❱❱ Robot assisted minimally invasive surgery requires specialist DC positioning motor to achieve precise control


Bristol laboratory develops robotic assistants for performing minimally invasive keyhole surgery with precision and dexterity

When undergoing even a minor operation, you’d expect the surgeon to have a list of skills, including excellent vision, dexterity and precision of movement. These are the qualities Bristol Robotics

Laboratory (BRL) sought to include as part of its smart surgical SMARTsurg project to develop advanced RAMIS (robot assisted minimally invasive surgery) technology. Using robots in keyhole surgery offers

many advantages compared with traditional minimally invasive surgery, including improving the above three vital attributes.

DOMAIN EXPERTISE Such a demanding project requires a wide range of expertise and SMARTsurg has taken on a team of highly experienced clinical,

academic and industrial partners from 10 institutions across Europe. To meet the exacting requirements of

drive and position motors, BRL teamed up with precision motor supplier, maxon. maxon DC motors and controllers are used to drive and position the three-finger operated surgical instruments. The instruments will be controlled by

exoskeletons that fit over the surgeon’s hands. In addition, smart glasses will provide the surgeon with a realistic view of what is taking place inside the body. The team found maxon products were easy to use and offered the required precision and power density for this application.

ONLINE CONFIGURATION BRL used maxon’s online tool to select and configure the DCX 19 S brushed DC motor, GPX 22 gearbox and ENX 10 encoder. This enabled BRL to put together the best package in terms of output torque, speed and encoder feedback. Physical dimensions could also be taken

into account, allowing full technical details, including 3D CAD model, to be published at the touch of a button. The maxon EPOS2

positioning controller and the CAN communication protocol ensure each axis responds to position, speed and torque commands from the master controller. Although the potential for using such

technology in minor surgical procedures is large, BRL nonetheless remains pragmatic. According to Sanja Dogramadzi, professor of medical robotics at BRL, while the popularity of RAMIS is steadily increasing, serious limitations in the current instrumentation, control and feedback to the surgeon is slowing potential improvement of patient outcomes and their transfer of this technology to other procedures. “Specifically, restricted access, lack of

force feedback, and use of rigid tools in confined spaces filled with organs pose challenges to full adoption,” says Prof Dogramadzi. “The development of robotic surgical platforms has introduced 3D vision and significant improvements in the levels of dexterity. “Robot assisted minimally invasive

surgery will reduce the demand on the surgeon, shorten training time and deliver accuracy, safety and reduced procedure time,” she concludes.

June 2019 /// Testing & Test Houses /// 7

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