title: Output control of da Vinci surgical system's surgical graspers.
abstract: BACKGROUND
  The number of robot-assisted surgeries performed with the da Vinci surgical system has increased significantly over the past decade. The articulating movements of the robotic surgical grasper are controlled by grip controls at the master console. The user interface has been implicated as one contributing factor in surgical grasping errors. The goal of our study was to characterize and evaluate the user interface of the da Vinci surgical system in controlling surgical graspers.
  
  
  METHODS
  An angular manipulator with force sensors was used to increment the grip control angle as grasper output angles were measured. Input force at the grip control was simultaneously measured throughout the range of motion. Pressure film was used to assess the maximum grasping force achievable with the endoscopic grasping tool.
  
  
  RESULTS
  The da Vinci robot's grip control angular input has a nonproportional relationship with the grasper instrument output. The grip control mechanism presents an intrinsic resistant force to the surgeon's fingertips and provides no haptic feedback. The da Vinci Maryland graspers are capable of applying up to 5.1 MPa of local pressure.
  
  
  CONCLUSIONS
  The angular and force input at the grip control of the da Vinci robot's surgical graspers is nonproportional to the grasper instrument's output. Understanding the true relationship of the grip control input to grasper instrument output may help surgeons understand how to better control the surgical graspers and promote fewer grasping errors.
authors: University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania. Electronic address: pjohnsonj@gmail.com.
authors: Paul J
authors: PJ
authors: Johnson
authors: David E
authors: DE
authors: Schmidt
authors: Umamaheswar
authors: U
authors: Duvvuri
mesh_terms: D004867:Equipment Design; D006801:Humans; D012371:Robotics / Q000295:instrumentation*; D025321:Surgery, Computer-Assisted / Q000295:instrumentation*; D014584:User-Computer Interface
keywords: Robotic surgery; Usability; User interface; da Vinci