Autonomous Free-Form Trenching Using a Walking Excavator

This letter shows accurate and autonomous creation of free-form trenches using a walking excavator. We present hardware extensions and modifications for full automation, a mapping approach specifically tailored to excavation, environment collision-free trajectory planning on these maps, an arm controller aware of various limits and an improved state machine that enables the execution on real hardware. Furthermore, previous work about excavation planning and the design of a single soil-independent dig cycle is extended and transferred from simulation to hardware. The entire system is tested on a four-segment, piecewise-planar trench, and a free-form curved trench. Both shapes were successfully excavated with unprecedented accuracy.