Pupper Julia Simulation

Overview

This repository contains the Julia code that runs on the Raspberry Pi-based Pupper robot, as well as the Julia code for simulating the same code in a MuJoCo environment on a desktop computer.

Installation for Simulation

Clone this repository

git clone https://github.com/Nate711/PupperSimulation.git

Acquire a license for MuJoCo at http://mujoco.org/. You can get a free trial of the professional license for a month, or with a student account, a free year.
Save the license mjkey.txt somewhere and set the environment variable MUJOCO_KEY_PATH to that location. One way to set the environment variable is through your bash profile. On a mac this is done by adding the line

export MUJOCO_KEY_PATH=[YOUR PATH]/mjkey.txt

to your ~/.bash_profile.

Install Julia by visiting https://julialang.org/downloads/
Install the required Julia packages

julia install.jl

Run Simulation

Enter the Julia REPL in the PupperJuliaSim directory.
Run

include("main.jl")

The MuJoCo simulator should then pop up in a new window with various interactive options. Press space to start the simulation.

Click and drag with the left mouse button to orbit the camera, and with the right mouse button to pan the camera.
To perturb the robot, double click on the body you want to perturb, then hold Control and click and drag with the mouse. Using the left mouse button will apply a rotational torque while the right button will apply a translational force.
Press space to play or pause the simulation.
Press backspace to kill the simulation window and then hit Control-C to interrupt the Julia simulation code.

Installation for Raspberry Pi Robot

Materials

Raspberry Pi 4
SD Card (32GB recommended)
Raspberry Pi 4 power supply (USB-C, 5V, >=3A)
Ethernet cable

Steps

Install Raspbian Buster Lite onto the Pi
- Download https://www.raspberrypi.org/downloads/raspbian/
- Use BalenaEtcher to flash the OS to the SD card
Set up the Raspberry Pi
- Before even ejecting the SD Card, follow the instructions on this repo to put the self-installing setup script on the Pi: https://github.com/stanfordroboticsclub/RPI-Setup
- Complete the “Actually Doing It”, “Getting Internet Access”, and “Getting Started With the Pi” sections
Test that the Pi works and connects to the internet
Install the PREEMPT-RT kernel onto the Pi
- Download the kernel patch https://github.com/lemariva/RT-Tools-RPi/tree/master/preempt-rt/kernel_4_19_59-rt23-v7l%2B
- Follow these instructions starting from “Transfer the Kernel” https://lemariva.com/blog/2019/09/raspberry-pi-4b-preempt-rt-kernel-419y-performance-test
- Test by running in the shell:
```
uname -r
```
Install Julia
```
sudo apt-get install julia
```
Get the Pupper Code
- Clone the Pupper repository https://github.com/Nate711/PupperSimulation
- Enter the julia repl in shell:
```
julia
```
- Install requirements by running the installation script:
```
include("install_for_robot.jl")
```

Running the Robot

Start the PiGPIO daemon by executing in shell:
```
sudo pigpiod
```
Load the robot code in the Julia REPL:
```
include("run_robot.jl")
```
Run the main program:
```
main()
```