title: Palpation simulator with stable haptic feedback.
abstract: BACKGROUND
  The main difficulty in constructing palpation simulators is to compute and to generate stable and realistic haptic feedback without vibration. When a user haptically interacts with highly non-homogeneous soft tissues through a palpation simulator, a sudden change of stiffness in target tissues causes unstable interaction with the object.
  
  
  METHODS
  We propose a model consisting of a virtual adjustable damper and an energy measuring element. The energy measuring element gauges energy which is stored in a palpation simulator and the virtual adjustable damper dissipates the energy to achieve stable haptic interaction.
  
  
  RESULTS
  To investigate the haptic behavior of the proposed method, impulse and continuous inputs are provided to target tissues. If a haptic interface point meets with the hardest portion in the target tissues modeled with a conventional method, we observe unstable motion and feedback force. However, when the target tissues are modeled with the proposed method, a palpation simulator provides stable interaction without vibration.
  
  
  CONCLUSIONS
  The proposed method overcomes a problem in conventional haptic palpation simulators where unstable force or vibration can be generated if there is a big discrepancy in material property between an element and its neighboring elements in target tissues.
authors.affiliation: Interaction Lab., Advanced Technology Research Center, Korea University of Technology and Education , Cheonan, Chungnam , Korea.
authors.forename: Sang-Youn
authors.initials: SY
authors.lastname: Kim
authors.forename: Jee-Hwan
authors.initials: JH
authors.lastname: Ryu
authors.forename: WooJeong
authors.initials: W
authors.lastname: Lee
mesh_terms: D003198:Computer Simulation; D005246:Feedback; D006801:Humans; D010535:Laparoscopy / Q000193:education*; D010173:Palpation; D014584:User-Computer Interface
keywords: Haptic interaction; palpation simulator; soft tissue modeling; stable interaction