Why don't bipedal robots ever feature natural movement?

Question

I'm a programmer and I've decided to make some bots for fun. I might start with wheels but my ultimate goal is to make bipedal robots. To that end I first decided to watch a bunch of videos of such bots to see what their motion and parts looked like. One thing that struck me as counter-intuitive is how the forward motion of the robots is being carried out in every example I see.

When a human walks forward, they walk heal-first to toe upon their stride with one leg while pushing off the ground with their opposing heal (Or is it toe). In any case, I don't see any bipedal robots doing this. But why not? It seems to me that given sufficiently replicated feet and legs, bipedal robots should be able to carry out the same motion. Sure, the programming and/or training for this might be difficult but obviously doable. Or am I missing something?

Edit: I do realize that when a person walks, they shift their weight to perform their stride. Also doable though right? There isn't anything magical about the motion of a walking human as far as I know.

Answer 1

From my side I can provide two remarks. First the human have elastic actuators (muscles) with a lots of sensors for balance. Whereas robots have mostly rigid actuators with a few dampers here and there to avoid breaking the motors on collision, and then they have far less sensing capabilities to maintain balance. So the two are not really comparable. Another point is that walking is very unstable, you are virtually loosing equilibrium and saving it last minute to go forward. The same strategy is usually not applicable to expensive robots. The main reason being that human have local close loop of control (reflexes) whereas robots need to have complex centralized motion algorithms.

If you want to see human like walking have a look at mechanical systems tailored for that and using the same springy behavior as humans, like "A bipedal walking robot with efficient and human-like gait" from Collins at ICRA 2015.