apc2016

Install Instructions

• Install ROS and source the setup scripts.

• Let WS be an environment that holds the path to your ROS workspace.
  For example, to create a new workspace, run

  export WS=~/workspace/apc/ws
  mkdir -p $WS/src && cd $WS/src
  catkin_init_workspace
  cd ..
  catkin_make
  . devel/setup.bash
  

• Clone the code repository into the $WS/src directory:
  cd src/ && git clone ...

• Compile the code to create message definitions etc:
  cd $WS && catkin_make

• In the robot controllers, set the server IP to the IP address of the server running the arm_control_left/right nodes.

Run Instructions

• In one terminal, run roscore.
• In another terminal, run roslaunch launch-base.xml.
• On a Windows machine, start the RealSense and FX8 bat files with the correct ROS_MASTER_URI.

Now all the services are running and you can run python script/main_pick.py path/to/taskfile.json

Restarting/Reloading Components

All (most?) nodes in the launch-base.xml file are respawned on exit. This can be used to restart a single node, for example if the code has changed or if there has been some network issue that can be fixed most easily with a restart.

• To restart the arm_control_left/right node, run pkill -f arm_control_left or pkill -f arm_control_right, respectively.
• To restart all of the Arduino nodes (this may be necessary every couple of hours in order to recalibrate pressure values), run pgrep -f run_arduino.

If you want to shutdown a certain node temporarily because you want to run it on another machine, one possible solution is to insert

import time
while True:
    time.sleep(5)

into the respective file before the actual program code and then kill the node. That way the actual code is never executed, still the other nodes are unaffected.

Notes

• The Arduino components are usually available as /dev/ttyACM0, /dev/ttyACM1, and /dev/ttyACM2. However, there may be situations when these devices get renumbered (for example, to ...3, ...4, ...5). To deal with that situation there is a wrapper script arduino.sh that picks "the first unused ttyACM device" and uses it. The list of devices that are currently in use is stored in /tmp/usedttys.txt. If a process crashes so hard that it is unable to remove the used device from that file after exit, it may become necessary to remove the device name manually.

• The gripper_angle that is responsible for opening and closing the gripper hand maintains a file gripper_angle in the script/hand folder that contains the total angle of the rotary servo (because the servo itself only remembers values in the range [0, 360]). That is, if the machine that executes this node changes, the angle must be recalibrated. In order to do so:

  • Shut down the actuator_nodes.py script if it is running.
  • Write a large number (such as 5000) to the gripper_angle file (create it if necessary).
  • Start the actuator_nodes.py script. When doing so, the rotary servo moves back (or forward) to the next multiple of 360, e.g., 5040 degrees.
  • Decrease the angle in steps of 360 degrees until the gripper is only slightly opened, i.e., the last step before the gripper closes.
  • Stop the actuator_nodes.py script.
  • Write 720 to the gripper_angle file.
  • Now, when you restart the actuator_nodes.py script, you will be able to send values between 0 (tightly closed) and something like 4000 (wide open).

Conventions

The numbering of the shelf bins is as follows:

 A | B | C
---+---+---
 D | E | F
---+---+---
 G | H | I
---+---+---
 J | K | L

About Item Names

The file item_data.csv contains the list of item types together with a [a-z0-9_]+-shaped string identifier and a numeric ID. Whenever possible, when referring to an item type in code or data files, use these identifiers and avoid using other IDs.