NVlabs
Motion Generation seems not use my specified EEF link
Hi,
I'm trying to do motion generation based on moving_gripper setup, in the case that there's no whole robot arm planning, so the final generated trajectory should look like a straight line. The issue is, if I choose to use panda_hand as my eef_link (which does have a collision body), the final trajectory looks good to me as in the first image; However, if I choose to use panda_hand_tcp as my eef_link (which doesn't have a collision body), the final trajectory looks really weird as in the second one. Then if I still use panda_hand_tcp as my eef_link and double the distance between panda_hand_tcp and panda_hand in my urdf file, the trajectory is even more twisted as in the third figure. From observation, it seems all three of them are planned based on panda_hand rather than the EEF I specified, and then because there are some twisting during the trajectory, so the fixed distance between the panda_hand and the EEF I specified will enlarge this twist and that's why it looks like that.
That's why I'm wondering if the motion generation really changes when I specify the ee_link in the .yml file. I also attached my moving_gripper.yml and moving_gripper.urdf files here. Could you please let me know is there any problem with it? Thank you!
moving_gripper.yml
robot_cfg:
kinematics:
usd_path: null
usd_robot_root: null
isaac_usd_path: ""
usd_flip_joints: {}
usd_flip_joint_limits: []
urdf_path: "robot/franka_description/moving_gripper_2.urdf"
asset_root_path: "robot/franka_description"
base_link: "base"
ee_link: "panda_hand_tcp"
link_names: null
lock_joints: null
extra_links: null
collision_link_names: ["panda_hand"] # List[str]
collision_spheres:
panda_hand:
- "center": [0.0, -0.075, 0.01]
"radius": 0.023
- "center": [0.0, -0.045, 0.01]
"radius": 0.023
- "center": [0.0, -0.015, 0.01]
"radius": 0.023
- "center": [0.0, 0.015, 0.01]
"radius": 0.023
- "center": [0.0, 0.045, 0.01]
"radius": 0.023
- "center": [0.0, 0.075, 0.01]
"radius": 0.023
- "center": [0.0, -0.08, 0.03]
"radius": 0.022
- "center": [0.0, -0.045, 0.03]
"radius": 0.022
- "center": [0.0, -0.015, 0.03]
"radius": 0.022
- "center": [0.0, 0.015, 0.03]
"radius": 0.022
- "center": [0.0, 0.045, 0.03]
"radius": 0.022
- "center": [0.0, 0.08, 0.03]
"radius": 0.022
- "center": [0.0, -0.08, 0.045]
"radius": 0.022
- "center": [0.0, -0.045, 0.045]
"radius": 0.022
- "center": [0.0, -0.015, 0.045]
"radius": 0.022
- "center": [0.0, 0.015, 0.045]
"radius": 0.022
- "center": [0.0, 0.045, 0.045]
"radius": 0.022
- "center": [0.0, 0.08, 0.045]
"radius": 0.022
collision_sphere_buffer: 0.005
extra_collision_spheres: {}
self_collision_ignore: {}
self_collision_buffer: {} # Dict[str, float]
use_global_cumul: True
mesh_link_names: null # List[str]
cspace:
joint_names: ["x_joint", "y_joint", "z_joint", "rx_joint", "ry_joint", "rz_joint", "panda_hand_tcp_joint"] # List[str]
retract_config: [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0] # List[float]
null_space_weight: [1,1,1,1,1,1,1] # List[str]
cspace_distance_weight: [1,1,1,1,1,1,1] # List[str]
max_jerk: 500.0
max_acceleration: 150.0
URDF
<?xml version="1.0"?>
<robot name="moving_gripper">
<link name="base"/>
<link name="base1"/>
<link name="base2"/>
<link name="base3"/>
<link name="base4"/>
<link name="base5"/>
<joint name="x_joint" type="prismatic">
<origin xyz="0 0 0" rpy="0 0 0"/>
<parent link="base"/>
<child link="base1"/>
<axis xyz="1 0 0"/>
<limit effort="12" lower="-2.8973" upper="2.8973" velocity="2.6100"/>
</joint>
<joint name="y_joint" type="prismatic">
<origin xyz="0 0 0" rpy="0 0 0"/>
<parent link="base1"/>
<child link="base2"/>
<axis xyz="0 1 0"/>
<limit effort="12" lower="-2.8973" upper="2.8973" velocity="2.6100"/>
</joint>
<joint name="z_joint" type="prismatic">
<origin xyz="0 0 0" rpy="0 0 0"/>
<parent link="base2"/>
<child link="base3"/>
<axis xyz="0 0 1"/>
<limit effort="12" lower="-2.8973" upper="2.8973" velocity="2.6100"/>
</joint>
<joint name="rx_joint" type="revolute">
<origin xyz="0 0 0" rpy="0 0 0"/>
<parent link="base3"/>
<child link="base4"/>
<axis xyz="1 0 0"/>
<limit effort="12" lower="-2.8973" upper="2.8973" velocity="2.6100"/>
</joint>
<joint name="ry_joint" type="revolute">
<origin xyz="0 0 0" rpy="0 0 0"/>
<parent link="base4"/>
<child link="base5"/>
<axis xyz="0 1 0"/>
<limit effort="12" lower="-2.8973" upper="2.8973" velocity="2.6100"/>
</joint>
<joint name="rz_joint" type="revolute">
<origin xyz="0 0 0" rpy="0 0 0"/>
<parent link="base5"/>
<child link="panda_hand"/>
<axis xyz="0 0 1"/>
<limit effort="12" lower="-2.8973" upper="2.8973" velocity="2.6100"/>
</joint>
<link name="panda_hand">
<visual>
<origin xyz="0.0 0.0 0.0" rpy="0.0 0 0"/>
<geometry>
<mesh filename="file:///home/ryf/AugImagination/robot/meshes/visual/hand.dae"/>
</geometry>
</visual>
<collision>
<origin xyz="0.0 0.0 0.0"/>
<geometry>
<mesh filename="file:///home/ryf/AugImagination/robot/meshes/collision/hand.obj"/>
</geometry>
</collision>
<inertial>
<mass value="0.73"/>
<origin xyz="-0.01 0 0.03"/>
<inertia ixx="0.001" ixy="0" ixz="0" iyy="0.0025" iyz="0" izz="0.0017"/>
</inertial>
</link>
<link name="panda_hand_tcp"/>
<joint name="panda_hand_tcp_joint" type="fixed">
<origin rpy="0 0 0" xyz="0 0 0.1034"/>
<parent link="panda_hand"/>
<child link="panda_hand_tcp"/>
</joint>
</robot>
