A Bipedial Robot
After watching lots of Boston Dynamics videos, I thought to myself: "How hard can making a walking robot really be?", so I made this prototype.
I did not want to spend a lot of time on this project because it could of course be only so good with the hardware available to me. So instead of designing and 3D printing a frame for the robot, I just cut links out of cardboard and glue gunned them to the servos that I would be using to control the limbs. I take a similar approach for my quadrupod robot, but used plywood there.
The key to making the two-legged robot work is to be able to have some kind of method of adjusting weight distribution. A more advanced robot than mine could then use an inertial measurement unit (accelerometer + gyro) to compute the robot's motion and adjust how it balances accordingly. This is just like how we sense our rotation with the fluid in our ears and then move our arms and torso to stop us falling over, or how a cat can right itself using its tail.
I did not want to go to the lengths of developing the control software for this though, and I also didn't think the servos I had would be accurate enough to facilitate this. So instead of having full arms that wave about to adjust weight, I went for a simple "heavy head" approach: glue about ten 2p coins to the head of the robot and then shift this side to side as it walks to free up one leg to move into the air.
This was a pre-defined appraoch whereby the robot does not do ay active stabalisation and just sequences through a set of motor positions. To set these motor positions I created a little Tkinter application that writes the positions over serial to the controlling Arduino microprocessor. This then also has a replay button. I took a similar approach when making my my second robot arm.
And that's all for this project: it can just about walk, but very slowly, and very wobbly! I have no futher plans for this project, it was just a little experimentation.
Here is a video of me demonstrating the Tkinter application and then playing a pre-programmed sequence of walking moves.
Finally here is a sped up video of it walking.