mujoco interface for mc-rtc

Usage

First, install the required apt packages:

$ sudo apt install libxrandr-dev libxinerama-dev libxcursor-dev libxi-dev libglew-dev

Then, execute the following command to install mujoco ($HOME/.mujoco/mujoco301), and build mc_mujoco:

$ git clone --recursive [email protected]:rohanpsingh/mc_mujoco.git
$ cd mc_mujoco
$ mkdir build && cd build
$ cmake .. -DCMAKE_BUILD_TYPE=RelWithDebInfo
$ make
$ make install

If mujoco is already installed, you can add the following option to specify the path :

$ cmake .. -DCMAKE_BUILD_TYPE=RelWithDebInfo -DMUJOCO_ROOT_DIR=$HOME/.mujoco/mujoco301

Add the following line to your ~/.bashrc:

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:${HOME}/.mujoco/mujoco301/lib:${HOME}/.mujoco/mujoco301/bin

Then, to run the interface:

$ mc_mujoco

Docker

Assuming docker has been installed, the easiest way to get started is as follows:

$ git clone --recursive [email protected]:rohanpsingh/mc_mujoco.git
$ cd mc_mujoco/docker
$ make run

Then, inside the docker container:

$ mc_mujoco

---

To load additional objects in the scene

There are several steps needed to be followed:

• First, create your object's XML file under mc_mujoco/robots. For example, longtable.xml
• Then, create a simple config file with the xmlModelPath attribute. For example, longtable.in.yaml
• Then, install your object by adding it to the end of mc_mujoco/robots/CMakeLists.txt. For example, add setup_env_object(box object)

Your object is now created and installed. Next you want to tell mc-mujoco to load it and place it at the desired pose. Find ~/.config/mc_rtc/mc_mujoco/mc_mujoco.yaml (create it manually if needed) and paste the following:

objects:
  box1:
    module: "box"
    init_pos:
      translation: [3.1, 0, 0.9]
      rotation: [0, 0, 0]
  box2:
    module: "box"
    init_pos:
      translation: [3.7, 0.2, 0.9]
      rotation: [0, 0, 0]

---

To load MuJoCo plugins

To load MuJoCo plugins, specify the paths to the directories containing the plugin libraries in the PluginPaths entry in ~/.config/mc_rtc/mc_mujoco/mc_mujoco.yaml.

PluginPaths: ["<path-to-plugins>"]

---

GUI: Mouse Interaction

An object is selected by left-double-click. The user can then apply forces and torques on the selected object by holding Ctrl key and dragging the left-mouse-button for torques and right-mouse-button for forces.

Example

A basic example of what you can do using this package is here.

Datastore callbacks

The following callbacks are available for the controller when running inside mc_mujoco

Signature	Description
{robot}::SetPosW(const sva::PTransformd &)	Set the position of the given robot. Also works with objects
{robot}::SetPDGains(const std::vector<double> & p, const std::vector<double> & d)	Set the PD gains for the actuation of the given robot. p and d must follow the robot's reference joint order
{robot}::SetPDGainsByName(const std::string & jn, double p, double d)	Set the PD gains for a given joint jn in robot
{robot}::GetPDGains(std::vector<double> & p, std::vector<double> & d)	Get the current PD gains for robot actuation
{robot}::GetPDGainsByName(const std::string & jn, double & p, double & d)	Get the current PD gains for a given joint jn in robot

Citation

@inproceedings{singh2023mc,
  title={mc-mujoco: Simulating Articulated Robots with FSM Controllers in MuJoCo},
  author={Singh, Rohan P and Gergondet, Pierre and Kanehiro, Fumio},
  booktitle={2023 IEEE/SICE International Symposium on System Integration (SII)},
  pages={1--5},
  year={2023},
  organization={IEEE}
}

Credits

This package includes code from:

• imgui v1.84.2
• implot v0.11
• ImGuizmo
• pugixml v1.11.4
• Roboto font