| Summary: | One of the drawbacks of using current telesurgical devices is the absence of force and tactile feedback from the remote surgical manipulators. The lack of tactile feedback in particular limits the surgeon's perception of tissue characteristics during palpation. This project aims to further the current knowledge about tactile feedback for these applications. Through an extensive literature review the tactile information of importance for the perception of soft tissue features was investigated, concluding that feedback of distributed skin deformation from a compliant finger-like sensor is desired. This is unlike the few existing tactile feedback systems, which use rigid/semi-rigid sensors and detect distributed contact pressure. The specification, suitability and effectiveness of a deformation-based tactile feedback system were subsequently investigated. A detailed set of criteria were compiled for a deformation-based tactile sensor and display, and the design options, issues and existing devices discussed for each. An existing biologically-inspired optical tactile sensor, the TACTIP [Chorley et al., 2009], was modified to encode realistic finger pad deformation information and a remotely-actuated tactile display created to output it on a human operator's finger pad. The final deformation-based system was found to offer a good solution suitable for further testing. Qualitative testing found that the relayed tactile information allowed differentiation between different stiffness tissues and localisation of hard lumps in tissues, even when the encapsulating tissue was stiffer than the sensor. The addition of the system to a teleoperated environment with force and visual feedback greatly improved the lump detection rate from 64% to 98% and the localisation error from 18 mm to 11 mm. Finally, the feedback of bulk shear displacement information in addition to the indentation deformation was explored. Following modification of the tactile system, experiments were conducted to establish its impact on lump localisation. Minimal effect was found, indicating that this information is unnecessary for these interactions. The results of this study are expected to benefit the future development of telesurgical systems for remote palpation.
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