allegro-hand unofficial fork
This is an unofficial fork of SimLab's allegro hand ros package.
It improves significantly upon the SimLab version by providing a catkin-ized version, simplifies the launch file structure, updates the package/node names to have a more consistent structure, improves the build process by creating a common driver, introduces an AllegroNode C++ class that reduces the amount of duplicated code. It also provides a python library that can control the hand directly.
It also provides the BHand library directly in this package (including both 32-bit and 64-bit versions, though 32-bit systems will need to update the symlink manually).
At this point no effort has been made to be backwards compatible.
Launch file instructions:
There is a single file to start any hand, allegro_hand.launch that starts the hand. It takes many arguments, but at a minimum you must specify the handedness:
roslaunch allegro_hand allegro_hand.launch HAND:=right
You can also simulate the hand very easily:
roslaunch allegro_hand allegro_hand.launch HAND:=right CONTROLLER:=sim
Optional (recommended) arguments:
NUM:=0|1|... ZEROS:=/path/to/zeros_file.yaml CONTROLLER:=grasp|pd|velsat|torque|sim RESPAWN:=true|false Respawn controller if it dies. KEYBOARD:=true|false (default is true) AUTO_CAN:=true|false (default is true) CAN_DEVICE:=/dev/pcanusb1 | /dev/pcanusbNNN (ls -l /dev/pcan* to see open CAN devices) VISUALIZE:=true|false (Launch rviz) JSP_GUI:=true|false (show the joint_state_publisher for *desired* joint angles)
AUTO_CAN: There is a nice script
detect_pcan.py which automatically
finds an open
/dev/pcanusb file. If instead you specify the can device
CAN_DEVICE:=/dev/pcanusbN), make sure you also specify
AUTO_CAN:=false. Obviously, automatic detection cannot work with two hands.
The second launch file is for visualization, it is included in
VISUALIZE:=true. Otherwise, it can be useful to run
it separately (with
VISUALIZE:=false), for example if you want to start rviz separately
(and keep it running):
roslaunch allegro_hand allegro_viz.launch HAND:=right
Note that you should also specify the hand
NUM parameter in the viz launch if
the hand number is not zero.
- allegro_hand A python client that enables direct control of the hand in python code, and all generic launch files.
- allegro_hand_driver Driver for talking with the allegro hand.
- allegro_hand_controllers Different nodes that actually control the hand.
The AllegroNode class handles all the generic driver comms, each class then
computeDesiredTorquedifferently (and can have various topic subscribers):
- grasp: Apply various pre-defined grasps, including gravity compensation.
- pd: Joint space control: save and hold positions.
- velsat: velocity saturation joint space control (supposedly experimental)
- torque: Direct torque control.
- sim: Just pass desired joint states through as current joint states.
- allegro_hand_description xacro descriptions for the kinematics of the hand, rviz configuration and meshes.
- allegro_hand_keyboard Node that sends the commanded grasps. All commands are available with the grasp controller, only some are available with the other controllers.
- allegro_hand_parameters All necessary parameters for loading the hand:
- gains_pd.yaml: Controller gains for PD controller.
- gains_velSat.yaml: Controller gains and parameters for velocity saturation controller.
- initial_position.yaml: Home position for the hand.
- zero.yaml: Offset and servo directions for each of the 16 joints, and some meta information about the hand.
- zero_files/ Zero files for all hands.
- bhand Library files for the predefined grasps, available in 32 and 64 bit versions. 64 bit by default, update symlink for 32 bit.
Note on polling (from SimLabs): The preferred sampling method is utilizing the Hand's own real time clock running @ 333Hz by polling the CAN communication (polling = true, default). In fact, ROS's interrupt/sleep combination might cause instability in CAN communication resulting unstable hand motions.
Installing the PCAN driver
Before using the hand, you must install the pcan drivers. This assumes you have a peak-systems pcan to usb adapter.
Install these packages
sudo apt-get install libpopt-dev ros-indigo-libpcan
Download latest drivers: http://www.peak-system.com/fileadmin/media/linux/index.htm#download
Install the drivers:
make clean; make NET=NO_NETDEV_SUPPORT sudo make install sudo /sbin/modprobe pcan
Test that the interface is installed properly with:
You should see some stuff streaming.
When the hand is connected, you should see pcanusb0 or pcanusb1 in the list of available interfaces:
ls -l /dev/pcan*
If you do not see any available files, you may need to run:
sudo ./driver/pcan_make_devices 2
from the downloaded pcan folder: this theoretically creates the devices files if the system has not done it automatically.
Gazebo alpha support
Gazebo is supported in theory, thanks to inertial parameters from @trhermans. However, I have not been successful at running a physical simulation of the robot hand. I am leaving the gazebo option for others to experiment; to try it out, pass GAZEBO:=true to the launch file.
Contributions (pull requests) to fix the simulation are welcome.