Seeking the Holy Grail: Full-Size Dynamic Model of Giant Excavator

Virtual prototyping has long been the holy grail for enterprises looking to streamline their product development cycle. Using physical prototypes to test new concepts and improvements can cost manufacturers millions of dollars for downstream testing and prototype production. A virtual prototype is essentially an exact 3D digital replica of a physical object. This precise CAD model can be used as the basis for motion simulation, analysis, design, interference checking, animation and many other engineering tasks.

Caterpillar's earthmoving equipment is extraordinary not only because of its enormous size. A bulldozer or excavator has thousands of moving parts, all interacting with each other, all impacting the physics of the machine-to-earth interface and human-tomachine interaction. This complexity characterizes some of the major challenges Caterpillar faced in creating an effective model. However, the tremendous benefits of having such a model fully justify the ensuing effort.

Track-type traction has been around for almost a century. Bulldozers create propulsion as they push against the soil. The ground is a tremendous energy dissipater at the track-to-ground interface. Caterpillar engineers were interested in creating very detailed dynamic models to predict traction performance and evaluate designs in a highly sophisticated way. This advanced approach to product development has the potential to reduce overall R&D costs dramatically, which was one of the key factors driving this project.

The research engineering team at Caterpillar came up with a set of requirements for the system that would capture a D9 bulldozer'strack-in-motion data as well as other relevant 3D coordinate data derived from the bulldozer's surface and movement. This unique data collection project necessitated an extraordinary mixture of high-tech measurement instruments that would generate 123 channels of data gathered simultaneously from instruments fixed to the ground moving with the tractor chassis, and over 40 channels of two-stage telemetry data rotating with the track. . . . .