The use of robotic systems to perform MIS was given a boost in 2000, when Da Vinci Surgical system was granted FDA approval. Senhance surgical system by Transenterix, was the newest surgical system to be granted FDA approval in Oct 2017. The use of these systems is limited to high income countries due to its high costs and specialised components.
PoLaRs for laparoscopic surgery is being developed at Surge-On Medical B.V. with the goal of being cost effective, light weight, compact and portable making it easier to be accepted in high income and low and middle income countries .The Shaft Actuated Tip Articulation (SATA) Instrument being used in the PoLaRS can pitch and yaw when its tubes are rotated.Opening and closing of the gripper is activated when its middle tube is moved forward or or backwards linearly.
The 5-DOF controlled by the Control Box and the Z Translation Mechanism (ZTM) include opening/closing of the gripper, pitch, yaw , rotation and linear movement of the SATA instrument towards and away from the surgical site. The Control Box can be attached to the ZTM and this system is designed to fit on the PoLaRS slave arm, which provides additional 2-DOF and the result is; the SATA Instrument can be controlled in 7-DOF in total.
A leadscrew mechanism is used to move the Control Box attached to the rails of the slide in the ZTM. The rotaions of the SATA instrument are controlled by a timing pulley and timing belt system inside the Control Box. A leadscrew mechanism is used to control the linear movement of the middle coupling piece. A mechanism to enable easy detachment of the coupling rods in case of an emergency is also designed in the Control Box.
A functional prototype was build and the results for the performed tests indicate that the prototype has the required rotational range and speed for the CBC and ZTM, but higher torque was needed to rotate the instrument coupling piece. The timing belts and pulleys used in the prototype were created by using 3-D printing and lasercutting techniques.
In this thesis, the functional mechanism for the control of the SATA instrument in 5-DOF was designed, prototyped and validated. There are still limitations in the design; higher torques are needed for the rotations of the SATA instrument cylinders, higher tolerances for the manufactured components and better materials are needed to improove the prototype further.