RoboClaw ROS

RoboClaw node for melodic & humble

Thanks to Brad Bazemore (sonyccd) for developing the original driver.

This is a ROS1/ROS2 driver for the RoboClaw motor controllers made by Basicmicro Motion Control. It is actively maintained by the Northern Robotics Laboratory of Université Laval.

Dependencies

This ROS driver is using the python driver developed by Team Chat Robotique (Thanks!). Install it with pip :

pip install tcr-roboclaw

Before you begin

For the ROS1 (melodic) version : melodic

Before you use this package, you need to calibrate the velocity PID on the RoboClaw. This will require to use BasicMicro's Motion Studio software (only available for Windows).

From the RoboClaw user manual:

Motion Studio provides the option to auto tune velocity and position control. To use the auto tune option, make sure the encoder and motor are running in the desired direction and the basic PWM control of the motor works as expected. It is recommend to ensure the motor and encoder combination are functioning properly before using the auto tune feature.

Go to the PWM Settings screen in Motion Studio. Slide the motor slider up to start moving the motor forward. Check the encoder is increasing in value. If it is not either reverse the motor wires or the encoder wires. The recheck. To start auto tune click the auto tune button for the motor channel that is will be tuned first. The auto tune function will try to determine the best settings for that motor channel.

Usage instructions

Just clone the repo into your colcon workspace. Remember to make sure ROS2 has permissions to use the dev port you give it.

cd <workspace>/src
git clone https://github.com/norlab-ulaval/roboclaw_ros.git
cd <workspace>
colcon build --symlink-install --packages-select roboclaw_ros
. install/local_setup.bash
ros2 launch roboclaw_ros roboclaw_node.launch.py

Parameters

The launch file can be configured at the command line with arguments, by changing the value in the launch file or through the ros2 param server.

Parameter	Default	Definition
dev	/dev/ttyACM0	Path to the RoboClaw device path
baud	115200	Baud rate the RoboClaw is configured for
address	128	The address the RoboClaw is set to, 128 is 0x80
max_speed_linear	2.0	Max linear speed allowed for motors in meters per second
max_speed_angular	2.0	Max angular speed allowed for motors in meters per second
stop_if_idle	true	Stops movement if no velocity commands are received for idle_timeout
idle_timeout	1.0	Duration, in seconds, after which motors are stopped when idle
ticks_per_meter	4000	The number of encoder ticks per meter of movement
ticks_per_rotation	2000	The number of encoder ticks per rotation of wheel
base_width	0.315	Width from one wheel center to another, in meters
custom_pid	true	Whether the driver should overwrite the PID parameters or not
p_constant	3.0	Proportional gain of PID controller (unused if custom_pid is false)
i_constant	0.42	Integral gain of PID controller (unused if custom_pid is false)
d_constant	0.0	Derivative gain of PID controller (unused if custom_pid is false)
qpps	6000	Maximum speed of motor, in ticks/sec (unused if custom_pid is false)
odom_rate	30	Rate of polling and publishing odometry data
elec_rate	10	Rate of polling and publishing electrical data
publish_odom	true	Publishes Odometry if set to true
publish_encoders	true	Publishes EncoderState if set to true
publish_elec	true	Publishes MotorState if set to true
publish_tf	false	Broadcasts TF from odom to base_link if set to true

Topics

Subscribed

/cmd_vel (geometry_msgs/Twist) Velocity commands for the mobile base.

Published

/motors/odometry (nav_msgs/Odometry) Odometry output from the mobile base.

/motors/{left/right}/encoder (norlab_custom_interfaces/EncoderState) Encoder state for the left and right motors.

/motors/{left/right}/electrical (norlab_custom_interfaces/MotorState) Electrical data for both motors.

RoboClaw Node graph

flowchart LR

/roboclaw_node[ /roboclaw_node ]:::main
/twist_mux[ /twist_mux ]:::node
/foxglove_bridge[ /foxglove_bridge ]:::node
/twist_mux/cmd_vel([ /twist_mux/cmd_vel<br>geometry_msgs/msg/Twist ]):::topic
/diagnostics([ /diagnostics<br>diagnostic_msgs/msg/DiagnosticArray ]):::topic
/motors/left/electrical([ /motors/left/electrical<br>norlab_custom_interfaces/msg/MotorState ]):::bugged
/motors/left/encoder([ /motors/left/encoder<br>norlab_custom_interfaces/msg/EncoderState ]):::bugged
/motors/odometry([ /motors/odometry<br>nav_msgs/msg/Odometry ]):::bugged
/motors/right/electrical([ /motors/right/electrical<br>norlab_custom_interfaces/msg/MotorState ]):::bugged
/motors/right/encoder([ /motors/right/encoder<br>norlab_custom_interfaces/msg/EncoderState ]):::bugged


/twist_mux/cmd_vel --> /roboclaw_node
/diagnostics --> /foxglove_bridge
/roboclaw_node --> /diagnostics
/roboclaw_node --> /motors/left/electrical
/roboclaw_node --> /motors/left/encoder
/roboclaw_node --> /motors/odometry
/roboclaw_node --> /motors/right/electrical
/roboclaw_node --> /motors/right/encoder
/twist_mux --> /twist_mux/cmd_vel




subgraph keys[<b>Keys<b/>]
subgraph nodes[<b><b/>]
topicb((No connected)):::bugged
main_node[main]:::main
end
subgraph connection[<b><b/>]
node1[node1]:::node
node2[node2]:::node
node1 o-.-o|to server| service[/Service<br>service/Type\]:::service
service <-.->|to client| node2
node1 -->|publish| topic([Topic<br>topic/Type]):::topic
topic -->|subscribe| node2
node1 o==o|to server| action{{/Action<br>action/Type/}}:::action
action <==>|to client| node2
end
end
classDef node opacity:0.9,fill:#2A0,stroke:#391,stroke-width:4px,color:#fff
classDef action opacity:0.9,fill:#66A,stroke:#225,stroke-width:2px,color:#fff
classDef service opacity:0.9,fill:#3B8062,stroke:#3B6062,stroke-width:2px,color:#fff
classDef topic opacity:0.9,fill:#852,stroke:#CCC,stroke-width:2px,color:#fff
classDef main opacity:0.9,fill:#059,stroke:#09F,stroke-width:4px,color:#fff
classDef bugged opacity:0.9,fill:#933,stroke:#800,stroke-width:2px,color:#fff
style keys opacity:0.15,fill:#FFF
style nodes opacity:0.15,fill:#FFF
style connection opacity:0.15,fill:#FFF

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