Tutorials/drcsim/2.5/slider teleop


 * 1) DRC Tutorial: Mixer teleop of Atlas #

This tutorial will explain how to use a music mixer, to teleoperate the Atlas model. It's a handy way to try things out.

'''Note: This is a tutorial, not a polished teleoperation tool. It's meant to be a demo to get you started, nothing more.'''


 * 1) Hardware requirements

The tools described in this tutorial assume the use of a KORG nanoKONTROL device. We have tested only with version 1 of this device, which looks like this:



This version of the device has been discontinued by the manufacturer, but can still be ordered online, e.g., via [Amazon](http://www.amazon.com/Korg-nanoKONTROL-USB-Controller-White/dp/B001H2P294). Newer versions of the device can probably be made to work, but some modifications to the driver code (nanokontrol.py) might be required.


 * 1) Driver installation

1. Install the `pygame` library, which we'll use to access the mixer:

sudo apt-get install python-pygame

Note: older versions of this package were broken. To check whether your version works, run this command to try to import pygame:

python -c 'import pygame.pypm'

You should see nothing in response; if you instead get an error (probably about an unresolved symbol), then try to get a newer version:

sudo apt-get update sudo apt-get install python-pygame

Let's start simulation with Atlas in a world where there's something to manipulate (be sure to do the usual `source /usr/share/drcsim/setup.sh` first):
 * 1) Simulation setup

roslaunch atlas_utils qual_task_2.launch

You'll see the robot at a table with a drill on it:




 * 1) Teleop package setup

Note: the ROS package being created here is also available in the drcsim 2.5.0 source release, in the directory `tutorials/atlas_teleop`.

1. Create a ROS package to contain the code for this tutorial. You should do this somewhere in your ROS_PACKAGE_PATH.

cd ~/ros roscreate-pkg atlas_teleop osrf_msgs rospy roscd atlas_teleop

1. Download the [[Media:Nanokontrol.txt|nanoKONTROL driver]], save it as `nanokontrol.py` in your `atlas_teleop` package, and make it executable:

chmod a+x nanokontrol.py

This driver receives events from the mixer and publishes ROS [sensor_msgs/Joy](http://ros.org/doc/api/sensor_msgs/html/msg/Joy.html) messages on the `/joy` topic. I.e., it makes the mixer look like a big joystick, with many axes and many buttons.

1. Download the [[Media:Atlas_teleop.txt|Atlas teleop controller]], save it as `atlas_teleop.py` in your `atlas_teleop` package, and make it executable:

chmod a+x atlas_teleop.py

This controller subscribes to ROS [sensor_msgs/Joy](http://ros.org/doc/api/sensor_msgs/html/msg/Joy.html) messages on the `/joy` topic and commands Atlas and the Sandia hands by publishing [osrf_msgs/JointCommands](https://bitbucket.org/osrf/osrf-common/raw/default/ros/osrf_msgs/msg/JointCommands.msg) messages on the `/atlas/joint_commands`, `/sandia_hands/l_hand/joint_commands`, and `/sandia_hands/r_hand/joint_commands` topics. It requires as a command line argument a YAML configuration file that tells it how to map incoming `/joy` messages into commands for the robot and hands (more on this below).


 * 1) Finding your mixer device

1. Plug your KORG nanoKONTROL device into a free USB port. Depending on the details of your computer, the mixer might show up with any of a number of integer IDs. You need to find it. One way to do this is to walk through the possible IDs until it works, starting with:

# Start a listener on the /joy topic, which the driver will publish to when it's working rostopic echo /joy & # Try the driver with ID 0 rosrun atlas_teleop nanokontrol.py 0

1. Move the sliders around; you're looking for a stream of output from `rostopic` similar to:

---       header: seq: 7 stamp: secs: 3073 nsecs: 235000000 frame_id: '' axes: [0.06299212574958801, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0] buttons: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0] ---

1. If you see that output, you've found the right ID. If you see nothing, or if `nanokontrol.py` exits with an error about the wrong ID, start it again (kill `nanokontrol.py` with Ctrl-C first, if needed), with the next ID:

# It wasn't ID 0. Try the driver with ID 1 rosrun atlas_teleop nanokontrol.py 1

Repeat this procedure until you find the right ID. Remember that ID. For the rest of this tutorial, we'll assume that the correct ID is 3 (it seems to often be 3).


 * 1) Pick up the drill

The `atlas_teleop.py` controller is configured with a YAML file. Here's an example:

# back       left leg      right leg      left arm      right arm                                     LH        RH    0: "0 0 0 0   0 0 0 0 0 0   0 0 0 0 0 0    0 0 0 0 0 0   0      0     0      0      0       0       cyl 0   cyl 0" 1: "0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -0.4271259903907776 1.262315034866333 1.4657480716705322 -0.9703150391578674 -0.2356692999601364 -0.6822677254676819 cyl 0   cyl 0" 2: "0 0 0 0  0 0 0 0 0 0   0 0 0 0 0 0    0 0 0 0 0 0   -1     1     0     -1      0       0       cyl 0   cyl 0" 3: "0 0 0 0  0 0 0 0 0 0   0 0 0 0 0 0    0 0 0 0 0 0   0      0     0      0      2.0     0       cyl 0   cyl 0" 4: "0 0 0 0  0 0 0 0 0 0   0 0 0 0 0 0    0 0 0 0 0 0   0      0     0      0     -2.0     0       cyl 0   cyl 0" 5: "0 0 0 0  0 0 0 0 0 0   0 0 0 0 0 0    0 0 0 0 0 0   0      0     0      0      0.0     2.0     cyl 0   cyl 0" 6: "0 0 0 0  0 0 0 0 0 0   0 0 0 0 0 0    0 0 0 0 0 0   0      0     0      0      0.0    -2.0     cyl 0   cyl 0" 7: "0 0 0 0  0 0 0 0 0 0   0 0 0 0 0 0    0 0 0 0 0 0   0      0     0      0      0       0       cyl 0   cyl 1" 8: "0 0 0 0  0 0 0 0 0 0   0 0 0 0 0 0    0 0 0 0 0 0   0      0     0      0      0       0       cyl 0   sph 1"

Save that content to a file called `drill.yaml`. We'll explain the format below. First, let's try it:

# The integer argument should be the ID for your device, which you discovered earlier; it might not be 3 rosrun atlas_teleop nanokontrol.py 3 & rosrun atlas_teleop atlas_teleop.py drill.yaml

Now start moving the sliders around. You'll notice that sliders 1-6 make the right arm do various things. Sliders 7 and 8 make the right hand open and close in different ways.

With a bit of practice, you should be able to pick up the drill and drop it in the bin:


 * 1) Configuration file format

The configuration file for `atlas_teleop.py` is written in [YAML](http://www.yaml.org/), with the following structure:

* The first 28 numbers are joint values for the Atlas robot, given in the [usual order](https://bitbucket.org/osrf/drcsim/raw/default/ros/atlas_msgs/msg/AtlasState.msg). * The next two elements specify a grasp posture for the left hand (the following two elements do the same for the right hand), in two parts: * The string specifies the grasp type, which should be one of: `cyl` (cylindrical) or `sph` (spherical). * The number specifies a grasp position between fully open (0.0) and fully closed (1.0). * When a slider is at 0.0 (all the way down), it commands the origin pose. * When a slider is at 1.0 (all the way up), it commands its target pose. * When a slider is between 0.0 and 1.0, it commands the pose that results from linearly interpolating between the origin and its target pose.
 * Each line defines a robot pose:
 * The `0:` line is special, in that it defines the origin pose.
 * Each of the other (non-zero) lines defines the target pose for a given slider (1, 2, etc.).
 * Slider commands are *added* together. As a result, you can easily blend different postures (blending doesn't always make sense, of course).


 * 1) Known issues / caveats


 * The mixer produces events only when a slider (or knob, or button) is changed. So joystick messages and the resulting robot/hand command messages are not published continuously, but rather only when you're moving the sliders.
 * After the `nanokontrol.py` driver starts, the initial position of each slider is not known until that slider is moved. Unexpected things (e.g., sudden jumps) can occur on the first movement of a slider.