ROS Driver for Motion Capture Systems

This package contains ROS drivers for two different motion capture systems,VICON And QUALISYS. NOTE: This fork focuses on the Qualisys ROS driver. Some alterations have been made to the Vicon package to ensure compatability with the mutual interface.

License

For the VICON driver, we use the offical SDK.

For the QUALISYS driver, we use the Qualisys CPP SDK.

For the rest of the software, the license is Apache 2.0 wherever not specified.

Compiling

This is a catkin package. Make sure the package is on ROS_PACKAGE_PATH after cloning the package to your workspace. Drivers for different motion capture system can be independently compiled.

cd your_work_space
catkin_make --pkg mocap_{sys} --cmake-args -DCMAKE_BUILD_TYPE=Release

This will compile the drivers for {sys}

Example Usage

Common Parameters

server_address (string)

IP address of the server of the motion capture system to be connected.

server_base_port (string, default: 22222) The port used for setting up the connection with the motion capture server. Should be left to the default value.

frame_rate (int, default: 0)

The frame rate of the motion capture system. A value of 0 uses whatever framerate the motion capture server is transmiting at. If lower frame rates are requested the server will drop frames to get close to the requested rate. For example, if the server is capturing at 100 FPS and 80 FPS is requested, every other frame will be dropped resulting in 50 FPS.

max_accel (double, default: 10.0)

The max possible acceleration which serves to construct the noise parameters.

publish_tf (bool, default: false)

If set to true, tf msgs for the subjects are published.

fixed_frame_id (string, default: mocap)

The fixed frame ID of the tf msgs for each subject. Note that the child frame id is automatically set to the name of the subject.

udp_port (int, default: 0)

The UDP port that the server will send data to. If set to 0 a random valid port is used. If set to -1 TCP will be used instead of UDP.

qtm_protocol_version (int, default: 18)

The minor version of the QTM protocol that should be used (the only valid major version is 1). Might have to be lowered for very old versions of QTM. should not be set lower than 8 due to a bug in the protocol version 1.7 and prior causing the rotations to be incorrectly searialized.

model_list (vector<string>, default: [])

A vector of subjects of interest. Leave the vector empty if all subjects are to be tracked.

Published Topics

/{mocap_sys}/{subject_name}/odom (nav_msgs/Odometry)

Odometry message for each specified subject in model_list.

To be compatible with the name of the topics published of vicon_odom in vicon repo of KumarRobotics, you can uncomment the following line in the launch file: <remap from="{mocap_sys}/{subject_name}/odom" to="/{subject_name}/odom">

Node

roslaunch {mocap_sys} {sys}.launch

For example,

roslaunch mocap_qualisys qualisys.launch

A node for making comparisions between the mocap system and for example the internal odometry of a robot is also provided roslaunch mocap_qualisys comp_qualisys.launch The settings will ofcourse have to be tweaked to suit your purpose.

FAQ

1. Will the msgs be delayed if the driver is handling several subjects? Possibly. It's not recommended to for example, try to run the node for two dozen bodies on a raspberry pie. The multithreading in earlier versions were removed since it often caused more overhhead than actual gain.

2. How to calibrate the transformation between the subject frame (centered at the centroid of the markers) and the body frame of a robot?

Bug Report

Open an issue.