College - Author 1

College of Engineering

Department - Author 1

Industrial and Manufacturing Engineering Department

Degree Name - Author 1

BS in Industrial Engineering

Date

6-2018

Primary Advisor

Karla Carichner

Abstract/Summary

For this project the team PLANT3D worked along with Rory Aronson and FarmBot to generate a cheaper more user-friendly design for the FarmBot Genesis 1.3. Working with Rory and FarmBot, we as a team generated a list of design requirements and engineering specifications for the project. These requirements centered around creating a more accessible FarmBot model for the average person to be able to purchase and set up with ease. Much of this required taking the existing system and eliminating the most common problem areas. These were the track system, built using 1.5 meter aluminum extrusions and the complex interchangeable tooling system. Identifying the two main problem areas in the design allowed us to focus on potential solutions. With many potential systems looked at and analyzed the best ones to come out of the brainstorming process were a timing belt system that could exist directly on top of the raised bed and an all-in-one tool head system that could eliminate the need for constant changing of different tool heads. Several other designs were experimented with but ultimately were deemed to impractical or complex to reasonably fulfill the design requirements. Through multiple iterations of designs an ideal shape and layout of the wheel plates was developed. This design featured an edge which could reach below the edge of the raised bed and act as a hard stop from the FarmBot main gantry falling off either side of the raised bed. This also led to the design of aluminum end stops being placed along the corners of the raised bed in order to prevent the FarmBot gantry from running off of the ends of the bed. A double wheel design was implemented, not only to help improve the allowable deviations in the bed sides, but to provide a groove for the timing belt to easily pass. Along with the groove two idler pulleys were added onto the wheel plate to help in guiding the timing belt to the stepper motor pulley. The tool head was designed to take all the functionality of the different FarmBot tools and put them onto one tool head. In order to fit everything into one space the same size as one of the old tools, several of the components were replaced with higher quality sleeker alternatives. A new anti-clog water nozzle was added to replace the old plastic shower head. This nozzle also acts as a double for the weeder to save on space. The same Luer Lock and soil sensor were placed onto this tool head to maintain their functionality. By making these design changes costs of the system were significantly decreased. The combination of drive and tool system savings is almost 30%. The part count was reduced by over 65% by eliminating lots of small redundant parts. These changes also greatly reduced overall weight and complexity of the system. Testing the performance of our design showed no significant loss in function of the FarmBot. Precision remained within 2cm of targets everywhere around the raised bed. All but one of the parts of our new design are through current FarmBot vendors. The only new vendor is a plastic machining company manufacturing the delrin spacers. All the other custom parts will be waterjet cut by BigBlueSaw. The rest of the design is made from standard parts purchased through Open Builds and McMaster Carr. Moving forward this design shows that FarmBot could succeessfully operate as a more simplistic system, riding directly on top of a raised bed using only one tool head without any significant loss in precision or functionality.

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