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joint damping has no effect

asked 2016-10-20 09:09:26 -0500

djou07 gravatar image

updated 2016-10-21 04:36:48 -0500

Hi there,

damping has no effect to avoid bouncing and flying of robots.I want to do like this but It doesn't work for me!

here is my SDF file. with a force of 0.051Nm and what ever damping value I set, alwayes the same behaviour.

<?xml version='1.0' ?>
<sdf version='1.4'>
<world name="default">
 <include>
   <uri>model://ground_plane</uri>
 </include>
<include>
   <uri>model://sun</uri>
 </include>
 <model name='0'>
<link name='1'>
    <pose>0.00503991 0.00855352 0.0245165 0 4.71239 0</pose>
    <inertial>
        <mass>0.05</mass>
        <inertia><ixx>0.000003333</ixx>
            <ixy>0</ixy>
            <ixz>0</ixz>
            <iyy>0.000004271</iyy>
            <iyz>0</iyz><izz>0.000004271</izz>
        </inertia>
    </inertial>
    <collision name='collision'>
        <geometry>
            <box>
                <size>0.0125 0.01 0.01</size>
            </box>
        </geometry>
    </collision>
    <visual name='visual'>
        <geometry>
            <box>
                <size>0.0125 0.01 0.01</size>
            </box>
        </geometry>
    </visual>
</link>

<link name='2'>
    <pose>0.00503991 0.00855352 0.0370165 0 4.71239 0</pose>
    <inertial>
        <mass>0.05</mass>
        <inertia><ixx>0.000003333</ixx>
            <ixy>0</ixy>
            <ixz>0</ixz>
            <iyy>0.000004271</iyy>
            <iyz>0</iyz><izz>0.000004271</izz>
        </inertia>
    </inertial>
    <collision name='collision'>
        <geometry>
            <box>
                <size>0.0125 0.01 0.01</size>
            </box>
        </geometry>
    </collision>
    <visual name='visual'>
    <geometry>
        <box>
            <size>0.0125 0.01 0.01</size>
        </box>
        </geometry>
    </visual>
</link>

<joint type="revolute" name="0_1">
    <pose>-0.00625 0 0 0 0 0</pose>
    <child>1</child>
    <parent>2</parent>
    <axis>
        <xyz>0 0 1</xyz>
        <limit>
            <lower>0.5</lower>
            <upper>-0.5</upper>
        </limit>
        <dynamics>
            <friction>0.05</friction>
            <damping>1000000000000000000000000000000000000000000000000000</damping>
        </dynamics>
    </axis>
    <physics>
        <ode>
            <implicit_spring_damper>1</implicit_spring_damper>
        </ode>
    </physics>
</joint>
<plugin name="controller" filename="build/libcontroller.so"/>
</model>
</world>
</sdf>

I have Gazebo version 6.1.0

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Comments

you realize it's spelled implicit_spring_damper, right?

Peter Mitrano gravatar imagePeter Mitrano ( 2016-10-20 21:51:25 -0500 )edit

sorry, it was a typo...I'll correct it, still doesn't work!

djou07 gravatar imagedjou07 ( 2016-10-21 02:31:14 -0500 )edit

OMG you cannot set damping that high.... your model will expode O_O can you explain more specifically how you want the robot to behave?

Peter Mitrano gravatar imagePeter Mitrano ( 2016-10-21 13:11:14 -0500 )edit

it is the same behaviour if I set damping to 0 or 10 or 100.... I have deferent robot shapes that I generate randomly, sometimes the robot is heavy and the force applied to the joint is big (30Nm) so robot starts to fly and bounce. I want whenever big is the force, the joint moves slowly but strong enought to lift other robot parts...I hope I well explained what I want.

djou07 gravatar imagedjou07 ( 2016-10-22 01:51:12 -0500 )edit
1

Your upper limit is lower than your lower limit, that's strange

eugene-katsevman gravatar imageeugene-katsevman ( 2017-04-09 17:02:32 -0500 )edit

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answered 2016-10-24 04:48:17 -0500

djou07 gravatar image

updated 2016-10-24 04:49:56 -0500

I removed the joint limite and it workd !! can someone explain why...

<limit>
    <lower>0.5</lower>
    <upper>-0.5</upper>
</limit>
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Asked: 2016-10-20 09:09:26 -0500

Seen: 1,306 times

Last updated: Oct 24 '16