Optical marker‐based end effector pose estimation for articulated excavators

• The use of camera-marker sensors for excavator pose estimation was demonstrated.
• Several marker-based excavator pose estimation prototypes were designed and tested.
• A prototype employing cameras, markers, and a cable potentiometer proved successful.
• Camera-marker pose estimation accuracy degrades in the vicinity of zero marker yaw.

Marker-based pose estimation, in which optical cameras monitor fiducial markers to determine the three-dimensional positioning and orientation of an articulated machine's end effector, has been identified as a potential low-cost alternative to currently available machine control and guidance systems. In an effort to develop such a marker-based pose estimation system for excavators, several iterations of prototypes were designed, fabricated, and tested. Performance was measured in terms of the system's ability to estimate bucket tooth position, with an acceptance criterion of 2.5 cm (1 in.) of absolute error. Although initial prototypes were found to possess practicality and performance issues, a fourth prototype offered encouraging experimental results suggesting the feasibility of marker-based sensor technology for excavator pose estimation. Further work needed to refine the technology for large-scale practical implementation was also identified.

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