Research On The Manipulator System Of Single Port Access Abdominal Surgery Robot

Single port access abdominal surgery (SPAAS) needs a single incision only toperform surgery. Compared with multi-ports minimally invasive surgery andtraditional operative methods, the same desired effect can be obtained by SPAASwhich features slight trauma, little pain, fast rehabilitation, and slinky scar etc.Compared with NOTES, SPAAS has a wider range of application, for it’s notrestricted by the the location of natural orifices.This project was funded by Natural Science Foundation of China (Grant No.61175078). In this paper a robot for single port access abdominal surgery (RSPAAS)is presented in detail.First, according to function requirements of RSPAAS in operation process, arobot with7DOFs is proposed. Robot’s3D model, surgical instrument module,flexible manipulator module and motor drive module are introduced and describedin detail. The driving cables are configured dexterously, which avoids theinterference among them. Besides that, a decoupled mechanism for the end-effecteris also proposed, which eliminates the coupling influence between fingers and wrist.Moreover, a manipulator arm is designed, which is constructed from asuperelastic Nitinol tube with triangular notches and can be bended freely. Themanipulator with bilateral staggered notches is driven in plane by cables embeddedin bilateral symmetry channels of Nitinol pipe wall. A cross-configuration of twosegments can achieve two bending DOFs. In addition, the design of the manipulatorrealizes multi-DOFs of end instruments because it has a large open lumen for drivencables, power and signal wires. Based on Timoshenko’s beam theory, mechanicsmodel of the flexible joint manipulator with triangular notches is established. Themechanics model’s calculation results match the ANSYS simulations andexperimental data, which demonstrates the effectiveness of the proposed mechanicsmodel.Finally, some key components of RSPAAS are double-checked, and flexiblemanipulator’s geometry size, processing technology and material requirement arecompared via experiments, which is significant to the final determination of the design. Then, inverse/forward solution of kinematics equation and workspace alsoare validated by the experiments.