Using the Optional Logitech Controller
A standard Silver or Gold Magni equipped with a Raspberry Pi 3 with a Ubiquity Robotics SD card image is by default set up to work with a Logitech gamepad Controller out of the box without bothering to connect via laptop over a network. In particular the robot is tested to work with the logitech F710 controller that is widely available. It may work with other similar logitech gamepads although these are not officially supported.
If you have such a controller plug the dongle in to any USB port on the Raspberry Pi 3 that is attached to the front of the robot. If you booted up with a Ubiquity Robotics RPi image, and have the Logitech controller USB dongle installed, the joystick should start to work in a couple of minutes. The Dongle is automatically paired to the Logitech controller it does not require separate software installation.
You can test this by using the Joystick and seeing if the robot responds to commands. For safety sake, raise the robot’s wheels above the floor first. (SAFETY TIP).
If the wheels don’t move, check the troubleshooting section further below.
To operate the controller, hold down the deadman button (LB) and move the joystick.
Up - Forward, Down - Back, Left - rotate counter clockwise, Right - rotate clockwise
The controller is set to be very slow. You can increase the speed by using the (LT) button below the deadman, this will increase the maximum speed by about 25%. Moving the joytick to a position between full up and full right will move the robot in a curved path.
If nothing happens, you’ll need to go back to the unboxing section and check to see if the robot is gettting power, the MCB is working and you can connect to the robot via a network (see connecting to your robot for the first time.) Check to see that your dongle is installed in the Raspberry Pi, there are fresh batteries in the Logitech Controller, and there is power going to both the Raspberry Pi and the motors. If the LEDs and the power switched are lit, you can additionally test to see if the wheels resist being turned.
Next, see if you can connect to your robot using access point (AP) mode:
(See the section on connecting to the robot.)
the robot responds by giving you its IP number. Type Control-C
to kill off the
Then use the following command to login to the robot for example from a laptop networked:
You may get asked to authorize your key, say
You next should be prompted for your password, type it in and you’ll be logged in
--------- Welcome to Ubuntu 16.04.2 LTS (GNU/Linux 4.4.43-v7+ armv7l) * Documentation: https://help.ubuntu.com * Management: https://landscape.canonical.com * Support: https://ubuntu.com/advantage 0 package can be updated. 0 updates are security updates. Last login: Sat May 6 15:57:19 2017 from 10.53.5.19
To see if the joystick is running, type:
If you see
/joy you are good to go!
If you don’t see any topics you need to launch the logitech on the robot:
roslaunch magni_bringup base.launch >/dev/null 2>&1 &
/dev/null 2 >&2 & puts into background and stops output to screen)
roslaunch magni_teleop logitech.launch >/dev/null 2>&1 &
The folowing command
rostopic list /cmd_vel /diagnostics /joint_states /joy /left_error /motor_node/parameter_descriptions /motor_node/parameter_updates /right_error /rosout /rosout_agg /tf /tf_static /ubiquity_velocity_controller/cmd_vel /ubiquity_velocity_controller/odom
Shows everything is running. You now should be able use the controller to drive the robot.
Modify The Logitech Joystick Default Parameters
The Logitech F710 is an approved joystick controller for the Magni robot. The default scale for the joystick is 0 to 1.0. Output values can be found in the file /opt/ros/kinetic/share/magni_teleop/param/logitech.yaml. The values most commonly modified are these:
scale_linear This value controls the maximum velocity the joystick will control for maximum forward or reverse joystick movement.
scale_angular This value controls the maximum turning rate in radians per second. Some users lower this for slower turning when the joystick is pushed all the way right or left.