Hey there i am new to gazebo and trying out all tutorials mentioned on Gazebo's wiki page. I am facing problem particularly in picking up a object in Gazebo. the object seems to slip from the gripper's grip . I tried to increase friction on both tip and cube but same thing was happening. I also used tag but that also didn't help. if anyone could tell error in my attached code , it would be appreciated. Thank you

<?xml version="1.0"?> -0.15 0.0 0.5 0 0 0 0 0 -0.5 0 0 0 0.01 0 0 0.01 0 0.01 10.0 0.2 0.2 1.0 0.2 0.2 1.0 0.0 0.0 0.05 0 0 0 0.01 0 0 0.01 0 0.01 0.5 0.1 0.2 0.1 0.1 0.2 0.1 0.1 0.2 0.05 0 0 -0.78539 0.01 0 0 0.01 0 0.01 0.1 0.1 0.3 0.1 0.1 0.3 0.1 0.336 0.3 0.05 0 0 1.5707 0.01 0 0 0.01 0 0.01 0.1 0.1 0.2 0.1 0.4 0.4 0.6 0.6

    <visual name="visual">
        <geometry>
            <box>
                <size>0.1 0.2 0.1</size>
            </box>gedit ~/.gazebo/models/my_gripper/simple_gripper.sdf
        </geometry>
        <material>
            <script>Gazebo/Blue</script>
        </material>
    </visual>
</link>
<link name="right_finger">
    <pose>0.1 -0.2 0.05 0 0 .78539</pose>
    <inertial>
        <inertia>
            <ixx>0.01</ixx>
            <ixy>0</ixy>
            <ixz>0</ixz>
            <iyy>0.01</iyy>
            <iyz>0</iyz>
            <izz>0.01</izz>
        </inertia>
        <mass>0.1</mass>
    </inertial>
    <collision name="collision">
        <geometry>
            <box>
                <size>0.1 0.3 0.1</size>
            </box>
        </geometry>
    </collision>
    <visual name="visual">
        <geometry>
            <box>
                <size>0.1 0.3 0.1</size>
            </box>
        </geometry>
        <material>
            <script>Gazebo/Green</script>
        </material>
    </visual>
</link>
<link name="right_finger_tip">
    <pose>0.336 -0.3 0.05 0 0 1.5707</pose>
    <inertial>
        <inertia>
            <ixx>0.01</ixx>
            <ixy>0</ixy>
            <ixz>0</ixz>
            <iyy>0.01</iyy>
            <iyz>0</iyz>
            <izz>0.01</izz>
        </inertia>
        <mass>0.1</mass>
    </inertial>
    <collision name="collision">
        <geometry>
            <box>
                <size>0.1 0.2 0.1</size>
            </box>
        </geometry>

0.4 0.4 0.6 0.6

    <visual name="visual">
        <geometry>
            <box>
                <size>0.1 0.2 0.1</size>
            </box>
        </geometry>
        <material>
            <script>Gazebo/Green</script>
        </material>
    </visual>
</link>

0 -0.15 0 0 0 0 left_finger palm 0.4 -0.4 0 0 1

0 0.1 0 0 0 0 leftfingertip left_finger 0.4 -0.4 0 0 1

0 0.15 0 0 0 0 rightfinger palm -0.4 0.4 0 0 1 <joint name="rightfingertip" type="revolute"> 0 0.1 0 0 0 0 rightfingertip rightfinger -0.4 0.4 0 0 1 palm riser 0 0.9 0 0 1

20 40 1 rightfingertip leftfingertip palm false