Automated Harvesting
Description



Robotic harvester operating in California

For robot positioning and navigation, NREC implemented a differential GPS-based teach/playback system. Differential GPS involves the cooperation of two receivers, one that's stationary and another that's roving around making position measurements. The stationary receiver is the key. It ties all the satellite measurements into a solid local reference.

With the teach/playback system, the Windrower "learns" the field it is cutting, store the path in memory and then is programmed to repeat the path on its own.

Early in the project, the NREC team used color segmentation to determine the cut line for machine servoing. The approach differentiates the percentage of green representing the standing crop and the brown stubble of the cut crop. The system’s computer scans the cut line to determine machine direction. The Windrower is guided at speeds of 4–8 mph to about a 3-inch variance from this crop line.

Other guidance and safety instruments include an inclinometer to protect the machine from rollover and tipover and a gyroscope for redundant guidance.