For seamless integration with Seirios RNS, it is important to set up some key robotics software and drivers in your robot system. The following is a checklist of things that Seirios RNS requires your robot system to have before Seirios is installed:

• Motor drivers

  • Ensure that the motor driver node is running properly and can be controlled via teleoperation from the command line.

  • Ensure that the motor driver node is subscribed to the /cmd_vel topic

  • Else, remap it to subscribe to /cmd_vel topic

• Sensors

  • Ensure that the sensors are launched and running properly

  • Ensure that they are publishing data to the appropriate ROS topics

  • Ensure that the lidar is publishing a 2D scan to /scan topic

• TF check

  • Ensure that all the robot links have an appropriate tf to the odom link

  • The tf tree can be visualized using $ rosrun rqt_tf_tree rqt_tf_tree

TF for base_link to scan:

• Ensure that there is a direct tf link between the base_link frame and the laser frame as it is required by Seirios RNS

• RVIZ sensor data visualisation

  • Using RViz, visualize the sensor data. The fixed frame used should be odom

  • Add the tf visualization and ensure all the frames tfs have no warnings

Robot Checks:

• (0.5/4) Before Starting Robot Checks

• (1/4) Linear Speed Calibration Check

• (2/4) Angular Speed Calibration Check

• (3/4) Odometry Check

• (4/4) Straight-line Check

1. Open a new terminal window. Execute this command: rostopic pub /cmd_vel geometry_msgs/Twist "linear: x: 0.0 y: 0.0 z: 0.0 angular: x: 0.0 y: 0.0 z: 0.0"

2. Change the linear: x: to 0.1-0.5 as we only want to move the robot straightly forward. Leave all the other values to 0.0.

3. Measure the distance the robot moved. And record the time between when the robot started to move and when the robot stopped. Calculate speed by dividing the distance over time.

4. Check whether your calculated speed matches up to the value that you have given for linear x.

5. If not, please recalibrate your wheels.

Alternatively, you may use rosrun telelop_twist_keyboard teleop_twist_keyboard.py. Similarly, give it a linear speed between 0.1-0.5. Then repeat Steps 3 - 5 above.

Note:

• If your robot is non-holonomic, it shouldn't be able to slide sideways. y should be 0.0.

• If your robot is not flight-capable, z should be 0.0.

Validating Odometry Data

We provide you with a script that enables you to verify the odometry data by inputting the velocity and duration. The robot will then move at the specified velocity for the given duration. Subsequently, the script will calculate and provide the distance traveled by the robot based on these inputs.

This will facilitate the verification of your odometry data, making it easier and more efficient for you.

You can download the script here.

Linear check

• Align the bot appropriately to test 3-4 meters of linear, straight distance without an angular component. Test using the following command in Terminal: rostopic pub /cmd_vel geometry_msgs/Twist "linear: x: 0.0 y: 0.0 z: 0.0 angular: x: 0.0 y: 0.0 z: 0.0"

• Restart motor

• Check odom pose is zero.

• Publish only linear vel x: 0.1 and stop the bot at the 3-4 m mark.

• Echo the odom topic: rostopic echo /odom.

• Compare the pose of the updated odom with linear and angular bot travelled (offset 1-2%).

Angular check

• Align the bot properly. Mark the spot where the bot will begin rotating.

• Restart the motors.

• Rotate the bot clockwise. Quaternion should be updated to negative.

• Restart the motor and rotate the bot anticlockwise. Quaternion should be updated to positive.

• Restart the motor. Rotate and stop the bot at the original marked spot.

• Make sure that the angular pose is a 0 rad change.

Validating Odometry Data

We provide you with a script that enables you to verify the odometry data by inputting the velocity and duration. The robot will then move at the specified velocity for the given duration. Subsequently, the script will calculate and provide the distance traveled by the robot based on these inputs.

This will facilitate the verification of your odometry data, making it easier and more efficient for you.

You can download the script here.

• Move the robot straight, and echo the /odom topic.

• Align the wheels accordingly to test straight linear movement. It’s recommended to draw lines on the floor for accuracy.

• Give only linear speed. Check the robot is travelling straight. A slight deviation is acceptable (1 - 2 degrees), but no more than 5 degrees.

Click the following tab to view checklists

Before starting Robot checks:

1. Kill all Movel nodes (if you already have it previously installed)

2. Launch only the motor controller and the teleoperation keyboard twist for testing [OR] Run the following command: rostopic pub -r 10 /cmd_vel - for linear linear: x-0.1 for rotation only : angular: z-0.1

Likewise, repeat the same method to check angular speed calibration.

1. Run rostopic pub /cmd_vel geometry_msgs/Twist "linear: x: 0.0 y: 0.0 z: 0.0 angular: x: 0.0 y: 0.0 z: 0.0"

2. Set angular x value between 0.1-0.6. Leave the other values as 0.0.

3. Measure how much the robot turns. And similarly, record the time it took to turn.

4. Check that your calculations match the value you set for angular z.

Alternatively, you may use rosrun telelop_twist_keyboard teleop_twist_keyboard.py. Set angular speed between 0.1-0.5. Then repeat Steps 3 - 5 above.

Validating Odometry Data

We provide you with a script that enables you to verify the odometry data by inputting the velocity and duration. The robot will then move at the specified velocity for the given duration. Subsequently, the script will calculate and provide the distance traveled by the robot based on these inputs.

This will facilitate the verification of your odometry data, making it easier and more efficient for you.

You can download the script here.