Electromagnetism Force Feedback Control of Bionic Grippers for Robotic Endovascular Intervention System At present, the operation of most Robotic Endovascular Intervention (REI) can only through visual feedback, that is, the operator can only observe the situation on the scene through the Xray equipment, and issue manipulation commands according to the observed scene conditions. Although the masterslave system with force feedback has made significant progress, some essential problems still need to be solved, especially the complicated structure and large external dimensions, which gives the operator a strong sense of weight and affects the sense of teleoperation. For a high safety of remote operation, this research proposed a kind of REI with bionic grippers and developed a prototype to verify its expectation of telepresence. The REI used the sliding table and steel wire to realize the forward and backward delivery of guidewire and catheter, and the bionic grippers were used to accomplish the twisting of guidewire and catheter imitating hands and fingers of human. A highresolution force sensor is used to acquire the intervention resistance on bionic grippers, and a loading mechanism composed of electromagnetic coil, handle, and spring will reproduce the resistance on the doctorxe2x80x99s fingers through the handle. Laser displacement sensors and Rotary encoders are used on a master manipulator to control the movement and rotation of slave grippers. The experiments show that force feedback precision can reach 0.03 N, and response delay is less than 100ms when the frequency of the loaded force is above 3Hz. This research has laid a necessary foundation for REI technology.

An MR Fluidsbased Master Haptic Interface with Adjustable Protection Threshold for Endovascular Catheterization Insufficient force feedback and collision warning of teleoperation surgical tools increase the risk of endovascular catheterization. This paper proposed a master haptic interface with the adjustable threshold that takes advantage of a surgeonxe2x80x99s natural manipulation skills obtained through experience, as well as generates collision warning with haptic cues to ensure safe operation. The experiments for performance evaluation regarding the haptic force assessment and the realtime adjustment of threshold are conducted. Results show that the magnitude of the instantaneous haptic change in the haptic interface is sufficient to elicit the operatoru0027s response, even for novices. Furthermore, for the setting thresholds after adjustment, the operator has a fast reaction to distinguish whether the catheter tip collides with blood vessels or not by collision warning with haptic cues, thus achieving the goal of safe operation.