Unit6 : total_distance calculation from grader bot

Course Support ROS2 Basics in 5 Days Humble (C++)
1

Hello @girishkumar.kannan , @bayodesegun

I am getting a feedback from gradebot for chapter 6 as below.
The total distance calcualted is not correct.

I am using odometry callbacks as below. Can you please tell me where i could look more for this item ? Thanks for your time in adv.

void odometry_callback(const nav_msgs::msg::Odometry::SharedPtr msg) {
double current_x = msg->pose.pose.position.x;
double current_y = msg->pose.pose.position.y;

if (last_x_ == 0.0 && last_y_ == 0.0) {
    last_x_ = current_x;
    last_y_ = current_y;
    return; 
}

double delta_x = current_x - last_x_;
double delta_y = current_y - last_y_;

double delta_distance = std::sqrt(delta_x * delta_x + delta_y * delta_y);

total_distance_ += delta_distance;

last_x_ = current_x;
last_y_ = current_y;
}

I am having a simulation loading issue with Unit 6 which is why it gives 0 for distance.
Unit 5 simulation gives me numbers correctly - please check the video below !!

Thanks,
Venkat

2

Hello @vadhrivenkat ,

Your code looks correct, and from the video you shared, it seems to be working as intended. Therefore, I believe the issue lies with the simulation. I tested the Unit simulation, and it appears to be working fine on my end. It’s possible that you encountered an isolated issue while trying to correct your quiz. I recommend resubmitting your quiz for revision and ensuring that the simulation is functioning as expected beforehand.

Best,

3

@vadhrivenkat
Adding to @albertoezquerro’s post above,

I have just changed the simulation to a faster one (the same one used in unit 5). Please try submitting again on unit 6, after the simulation has loaded.

4

Hello @albertoezquerro @bayodesegun
I can load the simulation now,
The bot is put into motion with the keyboard. ( or its equivalent by the grader bot ). The client submitted only submits the goal. is that the right understanding ? when i run the grader bot i dont see the robot moving in the background ( i got 8 pts - i crossed section - but just to keep you posted. )

Running independently in the console ( without grader bot ) - looks fine.

image
image607×593 54.5 KB

can you please confirm ?

Thanks,
Venkat