Advanced motion control and highly compact servo drives are controlling steerable surgical devices in high precision neurosurgery
A robotic brain surgery tool will allow drugs to be delivered to a tumour without damaging other parts of the brain
Four servo drives and a motion controller are used to control a four-axis robotic system, guiding a flexible catheter to a precise location in the brain.
The EDEN2020 project at Imperial College London, aims to improve neurosurgery by making it less invasive and reducing the risk of damaging healthy brain tissue.
This is achieved using a programmable bevel-tip needle (PBN), constructed of four flexible interlocking plastic segments. Each segment has a channel for drug delivery and a channel containing a fibre cable used for shape sensing. Powered by a small ironless motor, each segment can move independently, allowing the PBN to change direction and be guided around brain structures to the right area.
This demanding application required a motion controller capable of high synchronisation of the four axes, while achieving a positional accuracy down to 10µm.
Each segment motor is driven by an Elmo Gold-Twitter servo drive, while all controlled by an Elmo Platinum Maestro motion controller.
Platinum Maestro uses EtherCAT, an Ethernet protocol for motion control applications. The motion controller can command the axes at a 250µs EtherCAT cycle rate, allowing it to quickly respond to or command the PBN to change direction to move around obstructions and avoid damage to brain structures.
Prof. Ferdinando Rodriqugez Y Baena, project coordinator for EDEN2020, says: “The system will be able to sense continuously deforming brain anatomy at unmatched accuracy, precision and update rates.”
Gold-Twitter, the world’s smallest, most powerful servo drive, was chosen because its compact size allowed the robotic surgery station to be portable. The servo drive also produces a very low level of electro-magnetic interference, avoiding distortion and disruption to medical imaging processes.
Reduced development time was a key factor in the project’s selection of motion controller. The Platinum Maestro is an off-the-shelf motion controller offering tools and features that simplify and streamline the implementation of machine motion applications. Simple interconnection of the Platinum Maestro to all drives, automatic EtherCAT configurations to all nodes and control over all drive parameters from the Platinum Maestro were other major benefits.