Robotics Case Studies
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Advancing Sweet Potato Transplanting Technology
Motivo Engineering Posted 08/08/2019
Black Gold Farms is a nationwide, family-owned potato grower with an appetite for innovation. With challenges like increasing labor scarecity and rising costs, Black Gold Farms is taking the future of their business into their own hands.
An automated sweet potato transplanter needs to make business sense: improve transplanting speed and quality, reduce the required number of operators, all while being robust and reliable for the lifetime of the machine. A typical transplanting season occurs over 10 weeks, requiring hundreds of laborers to keep up with the pace of ~500,000 slips/hour during the brief windows of cooperative weather. To complicate matters, planting season comes once a year and doesn't wait. Motivo needed to design, build, and test the first automated transplanter in 4 months in order to meet the 2018 transplanting season.
Sweet potatoes have a unique lifecyle, one that has prohibited automation until now. The challenge comes down to the sweet potato "slip," an approximately 1 foot long, highly variable plant stem harvested from the mother bed potatoes and individually transplanted into the growing fields at the start of each season. Traditionally, only human hands have been capable of gently manipulating individual slips without tearing leaves or tangling multiple slips, and inserting the slips into the ground using early 1900's designed manual planters borrowed from the tobacco industry.
After an on-site tour of one of Black Gold Farms' sweet potato operations, Motivo generated a roadmap taking a holistic view of the entire existing sweet potato process from slip harvest to end customer delivery. Constant collaboration with Black Gold Farms agricultural engineers and Motivo's multiple subsystem approach enabled parallel development of different process concepts for accelerated design iteration. The transplanting step of the entire process was identified as the optimum opportunity for return on investment. To manipulate individual sweet potato slips, Motivo developed several custom articulators and novel singulated transportation methods. Each subsystem consisted of patentable innovations protecting Black Gold Farms investment. The prototype system developed is capable of taking bulk stored harvested slips from a minimal operating crew and outputting a consistent planted row of evenly spaced transplanted slips. The system is also capable of slip rejection and buffering input to ensure maximum field utilization.
In preparation for field testing, Motivo conducted iterative testing initially in our lab, and then in local fields. During these local field tests, Motivo focused on replicating field conditions present in Spring planting season in Louisiana during Winter in California including soil type and moisture content. Less than a year after Motivo first met Black Gold Farms, the team had successfully transplanted the first sweet potato slip using our prototype system.
After starting the design phase in March 2018, Motivo completed a successful field test of the first prototype transplanting system, in June 2018, just in time for the normal sweet potato transplanting season. Further development including demonstration of a production representative machine are planned for this coming 2019 season.