surgical robots

Supervisory controlled robotic surgery system

Supervisory controlled

Shared control robotic surgery system

Shared control

Tele surgery system :

Tele surgery , also called remote surgery , is performed by a surgeon at a site removed from the patient . Surgical tasks are directly performed by a robotic system controlled by the surgeon at the remote site

Tele surgical

Movement Control

Through the surgeon’s control, forces spanning as little as a fraction of an ounce (28 grams), and up to several pounds can be applied . The surgeon’s hand movement and applied force is translated by the control system to the tools used. The translation involved within the control system includes scaling large hand movements to smaller movements as well as distinguishing between hand tremors and intentional movements made by the surgeon. The functionality of pressure/force detection works both ways; the surgeon is able to ‘feel’ physical boundaries despite remotely controlling the robot due to sensor systems fixed to the tools and pressure valves located near the surgeon’s hand. The net result of all these factors is smooth movement by the robot via the surgeon with minimal mistakes. The whole process is however fairly tedious in terms of control systems involved.

Velocity Control

Velocity control allows for large or shorter distances of the tools to be moved that may be beyond the scope of the surgeon’s capabilities at the control side.

Instability for this system happens when slow communication occurs between the robot and the controller. The velocity control is used with an observer, this is because the tools used don’t have velocity sensors, the observer allows for velocity control loop to be closed.

Velocity Control

Collision Control

Collision Control

The Da Vinci Surgical system is able to detect and provide feedback for tool on tool collisions as well as have force control. Force Control refers to the ability of the tools to detect force applied and compensate for the force. A useful example of this is for surgeries involving the direct contact of a beating heart by the tools. A Force controlled robot would be able to exert a constant force to the heart and compensate for its motion. A factor in good performance of the force control is knowing the stiffness of the tissue, which varies from environment to environment as well as person to person. However, this factor is estimated , as well as the applied force, within the control system.

Without a stiffness estimation, the performance of the closed loop system is reduced. If the stiffness is too large it would lead to a tracking error and a stiffness too small would lead to an unstable control loop. This technology allows for the surgeon to work on a virtually stable organ by compensating the organs motion.

Temperature Control

In addition to the other control systems, temperature control systems are also used. The endoscope used to create the 3D map is programmed to regulate the temperature of the endoscope end. This is done to help prevent fogging of the camera. The control system used is a basic temp control system.

Temperature Control

conclusion

Opinion

Although still in its infancy, robotic surgery has already proven itself to be of great value, particularly in areas inaccessible to conventional laparoscopic procedures. It has the potential to expand surgical treatment modalities beyond the limits of human ability. Although feasibility has largely been shown, more prospective randomized trials evaluating efficacy and safety must be undertaken. Further research must evaluate cost effectiveness or a true benefit over conventional therapy for robotic surgery to take full root.