich and easy imaging, path planning, and system control.
Abstract