Robots and I

Prof. Moshe Shoham of the Faculty of Mechanical Engineering and the head of the Center for Manufacturing Systems and Robotics at the Department of Mechanical Engineering at the Technion speaks about the development of a medical micro-robot, a goalkeeper robot and what lies between them

Prof. Moshe Shoham

By Noam Bercovitz

If everything goes according to Prof. Moshe Shoham's plan, come next year or so, at the opening of the Year of the Robot at MadaTech-The Israel National Museum of Science, a star from Israel's National Football Association will challenge a robot goalkeeper, courtesy of the Technion, and try to beat him by kicking a penalty shot. Assuming that by then the development will have been completed, the robot will deflect the airborne ball, regardless of the human player's talent and skill.

The robot goalkeeper comprises a video camera, a computer and a metal plate that is moved about at high speed by four engines positioned at the four corners of the goal. The plate is meant to get to the point at which it is estimated the ball will be coming and deflect it.

Shoham says that at this stage some of the robot's systems have been completed and it can calculate where exactly the ball that is kicked will be heading. However, development is still required so that the plate will move fast enough to arrive at the exact point where it is needed. The technological challenge is not simple and the problem rests in identification, course estimation and reaction mechanics. The ball is in the air for about a half of a second after it is kicked and until it reaches the goal. During this period of time the robot must photograph the ball at several points along its course, and using this data in combination with the ball's freefall, pinpoint where it will impact the goal line, and then accelerate and stop the "goal" at this point.

Shoham believes that his team will complete development in time. He is anxious not to miss the media opportunity to capture the attention of youngsters all over the country and get them interested in robotics and the activities at the Technion's Robotics Institute, which Prof. Shoham heads, and which was recently set up, with the help of Leumi Bank. Prof. Shoham's goal: to foster education and knowledge in the area of robotics in Israel.

Robotics Pioneers

Prof. Shoham is one of the pioneers of robotics in Israel and was a member of the team that greeted the first robot that arrived at the Technion in 1982. About a decade ago, Shoham launched a new area of robotics - medical robots, and today Mazor Surgical Technologies Ltd., which he set up together with the Technion, is one of the four leading companies in the world in this field.

When he entered the field of medical robots, Shoham first turned to medical centers in Israel and the world, asking them for proposals and requests to develop tools that would help them improve their work. His group received several ideas for implementation and at the end, focused on one product - a robot for back surgery, which enables surgeons to implant screws during spinal fusion operations. This surgery requires surgeons to position implants between vertebrae where the cartilage has been destroyed. Drilling the holes for the screws mandates precision positioning and is risky given the proximity to the central nervous system. The robot's job is to guide the surgeon to the drilling site during the operation. Using the robot enables great precision and stability, minimal invasiveness, and as a result, a speedier recovery by the patient.

The robot, which is about the size of a human fist, lies on the patient's back during the operation. It has passed all the clinical tests and has been authorized for use in operations in four countries: the U.S., Russia, Germany and Israel. Today, about 25 systems worldwide have been used in about 1,000 operations. In regular spinal fusion surgery, 5% of patients suffer from different levels of nerve damage, but in operations that have used Shoham's robot, no permanent  nerve damage at all has been reported.

About a half a million spinal fusion operations take place annually all over the globe, so the marketing potential of the device is indeed huge. However, Prof. Shoham conditions this optimism and explains that using the robot changes the way surgeons usually work, and therefore, he estimates that increased use of the robot will be gradual and a certain market education will be required.  In this framework, ISRACAS is held annually in Israel. Prof. Shoham is one of the organizers of this symposium in which engineers, researchers and doctors from different fields meet to discuss the integration of computers and robots in medicine.

The future in miniature

The next challenge in medical robots is to create a micro-robot that can be introduced into the human body and carry out a series of tasks. The concept is old and immortalized in Fantastic Voyage, a movie that came out in 1966. Only today, however, are there technologies that allow the illusion to become reality.

Shoham and his team - Oded Salomon and Dr. Nir Shvalb - built a micro-robot called Virob, seen here in a CNN news report. The robot is about a millimeter wide and 4 mm long. It is designed to move  inside blood vessels, tissue and even within the lungs and it is designed so that it can carry out a series of medical activities.

Among others, it is expected that these robots will be able to carry medication, releasing it at a precise spot, so that, for example, anti-cancer drugs can be released inside a tumor itself. In addition, these robots can clean drainage pipes that are implanted in surgery and become blocked, can perform delicate surgery, biopsies and more.

Because of its small size, the Virob does not carry an autonomous power source and is guided by a control that identifies its location using imaging equipment. Prof. Shoham explains that labs all over the world are working on micro robots that can travel inside blood vessels but that these kinds of robots may be particularly difficult to develop due to the strong flow of blood within the vessels. Likewise, a robot of this type is meant to grab onto the blood vessel walls in order to advance or remain in place and there is a risk that it will peel off layers of material that have become attached to the walls and thus cause this material to move to places where it may plug the vessels and cause a cerebrovascular accident (CVA).

The miniaturization itself raises an array of problems. For instance, for bodies that are measured in millimeters, water appears as viscous as honey. This phenomenon is defined in flow mechanics through Reynolds numbers, which express the relation between the inertial forces of the body and the friction forces acting between it and the liquid surrounding it. The smaller the body is, the smaller are the inertial forces and the viscosity effect grows and makes movement difficult.

Shoham's doctoral student, Gabor Kosa, now a post doc in ETH Zurich  has shown that for micro robots that are meant to advance by using a swimming mechanism, there is no need to develop a mechanism that includes fins (as fish have). The solution is a flagella mechanism that creates an advancing wave, similar to what miniature-sized creatures use in nature.

A robot for every purpose

On the entrance level of the Robotics Center, one can see the goalkeeper robot, and further on lies an area for "robotraffic" in which high school students build robotic cars that move autonomously along a course that simulates an urban landscape. Nonetheless, one's attention is captured by a three-legged, gangly and odd-looking robot, which turns out to be a prototype of a painter robot, that is, a robot designed to paint walls. It is difficult not to imagine a world full of painter robots working alongside plasterer robots, gardener robots and heavens knows what else - a perfect world in which everyone works without any problems and without "I'll be there first thing in the morning" and not showing up. On second thought, though, to paint a wall once every few years, no one will buy a robot. The only person who would buy such a robot would be a painter, and then most likely, at the end of the negotiations he'll still warmly promise: "I'll be at your home first thing in the morning with my robot"...