Multifunctional Ag Vehicle

The MAV: A Multifunctional Agriculture Vehicle with Twiner, Staker, and Top Cutter Attachments

In 2019, 2nd Sight was commissioned by the Washington Hop Commission and supported by the USDA Specialty Crop Block Grant Program (SCBGP) and matching grants from the Spokane Health Sciences and Services Authority (HSSA) to design and build the MAV, or "Multifunctional Agriculture Vehicle." This innovative new piece of farm equipment will support modular attachments designed to automate several labor-intensive processes required in growing hops and other specialty crops.

$50,000 in labor savings

(250 acres)

7 seconds to tie

(2 knots)

6 weeks to twine

(250 acres)

About

After working with growers using our electronic farm labor tracking systems in the Prosser/Yakima area of Washington, we learned of other challenges that these growers face with their hops operations. Manually tying and staking the twine on which hops bines grow is a tedious process that is very labor intensive, causes a lot of grief, and costs money.

Hop yards in WA, OR, and ID are laid out nearly identically in all areas. Growers install support poles at set distances, place plants in a specific pattern from poles, and tie knots to the trellis cables at consistent positions as well. Automation is ideal for repetitive work with unchanging conditions on nearly identical growing grids.

The automated mechanism for tying took priority and has taken our skilled team of mechanical and electrical engineers over a year to develop. One of the first challenges to address was the current material used to twine hops: coir. Coir is made from the inner husk of a coconut. Although it is a low-cost option, coir fluctuates in thickness, is inconsistent in durability, and is inflexible (without pre-soaking). These are all factors that would not be conducive to automation equipment. The Twiner requires a material that is consistent and tough yet maintains the eco-friendly and low-cost nature of coir. Cost is critical because it requires about 55,500 feet of string to twine one acre of hops. That is over 25 million feet of twine for a 500-acre hops farm!

The best solution is to use an organic raw material called PLA (polylactic acid) made from renewable resources such as the plant starch from corn. PLA is a bioplastic that has become commonly used in a variety of applications such as 3D printing, “plastic” cutlery, and even for growing peppers and tomatoes in greenhouses. It is biodegradable when composted, strong for its thickness, more consistent in quality, can withstand exposure to the elements (sun and moisture), and can be easily packaged in spools where one twine end can be “pig-tailed” to a new spool. PLA is an ideal material for the automated Twiner attachment.

As development on the knotter or “Twiner” progressed, one of the issues we faced was removing the PLA twine from the trellis cables so that we could reuse the trellis cables for additional testing. To improve the speed and efficiency of removing these twines, we developed a “Top Cutter”. Hops growers currently use a variety of machines that cut the hops bines and twine from the top trellis cables during harvest. The machines were clunky, and when we tested them with the PLA, we found that PLA was a little too tough for them to cut efficiently. Since the twining automation already required a custom vehicle, it made logistic and financial sense to develop new Top Cutter attachments that could be mounted to the operator platform just like the Twiner mechanisms. What we found was that the Top Cutter attachment we developed to remove PLA twine was easier to use and more efficient than the growers’ current systems for harvesting hops. Thus, the MAV (Multifunctional Agriculture Vehicle) was born! 

In the agricultural industry, and especially in specialty crops, machinery is often specialized and only used during a short window of time each year. This can get expensive. Expanding the toolset of the “MAV” from twining and staking to top cutting provides more value to the grower and spreads the cost of the machine out over several months of use versus only two months during the spring when twining occurs.

Having already developed the knotter mechanism and having shown that they can tie two knots in seven seconds, the engineering team at 2nd Sight is now focused on building the staking mechanism. The Staker attachment development is scheduled to begin in 2023 with a completion date of early 2025.

The support from our hops grower partners, the USDA, and the HSSA has been critical in developing the MAV and its Twiner, Staker, and Top Cutter attachments. The 2nd Sight engineering team designed this system to align with our mission, “To advance automation in Ag by engineering innovative and reliable products that maximize productivity and efficiency in order to minimize costs and stress.” Sign up for our monthly eNewsletter to stay informed about the progress of the MAV as it moves out from the lab to the field!
PLA Twine for Stringing Hops

Benefits

Labor

  • No scrambling for workers
  • Reduce HR issues
  • No mid-job rate renegotiations
  • Decrease labor costs
  • No repetitive stress injuries
  • Minimize the gap between available labor and crop demand

Multifunctional

  • Easily and safely work on trellis cables
  • Work lights for extended workday
  • Quick attach modules
  • Great ROI
  • Improve quality controls
  • Robust field design

Service/Support

  • Three onsite visits annually
  • 24/7 technician on-call
  • Repair technician in three hours

PLA Twine

  • No presoaking
  • Biodegradable
  • Compostable
  • User-friendly packaging
  • Load pallet directly onto vehicle
  • Less retying due to failure
  • Part of service contract

Applications

Crop Compatibility

  • Hops tying/twining
  • Hops staking
  • Hops top cutting
  • Field pepper staking
  • Field tomato staking
  • Field pepper tying/twining
  • Field tomato tying/twining
  • Ornamental nursery tree staking 
Hops Plants Cone

Features

Elevated Platform and Boom

Multifunctional Agriculture Vehicle used for general field work as a mobile platform with elevated platform capabilities.

Features:
  • Engine
    • 74 Hp F34 Diesel
    • 74 Hp @ 2300rpm, max 236 Ft-lb torque @ 1300 rpm
    • Fuel Consumption - ~2.5 gph@ 100% load
    • 25 Gallon Fuel Tank ~ 10 hrs. at full load
  • Drive Train
    • Hydrostatic torque-hubs (can be configured as 2wd or 4wd)
    • Hydraulic Steering (can be configured as 2 wheel or 4 wheel steering modes)
    • 40-gallon hydraulic tank
  • Performance
    • 0.5 mph in twining operation
    • 3 mph max low-speed setting, 6mph high speed setting
    • 5% grade side hill operation (when fully raised)
  • Weight
    • Max 20,000 lbs. (est.)
  • Dimensions
    • Length = 21’, Width = 10’4”, Wheelbase = 139”, Height (lowered) = 9’9”,
    • Height (raised) = 18’, Deck: 11’6” long X 10’4” Wide

Twiner Attachment

Automated tying mechanism to attach twine (PLA) to a wire.

Features:
  • Two quick attach knotters
  • Pneumatically and electrically driven
  • 24 V motor power and control

Staker Attachment (Under Development)

Automated staking mechanisms to drive twine ends into the ground.

Features:
  • Two quick attaach staking mechanisms
  • Scheudled for 2022 implementation

Top Cutter

Automated top cutting mechanisms to cut hops bine and twine.

Features:
  • Two quick attaach top cutting mechanisms
  • Retract/expand pushers to adjust catch vehicle spacing
  • Compactor to presh hops down into catch vehicle


MAV leaves the lab for engine testing and diagnostics before field trials in the hops yard.
Field trials of the MAV were a success at a hops yard in Prosser, WA in October 2020.
Watch the Twiner tie knots to a trellis cable in seven seconds.
October 2021 Field Trials of the updated Twiner module ready for the staking mechanism.

FAQS

How did the hops project begin?

One of our long-time customers grows apples, cherries, grapes, blueberries, and hops. This farm asked if we could design a way to automate the stringing and staking of hops because it is a growing problem in the industry. After speaking with a number of hops growers in WA, ID, and OR, we found that EVERY grower listed this project as their highest priority to improve hop production. This project was funded by the Washington Hop Commission, the Washington State Specialty Crop Block Grant Program, the Spokane County HSSA, and by our company.

What is stringing and staking?

Stringing or twining is the process of affixing a length of twine to the hop trellis. This twine is typically about 21 ft. in length and extends to the ground from the 18 ft-high trellis cable. Staking is the operation of securing the twine to the ground near the hop plant. This is typically done by driving a “W” clip into the ground while capturing a loop of the twine.

What is the MAV?

The MAV stands for, "Multifunctional Agricultural Vehicle." The biggest issue in bringing automation to farming, is that much of the equipment is only needed for a very short time during the growing season. Thus, any automation would have to pay for itself quickly. Since automation is quite expensive to build, it is critical to evaluate the return on investment (ROI) of a new system. The MAV was designed to automate several operations on the farm so that implements can be quickly attached and removed. For example, the Twiner and Staker modules can be added in the early spring for stringing hops. These implements can then be removed and replaced with the Top Cutters for harvesting. At any time, the unit can be used as an elevated platform for work on trellis systems. In general, growers should be able to use this system nearly half the year which helps justify the investment. In the future, we plan to add additional attachments such as a hop combine and chopper so that the hops bines do not have to be removed from the field but can be processed immediately after cutting.

In which phase of development is this automation?

We accomplished Phase 1 of our plan by completing the automation in our facility. We completed Phase 2 in October 2021 by building the mobile platform (MAV), mounting the automation, and performing trials with the Twiner system. After several iterations of the Twiner mechanism, we have a knotter that meets all our specifications. Phase 3 is the development of the Staker. This project is currently under development and will be completed by 2024. Phase 4 will be the build and field testing of one production-ready MAV. This phase will be completed during the spring of 2025.

Can we still use coir twine?

No, unfortunately coir twine is not suitable to run through automation. After initial evaluation, coir was too stiff and inconsistent. Fortunately, we have found other twine materials that work very well both in the automation and in growing hops. MAV with Twiner and Top Cutter modules will be available.

What twine can we use in this device?

Currently, we have approved PLA twine from two different vendors and are working on jute twine as well. PLA stands for polylactic acid and is biodegradable plastic made from corn. This is a material that is very strong and maintains its strength throughout the growing season. Working with our grower partners, we have shown that PLA twine has worked with both adult and baby plants on every variety that has been tested (over 20 different varieties).

What is the cost of PLA twine?

PLA is comparable in cost to coir twine but has the advantage that it is much smaller in diameter so that the MAV can carry a lot more onboard. Jute twine is slightly more expensive than either coir or PLA and will only be used as a backup should there ever be an issue sourcing PLA.

How fast does the MAV travel?

The MAV has two speeds. In high speed it can travel from 0-6 mph and in low speed it can travel from 0-0.35 mph. The low speed is determined by how fast the machine can twine. All hop yards are on a 56 ft. pole to pole spacing on a diamond pattern with rows that are either 12 ft. or 14ft. in width. This means that trellis support cables are located every 28 ft. Each row typically contains 16 twines. Twines are placed 1.75 ft. from the pole, then every 3.5 ft. with 16 twines between poles. This means that the machine must be able to tie a twine 1.75 ft. from each pole and 1.75 f.t on either side of the support cables. If the MAV were to travel at 0.5 mph, we would only have two seconds to tie the knot to the trellis cable before we ran into the support cable and we simply cannot tie that quickly. At a speed of 0.3 mph, we have 3.8 seconds to tie the knot which is feasible.

How long does it take to twine a field?

The MAV was designed to twine and stake 250 acres in six weeks working 20 hours per day. It will twine one acre every 3.36 hours with just one person.

How much twine can the MAV hold?

At a minimum, the MAV holds enough twine onboard for one 10-hour shift. We may be able to hold enough twine for a full 20-hour shift.

My hop yards do not have that much room at the ends to turn, can the MAV be used in tight quarters?

Yes, the MAV was designed with both front and rear wheel steering. The vehicle can turn tight corners and even “crabwalk” between poles.

We tend to start twining when our fields are still quite soft and muddy, are we going to get stuck?

Probably not. The wheels are very wide, and the vehicle has four-wheel drive. There is an option to put treads on the system so that you could have a tracked vehicle if soft soil is a problem.

Is there going to be a problem with the machine tipping over when the operator is elevated?

The machine was designed to be safe for operation in fields with up to a 5% grade. When the machine is on a 0-3% grade, the tilt indicator light is green. If the grade exceeds 3% but is less than 5%, the indicator light goes from green to yellow. If the grade exceeds 5%, the machine will halt until the operator lowers the operator basket.

What does the machine cost?

The projected cost of the MAV with Twiner and Staker attachments is in the $250,000 to $300,000 range. When used for top cutting and as an elevated platform for trellis work, the ROI on this equipment is only a couple of years.

Are there any additional costs?

Yes, you will need to sign up for our Service, Support, Maintenance, and Twine Agreement. This is a five-year contract that includes service, support, maintenance, and enough twine for 250 acres for a fixed price. This guarantees your costs for a five-year period so that you do not have to worry about the machine maintenance. Except for normal wear and tear or negligence, any problems with the machine are covered by this contract

How would we break even in the first year by purchasing the MAV?

As per our grower partners, the average cost to twine 250 acres is $147,086. This includes labor, twine, and miscellaneous costs such as preparing the twine and stringing loses. This cost does not include L&I costs or other labor-related expenses which should be eliminated with this automation. The value of this machine for top cutting purposes is placed at $35/hr. for 360 hours and for elevated platform work at $35/hr. for 160 hours. Based on these numbers, the expected minimum yearly value for this machine will be approximately $164,700 per year.

Currently, capital equipment farm loans are advertised at 3% over a five-year period. For a $250,000 loan, this yields an annual rate of $53,906 in principle and interest payments. When combined with the cost of the Twine/Service/Support contract, the first-year cost for this automation is $164,156, slightly better than breakeven for the grower in the first year of purchase. If labor costs rise at 8% per year and twine cost rises by 3% per year, this automation will save the average grower almost $450,000 over a 10-year period.