Aion Robotics - r1_control pkg

The r1_control pkg allows for manual ROS Joystick control of the R1 rover. This is accomplished by establishing a direct serial connection between the companion computer and Roboclaw motor driver.

Physical control is provided by a wireless Joystick controller. (Playstation, Xbox etc)

The following topics are also published for use within more advanced projects:

/cmd_vel
/diagnostics
/joy
/motors/commanded_speeds
/motors/read_currents
/odom
/rosout
/rosout_agg
/tf

Configure Roboclaw Firmware

Setup Roboclaw motor driver

Mode	Option	Definition
Packet Mode	7	address 0x80 (128)
Serial Mode	6	115200 Baud rate

• Connect Wheel Encoders to Roboclaw
• Tune Encoders and perform Velocity Calibration within Ion Motion Studio App

Detailed setup instructions HERE

The following prerequisites must be installed/setup on NVIDIA Jetson TX2

• Ubuntu 16.04lts
• ROS Kinetic-Desktop
• Package - "joy" (Installed for you if using the script)
• Package - "teleop-twist-joy" (Installed for you if using the script)
• Package - "joystick-drivers" (Installed for you if using the script)
• Connection to the internet
• Enable Bluetooth and trust/pair joystick device

Easy Button? - Click HERE for script to flash the required Jetson image.

Joystick Setup

• Find Joystick:

ls /dev/input

This will print a list of input devices. The Joystick will show up as jsX or, js0 in our example.

• Test Joystick:

jstest /dev/input/js0

Joystick readings will print to screen. press ctrl-q to stop process

• Map Joystick to match ROS:

gstest-gtk /dev/input/js0

Note: If ssh into TX2 you must first export display to remote machine:

export DISPLAY=:10

Sample mapping for Playstation Navigation Controller:

Function	Map To	Invert
Linear Axis	1	no
Angular Axis	0	yes
Enable Button	8	N/A
Turbo Button	14	N/A

Note: The "Enable" button acts as a "Safety Switch". The Robot will not move unless the enable button is mapped correctly and held down. Ultimately, you should map the button layout according to your preference and Joystick type.

Installing r1_control pkg on the TX2

User: nvidia Password: nvidia

(Unless you changed after install)

Open a terminal from the TX2 desktop or ssh into the TX2 from a host machine.

If ssh from remote machine:

ssh -X nvidia@<ipaddress>

1. Setup Workspace:

mkdir catkin_ws
cd catkin_ws
mkdir src

2. Clone roboclaw_node:

cd <workspace>/src
git clone https://github.com/aionrobotics/roboclaw_ros.git

3. Clone r1_control pkg:

git clone https://github.com/aionrobotics/aion_r1.git
cd ..
catkin_make

4. Source:

source devel/setup.bash

(Must be done each time you open a new terminal before attempting to launch from that terminal)

5. Launch r1_control pkg:

roslaunch r1_control teleop.launch

(If you get "not found" error, source from /catkin_ws

Running Tests

Open a new terminal

• View Topics:

rostopic list

• View Topic Output:

rostopic echo <topic_name>

• Visualize Nodes/Topics:

rqt_graph

Note: If ssh into TX2 you must first export display to remote machine:

export DISPLAY=:10

User Parameters

• To modify robolaw_node, edit:

~/aion_r1/r1_control/launch/teleop.launch

Parameter	Default	Definition
dev	/dev/ttyACM0	Device that is Roboclaw
baud	115200	Baud rate the Roboclaw is configured for
address	128	The address the Roboclaw is set to, 128 is 0x80
max_abs_linear_speed	2.0	Max linear speed allowed in meters per second
max_abs_angular_speed	2.0	Max angular speed allowed in meters per second
accel_lim	2.0	Max accel allowed in m/s^2
ticks_per_meter	2263.6	The number of encoder ticks per meter of movement
base_width	0.431	Width from one wheel edge to another in meters

• To modify teleop_twist_joy, edit:

~/aion_r1/r1_control/config/teleop.yaml

  axis_linear: 1
  scale_linear: 1
  scale_linear_turbo: 2
  axis_angular: 0
  scale_angular: 2
  scale_angular_turbo: 2
  enable_button: 8 #L2 trigger
enable_turbo_button: 14 #L1 trigger

Note: This changes ROS mapping

License

This project is licensed under the GPLv3 License - see the LICENSE.md file for details