The third week of work was primarily spent on understanding the code previously created by former students that worked on the ATLASCAR project, mainly:
- Visual perception unit, created by Diogo Correia as part of his masters thesis, more specifically the code that interfaces with the sensors, their calibration and the positioning of their respective coordinate frames.
- Inclination module, developed by Armindo Silva, to understand how it calculates the vehicle orientation components (roll and pitch).
- Dynamic map reconstruction, created by Pedro Salvado in his masters thesis, was the most thorough analysis, to understand and replicate how the local map reconstruction was achieved.
In this week there was also a small presentation for the LAR members and advisers in which we presented a crude tasks roadmap for the masters thesis followed by a discussion with the advisers.
In the fourth week began the code development.
The arduino code created by Armindo Silva was rebuilt to be used as a ROS node that uses RS232 communication to publish the orientation calculated from the sensor data.
In this first approach it was considered that the road is always flat. This simplification allows to ignore the spacial positioning of the vehicle in relation to the world frame, since in order to calculate it IMU and odometry data is necessary and is not available at the moment. So the efforts where focused on the relation between the car and the road, with the possibility of defining the relation between the road and the world in the future.
To do that two more coordinate frames where added to the car “robot” model, to represent the ground (static) and the centre car axis (transformation matrix calculated with the data sent from the orientation module).
Following that all the sensor frames where also changed to depend on the centre car axis (which moves according to the rotation of the vehicle), so that the measurements depend on a moving frame.
A ROS bag with the orientation information was created to test the system and the result was quite good.
As we can see all the sensor frames move accordingly to the centre car axis.
Lastly it was also acquired a pointcloud dataset from the Sick LD-MRS sensor in order to verify its movement in relation to the movement of the car, but there was a small problem with the program that lead to some unexpected frame behaviour caused by the use of Rosbag, that needs to be corrected.
It was also created a GitHub repository where the developed code will regularly be updated. https://github.com/TiagoSMarques/Masters-Thesis_ATLASCAR2