High Stakes: Agricultural Robot
The Problem
Farmers growing crops like bell peppers, tomatoes, beans, and other specialty crops use 3-6 foot wooden stakes and rope to support their crops' vertical growth.
Across 15 million acres in the US, these wooden stakes are being pounded into the ground manually by laborers. The high cost of labor plus a shortage of workers across the country make these types of crops very costly to grow.
High Stakes aims to address this pain point by developing an automate solution to stake insertion.
Product Requirements
Working with local specialty crop farmers, the team devised a set of engineering requirements. Experiments were conducted using an Instron to determine the force needed to insert the stakes into farm soil.
Design Ideation
To best meet the needs of the customer, the machine design was selected to be a tractor attachment with an independent battery and motor. There were 2 key stake insertion mechanisms considered for the design, using circular motion or vertical motion to push the stake into the ground as shown in the figure.
Ultimately the circular insertion mechanism which would rotate at a speed proportional to the machine's horizontal movement was selected because this design allowed the machine to move continuously while inserting the stakes, whereas for the other design, the machine would have to come to a full stop to insert the stake, reducing the efficiency. This design creates a controls problem when trying to keep the stake upright, as shown in the figures.
Proof Of Concept
To validate the design, the team developed a 1/6th scale prototype. This also allowed for the development of the controls code while fabrication of the full scale prototype was in progress. The procedure used to insert the stakes is shown in the figure below.
Full Scale Prototype
I led CAD development of the full scale prototype. Wood working was used to create the outer frame, while welding was used to create the chassis of the prototype. A metal arm with an attached 3D printed gripper is driven by a variable speed motor to insert the stakes. The successful insertion of stakes into the ground is shown in the video below.
