Engineers at MIT are working on four-legged robots designed to enter burning buildings to rescue people, reducing the risk to firefighters.

Someday, the physically disabled and the elderly may be able to ride or even “walk” to their destinations without cumbersome and clunky assistive aids like wheelchairs or walkers. In fact, the need for ramps and hard surfaces may be completely unnecessary. Or imagine a robot designed to enter burning buildings, navigating through obstacles and obstructions on its own to reach and rescue people or pets, reducing the risk to firefighters. That and other helpful applications are the idea behind cheetah, a robotic device built by engineers at the Massachusetts Institute of Technology (MIT) in Cambridge.

Dr. Sangbae Kim, who is the director of the engineering school’s Biomimetic Robotics Lab and an associate professor of mechanical engineering, heads the team that created a prototype resembling the world’s fastest land animal, complete with four legs and a sleek compact design.

Built and upgraded over the past four years, the cheetah can run up to 10 m.p.h. and is able to leap 15 inches in the air, ostensibly over obstacles, and weighs just 70 pounds.

The robot was built with off-the-shelf components, including an Xbox controller that maneuvers the robot, and wireless Internet communications that sends commands to the mechanical device.

Three motors drive each leg that generates powerful forces, even at low speeds. A lithium polymer battery uses about as much energy as your average home microwave oven does, Dr. Kim points out.

The running mechanism was created through a complex algorithm created by MIT research scientist Hae-Won Park.

While still in the prototype stage, the cheetah robot has made notable strides in the past few years. Originally attached by wires to a conveyer belt in the lab, the latest incarnation can be operated remotely, as demonstrated earlier this fall on the MIT campus lawn.

More improvements are on the near horizon, as Dr. Kim told Not Impossible Now in an interview below: 

NIN: What are the origins of cheetah?

Dr. Sangbae Kim: This project is managed by Dr. Gill Pratt at Dartmouth (program manager in the Defense Sciences Office). He started this program called Maximum Mobility and Manipulation (M3). It started as a scientific project in enhancing the capability of robotics and almost every program under his direction is focused on disaster response.

Photo credit: Dr. Sangbae Kim

Photo credit: Dr. Sangbae Kim

What’s your goal at MIT’s Biomimetic Robotics Lab?

Dr. Kim: Our target is to make our mobility of robotics as good as possible. We’re trying to make them as efficient as possible as well as how fast we can go and how rough (the terrain) it can go. The cheetah is trying to maximize the ability of robots. We can only imagine how it can be used. On response to building fires, our intention is that we can one day send a robot instead of humans, which would be less dangerous. We can send it to mountain fires where they can do search and rescue for people.

With the technology we’ve developed for the cheetah, it rivals human and animal muscle. You can use that technology to develop better and enhanced prosthetics and assistive devices for the elderly. We’re going to have an additional 4 billion people on Earth by 2100, and many of them will be elderly. While medicine is allowing for longer life spans, many will still suffer with joint pain. So we have to look at this assistive technology to help people to move better.

Other applications would be for adapting wheelchairs. As it is now, people in wheelchairs need to ramps to get into building and hard surfaces to get around. The transition from wheelchair to car also is a challenging and long process. Once we apply this technology to robots, the handicapped can go from their home to workplace without those access challenges. You won’t need roads anymore, in certain cases. You can have an eco-city where people are riding these four-legged robots instead of cars, which preserves the natural environment. There are many different applications.

What’s the next step?

Dr. Kim: Currently, we’re focusing on developing vision sensors. So far, the cheetah robot doesn’t have any sensors for visual capability. Right now, it cannot distinguish obstacles or direct itself so we’re focusing on integrating vision sensory technology so it can detect obstacles so we’re going try and demonstrate that next June. After that, we’re going to focus on autonomous dedications. Our goal over the next five years is to send this robot autonomously into a building and, for example, have it go to the third floor. It would create a map and then it would go up automatically, retrieve data and send it to a human outside. We’re going to make the robot much smarter so that it could perform by itself.

How did you decide to incorporate an Xbox controller into the robot?

Dr. Kim: Dr. Park is our research scientist. He thought we’d need more for the interface than a simple joystick so the Xbox player has a lot more buttons than a simple joystick so it turned out to be the best interface.

Why did the cheetah inspire this robot in the first place? Why not another animal like a lion or a leopard?

Dr. Kim: If you think about those animals from a robotics perspective, they are all the same, to be honest. Of course, if you talked to a biologist, they would tell you those animals are very different. We’re not trying to copy an animal; we’re trying to find an animal that inspires us. All these features that we design to be the fast runners is much more obvious and prestigious in the fastest animal. Bears can run 35 mph but they don’t have a slender body and flexible spine because they don’t run that long. If you look at the cheetah, you can see that. Finding those features you can use in a robot is actually not that easy because there is a limited similarity between biology and engineering. The real answer is you have to look at many different animals and find a common feature. Obviously, a cheetah is a most exciting model to use.

What type of battery does it use?

Dr. Kim: Just the typical lithium polymer battery that most RC industry uses. It can run an hour or two with the battery. It consumes less power than your microwave oven.

How long do you estimate it will take to get to the next phase and what will that be?

Dr. Kim: Hopefully, within the next three years we can send this robot autonomously to navigate and see where it can go and where it cannot go. We won’t have to control it; it will be able to do so by itself.

With the search and rescue function, do you envision it equipped with some sort of gripping device or shovel?

Dr. Kim: Yes. We are actually developing another version that is slower than cheetah. In fact, it looks more like a monkey. It can walk on four legs and stand up and use the front “paws” as a manipulator. It uses the same technology that we use as cheetah. It’s called Highly Efficient Robotic Mechanical Electromagnetic Systems, or Hermes for short.

What would you like to see in the future?

Dr. Kim: I think energy-efficiency is the most important issue. Our robot can expend the same energy as an animal. When it runs 10 mph, it consumes 700 watts. If you look at the animal data, it matches exactly right now. So we can make a robot more efficient than an animal in the future.

Learn more about the cheetah robot in the video below:

Top photo credit: Jose-Luis Olivares