Compliant building blocks for the development of new portable robotized instruments for minimally invasive surgery

In this paper, we present the first steps towards the development of a high dexterity hand-held motorized laparoscopic instrument for the realization of complex surgical tasks (e.g. suturing) in areas of difficult access. To produce the required intracorporeal degrees of mobility with sufficient forces, a combination of compliant mechanisms and a locally embedded miniature hydraulic actuation of the end-effector are proposed. This article describes the design and optimization of the compliant bending joint and gripper. These two structural building blocks have been prototyped, and their individual theoretical and experimental performances have been evaluated. They have been integrated into the distal tip of a 5 mm diameter laparoscopic surgical instrument, which produces one bending, one distal rotation and the opening-closing of the gripper. These new building blocks, together with a motorization unit deported outside the patient body, should contribute to the portability, the miniaturization and a better integration of current robotic surgical instruments.