Hi,
I have the UR5e that has a tool at the flange and it is connected with one prismatic and three perpendicular angular joints.
I want the joint not to move when the episode starts even if it bumps into the ground. When I check the joint values, the tool does not bump into the ground, the four joints’ poses are (almost) the same as the initial setting. However, when the joint hits the ground, the joint values are changed.
Here is an example figure and value.
robot_dof_pos:
tensor([[-5.2402e-01, -7.2713e-01, 1.0427e+00, -1.7659e+00, -1.5033e+00,
1.6473e+00, 9.5430e-02, 1.2001e+00, 8.1442e-05, -7.2722e-02],
[-6.0413e-01, -6.8301e-01, 1.1180e+00, -1.7992e+00, -1.3264e+00,
1.5484e+00, 9.0777e-02, 1.2002e+00, -7.6110e-05, -2.2959e-01],
[-6.7578e-01, -8.0045e-01, 1.1788e+00, -1.8395e+00, -1.5079e+00,
1.5020e+00, 9.8078e-02, 1.2001e+00, -1.5564e-05, -1.0823e-01]],
device='cuda:0')
The top image is the robot of the middle one and the robot_dof_pos is the corresponding value with the image. I initialized that the 7th joint equals 0.09 and the 8th joint equals 1.2 then, the rest 9th, and 10th are 0.
I think the initial value that I put on the methods works well because the initialize value keeps until the robots’ tool hits the ground.
Does it seem the below robot class that I use in the environment code is wrong? I input extremely high stiffness, damping, and max force value but it did not work.
class UR5eTool(Robot):
def __init__(
self,
prim_path: str,
name: Optional[str] = "ur5e_tool",
usd_path: Optional[str] = None,
translation: Optional[torch.tensor] = None,
orientation: Optional[torch.tensor] = None,
rgb_cam_prim_name: Optional[str] = None, ### BSH
depth_cam_prim_name: Optional[str] = None, ### BSH
) -> None:
"""[summary]
"""
self._usd_path = usd_path
self._name = name
self._position = torch.tensor([0, 0.0, 0.0]) if translation is None else translation
# self._orientation = torch.tensor([0.0, 0.0, 0.0, 1.0]) if orientation is None else orientation
self._orientation = torch.tensor([1.0, 0.0, 0.0, 0.0]) if orientation is None else orientation
if self._usd_path is None:
isaac_root_path = "/home/bak/.local/share/ov/pkg/isaac_sim-2022.2.1/"
if isaac_root_path is None:
carb.log_error("Could not find Isaac Sim assets folder")
self._usd_path = isaac_root_path + "OmniIsaacGymEnvsAILAB/omniisaacgymenvs/skrl_examples/moving_target_point_cloud/ur5e/usd/ur5e_tool.usd"
# self._usd_path = isaac_root_path + "OmniIsaacGymEnvsAILAB/omniisaacgymenvs/skrl_examples/moving_target_point_cloud/ur5e/usd/ur5e_tool_wo_rigidbody.usd"
add_reference_to_stage(self._usd_path, prim_path)
super().__init__(
prim_path=prim_path,
name=name,
translation=self._position,
orientation=self._orientation,
articulation_controller=None,
)
dof_paths = [
"base_link/shoulder_pan_joint",
"shoulder_link/shoulder_lift_joint",
"upper_arm_link/elbow_joint",
"forearm_link/wrist_1_joint",
"wrist_1_link/wrist_2_joint",
"wrist_2_link/wrist_3_joint",
"wrist_3_link/wrist_3_link_flange_prismatic",
"flange_tool_rot_x/flange_revolute_x",
"flange_tool_rot_z/flange_revolute_z",
"flange_tool_rot_y/flange_revolute_y",
]
drive_type = ["angular"] * 6 + ["linear"] + ["angular"] * 3
default_dof_pos = [math.degrees(x) for x in [0.0, -1.75, 1.05, -1.57, -1.57, 1.57,
0.0, 0.0, 0.0, 0.0]]
stiffness = [400*np.pi/180] * 6
stiffness.extend([1000] * 4)
damping = [80*np.pi/180] * 6
damping.extend([10000] * 4)
max_force = [87, 87, 87, 12, 12, 12,
100, 100, 100, 100]
max_velocity = [math.degrees(x) for x in [2.175, 2.175, 2.175, 2.61, 2.61, 2.61,
2.61, 2.61, 2.61, 2.61]]
for i, dof in enumerate(dof_paths):
if i > 5: continue
set_drive(
prim_path=f"{self.prim_path}/{dof}",
drive_type=drive_type[i],
target_type="position",
target_value=default_dof_pos[i],
stiffness=stiffness[i],
damping=damping[i],
max_force=max_force[i]
)
PhysxSchema.PhysxJointAPI(get_prim_at_path(f"{self.prim_path}/{dof}")).CreateMaxJointVelocityAttr().Set(max_velocity[i])
I also attached my USD file.
usd.zip (3.4 MB)