Monday, January 19, 2009
Want to see some exciting biologically inspired robotic legs? Look no further than MIT's Robotic Leg Lab website. The site has several biologically inspired legged robot pictures and videos.
Kangaroos, Dinosaurs, Flamingos and Turkeys are all inspirations for legged bots. These mechanically correct, but cosmetically awkward, robots explore the ability for robots to jump, walk, and run. These three activates are actually quite different to control.
Stand up from your computer and take walk around the room. Notice that one of your feet is in contact with the floor all the time. Now try jogging. Notice that for short periods of time you are completely off the ground as you leap from one foot to the next. Now try jumping about. Your legs need to create upward momentum to leap and then they must absorb your weight as you land.
Jumping, walking and running are different because of what is called gate, or stride. Robotically controlling the different gates is difficult because it requires compensating for weight and balance. As human we do this quit easily…well for adults that is.
Another fun aspect of the MIT leg lab site are the simulations. The Cockroach Sim shows cockroaches scurrying around the floor. It’s life like, so try not to shiver too much. The “On The Run” video is comical as two robots run with kangaroos!
Have fun watching these long legged videos.
Friday, January 9, 2009
Have you noticed that there are several reassembling robots in the news and on the web? Discover Magazine highlights ckBot, a Rubiks Cube looking robot from the U Penn, that can reconfigure after being kicked apart. A self healing chair on U-tube a chair can break apart and reassembly itself. These may seem like parlor tricks, but they are really laying a foundation for a larger problem related to space exploration.
The key to making space exploration more affordable is reducing the cost of getting objects into space. Many scientists are testing the theory of launching several small objects and then assembling them in earth’s orbit to create a larger vehicle, station, or satellite. This is the premise behind the International Space Station, which is assembled by Astronauts. To make this theory cost effective, the vehicles must be assembled autonomously, which is why these small reassembling robots are so important. These projects can lead to great understanding for docking robots in space.
The Orbital Express program highlights the difficultly of assembling vehicles while orbiting the earth and without human interaction. This government funded program made a failed attempt at docking two satellites with a robotic arm. A failure in the navigation system caused the two robots to hit each other and bounce away.
There are several reasons for this project's failure that are common to all space operations. The remote distance of scientist and hardware creates problems. Also, the space environment itself creates challenges. Space has low gravity which makes holding two objects close together difficult because they tend to float away. Also, because of no atmosphere, surfaces that face the sun become extremely hot and surfaces in shadow are extremely cold. This can make material warp and can make connecting to interfaces difficult or impossible.
Add these space factors to the challenges of coordinating a group of robots and the task becomes even more difficult. Controlling a group of robots to work together autonomously is called swarm robotics. Swarm robotics has challenges of its own, which include getting robots to communicate with each other, knowing where one robots is relative to another, and determining mating locations. These reassembling robots are really solving the problem of swarm robots.
The information learned from these reassembling robots can be help space application. Think of a reassembly robot that can operate in a desert location. How different is that from operating on the moon? Two flying robots that become one is a very similar operation as docking two satellites. These reassembly robots are giving scientists better understanding of docking robot swarms, without the expense of sensing things into space. So next time you laugh at these parlor tricks, think again!
Monday, January 5, 2009
UAVs are often used in sandy or rocky terrain where it is easy for tires to slip. This is especially problematic because most wheeled robots use high tech odometers to collect distance information from the number of wheel revolutions. A slipping wheel distorts the distance that the robot has traveled. Like the crab, UAVs that have slipping tires will not arrive at their destination. Using the Fiddler crab’s navigation method, travel distance can be better predicted and therefore make for a better performing UAV.
The crab scientists found that crabs optimize for energy because the speed of the crab can vary. The crabs are capable of moving quickly or slowly, and therefore adjusting their stride lengths. This means the do not simply count steps. Researchers believe crabs monitor the amount of energy they expel over the duration of the journey.
Knowing a UAV’s energy usage on long endurance trip is very important because many UAVs use batteries. UAV’s must constantly conserve energy. Energy level can be important to decide what tasks can be completed or what speed to complete them.
Currently it’s not ground robots that are monitoring power levels, it’s air vehicles. High altitude solar powered aircraft such as Helios and Centurion move to different configurations to collect more sun rays. Because their main power source is the sun, they must constantly monitor usage. If an aircraft looses power, it doesn’t simply get stuck in the sand. It falls out of the sky. Using this type of method in ground robots may be beneficial for long trips.
In order to navigate using energy usage, more sensors and computers are required to be on the robot. This can add more complexity to the robot rather than simply counting wheel revolutions. However, for trips over varied terrain where precise locations are required, this may be the best method. So the best way for your UAV to travel may be the crab walk.
Tuesday, December 30, 2008
I was walking though CVS today and I noticed a product called "Robot Sliders." Now, my mother has these sliders to help her move large furniture when cleaning. You simply place them under the four corners of a large chest and it easily slides across the floor. Where is the robot in that? Robot Sliders! This is totally false advertisement!
Okay, this may be a bit of an over reaction, but it seems that the word robot is increasingly misused in order to sell products and other applications. The word robot has always seemed to convey a sci-fi and advanced mechanism. And in that vain, I can understand the word's use on components that have some electrical and sensing capability. But the robot sliders didn't even have a power cord.
Let's look at what the definition of robot is. According to the Robot Institute of America in 1979, a robot is "A reprogrammable, multifunctional manipulator designed to move material, parts, tools, or specialized devices through various programmed motions for the performance of a variety of tasks".
Essentially this means that a machine must have a programming center (computer chip) and able to execute several tasks. The machine may also have a set of tools to complete a task. The i robot's Roomba is a great example of this.
This definition is 30 years old and a great amount of computer and electronics invention has been completed since then. The idea of a robot has further been complicated with the addition of these components in everyday things. Is a cell phone that has an alarm on it a robot? Is a car that tells your the oil tank is low? Confusing questions.
I searched the web for a modern day definition, but many definitions on the web associate robots with human likeness or actions. This association of humans and robotic ties may come from the word robot itself. The word robot is a Czech word, robota, which means compulsory labor or serf. The meaning being that robots would be our slaves.
I wonder how much we are actually slaves to robots. At least in our pocket books!
Monday, December 29, 2008
I'm a fan of hopping robot's, mainly because for my Master's Thesis I designed micro robotic grasshopper with a new type of actuator. Granted my robotic hopper only leaped a few millimeters, but I'm still intrigued by the idea of a swarm of jumping robots.
Grasshoppers jump by using their upper and lower leg muscles to pull back on their knee joint. The knee is able to deform and create potential energy. To create this mechanically, a slot and pin are used. The pin is held in place by a spring. When the muscles compress the spring, enough force is created for jumping. When the muscles release, the object is propelled forward.
A great example of how this all works is on the website How Grasshoppers Jump by Heitler out of the UK. I used this site to understand the bio-mechanics of a grasshopper, way back when I was doing my Master works. I'm glad to see it's still up and running. Below are some snap shots.
One last thought on grasshoppers. I found this great video from the NewScientist. A grasshopper robot was able to jump 27 times higher than it's own height. This is a world record. It will be awesome when it can actually land a jump!
The intent for this jumping robot is for search and rescue in a forest. While jumping robots are good for uneven terrain, another advantage is the low computing power. Over long distances, hopping robots can make small adjustments to their path with out much power loss. Traditional wheel robots need to constantly be monitoring direction and require turning for correction.
While hopping robots are a fun concept, the challenges of hopping robots are numerous. Landing and stability are intrinsic problems with this type of design. I'll be blogging more about this in the future.
Saturday, December 27, 2008
What is a biologically inspired mechanism or robot? Well, it is anything that moves, operates, or thinks like humans, animals, or nature. Nature has been around for many thousands of years and has gotten pretty good at a lot of things. Birds fly long distances, fish swim to avoid being eaten, and plants grow in little light. These are all examples of nature being faced with a challenge and adapting to the situation. Scientists are problem solvers too.
What is a mechanism or robot? It's any man-made device that moves, operates, or computes. A robot is defined as a "multi-programmable manipulator". This basically means any thing that can be used many time to move or change something else. Mechanisms include aircraft, underwater vehicles, a latch on a car door, or a slingshot.
Scientist can look to nature to solve or improve of the problems they face. Let's look at how an insect flies around your house. An insect can flap it's wing to fly and avoid the walls as it looks for food. The wing is light weight and needs little power to propel it. The insect's brain is very small and requires little "computing power" to control the motion of the wing. These characteristic are very advantageous for designing small unmanned air craft, or UAV. Imagine what more efficient air travel could do for commercial travel.
Using humans, animals, and nature as a foundation for man-made systems is nothing new. In the late 1400's, Leonardo Da Vinci designed many contraption using architecture of humans muscles and tendons. Secretly, he would autopsy corpses to understand how the human body worked. Many of his gliders were based on his observations of bird in flight. Check out: http://en.wikipedia.org/wiki/Leonardo_da_Vinci
There is a lot of exciting research being conducted in todays labs. I hope to bring you a spattering of exciting new technologies. Many of the new technologies are finding their way into our consumer products. I hope I can be the translator for the "crazy scientific minds" to your technology inspired minds.