Where

Hi. I’m using spherical joint in the isaacgym preview 4, It seems like there are error that load some part of spherical joint twice. How can I fix it?

[/quote]

And here is a urdf file

<?xml version="1.0"?>
<robot name="robotiq_85_gripper_joint" xmlns:xacro="http://ros.org/wiki/xacro">
<!--with prismatic joint for translational motion -->
	<link name="world"/>
	<!-- </link> -->

	<joint name = "joint_x" type = "prismatic">
    <parent link="world"/>    
    <child link="pris_link1"/>    
    <origin xyz="0.0 0.0 0.0"/>    
    <axis xyz="1 0 0"/>    
    <limit effort="1e3" lower="-1.0" upper="1.0" velocity="1e9"/>
    <dynamics damping="20.0" friction="0.0"/>  
	</joint>

  	<link name="pris_link1">
		<inertial>
		  <mass value="0.001"/>
		  <inertia ixx="0.1" iyy="0.1" izz="0.1" ixy="0.0" ixz="0.0" iyz="0.0"/>
		</inertial>  
	</link>

	<joint name = "joint_y" type = "prismatic">
    <parent link="pris_link1"/>    
    <child link="pris_link2"/>    
    <origin xyz="0.0 0.0 0.0"/>    
    <axis xyz="0 1 0"/>    
    <limit effort="1e6" lower="-1.0" upper="1.0" velocity="1e9"/>
    <dynamics damping="20.0" friction="0.0"/>  
	</joint>

  	<link name="pris_link2">
		<inertial>
		  <mass value="0.001"/>
		  <inertia ixx="0.1" iyy="0.1" izz="0.1" ixy="0.0" ixz="0.0" iyz="0.0"/>
		</inertial>  
	</link>    

	<joint name = "joint_z" type = "prismatic">
    <parent link="pris_link2"/>    
    <child link="pris_link3"/>    
    <origin xyz="0.0 0.0 0.0"/>    
    <axis xyz="0 0 1"/>    
    <limit effort="1e6" lower="-1.0" upper="1.0" velocity="1e9"/>
    <dynamics damping="20.0" friction="0.0"/>  
	</joint>

  	<link name="pris_link3">
		<inertial>
		  <mass value="0.001"/>
		  <inertia ixx="0.1" iyy="0.1" izz="0.1" ixy="0.0" ixz="0.0" iyz="0.0"/>
		</inertial>  
	</link>    

	<joint name="spherical_joint" type="spherical">
    <origin xyz="0 0 0"/>
    <parent link="pris_link3"/>    
    <child link="gripper_base_link"/>        
    <limit effort="1000.0" lower="-4" upper="4" velocity="100"/>
    <!-- <dynamics damping="20.0" friction="0.0"/>   -->
	</joint>

    <link name="gripper_base_link">
        <visual>
            <geometry>
                <mesh filename="package://robotiq_85_description/meshes/visual/robotiq_85_base_link.dae"/>
            </geometry>
        </visual>
        
        <!-- <collision>
            <origin xyz = "0.0 0.0 0.0" rpy = "-1.57079632679 0.0 0.0"/>
            <geometry>
                <mesh filename="package://robotiq_85_description/meshes/collision/robotiq_85_base_link.stl"/>
            </geometry>
        </collision> -->
        
        <inertial>
            <mass value="0.636951" />
            <origin xyz="0.0 0.0 0.0" />
            <inertia ixx = "0.000380" ixy = "0.000000" ixz = "0.000000" iyy = "0.001110" iyz = "0.000000" izz = "0.001171" />
        </inertial>
    </link>

    <joint name="gripper_finger1_joint" type="revolute">
        <parent link="gripper_base_link"/>
        <child link="gripper_finger1_knuckle_link"/>
        <axis xyz="0 1 0"/>
        <origin rpy="3.14 0.0 0.0" xyz="0.05490451627 0.0 -0.03060114443"/>
     
        <!--<origin rpy="3.14 0.0 0.0" xyz="0.05490451627 0.03060114443 0.0"/>-->
        
        <limit lower="-0.804" upper="0.804" velocity="10.0" effort="5000"/> <!--lower = 0-->
    </joint>

    <joint name="gripper_finger2_joint" type="revolute">
        <parent link="gripper_base_link"/>
        <child link="gripper_finger2_knuckle_link"/>
        <axis xyz="0 1 0"/> <!--0 1 0-->
        <origin rpy="0.0 0.0 0.0" xyz="0.05490451627 0.0 0.03060114443"/>
        <!--<limit lower="-3.14" upper="3.14" velocity="100.0" effort="1000"/>-->
        <limit lower="-0.804" upper="0.804" velocity="10.0" effort="5000"/>        <!--lower = 0-->
        <mimic joint="gripper_finger1_joint"/>
    </joint>

    <link name="gripper_finger1_knuckle_link">
        <visual>
            <geometry>
                <mesh filename="package://robotiq_85_description/meshes/visual/robotiq_85_knuckle_link.dae"/>
            </geometry>
        </visual>
        
        <!-- <collision>
            <origin xyz = "0.0 0.0 0.0" rpy = "-1.57079632679 0.0 0.0"/>
            <geometry>
                <mesh filename="package://robotiq_85_description/meshes/collision/robotiq_85_knuckle_link.stl"/>
            </geometry>
        </collision> -->
        
        <inertial>
            <mass value="0.018491" />
            <origin xyz="0.0 0.0 0.0" />
            <inertia ixx = "0.000009" ixy = "-0.000001" ixz = "0.000000" iyy = "0.000001" iyz = "0.000000" izz = "0.000010" />
        </inertial>
    </link>

    <link name="gripper_finger2_knuckle_link">
        <visual>
            <geometry>
                <mesh filename="package://robotiq_85_description/meshes/visual/robotiq_85_knuckle_link.dae"/>
            </geometry>
        </visual>
        
        <!-- <collision>
            <origin xyz = "0.0 0.0 0.0" rpy = "-1.57079632679 0.0 0.0"/>
            <geometry>
                <mesh filename="package://robotiq_85_description/meshes/collision/robotiq_85_knuckle_link.stl"/>
            </geometry>
        </collision> -->
        
        <inertial>
            <mass value="0.018491" />
            <origin xyz="0.0 0.0 0.0" />
            <inertia ixx = "0.000009" ixy = "-0.000001" ixz = "0.000000" iyy = "0.000001" iyz = "0.000000" izz = "0.000010" />
        </inertial>
    </link>

    <joint name="gripper_finger1_finger_joint" type="fixed">
        <parent link="gripper_finger1_knuckle_link"/>
        <child link="gripper_finger1_finger_link"/>
        <origin xyz="-0.00408552455 0.0 0.03148604435 " rpy="0 0 0" />
    </joint>

    <joint name="gripper_finger2_finger_joint" type="fixed">
        <parent link="gripper_finger2_knuckle_link"/>
        <child link="gripper_finger2_finger_link"/>
        <origin xyz="-0.00408552455 0.0 0.03148604435 " rpy="0 0 0" />
    </joint>

    <link name="gripper_finger1_finger_link">
        <visual>
            <geometry>
                <mesh filename="package://robotiq_85_description/meshes/visual/robotiq_85_finger_link.dae"/>
            </geometry>
        </visual>
        
        <!-- <collision>
            <origin xyz = "0.0 0.0 0.0" rpy = "-1.57079632679 0.0 0.0"/>
            <geometry>
                <mesh filename="package://robotiq_85_description/meshes/collision/robotiq_85_finger_link.stl"/>
            </geometry>
        </collision> -->
        
        <inertial>
            <mass value="0.027309" />
            <origin xyz="0.0 0.0 0.0" />
            <inertia ixx = "0.000003" ixy = "-0.000002" ixz = "0.000000" iyy = "0.000021" iyz = "0.000000" izz = "0.000020" />
        </inertial>
    </link>

    <link name="gripper_finger2_finger_link">
        <visual>
            <geometry>
                <mesh filename="package://robotiq_85_description/meshes/visual/robotiq_85_finger_link.dae"/>
            </geometry>
        </visual>
        
        <!-- <collision>
            <origin xyz = "0.0 0.0 0.0" rpy = "-1.57079632679 0.0 0.0"/>
            <geometry>
                <mesh filename="package://robotiq_85_description/meshes/collision/robotiq_85_finger_link.stl"/>
            </geometry>
        </collision> -->
        
        <inertial>
            <mass value="0.027309" />
            <origin xyz="0.0 0.0 0.0" />
            <inertia ixx = "0.000003" ixy = "-0.000002" ixz = "0.000000" iyy = "0.000021" iyz = "0.000000" izz = "0.000020" />
        </inertial>
    </link>

    <joint name="gripper_finger1_inner_knuckle_joint" type="revolute">
        <parent link="gripper_base_link"/>
        <child link="gripper_finger1_inner_knuckle_link"/>
        <axis xyz="0 1 0"/>
        <origin xyz="0.06142 0 -0.0127" rpy="3.14 0.0 0.0" />
        <limit lower="-3.14" upper="3.14" velocity="100.0" effort="5000"/><!--effort0.1-->
        <mimic joint="gripper_finger1_joint" offset="0"/>
    </joint>

    <joint name="gripper_finger2_inner_knuckle_joint" type="revolute">
        <parent link="gripper_base_link"/>
        <child link="gripper_finger2_inner_knuckle_link"/>
        <axis xyz="0 -1 0"/><!--0 1 0-->
        <origin xyz="0.06142 0 0.0127" rpy="0 0 0"/>
        <limit lower="-3.14" upper="3.14" velocity="100.0" effort="5000"/><!--effort=0.1-->
        <mimic joint="gripper_finger1_joint" offset="0"/>
    </joint>


    <link name="gripper_finger1_inner_knuckle_link">
        <visual>
            <geometry>
                <mesh filename="package://robotiq_85_description/meshes/visual/robotiq_85_inner_knuckle_link.dae"/>
            </geometry>
        </visual>
        
        <!-- <collision>
            <origin xyz = "0.0 0.0 0.0" rpy = "-1.57079632679 0.0 0.0"/>
            <geometry>
                <mesh filename="package://robotiq_85_description/meshes/collision/robotiq_85_inner_knuckle_link.stl"/>
            </geometry>
        </collision> -->
        
        <inertial>
            <mass value="0.029951" />
            <origin xyz="0.0 0.0 0.0" />
            <inertia ixx = "0.000039" ixy = "0.000000" ixz = "0.000000" iyy = "0.000005" iyz = "0.000000" izz = "0.000035" />
        </inertial>
    </link>

    <link name="gripper_finger2_inner_knuckle_link">
        <visual>
            <geometry>
                <mesh filename="package://robotiq_85_description/meshes/visual/robotiq_85_inner_knuckle_link.dae"/>
            </geometry>
        </visual>
        
        <!-- <collision>
            <origin xyz = "0.0 0.0 0.0" rpy = "-1.57079632679 0.0 0.0"/>
            <geometry>
                <mesh filename="package://robotiq_85_description/meshes/collision/robotiq_85_inner_knuckle_link.stl"/>
            </geometry>
        </collision> -->
        
        <inertial>
            <mass value="0.029951" />
            <origin xyz="0.0 0.0 0.0" />
            <inertia ixx = "0.000039" ixy = "0.000000" ixz = "0.000000" iyy = "0.000005" iyz = "0.000000" izz = "0.000035" />
        </inertial>
    </link>

    <joint name="gripper_finger1_finger_tip_joint" type="revolute">
        <parent link="gripper_finger1_inner_knuckle_link"/>
        <child link="gripper_finger1_finger_tip_link"/>
        <axis xyz="0 1 0"/>
        <origin xyz="0.04303959807 0.0  0.03759940821" rpy="0.0 0.0 0.0"/>
        <limit lower="-3.14" upper="3.14" velocity="100.0" effort="5000"/><!--eff0.1-->
        <mimic joint="gripper_finger1_joint" multiplier="-1"/>
    </joint>

    <joint name="gripper_finger2_finger_tip_joint" type="revolute">
        <parent link="gripper_finger2_inner_knuckle_link"/>
        <child link="gripper_finger2_finger_tip_link"/>
        <axis xyz="0 1 0"/>
        <origin rpy="0.0 0.0 0.0" xyz="0.04303959807 0.0  0.03759940821"/>
        <limit lower="-3.14" upper="3.14" velocity="100.0" effort="5000"/><!--eff0.1-->
        <mimic joint="gripper_finger1_joint" multiplier="-1"/>
    </joint>

    <link name="gripper_finger1_finger_tip_link">
        <visual>
            <geometry>
                <mesh filename="package://robotiq_85_description/meshes/visual/robotiq_85_finger_tip_link.dae"/>
            </geometry>
        </visual>
        
        <collision>
            <origin xyz = "0.0 0.0 0.0" rpy = "-1.57079632679 0.0 0.0"/>
            <geometry>
                <mesh filename="package://robotiq_85_description/meshes/collision/robotiq_85_finger_tip_link.stl"/>
            </geometry>
        </collision>
        
        <inertial>
            <mass value="0.019555" />
            <origin xyz="0.0 0.0 0.0" />
            <inertia ixx = "0.000002" ixy = "0.000000" ixz = "0.000000" iyy = "0.000005" iyz = "0.000000" izz = "0.000006" />
        </inertial>
    </link> 

    <link name="gripper_finger2_finger_tip_link">
        <visual>
            <geometry>
                <mesh filename="package://robotiq_85_description/meshes/visual/robotiq_85_finger_tip_link.dae"/>
            </geometry>
        </visual>
        
        <collision>
            <origin xyz = "0.0 0.0 0.0" rpy = "-1.57079632679 0.0 0.0"/>
            <geometry>
                <mesh filename="package://robotiq_85_description/meshes/collision/robotiq_85_finger_tip_link.stl"/>
                <origin rpy="0.0 3.14 0.0"  xyz = "0.0 1.0 0.0"/>
            </geometry>
        </collision> 

        <inertial>
            <mass value="0.019555" />
            <!--<origin rpy = "0.0 3.14 0.0" xyz="0.0 0.0 0.0" />-->
            <inertia ixx = "0.000002" ixy = "0.000000" ixz = "0.000000" iyy = "0.000005" iyz = "0.000000" izz = "0.000006" />
        </inertial>
    </link>
</robot>