EMBEDDED TECHNOLOGY Minimally invasive robotic surgery


(MIRS) with the DLR mirosurge Robotics to operate on a beating Heart


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ignificant advances are occurring for conventional Minimally Invasive Surgery (MIS), commonly referred to as keyhole surgery. MIS is performed through small incisions to maximise the preservation of healthy tissue. However, it is still essentially done by hand, as the surgeon manipulates the surgical tools through extended instruments. MiroLab’s goals include giving surgeons a remote digital telepresence and telemanipulation capability to execute the most demanding surgery.


MiroLab, a robotic assistance research laboratory, is part of Robotics and Mechatronics Center (RMC) at the German Aerospace Center (DLR). RMC is a robotics research cluster and the competence center for DLR research and development in the areas of robotics, mechatronics and optical systems. RMC specialises in the interdisciplinary design, computer-aided optimisation, simulation and implementation of complex mechatronic systems and human-machine interfaces.


The MIRS system challenges the surgeons’ skills because of the lost


hand-eye-coordination and absent direct manual contact to the operation area. However, by inserting robotic controllers in the loop, we introduce the capability to deal with complex surgical operations far beyond what current MIS technology allows. For instance, operating on a beating heart requires the surgeon to perceive an almost static view of the heart to allow for greater control of highly precise directed cuts and stitches whilst performing the operation. This means that the camera and instruments need to be automatically coordinated with the movement of the heart and yet not disassociate the surgeon from the procedure at hand. The challenge is to give back the surgeons’ hand-eye capabilities and ‘feel’ while they are teleoperating. The robotic controllers and video view is remote from the robotic actuators and sensors, plus the sensitivity needed to give back the surgeons’ touch requires a highly reliable, distributed haptic feedback loop, executing at a deterministic high rate. In addition to this, the architectural approach should enable a very high degree of decoupling in the software so that researchers can work and experiment


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with the system firsthand. To ease future transfer of MiroLab technology into medical products, a clear path to safety critical implementation of the laboratory proof of concept is required.


To develop the “feel” for the surgeon requires a highly adaptable research facility that is able to rapidly prototype solutions for issues that surgeons raise as they are put into the control loop.


The more rapidly adaptable a system is, the more value can be derived from a surgeon’s very costly time. To facilitate this requirement, the MiroLab MIRS system has to be designed modularly. RTI Connext DDS provides the communications infrastructure between the three MIRO robots, the endoscope, the surgeon’s robot controllers and the surgeon and technician’s user interfaces, facilitating synchronisation and coordination between them. DLR’s MiroLab used RTI Connext DDS because it delivered high performance distributed communications with decoupled systems as a set up. With Connext DDS, they could implement a deterministic solution functioning at rates between 1KHz and


JULY/AUGUST 2024 | ELECTRONICS FOR ENGINEERS


3KHz, thus enabling the development of the distributed haptic closed control loops. The availability of RTI Connext Micro also means that systems can be developed today with an understanding of the medical certification route in the future. Using the ability of RTI Connext DDS to deliver a high degree of decoupling between sources and sinks of data and application modules, MiroLab is developing an extremely flexible surgical robotics research facility that allows for rapid prototyping of ideas and concepts. This flexibility is critical, allowing for surgeon and technician input and review in this emerging field of research.


Today’s system uses three robots, but the system can readily be expanded to insert four, five or more robots with minimal additional software communication development. For future deployment, RTI offers Connext DDS Cert as a safety-certifiable DDS implementation. This ensures that researchers have a clear path from the laboratory to future field deployments without complete re- engineering.


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