Fixes parsing of actuator parameters from dictionary (#265)

# Description

Quick fix for actuator config parsing.

## Type of change

- Bug fix (non-breaking change which fixes an issue)

## Checklist

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./orbit.sh --format`
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective or that my
feature works
- [ ] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [x] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

---------
Signed-off-by: David Hoeller <dhoeller@ethz.ch>
Co-authored-by: Mayank Mittal <mittalma@leggedrobotics.com>

source/extensions/omni.isaac.orbit/omni/isaac/orbit/actuators/actuator_base.py

@@ -216,8 +216,9 @@ class ActuatorBase(ABC):
                 param[:] = float(cfg_value)
             elif isinstance(cfg_value, dict):
                 # if dict, then parse the regular expression
-                indices, _, values = string_utils.resolve_matching_names_values(param, self.joint_names)
-                param[:, indices] = torch.tensor(values, device=self._device)
+                indices, _, values = string_utils.resolve_matching_names_values(cfg_value, self.joint_names)
+                # note: need to specify type to be safe (e.g. values are ints, but we want floats)
+                param[:, indices] = torch.tensor(values, dtype=torch.float, device=self._device)
             else:
                 raise TypeError(f"Invalid type for parameter value: {type(cfg_value)}. Expected float or dict.")
         elif default_value is not None:
@@ -226,7 +227,7 @@ class ActuatorBase(ABC):
                 param[:] = float(default_value)
             elif isinstance(default_value, torch.Tensor):
                 # if tensor, then use the same tensor for all joints
-                param[:] = default_value
+                param[:] = default_value.float()
             else:
                 raise TypeError(f"Invalid type for default value: {type(default_value)}. Expected float or Tensor.")
         else:

source/extensions/omni.isaac.orbit/test/assets/test_articulation.py

@@ -291,13 +291,41 @@ class TestArticulation(unittest.TestCase):
         torch.testing.assert_close(robot.actuators["body"].damping, expected_damping)
 
     def test_setting_gains_from_cfg(self):
-        """Test that gains are loaded from the configuration correctly."""
+        """Test that gains are loaded from the configuration correctly.
+
+        Note: We purposefully give one argument as int and other as float to check that it is handled correctly.
+        """
+        # Create articulation
+        robot_cfg = ArticulationCfg(
+            prim_path="/World/Robot",
+            spawn=sim_utils.UsdFileCfg(usd_path=f"{ISAAC_NUCLEUS_DIR}/Robots/Humanoid/humanoid_instanceable.usd"),
+            init_state=ArticulationCfg.InitialStateCfg(pos=(0.0, 0.0, 1.34)),
+            actuators={"body": ImplicitActuatorCfg(joint_names_expr=[".*"], stiffness=10, damping=2.0)},
+        )
+        robot = Articulation(cfg=robot_cfg)
+
+        # Play sim
+        self.sim.reset()
+
+        # Expected gains
+        expected_stiffness = torch.full((robot.root_view.count, robot.num_joints), 10.0, device=robot.device)
+        expected_damping = torch.full_like(expected_stiffness, 2.0)
+
+        # Check that gains are loaded from USD file
+        torch.testing.assert_close(robot.actuators["body"].stiffness, expected_stiffness)
+        torch.testing.assert_close(robot.actuators["body"].damping, expected_damping)
+
+    def test_setting_gains_from_cfg_dict(self):
+        """Test that gains are loaded from the configuration dictionary correctly.
+
+        Note: We purposefully give one argument as int and other as float to check that it is handled correctly.
+        """
         # Create articulation
         robot_cfg = ArticulationCfg(
             prim_path="/World/Robot",
             spawn=sim_utils.UsdFileCfg(usd_path=f"{ISAAC_NUCLEUS_DIR}/Robots/Humanoid/humanoid_instanceable.usd"),
             init_state=ArticulationCfg.InitialStateCfg(pos=(0.0, 0.0, 1.34)),
-            actuators={"body": ImplicitActuatorCfg(joint_names_expr=[".*"], stiffness=10.0, damping=2.0)},
+            actuators={"body": ImplicitActuatorCfg(joint_names_expr=[".*"], stiffness={".*": 10}, damping={".*": 2.0})},
         )
         robot = Articulation(cfg=robot_cfg)