In the build instructions you can find all the information necessary to build (in one week for less than $500.) a four leg module for Mike's Robot Dog. Control and power lines for the 12 servo motors are brought out to terminal blocks. Power, sensors and control signals must be supplied to make the dog stand or move.
The leg module stands! Here's a video. Go to log number 12, Wiring the Module for Power and Control, for details.
I designed a low cost tilt module, using four roller ball tilt switches, to provide tilt information for the control processor.
The switch module looks like this.
For more details, check out "Tilt Module" in the logs.
Here's the overview video for the robot leg module.
Let's go for an overview of the overall project and start with the video below:
Increase torque of legs
Decrease weight of legs
Build a stiff, low weight body
Stand on three legs
Add tilt sensors to facilitate adjustments when moving
Add onboard power
Add head with sound interaction
I had to show this . . . Google's AIY Vision Kit can be used to detect human faces or smiles (and probably other things). This will allow my dog to "know" that someone is there and if they are smiling. More information can be found in log number 10, "Google AIY Vision."
Spot Mini is an amazing (perhaps scary) robot dog built by Boston Dynamics--not for sale.
Using a 3d printer, off the shelf servo motors, an Arduino and a couple of ultracapacitors; I have started something along the same line--but the cost is more like $300.
She's young and shaky, but my dog can now stand. The body is longer and the rear legs reversed--look to my log, "The Forces Are Not All With Me."
Here's where we "stand" on March 28.
This is where it started.
If you want to use the 3d print files (and some of the design files) go to thingiverse.com. Some of my .stl files do not have a corresponding design file because the .stl files are 1) the combination of two or more .stl files in Tinkercad or 2) they are mirror images of .stl files, mirrored in Tinkercad. The leg pieces can take 10-12 hours each to print as they are sizable.
I use twelve high torque (277 oz.in) metal gear servo motors at a cost of about $18. each. These have no end stops and they draw a fair amount of current to move, but they respond consistently to commands.
Under heavy load, each servo motor draws 3.5 to 4.5 amps. To move from a sitting to upright position, eight motors need to provide significant torque--meaning 30 to 40 amps are required for a second or so. I use three 350 farad ultracapacitors (in series) across my motor power supply and they take care of the momentary load of the servo motors.
Here's where I am on March 16.
My first "shoulder connection" put all the "up/down" and "rotate" stress on the servo motor.
This looked like a bad idea, so I created a bearing block and...Read more »