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2015-06-22 09:57:58 -0500 commented answer IMU linear acceleration to position

Thank You I will try it.

2015-06-22 09:24:04 -0500 commented answer IMU linear acceleration to position

its not displacment its dx ?

2015-06-22 09:01:55 -0500 commented answer IMU linear acceleration to position

is this right ?

     Displacement_x +=Velocity_x*cos(yaw)*dt;

     x_pos += Velocity_x*Displacement_x;
2015-06-22 07:24:12 -0500 answered a question IMU linear acceleration to position

I will try using Kalman filter also I think it will be complicated. I considered the yaw because my model is for a car with yaw

    Velocity_x= Velocity_old_x+acceleration_x*dt;
    Displacement_x += Velocity_x*dt;


    x_pos = (Displacement_x * cos(yaw));
    y_pos =  (Displacement_x * sin(yaw));
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2015-06-19 09:57:41 -0500 asked a question IMU linear acceleration to position

Hey guys,

I have IMU 3dm_GX2 and I want to get position from it. I know that there will be accumulated error and will not be accurate but I need to get the best out of it. I excluded the gravity effect from linear acceleration

     acceleration_x = (msg->linear_acceleration.x + 9.81 * sin(pitch)) * cos(pitch);
     acceleration_y = (msg->linear_acceleration.y - 9.81 * sin(roll))  * cos(roll);

so whats is the best way for integrating linear acceleration twice because the ordinary integration is very bad.

     Velocity_x= Velocity_old_x+acceleration_x*dt;
     x_pos += Velocity_x*dt;

Thanks in advance

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2015-04-24 10:23:46 -0500 commented answer Extract data from bag as variables in CPP

Thank you very much. It worked

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2015-04-24 06:39:22 -0500 commented answer Extract data from bag as variables in CPP

Thank you for your answer but my problem is after subscribing how to make this for example double x=linear_acceleration.x;

2015-04-24 06:39:02 -0500 answered a question Extract data from bag as variables in CPP

Thank you for your answer but my problem is after subscribing how to make this for example double x=linear_acceleration.x;

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2015-04-24 04:14:28 -0500 asked a question Extract data from bag as variables in CPP

I have a imu bag file and I want to take linear acceleration values xyz in cpp in variables so I could integrate them twice to get position but I am new at ROS and I do not know how ? I hope my question is clear. Thanks in advance.

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2015-04-17 06:29:37 -0500 asked a question Gmapping odometry origin

I have a problem that after taking data from laser sensor indoors with fake odometry I set the odometry point moves as the robot moves I am working with the default parameters is there a way to fix the odometry point. Thanks in advance.

<launch>

<param name="use_sim_time" value="true"/>
<node pkg="gmapping" type="slam_gmapping" name="slam_gmapping" output="screen">
    <remap from="scan" to="/scan"/>
    <param name="maxUrange" value="80"/>        
    <param name="xmin" value="-100.0"/>
    <param name="Ymin" value="-100.0"/>
    <param name="xmax" value="100.0"/>
    <param name="ymax" value="100.0"/>
    <param name="throttle_scans" value="1"/>
    <param name="base_frame" value="base_link"/>
    <param name="map_frame" value="map"/>   
    <param name="odom_frame" value="odom"/>
    <param name="map_update_interval" value="5"/>
    <param name="sigma" value="0.05"/>
    <param name="kernelSize" value="1"/>
    <param name="lstep" value="0.05"/>
    <param name="astep" value="0.05"/>
    <param name="iterations" value="5"/>
    <param name="lsigma" value="0.075"/>
    <param name="ogain" value="3"/> 
    <param name="lskip" value="0"/>
            <param name="minimumScore" value="0.0"/>
    <param name="srr" value="0.1"/>
    <param name="srt" value="0.2"/>
    <param name="str" value="0.1"/>
    <param name="stt" value="0.2"/>
    <param name="linearUpdate" value="1.0"/>
    <param name="angularUpdate" value="0.5"/>
    <param name="temporalUpdate" value="-1.0"/>
    <param name="resampleThreshold" value="0.5"/>
    <param name="particles" value="30"/>    
    <param name="delta" value="0.05"/>
    <param name="llsamplerange" value="0.01"/>
    <param name="llsamplestep" value="0.01"/>
    <param name="lasamplerange" value="0.05"/>
    <param name="lasamplestep" value="0.05"/>
    <param name="transform_publish_period" value="0.05"/>
    <param name="occ_thresh" value="0.25"/>
    <param name="maxRange" value="80"/>

</node>

</launch>

2015-04-17 06:29:36 -0500 asked a question gmapping slam paramerter

I have a problem that after taking data from laser sensor indoors with fake odometry I set the odometry point moves as the robot moves I am working with the default parameters is there a way to fix the odometry point. Thanks in advance.

<launch>

<param name="use_sim_time" value="true"/>
<node pkg="gmapping" type="slam_gmapping" name="slam_gmapping" output="screen">
    <remap from="scan" to="/scan"/>
    <param name="maxUrange" value="80"/>        
    <param name="xmin" value="-100.0"/>
    <param name="Ymin" value="-100.0"/>
    <param name="xmax" value="100.0"/>
    <param name="ymax" value="100.0"/>
    <param name="throttle_scans" value="1"/>
    <param name="base_frame" value="base_link"/>
    <param name="map_frame" value="map"/>   
    <param name="odom_frame" value="odom"/>
    <param name="map_update_interval" value="5"/>
    <param name="sigma" value="0.05"/>
    <param name="kernelSize" value="1"/>
    <param name="lstep" value="0.05"/>
    <param name="astep" value="0.05"/>
    <param name="iterations" value="5"/>
    <param name="lsigma" value="0.075"/>
    <param name="ogain" value="3"/> 
    <param name="lskip" value="0"/>
            <param name="minimumScore" value="0.0"/>
    <param name="srr" value="0.1"/>
    <param name="srt" value="0.2"/>
    <param name="str" value="0.1"/>
    <param name="stt" value="0.2"/>
    <param name="linearUpdate" value="1.0"/>
    <param name="angularUpdate" value="0.5"/>
    <param name="temporalUpdate" value="-1.0"/>
    <param name="resampleThreshold" value="0.5"/>
    <param name="particles" value="30"/>    
    <param name="delta" value="0.05"/>
    <param name="llsamplerange" value="0.01"/>
    <param name="llsamplestep" value="0.01"/>
    <param name="lasamplerange" value="0.05"/>
    <param name="lasamplestep" value="0.05"/>
    <param name="transform_publish_period" value="0.05"/>
    <param name="occ_thresh" value="0.25"/>
    <param name="maxRange" value="80"/>

</node>

</launch>