Subject: Dynamic position control approach of a robotic assistant for percutaneous interventions under mri context and background

Medical interventions (surgery, interventional radiology, radiotherapy) can benefit from a significant boost for progress in terms of optimal planning, performance and consistence. The Computer Assisted Medical Interventional (CAMI LABEX) st3rategic vision is that an integrated approach of medical interventions will result breakthroughs in terms of quality of medical interventions, demonstrated in terms of medical benefits and degree penetration of CAMI technology in routine clinical practice.

In a thesis framework in collaboration with ICbue, we have developed an instrumented demonstrator that allows the control of a needle orientation for percutaneous interventions under MRI [1]. This prototype is a pre-constrained system actuated using two cables and passive compliant elements (linear and non-linear springs). It exhibits interesting properties for this applicative context, particularly a large workspace while being lightweight and a large stiffness variation. This latter property allows the device to modify the stiffness of the link needle/robot so that gestures on organs such as the liver may be performed without organ lacerations under physiological movements. Regarding the existing systems, the developed system is based on an original tensegrity structure that avoids the development of complex devices for needle grasping/releasing.

Two control approaches, based on the inversion of the robot static model, have been developed [1]. They have been evaluated on the developed prototype. The obtained results are satisfactory but only for low dynamic trajectories. For high dynamic trajectories, position tracking is poor, which limit the use of the developed control approach.

The internship objective is to develop a new position control approach to improve tracking performances. For this, the recruited student will work on the robot dynamic modeling, parameters identification and the implementation of the developed strategy on the prototype available at LIRMM.

Experience and skills in mechatronics, C/C++ languages and real-time programming are mandatory. Good command of English or French is expected.
3. Contact

To apply to this offer, send an email with a CV, a cover letter and your Master grades to Salih Abdelaziz and Philippe Poignet : salih.abdelaziz@lirmm.fr, poignet@lirmm.fr.