What if my console stops updating?

Sometimes the console stops updating. This problem can occur if you reboot Baxter without restarting the console as well. It can also happen if you restart Ein (for unknown reasons). To fix it, try restarting the console. Type ` ` :quit (note the double screen escape character, due to the subscreen inside the main Ein screen). Then go up one command in the command history to restart the screen session.

What if the robot won’t move?

First verify you are receiving state messages; the state window in the console should be updating as the robot’s pose changes. If not, you may be connecting to the wrong arm. Make sure if you are running on the left arm, you are using the left console window. Alternately, your ROS environment may be misconfigured. Verify that Baxter commands such as ` rosrun baxter_tools enable_robot.py -s work correctly, and that rostopic list and rostopic echo` work. A common problem is that the $ROS_IP xor $ROS_HOSTNAME environment variables are not correctly set. You should verify that one of these is set in the client machine, and that your Baxter can ping your client machine using the exact IP address/hostname that is set via the environment variable. One might think that a networking misconfiguration would result in no messages being sent, but in fact, often your client machine will receive messages from Baxter, but not be able to send messages, if your $ROS_MASTER_URI is correct, but not your $ROS_HOSTNAME or $ROS_IP.

Verify that you are not in zero gravity mode by checking the status window; it should be set to 0. Type zeroGOff to turn off zero gravity. You can also press the grey circular button on the arm to toggle zero gravity (the “Ok” button).

What if the wrist camera image is not updating?

Verify that your ROS environment is set up correctly ($ROS_IP, $ROS_HOSTNAME). For some reason, when these variables are not set, the client often receives one wrist camera image, and then not any others. (One would think it would receive zero images or all of them; but consistently it receives one and then stops. We are unsure why, but it happens all the time when the network is not set up correctly.)

What if Ein is not receiving wrist camera images?

The Baxter robot only allows two of the three cameras to be open at one time: left hand, right hand, and head. This is due to limitations in the badwidth of USB 2.0. More information about this is available here.

Ein tries to make this happen, but sometimes the robot doesn’t listen to camera control commands. We think this is a Rethink problem, but we haven’t set up a good bug report.

So before starting Ein, you should use camera_control.py to make sure that the camera you want to use with Ein is open (left or right). You should close the head camera and open the other two. Sometimes it takes several tries to get the robot to do this.

This command lists the cameras: rosrun baxter_tools camera_control.py -l

Run camera_control.py with no arguments to see usage. Open and close the cameras until only the left and right hand cameras are open. When it is set up correctly you should see this:

$ rosrun baxter_tools camera_control.py  -l
left_hand_camera  -  (open)
right_hand_camera  -  (open)

Sometimes we have needed to reboot the robot to make this go away. We have not been able to figure out why this happens or a reliable reproduce. It happens fairly rarely for us, but it is annoying when it does.

Ein appears to be frozen, with no movement, and the gui screen darkens and freezes.

Ein is a single threaded program, which means that robot callbacks, inferences, and gui callbacks are all serviced with a single thread. As a result, when computationally intensive tasks are being run, the gui will freeze. This effect occurs during calibrating the height reticles, as well as when running fillIkMapAtCurrentHeight. One way to see what is happening when this occurs is to run “Ctrl-C” to Ein in gdb and backtrace, to see what part of the code is getting stuck.

What is the difference between assumeBeeHome and goHome?

The assumeBeeHome word sets the target position to the home position but doesn’t wait. The goHome blocks until the arm arrives at the position. goHome does other good stuff such as “shoring up” so the arm is in a nice crane pose. goHome is what you should use for most things.

How do I save a home position longer than a session?

You can put arbitrary commands in the file init.back, which will be executed whenever Ein starts up, after all other initialization is complete.

I am getting strange TF errors about “Lookup would require extrapolation into the past” or “Lookup would require extrapolation into the future.”

This error most often means that Baxter’s system time is out of sync with client computers. Note that Baxter syncs its time using ntp to pool.ntp.org, and this server cannot be changed (as per Rethink’s instructions). We have had issues at sites that block pool.ntp.org, causing Baxter to stop updating its time and fall out of sync with other computers that were updating their time. We had to have our IT staff open a special port in their firewall to allow Baxter to sync up.

Where is data stored on the file system?

Ein stores its data in the default directory in the ein checkout. Configuration is stored in a directory named for the serial number. Objects are stored in the objects directory and gaussian maps are stored in the maps directory.