Isaac Sim Version
4.2.0
Operating System
Ubuntu 22.04
GPU Information
- Model: RTX 4080
- Driver Version: 570.124.06
I tried modifying start_isaac_sim_franka.py to load my own robot and implement the Isaac Manipulator example. However, my ROS2 Publish Joint States cannot recognize the robot and returning the error:
[Error] [omni.graph.core.plugin] /ActionGraph/PublishJointState: [/ActionGraph] Prim is not an articulation.
Using the Filter, I can see the articulation, joints, and drivers as the picture below. I also tried loading the robot directly via URDF in the UI and reconfiguring the targetPrim, but it still returns “Prim is not an articulation.”
Can anyone help me resolve this issue?
Error Messages
[Error] [omni.graph.core.plugin] /ActionGraph/PublishJointState: [/ActionGraph] Prim is not an articulation.
Screenshots or Videos
My Python Script
from isaacsim import SimulationApp
CONFIG = {"renderer": "RayTracedLighting", "headless": False}
simulation_app = SimulationApp(CONFIG)
from omni.isaac.core.utils import extensions
extensions.enable_extension("omni.isaac.ros2_bridge")
from omni.isaac.core import SimulationContext
simulation_context = SimulationContext(stage_units_in_meters=1.0)
# loading the robot USD
from omni.isaac.core.utils import prims, rotations
from pxr import Gf
import omni.isaac.core.utils
import numpy as np
ROBOT_STAGE_PATH = "/tcr6"
prims.create_prim(ROBOT_STAGE_PATH, "Xform",
position=np.array([0, -0.64, 0]),
orientation=rotations.gf_rotation_to_np_array(Gf.Rotation(Gf.Vec3d(0, 0, 1), -90)),
usd_path="/home/user/Documents/IsaacManipulatorProject/tcr6/urdf/tcr6/tcr6.usd",
)
# update view after loading
simulation_app.update()
# set ros domain ID
import os
try:
ros_domain_id = int(os.environ["ROS_DOMAIN_ID"])
except ValueError:
ros_domain_id = 0
except KeyError:
ros_domain_id = 0
# create an action graph with ROS component nodes
import omni.graph.core as og
GRAPH_PATH = "/ActionGraph"
try:
# setting input and output for nodes
og_keys_set_values = [
# ROS2 Context
("Context.inputs:domain_id", ros_domain_id),
# Articulation Controller Node
("ArticulationController.inputs:robotPath", ROBOT_STAGE_PATH), # Set the /TCR6_V600 target prim to Articulation Controller node
# ROS2 Publish Joint State
("PublishJointState.inputs:topicName", "isaac_joint_states"),
# ROS2 Subscribe Joint State
("SubscribeJointState.inputs:topicName", "isaac_joint_commands"),
]
# create nodes
og.Controller.edit(
# create ActionGraph tree node and execution
{"graph_path": GRAPH_PATH, "evaluator_name": "execution"},
{
# create and set input and output for nodes
og.Controller.Keys.CREATE_NODES: [
("OnImpulseEvent", "omni.graph.action.OnImpulseEvent"), # On Impulse Event
("ReadSimTime", "omni.isaac.core_nodes.IsaacReadSimulationTime"), # Isaac Read Simulation Time
("Context", "omni.isaac.ros2_bridge.ROS2Context"), # ROS2 COntext
("PublishJointState", "omni.isaac.ros2_bridge.ROS2PublishJointState"), # ROS2 Publish Joint State
("SubscribeJointState", "omni.isaac.ros2_bridge.ROS2SubscribeJointState",), # ROS2 Subscribe Joint State
("ArticulationController", "omni.isaac.core_nodes.IsaacArticulationController",), # Articulation Controller
("PublishClock", "omni.isaac.ros2_bridge.ROS2PublishClock"), # ROS2 Publish Clock
],
# setting nodes connect
og.Controller.Keys.CONNECT: [
# ("previouse node output", "connect to node input")
# On Impulse Event Node connect to ...
("OnImpulseEvent.outputs:execOut", "PublishJointState.inputs:execIn"),
("OnImpulseEvent.outputs:execOut", "SubscribeJointState.inputs:execIn"),
("OnImpulseEvent.outputs:execOut", "PublishClock.inputs:execIn"),
("OnImpulseEvent.outputs:execOut", "ArticulationController.inputs:execIn",),
# ROS2 Context Node connect to ...
("Context.outputs:context", "PublishJointState.inputs:context"),
("Context.outputs:context", "SubscribeJointState.inputs:context"),
("Context.outputs:context", "PublishClock.inputs:context"),
# Isaac Read Simulation Time Node connect to ...
("ReadSimTime.outputs:simulationTime", "PublishJointState.inputs:timeStamp",),
("ReadSimTime.outputs:simulationTime", "PublishClock.inputs:timeStamp"),
# ROS2 Subscribe Joint State Node connect to ...
("SubscribeJointState.outputs:jointNames", "ArticulationController.inputs:jointNames",),
("SubscribeJointState.outputs:positionCommand", "ArticulationController.inputs:positionCommand",),
("SubscribeJointState.outputs:velocityCommand", "ArticulationController.inputs:velocityCommand",),
("SubscribeJointState.outputs:effortCommand", "ArticulationController.inputs:effortCommand",),
],
# ActionGraph inilization
og.Controller.Keys.SET_VALUES: og_keys_set_values,
},
)
except Exception as e:
print(e)
# update view after add nodes in ActionGraph
simulation_app.update()
# setting the /Franka target prim to Publish JointState node
from omni.isaac.core.utils.prims import set_targets
from omni.isaac.core.utils import stage
set_targets(prim=stage.get_current_stage().GetPrimAtPath("/ActionGraph/PublishJointState"), attribute="inputs:targetPrim", target_prim_paths=[ROBOT_STAGE_PATH])
# update view after setting ROS2 Publish Joint State and
simulation_app.update()
# need to initialize physics getting any articulation..etc
simulation_context.initialize_physics()
# play simulation
simulation_context.play()
# do somthing while simulation
while simulation_app.is_running():
# run with a fixed step size
simulation_context.step(render=True)
# tick the Publish/Subscribe JointState, Publish TF and Publish Clock nodes each frame via Impulse signal of On Impulse Event Node
og.Controller.set(og.Controller.attribute("/ActionGraph/OnImpulseEvent.state:enableImpulse"), True)
# stop simulation
simulation_context.stop()
# close Isaac Sim
simulation_app.close()