Planting roses with the help of a robot has already been possible for some time. But John van de Ven, founder of Aventec, is taking the technology one step further. With Festo as a partner, he can use the latest technologies and innovations. And the valve terminal VTUX is just right for this.
As an electrical engineer, Van den Ven is very familiar with robots and image processing and he has implemented numerous process automation projects with Aventec. In 2013, in the early days of Aventec, Van de Ven was mainly involved in interim project management assignments. Nowadays, he does a lot of development work for greenhouse horticulture. Customers from his former employer – whose company no longer exists – approached him, and he soon had his hands full working on a machine for growing potted roses. These machines had been in operation for several years and were in urgent need of maintenance and repair. After an initial assessment, it turned out that even more was needed, and Van de Ven started the development phase.
"To ensure the continuity of these cutting machines, they had to be rebuilt using 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 to realise the vision of a fast and reliable machine that customers can depend on for many years to come.
In order to better monitor 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 twigs are hooked into a transport system by hand. Each cutting is hung in a holder and transported to one of the processing cells. Once in the cell, they are positioned in front of the image processing system and rotated 180° to create a 3D scan. This gives optimal cuttings, which 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, which has four cutting stations, can cut and plant up to 5,200 cuttings per hour.
While developing the machine, Van de Ven came into contact with Festo. "They helped me to select and integrate the different areas right from the start. Turning and cutting is the most exciting part. To see how we could achieve this by using Festo components, we sent some rose twigs and their holders to the Festo development centre in Delft. A week later I received a video from the team with the latest results. I was surprised at much progress they had made in a week! We then started to build a test module with Festo components and invited our customers to see it for themselves."
Van de Ven wants to source 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 doesn't work. And it is the end customer who suffers as a result. The modules now include linear guides and pneumatics from Festo, plus a PLC, an HMI and valve terminals. We have now 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 controller. As the machine was being developed, product development at Festo continued as usual, which meant we were able to switch to the latest HMI. It was surprisingly easy to transfer the work carried out in the previous generation up to that point to the new generation. The platform has become much faster and we have retained the overall structure." Van de Ven found the support from Festo very valuable during the process. "Festo takes into account the need for a specific solution. Why use a stepper motor when you can also control a function using pneumatics?"
One of the most specialised components that Van de Ven uses in his rose picking machine is the new valve terminal VTUX from Festo. Jeroen Holt from Festo tells us more about the technology behind this valve terminal. "What's special about this terminal is that it is suitable for both centrally and decentrallly installation of machines. In this case, this controller is decentralised. 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 degree of protection. And it is a very compact product with a much smaller installation space than its predecessors, which results in major design advantages." Van de Ven decided to use a decentralised controller primarily because it reduces the cabling work in the machine: "You can be closer to the sensors with your connection points," and there are fewer IO in the control cabinet, which means less space in the control cabinet and also less work on the control cabinets. "Even if a cable needs to be replaced, you don't have to go into the cabinet through a rod clevis, but just to the VTUX terminal."
Van de Ven explains that he worked with the predecessor of the VTUX, the VTUG, during the initial development phase. "It had an aluminium base plate and can be dismantled into individual parts. This advancement makes the VTUX the future of the valve terminal," he nods approvingly. "The 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 only need one supply to the terminal for air, electricity and communication. Before, we needed two control cabinets to accommodate everything, but now one is enough. Thanks to the decentralised controller, everything can be operated independently of each other."
According to Van de Ven, the greatest added value is the time saved. "We save hours of work, so the purchase price is recouped very quickly." But Holt and Van de Ven also want to mention the data communication. The new Festo automation platform CPX-AP-A offers various communication options for fast and error-free IO between components and with extended diagnostic functions. Holt: "If a cable breaks somewhere, for example in one of the sensors, the breakage point is visible right away." And it's very simple, he explains: "All tags are read into the VTUX, you just have to assign them." 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 device.
The speed is often decisive for the required force and stroke. Because the work is carried out in a dirty and dusty environment, cylinder contamination is also a consideration. The VTUX has an IP 67 rating, which is an important and decisive factor in the operating conditions for this application.
Van de Ven was one of the first VTUX customers in November 2023. "When Festo develops something like this, I don't want to use it straight away. But I've been to the factory in Esslingen and when you see 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 options. We went through the whole machine together; we then decided together what we wanted to do and he came 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 thinks about the new developments with us." Holt nods in agreement. "Thinking together is really crucial. I know the whole process and we start from a basic idea with unresolved questions. I like doing it that way."
It is plain to see that Van de Ven is satisfied. "We have written our own algorithm to speed up the entire process. To do this, we needed more computing power than in the old system. And we more than succeeded. We also wanted to separate two unique processes that run simultaneously. That is why 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 have set our sights on two."
Aventec is an engineering company that designs, builds and commissions machines. Specialising in automation solutions for horticulture, it develops technical solutions, including the electronics, mechanics and software, and applies them during the design, prototyping and engineering phases as well as during commissioning.
At its own workshop in Heesch, the Netherlands, Aventec offers all the specialisms required to provide customers with comprehensive support.