A robotic proximal sensing platform for in-field high-throughput crop phenotyping

Abstract

<p>A rapidly increasing world population and changing climate means plant scientists will need to be able to efficiently develop crop varieties to feed the world. Although the technology for sequencing the genomes of plants has advanced, the technology for characterizing the physical traits of plants has remained relatively static. This gap in technology has become known as the “Phenotyping Bottleneck.” To close this gap, researchers are working to develop robotic systems that can efficiently recognize various physical traits of plants. The goal of this research was to investigate how the design requirements for a vehicle that interacts with a biological system are translated into a working mechanical system. The design requirements include the ability to traverse and image crops in 30-inch wide space between crop rows. This thesis reports the concepts, design decisions, and manufacturing process around the construction of such as a phenotyping robot namely Phenobot 3.0, which stands for the 3rd generation of our phenotyping robot series. Phenobot 3.0 is optimized for phenotyping maize plants in the field but can be adapted for phenotyping other crops. Specifically, Phenobot 3.0 is designed to be narrow to fit between the rows but also tall for sensor placement so that it can gather data from the emergence to the full height of maize plants. To achieve the needed stability of the sensors (LiDAR, stereo cameras), the robot employs a self-leveling mast to cope with the uneven terrain while ensuring proper sensor to plant placement. Unlike many other field-based phenotyping robots, Phenobot 3.0 employs a 4-wheel-drive articulated drivetrain that has differentials on each pair of wheels to ensure maximum steering efficiency and prolonged operational time in the field. Phenobot 3.0 will be a member of PhenoNet, a network of five robots for maize plant phenotyping under different growing environments, a project funded by the National Science Foundation. The scale of this project implies that each design requirement must be carefully evaluated so that the manufacturing process can be easily scaled up to produce multiple units. The results from the preliminary tests of the Phenobot 3.0 prototype have demonstrated satisfactory functionalities and expected performance metrics.</p>