franka_experiments

Repo for Aalto University summer internship on human-robot interaction. Additional notes are available in the NOTES.md file.

Dependencies

Developed and tested on Ubuntu 20.04 with libfranka 0.10.0 and ROS Noetic.

• libfranka & franka_ros
• Moveit 1
• panda_moveit_config (for better perfomance some config files need to be edited, see Notes section)

Trajectory Deformation Controller

The controller accepts trajectories (e.g. from moviet interface) and tracks them with impedance control. Human interactions are used to smoothly deform the trajectory. The controller is based on the "Trajectory Deformations from Physical Human-Robot Interaction" paper. Implemented in joint-space (shy_joint_controller) and task-space (shy_cartesian_controller) versions. Deformations can be visualized in rviz.

To run the controller in a simulated environment:

roslaunch franka_experiments gazebo_moveit_shy_control.launch controller:=shy_joint_controller  # or shy_cartesian_controller

To run the controller with a real robot:

roslaunch franka_experiments hw_moveit_shy_controller.launch controller:=shy_joint_controller  # or shy_cartesian_controller

parameter_control.py - a high-level script that uses python moveit interface to send shy_controller goals and update parameters during the execution based on the robot state.

rosrun franka_experiments parameter_control_demo.py

traj_deform_demo.py - a simple python program that demonstartes trajectory deformation on a 1 DoF trajectory example.

Notes

Consider editing these files before your hardware experiments. Examples of the edited config files are available in config/examples folder.

• Edit the simple_moveit_controllers.yaml in the panda_moveit_config package config files to include shy_joint_controller and shy_cartesian_controller, regestring the controllers with moveit. Moveit is going to try to connect with all the controllers listed in the file though, so for faster bringup it's better to leave only the needed controller(s).
• Edit franka_control_node.yaml at franka_ros/franka_control/config/ to lower the external force thresholds.
• Edit default_controllers.yaml in franka_control package to set a higher update rate for franka_state_controller. It might be useful for parameter control.
• Edit franka_control.launch in panda_moveit_config to comment out default controllers bringup.
• Disable execution_duration_monitoring in trajectory_execution.launch.xml to avoid timeouts.

Notable parameters for shy_controller testing:

• admittance - proportional term between the external force and the deformation amplitude.
• deformation_length - the higher the longer is the deformation segment.
• maximum_waypoint_distance / minimum_waypoint_count of OMPL - set to increase trajectory resolution (doesn't seem to affect cartesian trajectories).
• velocity_scaling of motion planning in rviz - set to more comfortable for experiments values.
• impendance gains of the robot - the softer the gains the easier it is to push the robot around and the higher is the external force noise.

Other experiments

• cartesian_traject_controller.cpp - a slightly modified default cartesian_pose_controller. Follows an interactive marker until the first position message is recieved from a separate topic. Then listens to the second topic only.

  • gazebo_timeskip_control.launch - starts certesian_trajectory_controller in a simulated environment. Run trajectory_pub node to switch from interactive marker control to cartesian trajectory following. The trajectory can be published using trajectory_pub node.
  • hw_timeskip_control.launch - the same but with a real robot.
  • trajectory_pub.cpp - a node that publishes trajectory points to cartesian_traject_controller and tries to detect human interactions based on F_ext. Record the time someone interacts with a robot and thne skips to a waypoint 'interaction time' forward.

• move_group_direct_trajectory.py - plans and executes a cartesian trajectory using moveit. This trajectory is recorded in 1m_backforth.bag.

• /polymetis/ - experiments with Polymetis framework.

TODO

• External force correction
• Adapt parameter control to the cartesian controller (topics are hardcoded now)
• k_gains / d_gains dynamic reconfigure