Virtual Reality Based Minimally Invasive Surgical Simulator With Haptics Feedback
Project Description :

Mastering the art of minimally invasive surgery (mis) requires a special set of skills. these skills are gained either by experience or rigorous training. novice mis residents are typically trained under the supervision of experts. but transfer of training from expert to novice is affected by various factors like expert’s time, manpower, and non-availability of rare and complex cases. therefore, virtual reality simulator based training with haptics feedback is essential for imparting basic and complex mis skills in novices. there are many commercially available mis simulators that offer realistic haptics feedback. over the years these simulators have proven to be potential training tool to both novices and surgeons. but they are very expensive, complex in design and difficult to manufacture. some of these simulators have limited workspace. further, in current day healthcare, hospitals are trying to minimize the cost of training novices and surgeons. hence, there is a growing need for the development of cost-effective mis simulators with simple design and dexterous workspace. in this paper, we present a cost effective mechanical design of a 5 degrees-of-freedom (dof) haptic device for training mis residents with both basic and complex mis skills. the 5 dof device has been developed in agreement with the basic mechanical requirements for mis procedures such as torque, less friction, no backlash, less inertia, back drivability and dexterous workspace. our haptic device consists of four revolute and one prismatic joint. the first dof is a revolute joint which is responsible for the yaw (left-right) span of the mis tool handle attached to the end effector. the second dof is again a revolute joint coupled to the motor fixture link which is responsible for pitch (up-down) motion of the mis tool handle. the third radial (or insertion) dof is a prismatic joint (translational mechanism) which is responsible for linear (or in-out) motion of the tool. the fourth and fifth dof’s are both revolute joints. they provide twist (roll) and gripping facility to the user. a capstan drive mechanism is used in the yaw, pitch and roll axes of the mis tool handle to ensure zero friction and backlash. the motor torque is enhanced by 12 times in the yaw dof, 10 times in the pitch dof, and by 7 times in the roll dof . the capstan drive mechanism transmits the force generated by the motor to the gimbal mechanism and transmits any forces generated by the user on the gimba/joint mechanism to the motor. the force feedback for the opening and closing action of the mis grasper is achieved by directly coupling the lower loop of the grasper handle to the dc motor shaft. in our design, we have used simple links like a rectangular platform, rectangular motor fixture, and circular torque enhancer which are easy to manufacture. the 3d (x, y, and z) spherical workspace of first 3 dof (rrp) spans the yaw, pitch and insertion (linear) motions of the mis tool handle. the position of the tool tip is determined by optical encoder attached to the dc motor coupled to joints of the first 3 dof (rrp) of the manipulator. yaw, pitch and radial dof are defined as the x, y and z axes of the mis tool handle. the workspace of the manipulator tool tip is as follows: yaw motion varies from -80 deg to 85 deg, pitch motion is on the range of -75 deg to 75 deg, insertion (linear dof) is on the range of 0-200 mm, span of twist is -60 deg to 60 deg and opening and closing angle the of mis tool handle varies from 0 to 50 deg.

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Project Details :
  • Date : Dec 30,2014
  • Innovator : M.S.Raghu Prasad
  • Team Members : M.Manivannan
  • Guide Name : Manivannan M
  • College : Indian Institute of Technology Madras
  • University : Indian Institute of Technology Madras
  • Submission Year : 2015
  • Category : Biomedical Engineering
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