Hdifsttar's profile - activity

Hello,

I'm working on a Pioneer-3dx and was hoping to use the sonar data (as we only have sonar on it yet) to make it follow a moving object. I know I could juste use RosAria to get informations from the sonar but I also need to simulate it on Gazebo, thus I was advised p2os.

The problem is that I can't find a way to get p2os on Kinetic ROS for Debian Stretch. If someone could help me or provide me a link, I would warmly thank him.

Hdifsttar

Thank you very much for having found this, now it all makes sense ! I'll try to change it in the .cpp file directly to s

Thank you very much for having found this, now it all makes sense ! I'll try to change it in the .cpp file directly to s

Hi everyone,

I wrote this code in order to retrieve a sonar range message, calculate a velocity based on it, and send it to my robot. I'm publishing at a 100Hz rate but subscribing at only 10Hz.(I've verified with rostopic hz). I'd like to have the same rate for both publishing and subscribing in order to have a different velocity transmitted at each loop.(And not 10 loops in a row transmitting the same information like in my example...)

How can I do that ? Is there something wrong with my code ? If anyone could help me, I'd be very grateful !

Hdifsttar

N.B. : I've read about tcpnodelay, but couldn't really understand what that does and if it fits the situation.

#########Publisher

pub_r1 = rospy.Publisher('/r1/cmd_vel', Twist)
pub_r2 = rospy.Publisher('/r2/cmd_vel', Twist)
rospy.init_node('p3dx_mover')
twist_r1 = Twist()
twist_r2 = Twist()

########Variables
i=0
rate = rospy.Rate(rospy.get_param('~hz', 100))

s_min = 0.3                         #minimum space between slave & master
s_max = 2                           #maximum space between slave & master
v_max = 0.4                         #maximum velocity of slave
alpha = v_max / (s_max - s_min)     #slope of the velocity function
b = alpha*s_max - v_max             #intercept of the velocity function

#########Subscriber

def callback(msg):
    rospy.loginfo("Sonar 4 detects something at %s m" % round(msg.range,3))
    if msg.range < 0.22:
        rospy.loginfo("Obstacle too close ! Not normal, vehicule stopped (You might want to revise the code)")
        twistr_r1.linear.x = 0
        pub_r1.publish(twist)
        rospy.signal_shutdown("Simulation end")

    beta = alpha*msg.range - b
    gamma = min(beta,v_max)
    twist_r1.linear.x = max(0, gamma)

sub = rospy.Subscriber("/r1/sonar4/scan", Range, callback)

#########Loop

while not rospy.is_shutdown() :

    twist_r2.linear.x = (math.cos(i) +2)/8
    i+=0.1
    rospy.loginfo("r1 velocity is "+ str(round(twist_r1.linear.x,3))+ " m/s" )
    rospy.loginfo("r2 velocity is "+ str(round(twist_r2.linear.x,3))+ " m/s" )
    pub_r1.publish(twist_r1)
    pub_r2.publish(twist_r2)
    rate.sleep()

Thank you very much for having found this, now it all makes sense !

I used hector_model sonar sensor. By checking the frequency you mean "rostopic hz /r1/sonar4/scan" ? Because this comman

That does make sense. Does it mean the sensor publish at its maximum rate by default ? Because I never set it to publish

That does make sense. Does it mean the sensor publish at its maximum rate by default ? Because I never set it to publish

That does make sense. Does it mean the sensor publish at its maximum rate by default ? Because I never set it to publish

That does make sense. Does it mean the sensor publish at their maximum rate by default ? Because I never set it to publi

That does make sense. Does it mean the sensors publish at their maximum rate by default ? Because I never set them to pu

Fix the subscriber rate Hi everyone, I wrote this code in order to retrieve a sonar range message, calculate a velocity

Thanks @Humpelstilzchen and @ufr3c_tjc. It worked just fine. If anyone's interested here's the code : #!/usr/bin/env py

Python ros multiple publisher Hello, I'm working on two pioneer 3dx, and i'm trying to make one follow the other. To do

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Hector sonar implementation on a Pioneer 3DX Hello, I'm working on a simulation of two Pioneer-3DX robots on Gazebo. (D

Hector sonar implementation on a Pioneer 3DX Hello, I'm working on a simulation of two Pioneer-3DX robots on Gazebo. (D

Hector sonar implementation on a Pioneer 3DX Hello, I'm working on a simulation of two Pioneer-3DX robots on Gazebo. (D

Hector sonar implementation on a Pioneer 3DX Hello, I'm working on a simulation of two Pioneer-3DX robots on Gazebo. (D

Hector sonar implementation on a Pioneer 3DX Hello, I'm working on a simulation of two Pioneer-3DX robots on Gazebo. (D

Hector sonar implementation on a Pioneer 3DX Hello, I'm working on a simulation of two Pioneer-3DX robots on Gazebo. (D

Hector sonar implementation on a Pioneer 3DX Hello, I'm working on a simulation of two Pioneer-3DX robot on Gazebo. (De

Hector sonar implementation on a Pioneer 3DX Hello, I'm working on a simulation of two Pioneer-3DX robot on Gazebo. (De

P2OS ROS Kinetic Debian Stretch Hello, I'm working on a Pioneer-3dx and was hoping to use the sonar data (as we only ha

P2OS ROS Kinetic Debian Stretch Hello, I'm working on a Pioneer-3dx and was hoping to use the sonar data (as we only ha

Hi, I've just recently begun to work on a pioneer P3DX. Before trying to get it moving, I wanted to try it on a simulator. I've run Aria with MobileSim fairly easily with the examples. So did I with RosAria and MobileSim following the tutorial and this : https://github.com/pengtang/rosaria_c...

But when it comes to Gazebo and RosAria, I'm lost. I made a P3DX move with https://github.com/SD-Robot-Vision/Pi... and https://github.com/SD-Robot-Vision/p3... , but it's with ROS. And since I ultimately want my robot moving in real life, I'm lost as how to get the RosAria example work on Gazebo. (Because i want the same code both working on Gazebo and on the P3DX)

And since I still don't understand all of this, even when reading this post about the exact same problem : http://answers.ros.org/question/25705... I'd wanted to know if someone could perhaps clarify it / help me on this.

I also found this, which pretty much is the same problem as mine : http://answers.ros.org/question/21581... but there was no answers as of today.

I've tried to be as clear as possible, sorry if I still sound confusing.

Hdifsttar

Thanks Reed, I get it now.

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