It's hard to hide the fact that it's 2018 and we *still* don't have many *actually* useful robots in our homes. You know, the kind that skitter around and do maintenance work. Sure, we have robotic vacuum cleaners now, but those are right now extremely simple and limited in where they can get. To really advance this area of technology, we need reliable and cheap walking locomotion.
Bipeds are of course useless. Humans are bipedal because we needed a fast and energy-efficient means of locomotion to be able to chase our prey to death, but this is really sub-optimal for the kind of work that tiny maintenance robots do. Hexapods and more are common in nature at those sizes, but wasteful — you have to remember that every servo motor is extra cost, weight and failure point. Quadrupeds are the optimal choice. Four legs with at least three degrees of freedom in each let you have precise, statically-stable true walking on any surface, with a stable vehicle platform for any tooling needed. Speed and energy efficiency are secondary concerns indoors with a charging station nearby. So it seems we should be investing in research in quadrupeds. But how?
You get the best progress when a lot of different people are trying a lot of very different approaches, iterating fast. This would be prohibitively expensive with human-sized or even dog-sized robots, but guinea pig-sized robots, which is what we ultimately want for maintenance tasks, seem to be doable. But how to get a lot of people to experiment with them? By lowering the barrier to entry — both in terms of cost, as well as in terms of skill and time required to get the first prototype to work. That was the reasoning between the #Tote project, and its later iterations. However, that project failed in one important way.
People don't want to re-build a project someone designed for them. People generally want to to build their own robots, with their own unique designs, their own ideas, and their own execution. There were a number of projects inspired by Tote, but I don't know of any instance where it was actually built as a platform for further experimentation. It simply doesn't work that way, it seems.
So now this is an attempt to tackle the problem from a slightly different angle. Instead of providing people with a ready design to build and extend, I plan to provide them with some building blocks that solve some of the main difficulties in getting a quadruped walking. I'm starting with a leg controller, because this lets me handle the problem of inverse kinematics in a transparent way, at the same time providing some base for further experimentation with proprioception.
Of course for this to all work two conditions have to be met: the project has to be open, with everything available for modification if necessary, and it has to actually get used. For the latter condition, Hackaday Prize is a good opportunity to get the word out there, especially if it somehow manages to advance to the second round. Of course there is also a third condition, that the project has to work, but that's a requirement for any project, so it doesn't require mentioning.
Now, how do I do that? At some point, while experimenting with Tote, I came up with a way to use the extra old PCB as parts of the legs by cutting them into strips to which the servo horns can be attached. Then it occurred to me that I could put some components on those boards to reduce the number of wires. In particular, I could have a chip in there that generates the PWM signal for the servos, so that all the servo wires can be short and connected directly to the leg, while the leg itself only needs a few wires for signal and power. And if I used a bus, such as I²C, I could have all those wires shared between all the legs. That is the basic idea behind this project. All the rest is extra, but of course I hope I can do it.