Force Feedback for Endowrist Instruments

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Lin, Fang
The Graduate School, Stony Brook University: Stony Brook, NY.
The purpose of the project is to analyze current sensor designs, improve the design and fabricate a sensor attachment for the Endowrist Instruments. The predicament with the Endowrist Instruments is the lack of feedback regarding the interacting force between the gripper and the tissue. It is not safe to perform the surgery with Endowrist Instruments that do not give feedback, therefore only those surgeons with a great deal of experience can perform the surgery. Feedback can be added by attaching a sensor attachment to the instrument and the robot, but the problem is current sensor designs do not provide precise measurements. It will not be beneficial if there are any major changes to the infrastructure of the Endowrist Instruments, so the sensor attachment should be easily fit to the instrument and the robot. It will be located directly outside the input interface panel. To improve the design, all forces acting on the instrument must take into consideration. Some forces are difficult to measure, but this problem can be solved by applying some techniques. It is difficult to measure the supporting forces between the trocar and the instrument shaft; by using overcoat technique, the supporting forces can be measured. To measure the contact force between the instrument and the adapter, there must be two plates between the instrument and the adapter; one plate should be fixed to the instrument and the other plate should be fixed to the adapter. When place sensors between these two plates, contacting forces between these two plates can be measured. A force analysis is required to fully understand the situation. After performing a force analysis, the theoretical relationship between the force in the tip of the gripper and the input torque can be found. However, calibration using LabVIEW will be able to find the true approximate relation.