Effect of Load Force Feedback on Grip Force Control During Teleoperation: A Preliminary Study

During robot-assisted minimally invasive surgery, teleoperation systems allow surgeons to perform operations at a distance via instruments inserted through small incisions in the body, thereby minimizing patient pain and recovery time. While the patient-side manipulator allows precise, dexterous gripping and manipulation by the surgical tools, current clinical systems provide the surgeon with limited haptic feedback about tool-environment interactions. This differs from direct grasp and manipulation of hand-held objects, during which we receive feedback that provides cues regarding object surface properties, slip, and load force. We use a custom research version of the da Vinci Surgical System to study the control of grip force during teleoperated manipulation of an elastic environment. We tested a placement task that involved stretching of a rubber band, with and without feedback of the patient-side load forces to the user. We hypothesized that there is greater coupling between the applied grip force and the patient-side load force when force feedback is provided, as is observed during direct manipulation of hand-held objects. With an experienced surgeon user, coupling between the applied grip force and the load force was greater with force feedback than without.