Gazebo and ROS inertia problems for small robot

asked 2021-02-28 08:41:36 -0500

AndreaRoss gravatar image

I'm trying to control a gazebo robot using ros control but I have some problems after I load the joint controllers. This is the robot model before I load the controllers, the model seems to be correct ( but when I load the joint controllers the model implodes on the origin (, the controller.launch it's not showing errors.

This is my robot model (, this is the inertia matrix of one joint

<inertia ixx="4.5e-05" ixy="-3e-06" ixz="1e-06" iyy="3e-05" iyz="5e-06" izz="3.6e-05"/>

I can get the some information from the fusion 360 model. For exemple this is a leg informations:


Component instances (1)
Area    1.787E+04 mm^2
Density 9.520E-04 g / mm^3
Mass     66.794 g
Volume  7.016E+04 mm^3

Bounding box
    Length   150.172 mm
    Width    26.00 mm
    Height   35.00 mm
X, Y, Z global   0.00 mm, 0.00 mm, 0.00 mm
Center of mass  -68.611 mm, -83.519 mm, 118.34 mm

Moment of inertia at the center of mass   (g mm^2)
    Ixx = 7016.191
    Ixy = 1551.50
    Ixz = 15.726
    Iyx = 1551.50
    Iyy = 1.078E+05
    Iyz = -0.298
    Izx = 15.726
    Izy = -0.298
    Izz = 1.085E+05

Moment of inertia on origin   (g mm^2)
    Ixx = 1.408E+06
    Ixy = -3.812E+05
    Ixz = 5.423E+05
    Iyx = -3.812E+05
    Iyy = 1.358E+06
    Iyz = 6.602E+05
    Izx = 5.423E+05
    Izy = 6.602E+05
    Izz = 8.888E+05

The inertias seems to be okay (, so why I get the robot parts on the origin? If I use bigger values (but with big values the model it's not correct) the robot works fine.

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