Parameterized Path Planning for Reaping Operations

Path planning is crucial for autonomous reaping process and in particular reaping path should be as identical as possible to seeding trajectory so that autonomous vehicles can reap precisely．In the case of autonomous seeding, planned seeding path can be applied directly to reaping process, yet in the case of non-autonomous seeding in which there is no planned path, it is crucial to generate reaping path close to seeding trajectory．The most common applied path planning is the AB line which is generated by setting terminals of a path．However, in some specific cases, paths may be limited to curved and irregular shapes, hence AB line is no longer applicable．Through research, a lot of Chinese farmers prefer path planning similar to AB line when it comes to cases mentioned above．In order to meet needs presented by farmers, a solution for generating parameterized reaping paths wass proposed．Firstly, coordinates and attitudes of main antenna on a seeding vehicle were sampled and used for calculating coordinates of rear axis midpoint．Next, aggregated points and outlier points were eliminated and path nodes were picked which showed general shape of seeding trajectories．Finally, parameterized paths were generated using piece-wise interpolation based on cubic Bezier curves．LOVOL M1004 tractor was used as experiment platform and data was sampled in experimental station in Xiaowangzhuang, Changping District, Beijing City．Experiment results showed that maximum lateral errors between parameterized curves and raw trajectories were 0.52 and 0.40 m in two experimental groups under condition that average operation speed being 5 km/h, compression threshold for aggregated points being 1 cm, curvature threshold for outlier points being 1 m⁻¹ and compression threshold for path nodes being 30 cm．This solution proposed was confirmed to be effective in precisely restoring seeding trajectories restoration and generating reaping paths．