Improving the 3-D Force Measurement of a Single Port Parallel Kinematic Surgical Manipulator Using Friction Reduction by Vibration

Konferenz: ACTUATOR 2018 - 16th International Conference on New Actuators
25.06.2018 - 27.06.2018 in Bremen, Deutschland

Tagungsband: ACTUATOR 2018

Seiten: 5Sprache: EnglischTyp: PDF

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Bilz, J.; Matich, S.; Knaut, S.; Hatzfeld, C.; Schlaak, H. F. (Technische Universität Darmstadt, Darmstadt, Germany)

In order to provide haptic feedback in surgical robotics, a precise force measurement is essential. In the project FLEXMIN the interaction forces between the two parallel kinematic manipulators and the tissue are measured in 3-D using three 1-D force sensors for each manipulator. They are located in the distal drive unit outside of the patient’s body measuring the forces applied to the drive unit. Friction in the linear bearings of the push rods leads to measuring errors both when the manipulator is stationary and is moving. This work shows the benefit of adding a vibration to the push rods to reduce friction. The principle of the friction reduction is modeled. The grade of the friction reduction only depends on the ratio between the vibration velocity and the rod velocity. The robot is able to achieve vibration velocities of up to 45 mm/s. A total friction reduction of 75% was found.