In 2025, Microsure will begin clinical trials for its microsurgery robot. The encoder systems, which ensure highly precise movements, were designed by the Eindhoven-based company in consultation with sensor specialist Sentech, who sat at the table as a development partner with Microsure and system builder MTA.
This article was written by Alexander Pil and appeared in Link Magazine
Sentech became involved in the development of the Musa-3, the third generation of Microsure's microsurgery robot, at an early stage. Because Sentech also works very regularly with MTA, who is involved in the project as a system developer and production partner, the triangle was quickly formed. ‘It was quite a challenge in the first phase because it was clear which direction we needed to go, but how do you translate that into actual specifications?"
’The numbers were sometimes more gut feeling than exact science,‘ recalls Sean Ram, Account Manager at Sentech. ’It occasionally rubbed in a positive way, by challenging each other and by continuing to ask questions. We could brainstorm openly.'
As a sensor specialist, Sentech sat at the table to advise Microsure and MTA on all possible sensor techniques. ‘What are the pros and cons of each choice? How big or small is it? And what specs can you achieve with it?’ Ram lists. But importantly, it helped translate the specs. ‘You can easily say: I want an accuracy of 0.01 degrees. But what does that mean in practice, at the system level and at the sensor level? Because if a sensor is installed incorrectly by a tenth of a millimeter – and that's very human – the error is already ten times too large. How do you deal with that? We had interesting discussions to question each other thoroughly.’
To say no
Pieter van Wegberg, Project Leader at MTA, on the collaboration with Sentech: ‘There are many companies that, frankly, just move boxes. Sentech, however, is very good at thinking along.’ To be able to properly control the rotational movements in the robot arm, an encoder was needed that could offer that little bit extra within a limited installation space. ‘We ultimately settled on a standard component that we all got the most out of.’
Pieter van Wegberg, Project leader MTA
“They're also brave enough to say ‘no’ when something really isn't possible. Not everyone does that. In that regard, Sentech is not a supplier but a development partner.’
Apart printed circuit board
Ram adds: ‘There were also alternative components on the table, but they were exorbitantly more expensive. Then you have to wonder if that's worth it.’ It is because of considerations like that that Van Wegberg values Sentech: ‘They are very good at finding a solution that fits the business case.'.
The chosen absolute encoder is actually no more than a small chip. It was an option to integrate it directly into the small PCB that contains all the electronics for such a joint. ‘But what if that encoder breaks? Then you have to replace the entire module,’ says Jurre van Son, Account Manager at Sentech. ‘With our knowledge and expertise in sensor technology and integration, Microsure has therefore come up with a design where the encoder chip is on a separate circuit board.’
Sentech is responsible for the production of that sensor PCB. They have also set up the supply chain for it. ‘There are quite a few critical process steps involved in processing those encoder chips correctly’, according to Van Son. ‘That's why we prefer to manage it ourselves so that we can take responsibility if something goes wrong.’ The same applies to the ruler with the stripe pattern that the sensor uses to determine its position. Together with Sentech, MTA has designed and produced a small hub for this, onto which Sentech then very accurately glues the ruler. Van Son: ‘We check if the design has been executed correctly and arrange the supply chain.’
Flexible and rigid at the same time
When asked about the greatest challenge, Ram mentions the flexibility required during prototype development combined with a process that needs to be strictly regulated. ‘After all, it's a medical application, so your methodology must comply with the ISO 13485 standard. This requires very structured processes where everything is well secured. At the same time, you're in the middle of a development where something inevitably changes regularly. You have to keep your head in the game to ensure you continue to meet the standards while still being able to adapt flexibly.’
Sentech regularly works on medical systems, but these are usually patient assistance systems or equipment for laboratory environments. This project was therefore a new application. Van Son: ‘For our automotive customers, we integrated the very strict IATF standard into our organization. A great deal of precision also needs to be guaranteed there. In this process with Microsure, we had to record and document things differently, but the underlying structure and how you deal with tightly controlled processes and supply chains was not new to us.’
Ram excitedly decides: ‘It's super cool that we can be involved with this kind of development in the Netherlands. Someone comes up with something and within a radius of 60 kilometers, there's a complete chain that can answer the question in open collaboration: how?’
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