CONCRETE PAVING PRODUCTIVITY IMPROVEMENT USING A MULTI-TASK AUTONOMOUS ROBOT
ABSTRACT To improve productivity in conventional concrete construction, autonomous robots that perform specific tasks are being developed. Single-task robots are capable of enhancing specific functions, though their impact on the overall productivity remains unclear. A robot that incorporates each task-specific piece of machinery used in the concrete paving process into one fully autonomous unit is evaluated. Assessing potential productivity from the use of a fully automated process is a required step for developing a full scale-system. With the purpose of identifying productivity benefits in an automated concrete paving operation, two concrete paving processes will be compared using simulation tools. One process is the conventional operation using intensive labour, slip form paving machine and auxiliary equipment. The other process is the automated operation using a fully autonomous robot. Applications of this assessment methodology based in simulation will allow for the determination of productivity indicators of automated operations in hazardous environments, using the respective results to complement prototypical tests.
Stringless Portland Cement Concrete Paving
This paper describes results from a study evaluating stringless paving using a combination of global positioning and laser technologies. A concrete paver manufacturer and a machine guidance solution provider developed this technology and successfully implemented it on construction earthmoving and grading projects. Concrete paving is a new area for considering this technology. A concrete paving contractor in Iowa agreed to test the stringless paving technology on two challenging concrete paving projects located in Washington County, Iowa during the summer of 2003. The research team from Iowa State University monitored the guidance and elevation conformance to the original design. They employed a combination of physical depth checks, surface location and elevation surveys, concrete yield checks, and physical survey of the control stakes and string line elevations. A final check on profile of the pavement surface was accomplished by the use of the Iowa Department of Transportation Light Weight Surface Analyzer. Due to the speed of paving and the rapid changes in terrain, the laser technology was abandoned for this project. Total control of the guidance and elevation controls on the slip form paver were moved from string line to a global positioning system (GPS). Results indicate that GPS control is a feasible approach to controlling a concrete paver. Further enhancements are needed in the physical features of the slip form paver hydraulic system controls and in the computer program for controlling elevation.
Automation and robotics opportunities: Construction versus manufacturing
Automation and robots are frequently mentioned as solutions to industrywide problems of increasing costs, declining productivity, skilled-labor shortages, safety, and quality control. Despite numerous attempts to develop automation and robotics for construction field operations, few practical applications can be found on construction sites today. The promises of robotics remain unfulfilled, and attempts to transfer automation technology from manufacturing have not been optimal. Identification of opportunities for automation requires analysis of construction work at the appropriate level. This paper presents a hierarchical taxonomy that divides construction field operations into several levels. The basic-task level is the appropriate level for construction automation. The paper presents a set of basic tasks that describe construction field work. Construction is compared to highly repetitive manufacturing operations to gain insight into the relationships among product design, process design, and fabrication. In manufacturing, product and process design are closely interrelated. In construction, process design is completely separate from product design, but is intimately related to fabrication. Until construction product and process design become more highly integrated, automation must occur at the basic-task level. Advances in construction automation will continue to be characterized by a machine performing physically intensive basic tasks, operated by a human craftsperson performing the information-intensive basic tasks.