Robots can climb stairs, and they are doing it everywhere you look. "No big deal" you say, but it really is a big deal. Five to ten years ago almost nobody was doing it. Now grad students are doing it all by themselves for thesis projects.
Stair climbing may not seem like it is that hard, but it really is hard, especially if you don't take the easy way out by using a tracked system. Stair climbing only looks easy because we are building on the knowledge that those before us have so painstakingly accumulated. This is a common theme with technological advancement: things that once seemed hard (and really were hard!) often appear easy once we figure out how to do them and they become commonplace.
One of our favorite stair climbing robots is the appropriately named stairbot. Not only is the stairbot pretty awesome, but it is accompanied by an excellent website that offers a nice look at the engineering theory behind stair climbing robots. The stairbot can drive back and forth, pivot and turn, drive over small obstacles up to 4 cm high, and yes, go up and down stairs. Lets take a look at the stairbot in action:
One of the techniques that is key to the stairbot's success is its spindle driven ability to dynamically change its length. In order to navigate stairs both upwards and downwards, the stairbot is equiped with several sensors that allow it to sense its orientation and then make the necessary adjustments.
Below is a frontal view of the stairbot in all of its beauty, sensors and all!
Perhaps the easiest and most common technique for getting robots up stairs it to equip them with tracks, similar to your typical army tank. The tracked technique may require less skill and precision than other techniques, but still it gets the job done. Below is a video of the B2P2 robot, an Unmanned Ground Vehicle (UVG) initiative developed at the University of Angers in France. Also below is a video of the versatile army robot from iRobot, called the Packbot, which also uses tracks. There are several other tracked robots that go up stairs - these are only two such examples:
Of course one of the harder challenges in stair climbing is the humanoid variety. The famous Asimo robot from Honda conquered the task many years ago, as did the HRP-2 line of robots. Lets look at videos of the Asimo robot, first succeeding at stair climbing, and then in the second video failing. The video with the robot falling is quite hilarious so laugh all you want...but keep in mind that robots are likely to have the last laugh!
Finally, we end our survey of stair climbing robots with a short video of a robot developed at the department of Mechanical Engineering and Mechatronics, Ariel University Center, Israel. We don't have much information on the robot, but you have to admit the climbing technique is quite interesting and novel:
Stair climbing, a difficult challenge by itself, is just one of a long series of major challenges that robots can now perform quite easily, yet nobody seems to notice. Go ask the general public about the progress robots have made in the last ten years and most people will say "not much". Even though we are bombarded by small, specific signs of progress everyday, it is hard for us to step back and see the big picture.
Take a moment to step back, however, and the robotic revolution is all around us! Robots are in fact advancing at an incredible pace, and they are not simply replicating human abilities - they are building upon them and extending them. Humans can only climb stairs using their feet. Robots can climb stairs using feet, but they can also do it with tracks, wheels, shifting appendages, and more.
Moving beyond stairs for a moment, robots like Big Dog show us that robots can handle just about any terrain imaginable. The future certainly looks bright for robots. Lets hope that translates into an equally bright future for humans too.