by Steve Meyer, Contributing Editor
Decades of exposure to the realities of keeping farm equipment running have provided FireFly Equipment with insight to the problems, and the solutions, needed to making highly automated agricultural machinery a reality.
Forest for the trees? Sometimes we get too close to a problem and the big insights escape us. This is not the case for Steve Aposhian and his family at FireFly Equipment. Aposhian grew up on the family turf farm and landscaping business—and gained a deep understanding of how things work, as well as when some things don’t work. After spending a great deal of time repairing harvesters and turf equipment from other vendors, he had the expertise to begin the automation journey that has made his company a success.
Starting with a degree in mechanical engineering from the University of Utah, and later becoming a certified National Instruments Labview developer, as CTO of FireFly, Aposhian has taken turf harvesting into the 21st Century. His vision of a successful, highly automated harvester began from a solid mechanical foundation combined with a unique controls strategy that takes advantage of state-of-the-art actuator and communications technologies. This approach to automation provides the platform for creating the highest throughput, performance and reliability in the harvester. In fact, the entire engineering team at FireFly has decades of design, test, design for reliability and manufacturing process expertise, which has resulted in what is one of the most reliable products in agricultural equipment.
1. Key in on overall equipment effectiveness
How well equipment performs is the sum of several important metrics. Probably the most important is uptime, the percentage of time the machine operates correctly as a ratio of the total number of hours there is demand for production. Another element of effectiveness is mean time to repair—if something fails, how long will it take to repair and get back to work? Efficiency is also an important aspect of performance. Reducing operating cost per hour or per unit of production is a factor that is gaining greater attention in an energy-conscious environment.
All of these elements are important to farmers. Agricultural equipment must perform day in and day out, with a minimum of downtime. If something breaks it has to be easy to fix. Throughput and ease of use are just as important in the field just as they are in a manufacturing facility. And in spite of low fuel costs, reducing fuel consumption is always important. Firefly has focused on all of these elements to create the most productive and reliable sod harvester on the market.
2. Embrace complexity
Machines and projects that involve a lot of subsystems can become very complex to manage in development—and the process of meeting the overall performance goals of the system can be a daunting challenge. Sometimes the technology alternatives are not obvious and some investigation is required to explore the options.
The best way to approach complex projects is to divide the big project into its major parts. Evaluate a variety of alternative strategies and look for “best in class” for each subsystem. What works in one area may not be the best choice in another.
The starting point for any major piece of agricultural equipment is the drivetrain that propels the main tractor. FireFly uses a 115-hp John Deere engine and 4-wheel hydrostatic drive for primary motive power. The same power plant also provides hydraulic pressure to run the auxiliary systems. Among the key benefits of hydraulic technology are extremely high energy density, generally quiet operation and the efficiency of combining several loads on to a common source. The main conveyor, the raise and lower mechanism on the cutter and numerous other actuators are powered from the same highly efficient source. In addition, FireFly employs a continuous filtration system for the hydraulic fluid to extend operating life and efficiency of the equipment.
While most systems are hydraulic, the stacker requirements were considered to be beyond what could be reasonably accomplished using hydraulic actuators. High speed, smooth acceleration and extreme precision positioning are possible with hydraulics, but it is very expensive and there are serious packaging limitations that made a hydraulic solution for the stacker impractical.
3. Find creative solutions
Stacking cut pieces of sod on a pallet is not a problem best solved by hydraulics. The sod is generally soft and pliable as it is cut from the ground. If the stacks aren’t tight, the pallet contents can slip off the pallet and make a huge mess. Part of the stacking requirement is the ability to program different sizes and shapes of cut sod. This further requires different pallet stacking patterns to produce precise, tight pallets. Stacking patterns involve locking patterns that are turned 90° from each other in each layer. The stacking solution must run faster than the cutter and conveyor can deliver the pieces to the stacker. This means precision, speed and programmability for the FireFly to reach its maximum productivity.
A 5-axis electric servo system from Kollmorgen was implemented to provide the speed, smooth operation and programmability needed for the stacker. This hardware solution includes dedicated position sensors that ensure precise repeatability. The electric servo can manage smooth acceleration and deceleration with accuracies comparable to a CNC machine tool. In addition, the electric approach is energy efficient; the motion uses only the power needed during operation, so there’s no energy overhead.
The FireFly 155 carries a magazine of 20 pallets that are automatically loaded to the stacking area as they are needed. The ProSlab lowers the pallet as the stack is loaded and when full, it is gently dropped to the ground for later pickup, maintaining the high pace of productivity that makes the machine unique.
4. Different isn’t a bad thing
You’ll find a number of things you don’t typically see on agricultural equipment on FireFly’s ProSlab harvester. It uses a state-of-the art multiprocessor control system from National Instruments as the main control platform for the machine. The controller has 180 inputs and outputs including 40 hydraulic valves. The control software runs 30 parallel control loops to operate all the on-board equipment. The 5-axis stacker servo system is connected to the controller via EtherCat in a daisy chain configuration that eliminates a significant amount of interface wiring normally associated with electric servo actuators. The EtherCat interface is a dedicated, high-speed network that allows the main controller to manage the motion and stacking pattern. EtherCat reduces the wiring burden, eliminating the position feedback which is the most prone to failure. And because all the axes are well above ground and conveyor, there are no issues of dirt contamination causing problems with the stacker.
One of the big improvements in the Firefly approach to agricultural equipment is the use of polymer bushings in place of lubricated bearings. The beauty of this approach is the durability, low maintenance and ease of repair. No lubrication, in practice, means that there is nothing for dirt to stick to and no regular service intervals. Well-fitted solid polymer bearings actually reject contamination from particulates, which is ideal for agriculture. If a bearing wears out, replacement is usually a simple press fit operation.
5. Pay attention to control systems
Sometimes a little complexity is a good thing. The harvester’s electronic control system integrates full internet accessibility. The interface is able to communicate using cellular and conventional wireless internet. Monitoring functions for any device status are built into both the local operator screen for the driver, and mirrored on a dedicated cloud server for customer access. This also gives FireFly service personnel complete access to the harvester remotely. Full diagnostic checks can be run on the equipment which also helps operators with local machine functions if there are issues.
In addition to the main controller, the operator has a flat screen interface to the control system that monitors all aspects of machine production and equipment condition. Engine temperature, tractor speed and production are all available parameters on the monitor. Every sub-system condition is accessible from the screen. This information is also served up to a cloud-based database that is reporting back to the service staff at FireFly. The service department can not only monitor, but also remotely control any functions of the harvester if there is a need.
As you would expect, the FireFly ProSlab machine incorporates several U.S. patents generated during the process of developing the complete automation solution. Speed and accuracy requirements were pushed significantly as bottlenecks were eliminated. Unique control algorithms were developed to manage the pressure on the cutter so that consistent, even cuts are generated regardless of soil conditions. There are many unique examples of innovation along a path to automate and simplify a unique process.