Walking robots always excite me and I have a personal reason for that. I use a power wheelchair and I think if the wheels can be replaced by a pair of robotic legs and if these robotic legs can walk on all sorts of surfaces, there will be no accessibility problem. These wheelchairs (without the wheels) won’t require ramps. They will be able to climb stairs and even steep spaces in the wilderness or, on the beach.
Anyway, the video here shows a bipedal robot walking on an uneven surface. This is not a normal, real-world scenario and the video has been filmed in a lab sort of a setup, but this is the initial stage and knowing how fast these technologies develop I am pretty sure that within a few years we will have bipedal robots comfortably walking and running around. Here is the video of the bipedal robot:
When you look at a bipedal robot it is not a simple technology. Balancing on two feet uses a combination of brain and gravitation. It is not like walking on four legs or four wheels where once you are grounded, you can forget about having to balance. While walking on two legs your brain has to constantly evaluate your position vis-à-vis your centre of gravity and then within microseconds adjust your body so that it does not fall. The same sort of calculations must happen within the bipedal robot so that it can balance using its centre of gravity as well as the mental evaluation of the physical inclination.