Review of resistive force models for earthmoving processes

The force required to insert a tool into a medium is of major interest for the design and automation of earthmoving machinery. The present work review s previous investigations on forces encountered during earthmoving processe s by cyclic (but nonrotary) excavation machines. The objective is to integr ate the formulation for cutting and penetrating forces to those for excavat ion. Common practices for characterizing an unfrozen medium and the associa ted tool actions are discussed, followed by a general overview of various m odels describing earthmoving tasks of penetration, cutting, and excavation. Observation and analysis of cutting and excavation models reveals that the re is not a common ground for their validation, but it also identifies a co re of key parameters, reduced in number and essential to any further excava tion model. The paper suggests a normalized experimental verification and c omparison of the models before they can be further used.