Posted in | Medical Robotics

Researchers Develop New Controller for Robotic Arm Used in Robotic Surgery

A novel controller for robotic arms employed in robotic surgery has been developed by researchers at the Tokyo Institute of Technology. The controller integrates two different types of grips used in existing robotic systems, to exploit the benefits of both offering high precision and minimizing the efforts of the surgeon.

A new controller design for robot-assisted surgery. Image Credit: Tokyo Institute of Technology.

Robotics has made its way into several different fields, with medicine being no exception. In the last 10 years, robot-assisted surgery has drastically advanced in virtually every surgical subspecialty. In general, robot-assisted surgery is conducted by using surgical robot systems that include a master-slave configuration. In this configuration, the “master” is a controller device manipulated by the surgeon to control a robotic arm.

Systems such as these enhance the precision and dexterity of surgeons by preventing hand tremors and modifying their hand motions into smaller movements. In addition, they minimize the risk of common surgical complications like surgical site infection.

But robot-assisted surgery has its own drawbacks, specifically for the individual who performs the surgery. At times, robotic surgeons tend to feel physical discomfort while performing surgery. Finger fatigue is a more common discomfort related to the way they grasp the master controller.

In general, grips of two types are used to manipulate surgical robots: the “power grip” and the “pinch grip.” The power grip, which is used to grab a handle with the entire hand, is more ideal for large movements and forceful work. By contrast, the pinch grip involves the use of thumb, middle, and index fingers to realize high-precision movements, and has been used in traditional surgeries for many centuries.

Since the pinch grip applied tension on specific muscles of the fingers and hand, it could possibly cause fatigue. The power grip does not appear to cause such discomfort, but it provides less precise control. Thus, there is a trade-off between the lack of fine control of the power grip and the discomfort brought about by the pinch grip.

Luckily, Mr Solmon Jeong and Dr Kotaro Tadano, two researchers from Tokyo Tech, arrived at a smart solution to this challenge. In a study reported in The International Journal of Medical Robotics and Computer Assisted Surgery, they proposed that it is possible to design a master controller that integrates both types of gripping.

In robotic surgery, the limitations of the two conventional gripping methods are strongly related to the advantages and disadvantages of each gripping type. Thus, we wanted to investigate whether a combined gripping method can improve the manipulation performance during robotic surgery, as this can leverage the advantages of both gripping types while compensating for their disadvantages.

Dr Kotaro Tadano, Researcher, Tokyo Institute of Technology

Following a proof-of-principle experiment that produced propitious results, the scientists engineered a robotic surgery system equipped with a modular master controller that could be tweaked to use power, pinch, or combined gripping.

A pointing experiment was performed to test the system, where 15 participants were made to control a robotic arm to insert a needle’s tip into target holes in the least amount of time without making any contact with obstacles. For each gripping type, different conditions were tested, for example, the use of a handle, use of palm and armrests, pinch grip motion, and gripping type.

The outcomes revealed that the combined grip produced better performance in the pointing experiment on different fronts, such as the time required, number of failures (making contact with an obstacle), and overall length of the movements carried out to reach the targets. Furthermore, several participants reportedly preferred the combined gripping technique over the other two techniques, due to the comfort and ease of using this technique.

This innovative master controller design could be a path in the apt direction in robot-assisted surgery.

The manipulating method of master controllers for robotic surgery has a significant influence in terms of intuitiveness, comfort, precision, and stability. In addition to enabling precise operation, a comfortable manipulating method could potentially benefit both the patient and the surgeon.

Dr Kotaro Tadano, Researcher, Tokyo Institute of Technology

More research work is necessary to study other variables associated with robotic arm manipulation, but this research opens the door for sophisticated surgical robot systems, without any doubt.

Source: https://www.titech.ac.jp/english/

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