Position: Mechanical Design Engineer
Location: RMRL, Melbourne, Australia
Period: 2011 – 2012
The parallel robot assisted force feedback enabled minimally invasive surgery/microsurgery system (PRAMiSS) is composed of a 6-RRCRR parallel micromanipulator and a linear guide (monocarrier) carrying an actuated force feedback enabled laparoscopic instrument. The manipulator and the monocarrier are connected together through a closed chain RPRR mechanism whose last revolute joint is actuated (R) and is able to change the angular position of the monocarrier and the instrument attached to it. The actuated monocarrier also makes it possible to insert or withdraw the instrument linearly in the direction that it points. The RPRR mechanism is fixed to the moving platform of the parallel micromanipulator. The moving platform is connected to the base by six extensible RRCRR legs that enable it to have six translational and rotational DOFs. The motion control architectures proposed for this robotic assisted minimally invasive surgery/microsurgery system enable it to achieve milli/micro manipulations under the constraint of moving through a fixed penetration point or so-called remote centre-of-motion (RCM) point without any mechanical constraint. Two control structures suitable for minimally invasive surgery operations with submillimeter accuracy and for minimally invasive microsurgery operations with the desired accuracy in micron range were designed and implemented. Control algorithms also apply orientation constraint preventing the tip to orient around the instrument axis due to the robot movements as well as the minimum displacement constraint in order to minimise the movements of the parallel micropositioning robot. Experiments were performed and the results were analysed to verify accuracy and effectiveness of the proposed control algorithms for both cases of minimally invasive surgery and microsurgery operations. The experimental results presented good accuracy and performance of the control algorithms. The numerical modelling and graphical simulations were also carried out and the results demonstrated the correlation between the experimental results and physical responses.