Field Testing of an Automated Surface Finishing System for Large Diameter Storage Tanks

Abstract

Surface finishing of large storage tanks represents a typical area in which construction automation techniques can yield significant improvements over conventional methods. Current techniques are costly and laborious, and they expose workers to significant health and safety risks. Automation offers potential improvements in each of these areas and is well suited to the large, uniform surfaces of the tank wall. The University of Texas has developed a prototype automated surface finishing system for use on large diameter tanks. This system uses a computer-controlled motion module to refinish the vertical exterior walls of a tank. The module is configurable for both blasting and painting and utilizes conventional surface finishing equipment for these processes. The University of Texas' automated paint sprayer was field tested in January, 1992 at an Amoco pipeline facility in Alvin, Texas. These tests, which were used to demonstrate automation techniques to members of the construction community, are described in this paper. The successes of the system are reported along with the problems, and recommendations are given for improving the system. An economic analysis is presented along with future plans for the system.

Economic Analysis of Robots Employment in Building

“…The reported average output of a vertical finisher is c. 45-50 m2 per hour (70-150 m2 per hour per coat) and it saves 2-3 workers [4,20]. Let us assume that an average building in which it will be employed is 8 stories high, has a floor area of 1,000 m2 per story, and its gross facade area is c. 3,200 m2 (40% of the floor area).…”

“…The feasible investment is even more sensitive to the cost of labor: For average labor rate of $12.5 per hour (instead of $25) the value of the robot at 1,500 hours of utilization and 20-25 transfers will be $68,000, and at 500 hours and 5-10 transfers -only $20,000. If the robot can be improved to replace more workers, as envisioned [4,7,9,19], then its economic feasibility will substantially improve, even with low labor rates. According to one detailed report [17] one robot plus 3 workers should be able to perform equally to a team of 8 men.…”

Design and Fabrication of a Cartesian Painter Robot for the Construction Industry

“…This application, however, is limited to the painting of the exterior [9][10][11]. This system uses a computer-controlled motion module to refinish the vertical exterior walls of a tank.…”

“…T torque, kg-m J inertia, N-m 2 t time, s w angular velocity, radians/s g gravity constant, 9.81 m/s 2 W L weight of the load, N W S weight of the sprocket, N W C weight of the chain, N F frictional force, N R radius, m V linear velocity r density, kg/m d d design stress, N/m 2 d u ultimate stress, N/m 2…”

The Use of Simulation Results in the Economic Analysis of Robotized Construction Tasks

“…The evolution of the construction industry moves forward in several directions: management, the use of information technology and automation. Many attempts have been made to use robots in the construction industry in the last decade [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. The trend towards research into the use of robotic systems continues to increase significantly not only in the building construction sector but also in different areas such as inspection and service tasks, road construction and decommissioning.…”