Development of a low cost secondary slave manipulator for a minimally invasive robotic surgical system

[摘要] ENGLISH ABSTRACT: Minimally Invasive Surgery (MIS) in human beings is performed by making small incisions in the abdominal region of the patient and inflating the abdominal cavity with CO2. This procedure enables the surgeon to manipulate long rigid surgical instruments inside the patient in order to perform the surgery. Unfortunately the current methods of insertion and assembly of MIS instruments limit the surgeon to only five (of a possible seven) Degrees of Freedom (DOF). Along with this, the surgeon's movements are mirrored (called the Fulcrum effect) and scaled around the point of incision.Minimally invasive surgical robots attempt to alleviate these drawbacks by eliminating the Fulcrum effect, as well as improving dexterity and accuracy. These robots' abilities to improve the surgeon's hand-eye coordination, enables the surgeon to perform surgeries using their natural movements with reduced fatigue. As a result of this, the risk to both patient and surgeon is reduced.Existing MIS robotic systems are extremely expensive and large, and as a result they are not widely used. In this thesis a new, lower cost, seven DOF robotic manipulator is further developed. The thesis focuses on the external three DOF Secondary Slave Manipulator (SSM) and combines it with the Primary Slave Manipulator (PSM) that was developed by a previous Masters student. Tests done on the SSM showed that the manipulator has a minimum resolution of 0.7 ± 0.2 mm (mean ± standard deviation) on the shoulder joint's yaw rotation and 0.5 ± 0.2 mm in pitch rotation. The linear actuator used for insertion has a minimum resolution of 0.2 ± 0.2 mm. A strength test was also conducted and showed that the manipulator is easily capable of producing a 10 N actuation force as required during Minimally Invasive Robotic Surgery (MIRS) procedures. In conclusion the complete system has potential as a viable alternative to the existing systems due to its accuracy and lower cost.Future work will include the development of a user interface and control system for the complete robot.

[发布机构] Stellenbosch University