nanaky's profile - activity

I have the same question. Waiting for an answer!!!

Is this possible in Groovy anyhow?

Try deselecting the 3D accelerator box in Display in the VBox Manager.

It doesn't look like a ROS problem, it's a VirtualBox problem I believe.

Which version of VirtualBox are you using? Maybe you should update to the latest.

Hi, thanks again for answering. Let's see if someone else knows for sure.

Would it be correct if we used in the field scan_time of the LaserScan message a time difference like this?

sensor_msgs::LaserScan scan;

scan.scan_time= (current_time-last_time).toSec();

Being current_time and last_time two ros::Time objects, so the function toSec() returns the number of seconds between two callbacks (since I have this scan_time in a callback).

Thanks in advance

EDIT: If anyone is wondering why would I do this, it is because I'm defining IR sensors as a LaserScan for using them in the navigation stack. In the robot, the measures update every 33 ms, but the messages to ROS with this measures can come more or less randomly. I take this messages and shape them into a LaserScan.

Hi,

I have the same question. Did you finally get the answer?

Thanks

Ok, thank you very much, I missed that as I got the "template" from the LaserScan tutorial. That makes much more sense.

Hi everyone

I am using a Khepera III robot which happens to use TCRT5000 IR sensors.

I am trying to use ROS navigation package, but I don't know how to make the LaserScan message from the IR (which as far as I understand is possible).

The IR lectures are more or less 3900 when an object is close to the sensor and more or less 100 when it is at 10 cm (4 inches). I have a function that, given the IR lecture, returns how far in meters is the object.

I am going to use 6 IR sensors (the ones in the front and the ones in the side).

How does this look to you?

sensor_msgs::LaserScan scan;
scan.header.stamp = ros::Time::now();
scan.header.frame_id = "laser_frame";

scan.angle_min = -1.57;
scan.angle_max = 1.57;
scan.angle_increment = 3.14 / 5;//six is the number of sensors

scan.time_increment = (1 / 10) / (5); //assuming that we have 6 IR sensors and we want to make ten scans with the six sensors, would this be correct? (The time between the sensors measures is 3ms, but I only want to make a full scan ten times per second).

scan.range_min = 0.0;
scan.range_max = 0.1;

scan.ranges.resize(6);//six is the number of sensors.

//Now, the IR measures:

scan.ranges[0]= infrared_left; //left sensor info (in meters)
scan.ranges[1]= infrared_front_side_left; //front side left sensor info (in meters)
scan.ranges[2]= infrared_front_left; //front left sensor info (in meters)
scan.ranges[3]= infrared_front_right;
scan.ranges[4]= infrared_front_side_right; 
scan.ranges[5]= infrared_right;

I really don't know what to do with the scan.time_increment, or if I have to do something with the intensities array ( I suppose that nothing, but I have to ask).

Thanks in advance.

Hi,

I'm also trying to use ROS on the Khepera III with the KoreBotLE included. Before I continue, I have to say I'm a beginner with ROS.

Were you able to get ROS on the Khepera? Which was your solution?

Thanks for the support.