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Troubleshooting

The Battery
Fiducial Follow or Localization
Magni Does Not Move
Robot Commander
Rviz

The Battery

The quickest test: With Robot Commander connected to the robot, say “battery”. You should get a reasonable percentage answer. Also, the battery command should appear in the Command Log window.

Make sure your battery is installed correctly, with all the contacts fully attached and the batteries are fully charged. A pair of fully charged Lead Acid batteries should give around 26-27V - if you don’t have a voltmeter the robot can self report battery voltage which is covered later on in this message (point 5). A good way to make sure the batteries are fully charged is by plugging in the provided charger. If it switches off automatically then the the batteries are fully charged.

Make sure that both push buttons on the front of the robot are out all the way (one of the push buttons de-energizes the motor circuit as an emergency stop). Both blue and red LED on the PCB that has the switches should be illuminated.

Check the 5 LEDs on the master control board (the big PCB on the robot) that you can see on the front of the robot right above the switch PCB. All 5 should be illuminated. The top one should blink briefly every 6 seconds. If you don’t see this behavior then email contact@ubiquityrobotics.com.

Check the fuses on the robot - you should be able to visually see if the fuse is blown.

SSH in to the robot. Type

rostopic list

This will list all the available topics on the robot one of which will be /battery_state or similar then type

rostopic echo /battery_state

it will give you a bunch of diagnostic information about the battery state. Confirm that the battery voltage is at least above 25V. This is also a good way to confirm that you are getting correct communication between the raspberry pi main computer and the master control board.

Robot Commander

Connecting

In the following we assume that RC is connected to the robot. By voice, after connecting, command “battery”. You should get a response indicating the battery charge state. Now you know that the connection works.

Operation

Open a window on your workstation and ssh into the robot. Type

rostopic list

This will list all the available topics on the robot, one of which will be /cmd_vel. If it doesn’t, the trouble must be in the robot. Then type

rostopic echo /cmd_vel

Any new messages on the /cmd_vel topic will now be shown on the screen.

Now tap the forward arrow on the RC screen. You should immediately see something like the following on the workstation screen:

linear:
  x: 0.2
  y: 0.0
  z: 0.0

If you do, the command is getting from RC to the robot, and if the robot does not move, there is a fault in the robot. In this case, ssh in to the robot in a second window. In the robot try teleop by typing

rosrun teleop_twist_keyboard telelop_twist_keyboard.py

once this is running you should be able to drive the robot forward by typing the “I” key. Again you will see the command echoed in the first window. If the robot does not move it is clear that there is a fault in the robot alone.

If you do not see the command echoed, note the command log on the RC screen. If the command is not logged there, RC has not understood the command and issued it. If the command is logged and you know that the connection works, then the RC has tried to transmit the command. The problem may be with RC, with the connection between the phone and the robot or with the phone or with the network.

Sometimes if an Android phone is connected to a data plan then the phone will try to direct packets from robot-commander to the internet rather than the robot. It may help to switch off your external data plan before trying to make robot commander work.

Rviz Troubleshooting

Some users have reported that, when running on a virtual machine workstation, it is necessary to turn off hardware acceleration.