Harvest-Aid Robot

Mechanical Engineering Capstone Project

Our multidisciplinary engineering team developed an autonomous strawberry harvest-aid robot as part of a U.S. Department of Agriculture funded initiative. Before beginning our design, our team conducted field research to learn of harvesting procedures and of field conditions. We began with a plywood chassis prototype to allow the electrical engineering team to develop their navigation control system, while the mechanical engineering team continued to develop the final chassis.

Strawberry Tray

I designed and fabricated the strawberry crate tray and tray suspension. The tray accepts crates of various sizes, with quick and easy operation. Integrating the robot’s handles into the suspension mounts increased their strength while reducing their weight. A configurable, off-the-shelf bungee cord mounting system simplified fabrication and maintenance issues.

Tray Suspension

I developed a suspension simulation program through MatLab, using inputs gathered from an accelerometer mounted to our robot’s prototype. This allowed me to explore the relationship between the suspension’s dimensions and its behavior in a field setting.

Drivetrain

I designed a simple and effective mounting system for our Hall effect encoders and magnets. The black Delrin ‘donut’ design accurately centers the magnets on the motor shafts for easy assembly without adhesive. The milled aluminum mount, shown below, utilizes washers to adjust spacing between the encoders and magnets. The top images are of our prototype, which used a belt-driven drivetrain. The lower images are of the final version, using a chain-driven drivetrain.

Project managing this six-month project reinforced the importance of persistency, and of maintaining team chemistry in product development. We fabricated the majority of the robot’s components, on a 3-axis mill and a lathe.