Estimation of maximum lifting load capacities of a hydraulic excavator via multibody computer modeling and simulation

Abstract

A three dimensional multibody modeling of a hydraulic excavator is developed to estimate the load capacities via computer simulation. For the modeling of the operating parts, 16 bodies are connected by the several kinematic joints with 4 dof (degrees of freedom). And 5 bodies are connected by joints with 6 dof in the modeling of supporting and carrier parts. There are total 22 bodies in the multibody excavator DADS model including the ground, and the system has 11 dof including the rotation about the swing axis. To model the force interaction between the track and the ground, two experimental results are measured and utilized to estimate the stiffness of the spring. A four-step algorithm is developed to estimate the spring constant combining the force and moment equilibrium equations with the experimental results. Using the estimated spring stiffness, the maximum lifting load capacities of a crawler type excavator in various positions are calculated. The calculated results are in a good agreement to the experimental results before the turnover occurs and are acceptable for the design data.