Planting roses with the help of a robot has been possible for some time now. But John van de Ven, the founder of Aventec, has taken the technology one step further. With Festo as a partner, he uses the latest technologies and innovations. And the VTUX valve terminal is just right for this.
As an electrical engineer, Van den Ven is very familiar with robots and image processing, and has implemented various process automation projects with Aventec. In 2013, in the early days of Aventec, Van de Ven was mainly involved in interim project management assignments. Today, a lot of his development work involves greenhouse horticulture. Customers from his former employer – whose company no longer existed at the time – approached him, and he was soon working at full capacity with a machine for growing potted roses. These machines had been in operation for several years and were now in urgent need of maintenance and repair. After an initial assessment, it turned out that more than that was needed, and Van de Ven began development.
"To ensure the continuity of these cutting machines, the machines had to be rebuilt with new components. Many of the parts used had already reached the end of their service life. We then decided to redesign the machine with modern servo technology, which is controlled by the Festo CPX-E plc platform, together with a modern image processing system." Many parts had to be reprogrammed from scratch with the vision of a fast and reliable machine that customers could rely on for many years to come.
For better control of deliveries and the future reliability of the machines, he decided to manufacture them himself. To give you an idea of the complexity, we will briefly explain exactly what the machine does. At the start of the line, the rose branches are hooked into a transport system by hand. Each cutting is hung in a holder and transported to one of the processing cells. There they are positioned in front of the image processing system, where they are rotated 180° to create a 3D scan. This results in optimal cuttings. These are then trimmed by a robot and planted directly into new pots. All this happens at breakneck speed and with extreme precision. The complete machine with four "cutting stations" can cut and plant up to 5,200 cuttings per hour.
During the development of the machine, Van de Ven came into contact with Festo. "I was helped with the selection and integration of the different areas right from the start. Turning and cutting is the most exciting aspect. To see how we could achieve this with Festo components, we sent rose branches and their holders to Festo's development center in Delft. A week later I received a video from the team with the latest results. I was surprised at how far they had come in a week! We then started to build a test module with Festo components and invited our customers to see this for themselves."
Van de Ven wants to obtain as many components as possible from a single source. "Wherever possible, I use Festo. Otherwise there is a risk that suppliers will blame each other if something does not work. And it is the end customer who suffers as a result. The modules now include linear guides and pneumatics from Festo, PLCs, an HMI and valve terminals. In the meantime, we have retrofitted a complete machine with our newly developed modules and put it into operation. Each module has its own PLC, as this computing power is required for image processing. We used an HMI and new valve terminals for the main control system. During the development of the machine, product development at Festo continued as usual, so that we were able to switch to the latest HMI. The work carried out up to that point in the previous generation was surprisingly easy to transfer to the new generation. The platform has become much faster and we have retained the structure." During the process, Van de Ven found Festo's support very valuable. "Festo takes into account the need for a specific solution. Why use a stepper motor when you can also perform a function with pneumatics?"
One of the most specialized components that Van de Ven uses in its rose picking machine is the new VTUX valve terminal from Festo. Jeroen Holt from Festo tells us more about the technology behind this valve terminal. "The special thing about this terminal is that it is suitable for both decentralized and centralized installation of machines. In this case, this control is decentralized. This terminal does not have to be housed in a separate control cabinet, but can simply be installed in an open space thanks to its IP protection rating. And it is a very compact product with a much smaller installation space than its predecessors, which offers major design advantages." Van de Ven decided to use a decentralized control system primarily because of the reduced wiring effort in the machine: "You can be closer to the sensors with your connection points." There is less IO in the control cabinet, which means less space in the control cabinet and therefore less work on the control cabinets. "Even if a cable needs to be replaced, you don't have to go through a rod clevis into the cabinet, just to the VTUX terminal."
Van de Ven explains that he worked with VTUG, the predecessor of VTUX, when it was first developed. "It had an aluminum base plate and could be dismantled into individual parts. This further development makes VTUX the future of the valve terminal," he says, nodding. "This VTUX is more versatile and lighter." Thanks to the internal serial bushing, up to 128 valve functions can be assigned. "We don't have to wire every valve and every sensor individually. We go to the terminal once with air, electricity and communication. And where we used to need two control cabinets to accommodate everything, now one cabinet is enough. Thanks to the decentralized control system, everything can be operated independently."
According to Van de Ven, the greatest added value is the time saved. "We save working hours, so the purchase price is amortized very quickly." However, Holt and Van de Ven also want to mention the information on data communication. The new Festo automation platform CPX-AP-A offers various communication options for fast and error-free IO between components, with extended diagnostic functions. Holt: "If a cable breaks somewhere, for example in one of the sensors, the point of breakage is immediately visible." And it's very simple, he explains: "All tags are read into the VTUX, you just have to assign them yourself." Van de Ven uses 9 of the new valve terminals per machine. For each rose cutting module there is one terminal at the top, one at the bottom and one on the main unit.
The speed is often critical for the required force and stroke. However, cylinder contamination also has to be considered, because the work is done in a dirty and dusty environment. The VTUX has an IP 67 rating, which is an important and decisive factor in this application's operating conditions.
Van de Ven was one of VTUX's first customers in November 2023. "When Festo develops something like this, I don't want to start using it right away. I went to the factory in Esslingen. Having seen how thoroughly and extensively everything is tested there, I have complete confidence in the Festo team." And the collaboration with Holt is also running very smoothly. "I show them what I need and Jeroen shows me the possibilities. We went through the whole machine together. We then decide together what we want to do and he comes back with the answers and more information. We want the machine to still be operational in ten years' time, so the end-of-life expectation is important, and Jeroen is thinking along with us about the new developments." Holt nods in agreement. "Thinking along is really crucial, I know the whole process and we start from a basic idea with open questions. I'm happy to do that."
Van de Ven is satisfied, as it turns out. "We have written our own algorithm to speed up the whole process. To do this, we needed more computing power than in the old system. And we were successful beyond our expectations. We also wanted to separate two unique processes that run simultaneously. To do this, we have two queues, each with its own core in the PLC. The cycle time is and remains crucial. We are now at four milliseconds and are betting on two."
Aventec is a mechanical engineering company that designs, builds and commissions machines. Specializing in automation solutions for horticulture, Aventec develops technical solutions and implements them from design, prototyping and engineering through to commissioning – electrically, mechanically and in terms of software.
From its own workshop in Heesch, the Netherlands, Aventec offers all the specialist areas required to provide customers with comprehensive support.