Modeling and design of a gripper for a robotic surgical system integrating force sensing capabilities in 4 DOF

This paper reports the design of a Minimally Invasive Surgery (MIS) gripper with four degrees of freedom force sensing capabilities. It will be used to provide force feedback during surgical interventions in which the surgeon will remotely manipulate surgical instruments through the use of a robotic arm directly inserted into the patient´s insufflated abdominal cavity. Suturing, dissection and ablation instruments will be attached on this 8 mm× 9 mm× 3 mm MIS gripper. Finite Element Analysis is used to model the gripper and determine the deformation matrix coefficients. Gripping and XYZ Cartesian direction applied forces can be measured with a resolution of 0.1N for a maximum force of 10N. However a significant difference between the predicted values by the Finite Element model and those obtained in the characterization of the force sensor is found. This divergence is due to misalignments of the strain gages located on the blades of the gripper. Future work will be focused on reducing misalignment of force sensors as well as other error sources.