Research On Teleoperation Of Minimally Invasive Surgery Robot Based On Virtual Environment

In according to the demands of telesurgery training, combining the developed“MicroHand A” master-slave robotic system, this paper studies the teleoperationsystem of minimally invasive surgery robot based on virtual environment. Thefollowing contributions have been made in this dissertation.Firstly, according to the characteristics of developed master-slave robot systemand the network transmission, the architecture of virtual telesurgery system ispresented. The system involves hardware equipment, HCI(Human-ComputerInteraction) module, Internet communication and simulation environment modules.The involved hardware and software in these modules are presented.Secondly, the geometric model of slave manipulator is imported to virtual scene.After modeling, projection and viewport transformating in the virtual scene, the3Dobjects are displayed in the2D images. The kinematic model of master manipulatorand slave manipulator, and the motion control correspondence between them areestablished to realize the intuitive control of robot manipulator and ending tools.Thirdly, in according to the mechanical characteristics of soft tissue, combiningthe Marching Cube (MC) algorithm which is employed to form the triangle mesh, theelastic mechanics equation of tetrahedron element in mesh is established. The discretesolution process of visco-elastic model is achieved on the basis of the constitutiverelation of visco-elastic model. Simulation of the proposed visco-elastic model forsoft tissue is made by ANSYS.Fourthly, the impact of unstable time delay of the Internet on the teleoperationsystem is analyzed. The control signal dynamic queuing mechanism is built in thereceiving side, which aims at regulating the relationship among queue size, packetdropping rate, and the master manipulator sampling frequency. These experimentsverify the effectiveness of designed teleoperation system of minimally invasivesurgery robot based on virtual environment.