Sense of touch is crucial for surgeons to effectively identify tumours and boundaries, and, thus to achieve successful cancer resections. To overcome the touch information loss which occurs during robotic-assisted surgical procedures, researchers have proposed methods capable of acquiring partial haptic feedback and mimicking the physical interaction which takes place between surgical tools and human tissue during palpation. This thesis proposes and evaluates haptic palpation systems and suggests the combination of different feedback methods for tumour identification in medical training and robot-assisted minimally invasive surgery using tissue models based on rolling indentation. A real-time visual tissue stiffness feedback method is proposed and compared to the performance of direct force feedback using tumour identification performance based on user studies with human subjects. The trade-off problem between system transparency and stability, which is caused by direct force feedback using a tele-manipulation system, is circumvented with the introduction of an intra-operative haptic tissue model generation method capable of representing tissue stiffness distribution of the examined soft tissue. During palpation, force feedback is exerted based on this model. This thesis proposes pseudo-haptic feedback and visualization of tissue surface deformation as an effective method to provide realistic palpation experience, which does not require the use of expensive haptic devices and is capable of handling three-dimensional haptic information. The tumour identification results are compared using different input devices: a computer mouse, a 3-DOF motion tracking input device and force-sensitive 2D haptic surface input devices. Furthermore, it is shown that the performance of haptic systems can be improved beyond the performance of force-feedback-only haptic systems by intelligently combining force feedback and pseudo-haptic feedback. Multi-fingered palpation is more effective in detecting differences in stiffness in the examined tissue than single-fingered palpation methods. Two approaches of multi-fingered palpation are proposed, studied and evaluated in this thesis: (1) methods using pseudo-haptic feedback and (2) those that use stiffness actuators. The performance of these methods is compared with the performance of single-fingered palpation approaches.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:656922 |
| Date | January 2014 |
| Creators | Li, Min |
| Contributors | Althoefer, Kaspar Alexander; Seneviratne, Lakmal Dasarath |
| Publisher | King's College London (University of London) |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://kclpure.kcl.ac.uk/portal/en/theses/haptic-feedback-of-rigid-tool--soft-object-interaction-in-medical-training-and-robotassisted-minimally-invasive-surgery(ec321790-1b95-4ae6-a913-abd10a6a1f13).html |
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