15 Effects of Gripping and Translational Forces on Teleoperation

For minimally invasive surgical teleoperation systems, it is often impractical to provide the same number of degrees of freedom (dof) for position control at the slave and force feedback to the master. Sensor/actuator asymmetries are created when the user receives partial force feedback. This chapter presents an experimental study of the performance of telemanipulation with different combinations of grip and 3-dof translational force feedback. Users performed standardized tasks with varying force feedback conditions on a pair of 3-dof haptic interfaces configured for telemanipulation and augmented with 1-dof grippers. The system has four degrees of freedom of position tracking and allows modified force feedback conditions. Forcing conditions sent back to the master include (1) no forces, (2) grip forces only, (3) translational forces only, or (4) grip and translationa l forces (sensor/actuator symmetry). A position exchange controller is used to apply force feedback to the operator. We hypothesized that performance, measured by applied force, completion time and error rate, will be maximized for a system with sensor/actuator symmetry.