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URDF Robot Base Joint Falls or Falls Apart

See original GitHub issue

Describe the bug When I import a generic URDF file the link above the base link falls through the simulation or falls off to the side. I’ve replicated this with more than one urdf file. Any help would be appreciated.

To Reproduce Steps to reproduce the behavior:

  1. Create a new blank scene
  2. Go to attached pi_robot.urdf file and import the robot as per the normal instructions
  3. Click the play button to start the scene

Expected behavior Robot should hold together link in the scene window. image

Actual undesired behavior Robot falls through the base link like this. image

Environment (please complete the following information, where applicable):

  • Unity Version: Unity 2020.3.14f1 & 2021.2.0b4
  • Unity machine OS + version: Windows 10 & Ubuntu 18.04
  • ROS machine OS + version: N/A
  • ROS–Unity communication: N/A
  • Branch or version: 0.5.0

URDF File `<robot name="pi_robot">

<!-- * * * Link Definitions * * * -->

<link name="base_link">
	<visual>
	    <origin xyz="0 0 0.0425" rpy="0 0 0"/>
		<geometry>
			<box size="0.32 0.26 0.085"/>
		</geometry>
		<material name="Cyan1">
       		<color rgba="0 0.9 0.9 1.0"/>
     	</material>
	</visual>	
</link>

<link name="base_laser">
	<visual>
	    <origin xyz="0 0 0" rpy="0 0 0"/>
		<geometry>
			<cylinder radius="0.025" length="0.07"/>
		</geometry>
		<material name="Black1">
       		<color rgba="0.2 0.2 0.2 1.0"/>
     	</material>
	</visual>	
</link>

<link name="cpu_link">
	<visual>
	    <origin xyz="0 0 0.035" rpy="0 0 0"/>
		<geometry>
			<box size="0.19 0.19 0.07"/>
		</geometry>
		<material name="Cyan2">
       		<color rgba="0 0.7 0.7 1.0"/>
     	</material>
	</visual>	
</link>

<link name="upper_base_link">
	<visual>
		<origin xyz="0 0 0.05" rpy="0 0 0"/>
		<geometry>
			<cylinder radius="0.085" length="0.10"/>
		</geometry>
     	<material name="Cyan3">
			<color rgba="0 0.5 0.5 0"/>
		</material>
   </visual>
</link>

<link name="torso_link">
	<visual>
		<origin xyz="0 0 0.12" rpy="0 0 0"/>
		<geometry>
			<cylinder radius="0.05" length="0.24"/>
		</geometry>
     	<material name="Yellow2">
			<color rgba="0.8 0.8 0 1.0"/>
		</material>
   </visual>
</link>

<link name="head_pan_link">
	<visual>
		<origin xyz="0 0 0.0225" rpy="0 0 0"/>
		<geometry>
			<box size="0.05 0.045 0.045"/>
		</geometry>
     	<material name="Green1">
			<color rgba="0 1 0 1.0"/>
		</material>
   </visual>
</link>

<link name="head_tilt_link">
	<visual>
		<origin xyz="0 0 0.02" rpy="0 0 0"/>
		<geometry>
			<box size="0.03 0.038 0.04"/>
		</geometry>
     	<material name="Green2">
			<color rgba="0.1 0.8 0 1.0"/>
		</material>
   </visual>
</link>

<link name="neck_link">
	<visual>
		<origin xyz="0 0 0.021" rpy="0 0 0"/>
		<geometry>
			<box size="0.03 0.05 0.042"/>
		</geometry>
     	<material name="Green3">
			<color rgba="0.1 0.5 0.1 1.0"/>
		</material>
   </visual>
</link>

<link name="head_link">
	<visual>
		<origin xyz="0 0 0.025" rpy="0 0 0"/>
		<geometry>
			<box size="0.03 0.07 0.11"/>
		</geometry>
     	<material name="Grey1">
			<color rgba="0.9 0.9 0.9 1.0"/>
		</material>
   </visual>
</link>

<link name="antenna_link">
	<visual>
		<origin xyz="0 0 0.035" rpy="0 0 0"/>
		<geometry>
			<cylinder radius="0.002" length="0.05"/>
		</geometry>
     	<material name="Grey3">
			<color rgba="0.8 0.8 0.8 1.0"/>
		</material>
   </visual>
</link>

<link name="left_shoulder_link">
	<visual>
		<origin xyz="0 0 0" rpy="0 0 0"/>
		<geometry>
			<box size="0.025 0.015 0.05"/>
		</geometry>
     	<material name="Green1">
			<color rgba="0 1 0 1.0"/>
		</material>
   </visual>
</link>

<link name="right_shoulder_link">
	<visual>
		<origin xyz="0 0 0" rpy="0 0 0"/>
		<geometry>
			<box size="0.025 0.015 0.05"/>
		</geometry>
     	<material name="Green1">
			<color rgba="0 1 0 1.0"/>
		</material>
   </visual>
</link>

<link name="left_shoulder_forward_link">
	<visual>
		<origin xyz="0 0 0" rpy="0 0 0"/>
		<geometry>
			<box size="0.03 0.05 0.03"/>
		</geometry>
     	<material name="Blue1">
			<color rgba="0 0 0.9 1.0"/>
		</material>
   </visual>
</link>
	
<link name="right_shoulder_forward_link">
	<visual>
		<origin xyz="0 0 0" rpy="0 0 0"/>
		<geometry>
			<box size="0.03 0.05 0.03"/>
		</geometry>
     	<material name="Blue1">
			<color rgba="0 0 0.9 1.0"/>
		</material>
   </visual>
</link>

<link name="left_shoulder_up_link">
	<visual>
		<origin xyz="0 0 0" rpy="1.57 0 0"/>
		<geometry>
			<box size="0.03 0.05 0.03"/>
		</geometry>
     	<material name="Blue2">
			<color rgba="0 0 0.7 1.0"/>
		</material>
   </visual>
</link>

<link name="right_shoulder_up_link">
	<visual>
		<origin xyz="0 0 0" rpy="1.57 0 0"/>
		<geometry>
			<box size="0.03 0.05 0.03"/>
		</geometry>
     	<material name="Blue2">
			<color rgba="0 0 0.7 1.0"/>
		</material>
   </visual>
</link>

<link name="left_upper_arm_link">
	<visual>
		<origin xyz="0 0 0" rpy="0 0 0"/>
		<geometry>
			<cylinder radius="0.0075" length="0.05"/>
		</geometry>
     	<material name="Grey1">
			<color rgba="0.9 0.9 0.9 1.0"/>
		</material>
   </visual>
</link>

<link name="right_upper_arm_link">
	<visual>
		<origin xyz="0 0 0" rpy="0 0 0"/>
		<geometry>
			<cylinder radius="0.0075" length="0.05"/>
		</geometry>
     	<material name="Grey1">
			<color rgba="0.9 0.9 0.9 1.0"/>
		</material>
   </visual>
</link>

<link name="left_elbow_link">
	<visual>
		<origin xyz="0 0 0" rpy="0 0 1.57"/>
		<geometry>
			<box size="0.035 0.035 0.05"/>
		</geometry>
     	<material name="Blue2">
			<color rgba="0 0 0.7 1.0"/>
		</material>
   </visual>
</link>

<link name="right_elbow_link">
	<visual>
		<origin xyz="0 0 0" rpy="0 0 1.57"/>
		<geometry>
			<box size="0.035 0.035 0.05"/>
		</geometry>
     	<material name="Blue2">
			<color rgba="0 0 0.7 1.0"/>
		</material>
   </visual>
</link>

<link name="left_lower_arm_link">
	<visual>
		<origin xyz="0 0 0" rpy="0 0 0"/>
		<geometry>
			<cylinder radius="0.0075" length="0.11"/>
		</geometry>
     	<material name="Grey1">
			<color rgba="0.9 0.9 0.9 1.0"/>
		</material>
   </visual>
</link>

<link name="right_lower_arm_link">
	<visual>
		<origin xyz="0 0 0" rpy="0 0 0"/>
		<geometry>
			<cylinder radius="0.0075" length="0.11"/>
		</geometry>
     	<material name="Grey1">
			<color rgba="0.9 0.9 0.9 1.0"/>
		</material>
   </visual>
</link>

<link name="left_wrist_link">
	<visual>
		<origin xyz="0 0 0" rpy="1.57 0 0"/>
		<geometry>
			<box size="0.03 0.05 0.03"/>
		</geometry>
     	<material name="Blue2">
			<color rgba="0 0 0.7 1.0"/>
		</material>
   </visual>
</link>

<link name="right_wrist_link">
	<visual>
		<origin xyz="0 0 0" rpy="1.57 0 0"/>
		<geometry>
			<box size="0.03 0.05 0.03"/>
		</geometry>
     	<material name="Blue2">
			<color rgba="0 0 0.7 1.0"/>
		</material>
   </visual>
</link>

<link name="left_hand_link">
	<visual>
		<origin xyz="0 0 0" rpy="0 0 0"/>
		<geometry>
			<box size="0.03 0.01 0.06"/>
		</geometry>
     	<material name="Grey1">
			<color rgba="0.7 0.7 0.7 1.0"/>
		</material>
   </visual>
</link>

<link name="right_hand_link">
	<visual>
		<origin xyz="0 0 0" rpy="0 0 0"/>
		<geometry>
			<box size="0.03 0.01 0.06"/>
		</geometry>
     	<material name="Grey1">
			<color rgba="0.9 0.9 0.9 1.0"/>
		</material>
   </visual>
</link>

<!-- * * * Joint Definitions * * * -->

<joint name="cpu_joint" type="fixed">
	<parent link="base_link"/>
	<child link="cpu_link"/>
	<origin xyz="0.025 0 0.085" rpy="0 0 0"/>
</joint>

<joint name="base_laser_joint" type="fixed">
	<parent link="base_link"/>
	<child link="base_laser"/>
	<origin xyz="0.18 0 0.07" rpy="0 0 0"/>
</joint>

<joint name="upper_base_joint" type="fixed">
	<parent link="cpu_link"/>
	<child link="upper_base_link"/>
	<origin xyz="0 0 0.07" rpy="0 0 0"/>
</joint>

<joint name="torso_joint" type="revolute">
	<parent link="upper_base_link"/>
	<child link="torso_link"/>
	<origin xyz="0 0 0.10" rpy="0 0 0"/>
	<axis xyz="0 0 1"/>
	<limit lower="-3.1416" upper="3.1416" effort="10" velocity="3"/>
</joint>

<joint name="head_pan_servo" type="fixed">
	<parent link="torso_link"/>
	<child link="head_pan_link"/>
	<origin xyz="0 0 0.225" rpy="0 0 0"/>
</joint>

<joint name="head_pan_joint" type="revolute">
	<parent link="head_pan_link"/>
	<child link="head_tilt_link"/>
	<origin xyz="0 0 0.045" rpy="0 0 0"/>
	<axis xyz="0 0 1"/>
	<limit lower="-3.1416" upper="3.1416" effort="10" velocity="3"/>
</joint>

<joint name="head_tilt_joint" type="revolute">
	<parent link="head_tilt_link"/>
	<child link="neck_link"/>
	<origin xyz="0 0 0.04" rpy="0 0 0"/>
	<axis xyz="0 1 0"/>
	<limit lower="-1.57" upper="1.57" effort="10" velocity="3"/>
</joint>

<joint name="neck_joint" type="fixed">
	<parent link="neck_link"/>
	<child link="head_link"/>
	<origin xyz="0.05 0 0.015" rpy="0 0 0"/>
</joint>

<joint name="antenna_joint" type="fixed">
	<parent link="head_link"/>
	<child link="antenna_link"/>
	<origin xyz="0.0 -0.025 0.065" rpy="0 0 0"/>
</joint>

<joint name="left_shoulder_joint" type="fixed">
	<parent link="torso_link"/>
	<child link="left_shoulder_link"/>
	<origin xyz="0 0.055 0.165" rpy="0 0 0"/>
</joint>

<joint name="right_shoulder_joint" type="fixed">
	<parent link="torso_link"/>
	<child link="right_shoulder_link"/>
	<origin xyz="0 -0.055 0.165" rpy="0 0 0"/>
</joint>

<joint name="left_shoulder_forward_joint" type="revolute">
	<parent link="left_shoulder_link"/>
	<child link="left_shoulder_forward_link"/>
	<origin xyz="0 0.025 0" rpy="0 0 0"/>
   	<limit lower="-1.57" upper="1.57" effort="10" velocity="3"/>
    <axis xyz="0 0 1"/>
</joint>

<joint name="right_shoulder_forward_joint" type="revolute">
	<parent link="right_shoulder_link"/>
	<child link="right_shoulder_forward_link"/>
	<origin xyz="0 -0.025 0" rpy="0 0 0"/>
   	<limit lower="-1.57" upper="1.57" effort="10" velocity="3"/>
    <axis xyz="0 0 1"/>
</joint>

<joint name="left_shoulder_up_joint" type="revolute">
	<parent link="left_shoulder_forward_link"/>
	<child link="left_shoulder_up_link"/>
	<origin xyz="0 0.04 -0.01" rpy="0 -0.707 0"/>
   	<limit lower="-1.57" upper="1.57" effort="10" velocity="3"/>
    <axis xyz="0 1 0"/>
</joint>

<joint name="right_shoulder_up_joint" type="revolute">
	<parent link="right_shoulder_forward_link"/>
	<child link="right_shoulder_up_link"/>
	<origin xyz="0 -0.04 -0.01" rpy="0 -0.707 0"/>
   	<limit lower="-1.57" upper="1.57" effort="10" velocity="3"/>
    <axis xyz="0 1 0"/>
</joint>

<joint name="left_upper_arm_joint" type="fixed">
	<parent link="left_shoulder_up_link"/>
	<child link="left_upper_arm_link"/>
	<origin xyz="0 0 -0.05" rpy="0 0 0"/>
</joint>

<joint name="right_upper_arm_joint" type="fixed">
	<parent link="right_shoulder_up_link"/>
	<child link="right_upper_arm_link"/>
	<origin xyz="0 0 -0.05" rpy="0 0 0"/>
</joint>

<joint name="left_elbow_joint" type="revolute">
	<parent link="left_upper_arm_link"/>
	<child link="left_elbow_link"/>
	<origin xyz="-0.005 0 -0.05" rpy="0 0 0"/>
   	<limit lower="-3.146" upper="3.146" effort="10" velocity="3"/>
    <axis xyz="0 0 1"/>
</joint>

<joint name="right_elbow_joint" type="revolute">
	<parent link="right_upper_arm_link"/>
	<child link="right_elbow_link"/>
	<origin xyz="-0.005 0 -0.05" rpy="0 0 0"/>
   	<limit lower="-3.146" upper="3.146" effort="10" velocity="3"/>
    <axis xyz="0 0 1"/>
</joint>

<joint name="left_lower_arm_joint" type="fixed">
	<parent link="left_elbow_link"/>
	<child link="left_lower_arm_link"/>
	<origin xyz="0 0 -0.08" rpy="0 0 0"/>
</joint>

<joint name="right_lower_arm_joint" type="fixed">
	<parent link="right_elbow_link"/>
	<child link="right_lower_arm_link"/>
	<origin xyz="0 0 -0.08" rpy="0 0 0"/>
</joint>

<joint name="left_wrist_joint" type="revolute">
	<parent link="left_lower_arm_link"/>
	<child link="left_wrist_link"/>
	<origin xyz="0 0 -0.05" rpy="0 0 0"/>
   	<limit lower="-1.57" upper="1.57" effort="10" velocity="3"/>
    <axis xyz="1 0 0"/>
</joint>

<joint name="right_wrist_joint" type="revolute">
	<parent link="right_lower_arm_link"/>
	<child link="right_wrist_link"/>
	<origin xyz="0 0 -0.05" rpy="0 0 0"/>
   	<limit lower="-1.57" upper="1.57" effort="10" velocity="3"/>
    <axis xyz="1 0 0"/>
</joint>

<joint name="left_hand_joint" type="fixed">
	<parent link="left_wrist_link"/>
	<child link="left_hand_link"/>
	<origin xyz="0 0 -0.055" rpy="0 0 0"/>
</joint>

<joint name="right_hand_joint" type="fixed">
	<parent link="right_wrist_link"/>
	<child link="right_hand_link"/>
	<origin xyz="0 0 -0.055" rpy="0 0 0"/>
</joint>

</robot>`

Issue Analytics

  • State:closed
  • Created 2 years ago
  • Comments:14 (6 by maintainers)

github_iconTop GitHub Comments

1reaction
bryceikedacommented, Jan 19, 2022

I created a quick video tutorial on how to get the spot moving using Unity and ROS.

https://www.youtube.com/watch?v=3MYeBxFVBHI

Let me know if it helps and if you have any suggestions for improvement. In the description, I added an edit on how I get the spot movement smoother.

0reactions
ryangoh206commented, Jan 19, 2022

Ok thanks @bryceikeda ! I will take a look at the video.

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