run_lwr_with_ros.md

Run KUKA LWR with ROS

Quick start note

Proceeding to run a demo (In case of error, use the complete start note):

1. Select the appropriate tool 4 and base 2 frame with KRC unit

2. Once the KUKA LWR4+ is up and running:

3. Switch to automatic mode on KRC unit

4. Select code to run in KRC unit

5. Release motor breaks with KRC unit

6. Run roslaunch ros_fri ros_fri.launch or run roslaunch ros_fri ros_fri_roscontrol.launch for ros control

   • In case of error, acknowledge with KRC unit and proceed with 4.
   • Check if appropriate tool and base frame set
   • If success, you will see the following print out:

   [ INFO] [1624095025.084690764]: ros_fri: iteration 1 state 0
   [ INFO] [1624095025.084901195]: ros_fri: iteration 2 state 0
   [ INFO] [1624095025.089392390]: ros_fri: iteration 3 state 0
   [ INFO] [1624095025.099509523]: ros_fri: iteration 4 state 0
   [ INFO] [1624095025.109566996]: ros_fri: iteration 5 state 0
   [ INFO] [1624095025.119400841]: ros_fri: iteration 6 state 0
   [ INFO] [1624095025.129500956]: ros_fri: iteration 7 state 0
   [ INFO] [1624095025.139523725]: ros_fri: iteration 8 state 0
   [ INFO] [1624095025.149383478]: ros_fri: iteration 9 state 0
   

   • If not, run the command above again

7. Run roslaunch tams_lwr bringup.launch

Complete start note

KUKA LWR

• Presents ROS nodes for real-time (online) motion control.

• For the KUKA LWR-4+ via FRI and the ReflexxesTypeII motion library.

• KUKA LWR setup and device permissions

• Please boot a low-latency kernel for better realtime behaviour.

• The ros_fri interface is configured to run at 100Hz; with the host PC at 192.168.0.2, the LWR at 192.168.0.1, and the Schunk gripper at 192.168.0.20.

• Copy files:

  sudo mkdir -p /opt/FRILibrary/etc
  roscd tams_lwr/config/
  sudo cp 980039-FRI-Driver.init /opt/FRILibrary/etc
  sudo cp limits.conf /etc/security/
  sudo cp 70-persistent-net.rules /etc/udev/rules.d/
  sudo cp interfaces /etc/network/

• Change default network name (ens33) to old “eth0” on Ubuntu 18.04

  • Edit file:

  sudo vim /etc/default/grub

  Look for GRUB_CMDLINE_LINUX and add the following net.ifnames=0 biosdevname=0. From:

  GRUB_CMDLINE_LINUX=""

  To:

  GRUB_CMDLINE_LINUX="net.ifnames=0 biosdevname=0"

  • Generate a new grub file using the following command.

  sudo grub-mkconfig -o /boot/grub/grub.cfg
  # result:
  # Generating grub configuration file ...
  # Warning: Setting GRUB_TIMEOUT to a non-zero value when GRUB_HIDDEN_TIMEOUT is set is no longer supported.
  # Found linux image: /boot/vmlinuz-4.4.0-15-generic
  # Found initrd image: /boot/initrd.img-4.4.0-15-generic
  # Found memtest86+ image: /memtest86+.elf
  # Found memtest86+ image: /memtest86+.bin
  # done

  • Reboot

• Optionally, try setting scheduling policy to SCHED_RR, to set policy to SCHED_RR scheduling with 20 priority:

  chrt -r -p [1..99] {pid}
  chrt -r -p 20 1024

• Starting the LWR with ros_fri

  1. Power the robot up, wait until booted
  2. Check/set the correct robot tool: KRC2 -> Configure -> Set tool/base -> 4 (Schunk)-> Frame -> 2 (Table)
  3. Sometimes, the robot will not start in candle position, so: KRC2 -> Mode T1 -> Joint Level Motion -> move A1 .. A6
  4. KRC2 -> Mode C -> Navigator -> FRIControl -> Anwählen Starttaste (I) wait a few seconds
  5. press green run button -> wait a few seconds, press green run button again
  6. if startup fails (e.g. FRI bad communication quality), try to repeat. It might help to stop the motors (O), Navigator->FRIControl -> Abwählen, wait a few seconds, then repeat step 4) above.
  7. When ros_fri/FRILibrary crashes, FRI might still be active, but in inconsistent state. Reboot the robot.

Schunk WSG-50 driver:

• The gripper is running the newest firmware version available for the hardware. This still has issues with lua memory usage and garbage collection, and reading the gripper data is slow.
• The current ROS node runs about as fast as possible with our hardware; there are still some errors when reading the tactile sensors.