Design of 3D-Printed Flexible Joints With Presettable Stiffness for Surgical Robots

Continuum manipulators have been widely used in minimally invasive surgery due to their high dexterity. However, different surgeries have different stiffness and dexterity requirements. This paper describes a continuum manipulator for robot-assisted surgery. The flexible part is a joint that can be 3D-printed using various materials. The flexible joints made of each material are of the same size but have different stiffness and dexterity. In this way, the appropriate stiffness can be preset by selecting a suitable manufacturing material according to specific surgical needs. Kinematic and static models of the proposed flexible joints were designed. A finite element analysis method was used to calculate the correction factors. We analyzed the workspace and stiffness differences between flexible joints made of different materials quantitatively and qualitatively, respectively. We conducted experiments to verify the accuracy of the static model and the stiffness differences between the flexible joints. Finally, several design variations were introduced, which demonstrate the unique advantages of these flexible joints in the field of surgical robotics.