Milana is a small and relatively cheap robot on two wheels. For a general description on how I built this robot, see here
The robot has 6 motors on each side:
- A BDC 280KV motor controlling the wheel.
- A BDC 100KV motor controlling the knee (used for jumping).
- A 35kg servo motor controlling the hip.
- 3 1.5kg small servo motors, controlling the arm.
The brushless motors are controlled with two ODrives, each with custom firmware to enable some of the tricks demonstrated in the video. All motors, except for the arm motors, also have precise encoders attached. The robot is powered by two 3Ah 3S Lipo batteries and controlled by a Jetson Nano. The Jetson Nano is running custom control software on Ubuntu with a slightly modified Linux kernel. Beside the ODrives, the Jetson Nano is connected to the following:
- IMU sensor for 3D Orientation.
- Servo Driver to control all servo motors.
- A2D Converter for battery charge measurement.
- Microphone and speaker.
The robot can be controlled externally using various methods:
- With custom software (Control UI), running on a separate computer and connected via Wifi. This can also be used to tune and calibrate internal parameters, debug issues and simulate certain parts of the robot.
- With a wireless XBox controller.
- With speech recognition and a LLM. The robot can reply using speech synthesis and execute a number of commands.
The robot can...
- balance on its wheels while driving and changing its body posture.
- move its "knees" so fast that it will jump a few centimeters.
- control each arm with 3 degrees of freedom and pick up light objects with them.
- move up to about 10 km/h.
- keep balance while moving with one wheel on a small ramp.
This robot is completely Open Source: The code for the "brain" of the robot is in this repository in the robot folder. The software to control and debug the robot, Control UI, is also here. There are also modules for Automatic Speech Recognition, Large Language Model and Text To Speech included here that can optionally be used to have a conversation with the robot. Some of the code is in other repositories: The custom image for the Jetson Nano is here. And the custom firmware image for the ODrives is here. All of these links point to a readme with more information about each component.
The CAD files and the meshes that need to be printed with a 3D printer are here. Other things that you need to buy are listed in the Bill of Materials (the total is about 1200€). Here are some photos of the completed robot with some annotations for reference. More detailed information about each part is also in the comments of the code that controls it.
This is not a project for beginners. If you intend to make the robot, some experience in robotics and coding is recommended. I also don't provide any warranty of any kind. Use all of this at your own risk.