yarp-omega3

Simple YARP-enabled server for the Force Dimension Omega.3 device.

Supports Linux only at the moment.

Dependencies

• libpthread
• libusb
• YCM

Notes:

• the SDK of the robot is automatically downloaded during the build process
• libpthread and libusb, both required by the robot SDK, can be easily installed, e.g. in Ubuntu use

  apt install libusb-1.0-0-dev libpthread-stubs0-dev
  

How to build

git clone https://github.com/robotology-playground/yarp-omega3
cd yarp-omega3
mkdir build
cd build
cmake -DCMAKE_INSTALL_PREFIX=<where_to_install> ../
make install

In order to use the device in user space, you need to import the provided udev rule, e.g. in /etc/udev/rules.d.

How to use

Run yarp-omega3-server and send RPC commands to /yarp-omega3-server/rpc:i.

please run the yarpserver if you did not already before running the yarp-omega3-server

Available commands are

• help
• set_force(f_x, f_y, f_z) (send a force reference [N])
• set_position(x, y, z) (send a static position [m])
• track_position(x, y, z) (send a position, to be used in streaming mode [m])
• get_pos_move_parameters() (returns current amax [m/s2], vmax [m/s], jerk [m/s3] in position control)
• set_pos_move_parameters(amax, vmax, jerk) (set motion parameters amax [m/s2], vmax [m/s], jerk [m/s3] for position control)
• get_tracking_move_parameters() (returns current amax [m/s2], vmax [m/s], jerk [m/s3] in tracking control)
• set_tracking_move_parameters(amax, vmax, jerk) (set motion parameters amax [m/s2], vmax [m/s], jerk [m/s3] to be used in streaming mode)
• stop (completely disengange robot control)
• quit (close the module)

The state of the robot is available in forms of a yarp::sig::Vector sent over the port /yarp-omega3-server/robot_state:o. It comprises 9 values (3D Cartesian position [m], 3D linear velocity [m/s] and 3D exchanged force [N]).

The aforementioned motion parameters are:

• amax, the maximum linear acceleration in [m/s2];
• vmax, the maximum linear velocity in [m/s];
• jerk, the maximum jerk in [m/s3].

Sample modules written in Python are available.

Omega coordinate system and control range

Given the mechanical design, the following mentioned values are the maximum reachable per axis. The workspace is limited to a sphere around the center, the further the robot is positioned of center along the x-axis, the less you can move along the y- and z-axis (until you eventually can not move at all when reaching the max x value). The same is true for the other axis.

axis	min [m]	max [m]
x	-0.045	0.07
y	-0.09	0.09
z	-0.065	0.1

Note:

• when connected to a usb hub it might be neccesary to reboot system to connect to the robot for the first use.
• the module switches from position to force control depending on the input from the user. After calling tracking_parameters or position_parameters please call position or force control again. The server will not return in that state on its own.

Further readings

Further readings about the SDKs you can find when the download is finished in the SDK folder under documentation. We use the Robotic SDK to control the robot and we use the Haptic SDK to read the robot states.

Implenetation of further functions

The SDKs offer many further functionalities. To implement them add the function to the Server.h, Server.cpp and server_idl.thrift. In the server_idl.thrift function names must be distinct. set_position and set_position_params will not work. Instead use set_position and set_pos_params for instance.

Maintainers

This repository is maintained by:

	@xenvre