Soil Estimation Based on Dissipation Energy during Autonomous Excavation

This paper describes a new algorithm for the estimation of soils into different types employing an energy-based approach. Greatly simplifying the modeling of the tool-soil interaction process, energy components occurring during a dig are computed from simple force and bucket displacement measurements. In particular, the dissipation energy can be estimated allowing a prediction of the dynamic friction forces encountered during soil-tool interaction in the field of excavation. The proposed method measures force and displacement simultaneously during the extensively horizontal dragging phase while continuously recalculating the velocity, accumulated moved soil mass and total dissipation energy, creating a specific profile depending on the soil conditions. The creation of these profiles could be useful in providing information to a low level controller able to distinguish between different types soils. The method can thus be seen as an important component allowing robust and noise-free feedback in autonomous control in excavator vehicles. Copyright © 2008 IFAC