Universities give rise to biomimetic cheetah and gecko

What do cheetahs, geckos and biomimetics have in common? No, not auto insurance. Think "robots". Biomimetic refers to nature-imitating substances, devices, processes or systems that are created by humans. Sangbae Kim is a human at MIT [Massachusetts Institute of Technology] who is creating robots inspired by the animal kingdom. They have applications in industry, as well as surveillance and search-and-rescue mission capabilities for the military environment.

While a graduate student at Stanford University, Kim was on a team that created "Stickybot," a gecko-inspired climbing device. It was listed as one of Time Magazine’s Best Inventions of 2006. Unfortunately, then, it was only a prototype and categorized as a "toy." However, neither the completed Stickybot, nor the cheetah-like robot currently on the drawing board is made for children. Stickybot technology, for example, can be directed at exterior repair of underwater oil pipelines, or simply washing windows.

Sticky Sytem principle

If a little green gecko, or a man-made robot, must stick to a vertical surface in order to scale it, they must be able to "unstick" as each foot moves higher. Kim explains that stickiness "…can come from mechanical properties and geometry. The geometry enables strange phenomena such as directional adhesion, which sticks in only one direction."

Stickybot principle explainedKim explains his robot’s gecko-like appendage: "Itsfoot has four segmented toes controlled by single push-pull cable viatwo stage differential system. Three different polymers are used… tominimize shear stress concentration along adhesive pads." The robot is operated by 12 servo motors controlled by a PIC controller with force sensors.

Stanford professor Mark Cutkosky?s team continues to enhance the original Stickybot, in a version tentatively named Stickybot III which will use a PIC24HJ128GP202 microcontroller because of its multiple features, and the inclusion of 2 UARTS and 2 SPI [serial peripheral interface] for easier communication. The main board contains both a microSD slot and a 1 GB microSD card to log data at real-time. Wireless will be provided by Roving Networks Bluetooth UART [universal asynchronous receiver/transmitter] whose major advantage is that several new laptops, especially Macs, have Bluetooth radios. Thus, in the field, Stickybot III will only need a laptop to go to work. 

Biomimetic squirrel. Picture credit: Metro.co.ukKim, now an assistant professor at MIT, is working on a robo-cheetah,for want of a better name for his new project. This month in St. Louis,Missouri, Kim appeared at a workshop on Biologically Inspired Roboticsat the 2009 IEEE/RSJ International Conference on Intelligent Robots andSystems.

He is concentrating his efforts on "hyper dynamic locomotion." Kim plans initially to make a prototype that can reach 35 mph [56 km/h, kph] by copying the cheetah?s flexible backbone. The cheetah?s hip, knee, and ankle joints, with an extra boost from its unique backbone add up to supreme speed. Naturally, this is not as fast as the real-world cheetah, but to reach half the speed of real animal in the first generation is something that will capture imagination of hollywood scriptwriters.

Grad students are working with Professor Kim using a computer model to calculate the best length and weight for the limbs, and an optimum gait and torque for the hip and knee joints.

The goal is to develop a robot that can traverse flat or rough terrain quickly and efficiently without tipping over. 

Although robots abound, Kim contends that none of them can move as fast as he can walk over rough terrain or up stairs. Modeling a robot after a cheetah is not the only possibility. Squirrels also have dynamic behavior ? they run and climb. No robot can do both? yet.