Development of an automated stability control system for lifting machines at construction sites

Abstract

Overturning of mobile boom cranes remains one of the most severe failures at construction sites. A standard load moment limiter is tuned to the rated load chart obtained for a horizontal supporting area and registers neither the actual tilt of the supporting contour nor the settlement of outriggers. The aim of the work is an author's computational model of continuous load stability control that reduces the measurement of outrigger reactions, frame and boom angles and wind speed to a single coefficient computed in real time. The calculation follows the limit equilibrium scheme about the tipping edge for a model crane with a rated capacity of 25 t and an outrigger base of 5,62 by 5,84 m; the wind load is taken according to GOST 1451-77 and the regulatory framework is traced through the 2020-2026 editions. The critical tilt at which the rated capacity still corresponds to the normative coefficient of 1,15 varies from 1,76 degrees at a radius of 6.0 m to values above 6 degrees at a radius of 16 m and more, and at a tilt of 3 degrees the coefficient at short radii drops to 1,02. The expanded uncertainty of the computed coefficient amounted to 2,7%, with the dominant contribution from the error in determining the load mass. The smallest stability margin occurs at short radii with a heavy load, which reverses the customary view of the maximum radius as the most hazardous configuration.