A method for calculating static conditions of a dragline excavation system using dynamic simulation

A technique to numerically obtain the static equilibrium state of a conventionaldragline excavation system is reported, including static pose of the bucket as well as internal loads acting on elements of the excavation system. Equilibrium conditions are generated by numerically integrating the dynamic equations of motion with the hoist and drag rope lengths fixed. It is shown that this method can be greatly accelerated with the application of artificial forces and moments proportional to the velocity of the bodies that comprise the dragline excavation system. The benefits of appending artificial forces and moments are demonstrated on an exemplar conventional dragline excavation system using a complex three-dimensional dynamic simulation model. In this model, the bucket, spreader bar, hoist cluster, and drag cluster are modeled as rigid bodies with 6 degrees of freedom apiece while the drag rope, hoist rope, dump rope, hoist chains, and drag chains are discretized into a finite number of visco-elastic elements. Results generated from the numerical static pose simulation are compared against measured static pose data and agree favorably.