# Robotics simulator

A robotics simulator is a simulator used to create an application for a physical robot without depending on the physical machine, thus saving cost and time. In some case, such applications can be transferred onto a physical robot (or rebuilt) without modification.
The term robotics simulator can refer to several different robotics simulation applications. For example, in mobile robotics applications, behavior-based robotics simulators allow users to create simple worlds of rigid objects and light sources and to program robots to interact with these worlds. Behavior-based simulation allows for actions that are more biotic in nature when compared to simulators that are more binary, or computational. Also, behavior-based simulators may learn from mistakes and can demonstrate the anthropomorphic quality of tenacity.
One of the most popular applications for robotics simulators is for 3D modeling and rendering of a robot and its environment. This type of robotics software has a simulator that is a virtual robot, which can emulate the motion of a physical robot in a real work envelope. Some robotics simulators use a physics engine for more realistic motion generation of the robot. The use of a robotics simulator to develop a robotics control program is highly recommended regardless of whether a physical robot is available or not. The simulator allows for robotics programs to be conveniently written and debugged off-line with the final version of the program tested on a physical robot. This applies mainly to industrial robotic applications, since the success of off-line programming depends on how similar the physical environment of a robot is to a simulated environment.
Sensor-based robot actions are much more difficult to simulate and/or to program off-line, since the robot motion depends on instantaneous sensor readings in the real world.

## Features

Modern simulators tend to provide the following features:
* Fast robot prototyping:
** Using the own simulator as creation tool
** Using external tools
* Physics engines for realistic movements: Most simulators use Bullet, ODE or PhysX.
* Realistic 3d rendering: Standard 3d modeling tools or third-party tools can be used to build the environments.
* Dynamic robot bodies with scripting: C, C++, Perl, Python, Java, URBI, and MATLAB languages used by Webots; C++ used by Gazebo.

## Simulators

Among the newest technologies available today for programming are those which use a virtual simulation. Simulations with the use of virtual models of the working environment and the robots themselves can offer advantages to both the company and programmer. By using a simulation, costs are reduced, and robots can be programmed off-line which eliminates any down-time for an assembly line. Robot actions and assembly parts can be visualized in a three-dimensional virtual environment months before prototypes are even produced. Writing code for a simulation is also easier than writing code for a physical robot. While the move toward virtual simulations for programming robots is a step forward in user interface design, many such applications are only in their infancy.

### General information

| Software | Developers | Development status | License | 3D rendering engine | Physics engine | 3D modeller | Platforms supported |
| Gazebo | Open Source Robotics Foundation (OSRF) | Active | Apache 2.0 | OGRE | ODE, Bullet, Simbody, DART | Internal | Linux, macOS, Windows |
| RoboDK | RoboDK | Active | Proprietary | OpenGL | Gravity plug-in | Internal | Linux, macOS, Windows, Android, iOS, Debian |
| SimSpark | O. Obst et al. (+26) | Active | GNU GPL (v2) | Internal | ODE | None | Linux, macOS, Windows |
| Webots | Cyberbotics Ltd. | Active | Apache 2.0 | Internal (WREN) | Fork of ODE | Internal | Linux, macOS, Windows |
| OpenRAVE | OpenRAVE Community | Active | GNU LGPL | Coin3D, OpenSceneGraph | ODE, Bullet | Internal | Linux, macOS, Windows |
| CoppeliaSim | Coppelia Robotics | Active | Dual: commercial, GNU GPL | Internal | MuJoCo, Bullet, ODE, Vortex, Newton | Internal | Linux, macOS, Windows |
| Software | Developers | Development status | License | 3D rendering engine | Physics engine | 3D modeller | Platforms supported |

### Technical information

| Software | Main programming language | Formats support | Extensibility | External APIs | Robotics middleware support | Primary user interface | Headless simulation |
| Gazebo | C++ | SDF/URDF, OBJ, STL, COLLADA | Plug-ins (C++) | C++ | ROS, Player, sockets (protobuf messages) | GUI | Yes |
| RoboDK | Python | SLDPRT, SLDASM, STEP, OBJ, STL, 3DS, COLLADA, VRML, Robot Operating System URDF, Rhinoceros 3D, ... | API, Plug-In Interface | Python, C/C++, C#, Matlab, ... | Socket | GUI | Yes |
| SimSpark | C++, Ruby | Ruby Scene Graphs | Mods (C++) | Network (sexpr) | Sockets (sexpr) | GUI, sockets | Un­known |
| Webots | C++ | WBT, VRML, X3D, 3DS, Blender, BVH, COLLADA, FBX, STL, OBJ, URDF | API, PROTOs, plug-ins (C/C++) | C, C++, Python, Java, Matlab, ROS | Sockets, ROS, NaoQI | GUI | Yes |
| OpenRAVE | C++, Python | XML, VRML, OBJ, COLLADA | Plug-ins (C++), API | C/C++, Python, Matlab | Sockets, ROS, YARP | GUI, sockets | Yes |
| CoppeliaSim | C++, Python, Lua | 3DS, Blender, COLLADA, STL, OBJ, URDF, SDF, GLTF, XML | Plug-ins (C/C++), embedded scripts (Python, Lua), remote API (C, C++, Python, Java, MATLAB, Octave), add-ons (Python, Lua) | C, C++, Python, Java, MATLAB, Octave, ROS, ROS 2.0 | Sockets, ROS, ROS 2.0, ZeroMQ | GUI | Yes |
| Software | Main programming language | Formats support | Extensibility | External APIs | Robotic middleware support | Primary user interface | Headless simulation |

### Infrastructure
#### Support

| Software | Mailing list | API documentation | Public forum, help system | User manual | Issue tracker | Wiki | Chat |
| Gazebo | Yes | Yes | Yes | Yes | Yes | No |
| RoboDK | Yes | Yes | Yes | Yes | Yes | No | Un­known |
| SimSpark | Yes | Yes | No | Yes | Yes | Yes | Un­known |
| Webots | No | Yes | Yes | Yes | Yes | Yes | Yes |
| OpenRAVE | Yes | Yes | Yes | Yes | Yes | Yes | Un­known |
| CoppeliaSim | No | Yes | Yes | Yes | Yes | Un­known | No |
| Software | Mailing list | API documentation | Public forum, help system | User manual | Issue tracker | Wiki |

#### Code quality

| Software | Static code checker | Style checker | Test system(s) | Test function coverage | Test branch coverage | Lines of code | Lines of comments | Continuous integration |
| Gazebo | cppcheck | cpplint | gtest and qtest | 77.0% | 53.3% | 320k | 106k | Jenkins |
| RoboDK | Un­known | Un­known | Un­known | Un­known | Un­known | Un­known | Un­known | Un­known |
| SimSpark | Un­known | Un­known | Un­known | Un­known | Un­known | Un­known | Un­known | Un­known |
| Webots | cppcheck | clang-format | unit tests | 100% of API functions | master, develop | ~200k | ~50k | GitHub Actions |
| OpenRAVE | Un­known | Un­known | Python nose | Un­known | Un­known | Un­known | Un­known | Jenkins |
| CoppeliaSim | Un­known | Un­known | Un­known | Un­known | Un­known | Un­known | Un­known | Un­known |
| Software | Static code checker | Style checker | Test system(s) | Test function coverage | Test branch coverage | Lines of code | Lines of comments | Continuous integration |

### Features

| Software | CAD to motion | Dynamic collision avoidance | Relative end effectors | Off-line programming | Real-time streaming control of hardware |
| Gazebo | Un­known | Yes | Yes | Yes | Yes |
| RoboDK | Yes | Yes | Yes | Yes | Yes |
| SimSpark | Un­known | No | Un­known | No | No |
| Webots | Un­known | Yes | Yes | Yes | Yes |
| OpenRAVE | Un­known | No | Un­known | No | No |
| CoppeliaSim | Un­known | Yes | Yes | Yes | Yes |
| Software | CAD to motion | Dynamic collision avoidance | Relative end effectors | Off-line programming | Real-time streaming control |

#### Robot families

| Software | UGV (ground mobile robot) | UAV (aerial robots) | AUV (underwater robots) | Robotic arms | Robotic hands (grasping simulation) | Humanoid robots | Human avatars | Full list |
| Gazebo | Yes | Yes | Yes | Yes | Yes | Yes | Yes | |
| RoboDK | No | No | No | Yes | No | No | No | Yes |
| SimSpark | Yes | No | No | Maybe | Maybe | Yes | No | |
| Webots | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| OpenRAVE | Yes | Un­known | Un­known | Yes | Yes | Yes | Yes |
| CoppeliaSim | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Software | UGV (ground mobile robot) | UAV (aerial robots) | AUV (underwater robots) | Robotic arms | Robotic hands (grasping simulation) | Humanoid robots | Human avatars | Full list |

#### Supported actuators

| Software | Generic kinematic chains | Force-controlled motion | Full list | Circular kinematic chains | Kinematically redundant chains | Bifurcated kinematic chains |
| Gazebo | Yes | Yes | | Yes | Yes | Yes |
| RoboDK | Un­known | Un­known | | Un­known | Un­known | Un­known |
| SimSpark | Yes | No | SimSpark effectors | Un­known | Un­known | Un­known |
| Webots | Yes | Yes | Webots actuators | Yes | Yes | Yes |
| OpenRAVE | Yes | Yes | Joints,Extra Actuators | Yes | Yes | Yes |
| CoppeliaSim | Yes | Yes | | Yes | Yes | Yes |
| Software | Generic kinematic chains | Force-controlled motion | Full list | Circular kinematic chains | Kinematically redundant chains | Bifurcated kinematic chains |

#### Supported sensors

| Software | Odometry | IMU | Collision | GPS | Monocular cameras | Stereo cameras | Depth cameras | Omnidirectional cameras | 2D laser scanners | 3D laser scanners | Full list |
| Gazebo | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | |
| RoboDK | Un­known | Un­known | Un­known | Un­known | Un­known | Yes | Yes | Yes | Yes | Yes | |
| SimSpark | Yes | Yes | Yes | Partial | Yes | Partial | Un­known | Un­known | No | No | SimSpark perceptors |
| Webots | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Webots sensors |
| OpenRAVE | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Un­known | Yes | Yes |
| CoppeliaSim | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Software | Odometry | IMU | Collision | GPS | Monocular cameras | Stereo cameras | Depth cameras | Omnidirectional cameras | 2D laser scanners | 3D laser scanners | Full list |