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Control System Safely Moves a Robot During Invasive Neurosurgery

Linear Actuator for Neurosurgery (LANS)

altThe focus was on extending the PRS to patients with oblong tumor lesions, which are more common than spherical lesions. The dose would need to be distributed along the main axis of the lesion so the range of the radiation spheres could cover the entire tumor lesion. Due to the precision required to perform this movement, a robotic system was necessary for the application. As a result, the Linear Actuator for Neurosurgery (LANS) was developed.

The LANS is a robotic device designed to move the PRS source in a linear manner within a haptic master/slave procedure. The researchers used the NeuroMate, a commercial robot from the UK, as a spatial positioner for the LANS. This allows the source’s axis of progression to run along the main axis of the tumor lesion (Figure 2). The surgeon determines the probe’s movement within the cranial cavity.

Using the LANS, the surgeon can feel the forces interacting between the probe and the cerebral tissues and act accordingly. In addition, to improve the precision of the operation, a suitable virtual environment guides the surgeon during each phase of the operation.

CompactRIO for Automated Robotics Control

The control system of the entire haptic master/slave robotic system requires increased sturdiness and reliability in managing the surgical procedure. The first prototype was built with several homemade control devices, which guaranteed control redundancy and the essential safety conditions. However, the prototype had considerable limitations because it was bulky, lacked portability, and required a great deal of time to program the control and supervisory modules.

These challenges were addressed using a CompactRIO system and CompactRIO I/O modules from National Instruments (Austin, TX). The controller was built with CompactRIO and the haptic master/slave system was managed in real time with 1 kHz control loops. The redundancy control systems include two field-programmable gate array (FPGA) applications, which monitor and supervise the entire operation process and intervene when the system detects an emergency.

Due to CompactRIO and its flexible programming environment, the current solution is much more streamlined, reliable, and efficient than the original prototype. The new system is currently undergoing optimization, and researchers will begin preclinical tests in the near future.

This article was contributed by Mechatronics, Padova, Italy, and National Instruments, Austin, TX. For more information, visit http://info.hotims.com/28056-346.