Past Issues

Studies in Informatics and Control
Vol. 5, No. 3, 1996

Learning Assembly Operations: A Case Study With Real- World Objects

Marnix Nuttin, Hendrik Van Brussel
Abstract

This work presents a learning ap­ proach for industrial assembly tasks. lt was de­ veloped in the framework of the ESPRIT project B-Leam II. Often in industrial applications, often objects with a complex geometry have to be assem­bled. Compared to "top-down model-based" ap­ proaches, "data driven learning" approaches offer several advantages, such as (I) faster development ( 2) easier implementation and (3) computationally less expensive on-line. Model-based approaches be­ come very complex for real-world geometries and are ill-conditioned for relatively small objects. The test case consists of the insertion of an electric switch into a fixture. The learning task is to find the correct fixture position based on measured contact forces. Regression trees are compared with the cascade cor­relation architecture. Experiments with a KUKA industrial robot equipped with a force/torque sen­sor, validate the learning approach. Another con­tribution of this work is that the problem of toler­ances is identified and assessed. The reported ex­periments show the effect of tolerances on learning performance.

Keywords

Sensor Assisted Robotic Assembly, Learning Approach, Neural nets, Cascade Correlation Architecture, Regression Trees.

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