Experimental comparison of leveling control schemes for the hyperstatic-leg support platform

Abstract

Leveling control for the platform with four or more legs is the technical mainstay in outrigger leveling of truck cranes, height and leveling control of vehicles, etc. Due to the “implicated coupling” between the platform and legs, the addition of one leg will cause a significant increase in leveling time, severe oscillations in leveling process, deterioration in accuracy and stability, and even leveling failure. For evaluating and selecting an appropriate leveling control scheme, in terms of leveling theory, three control schemes based on the dominant point chasing principle, That is, lowest-point regulation, cyclic regulation, and synchronous regulation, are studied, in which the virtual leg compensation is carefully considered. More importantly, coupling control schemes of independent geometry leveling (GCC), and synchronous geometry leveling and load uniforming (G&LCC), are proposed relying on linearized coupling models established by our team. In terms of verification, considering the elastic deformation reality, electro-mechanical bench tests are conducted for a six-elastic leg support elastic platform. Results confirm that the synchronous regulation has advantages from speed, stability, and safety. And the G&LCC scheme by synchronous regulation has obvious advantages in terms of leveling accuracy, speed, load controllability, and process convergence, and is of good application value for accurate, fast, and reliable leveling of hyperstatic-leg support platforms.