seperate velocity_limits at actuator vs simulation level

Author: jtigue-bdai

Diff for: source/isaaclab/isaaclab/actuators/actuator_base.py

@@ -110,6 +110,8 @@ def __init__(
         # note: for velocity limits, we don't have USD parameter, so default is infinity
         self.effort_limit = self._parse_joint_parameter(self.cfg.effort_limit, effort_limit)
         self.velocity_limit = self._parse_joint_parameter(self.cfg.velocity_limit, velocity_limit)
+        self.effort_limit_sim = self._parse_joint_parameter(self.cfg.effort_limit_sim, effort_limit)
+        self.velocity_limit_sim = self._parse_joint_parameter(self.cfg.velocity_limit_sim, velocity_limit)
 
         # create commands buffers for allocation
         self.computed_effort = torch.zeros(self._num_envs, self.num_joints, device=self._device)

Diff for: source/isaaclab/isaaclab/actuators/actuator_cfg.py

@@ -33,13 +33,28 @@ class ActuatorBaseCfg:
     effort_limit: dict[str, float] | float | None = None
     """Force/Torque limit of the joints in the group. Defaults to None.
 
-    If None, the limit is set to the value specified in the USD joint prim.
+    This limit is used to clip the computed torque sent to the simulation. If None, the limit is set to the value
+    specified in the USD joint prim.
     """
 
     velocity_limit: dict[str, float] | float | None = None
     """Velocity limit of the joints in the group. Defaults to None.
 
-    If None, the limit is set to the value specified in the USD joint prim.
+    This limit is used by the actuator model. If None, the limit is set to the value specified in the USD joint prim.
+    """
+
+    effort_limit_sim: dict[str, float] | float | None = None
+    """Force/Torque limit of the joints in the group that will be propagated to the simulation physics solver. Defaults to None.
+
+    If None, the limit is set to the value specified in the USD joint prim. The simulation effort limits prevent
+    computed torques from exceeding. If effort limits are too tight issues with solver convergence may occur.
+    """
+
+    velocity_limit_sim: dict[str, float] | float | None = None
+    """Velocity limit of the joints in the group that will be propagated to the simulation physics solver. Defaults to None.
+
+    If None, the limit is set to the value specified in the USD joint prim. Resulting solver solutions will constrain
+    velocities by these limits. If velocity limits are too tight issues with solver convergence may occur.
     """
 
     stiffness: dict[str, float] | float | None = MISSING

Diff for: source/isaaclab/isaaclab/assets/articulation/articulation.py

@@ -1342,17 +1342,17 @@ def _process_actuators_cfg(self):
                 # the gains and limits are set into the simulation since actuator model is implicit
                 self.write_joint_stiffness_to_sim(actuator.stiffness, joint_ids=actuator.joint_indices)
                 self.write_joint_damping_to_sim(actuator.damping, joint_ids=actuator.joint_indices)
-                self.write_joint_effort_limit_to_sim(actuator.effort_limit, joint_ids=actuator.joint_indices)
-                self.write_joint_velocity_limit_to_sim(actuator.velocity_limit, joint_ids=actuator.joint_indices)
+                self.write_joint_effort_limit_to_sim(actuator.effort_limit_sim, joint_ids=actuator.joint_indices)
+                self.write_joint_velocity_limit_to_sim(actuator.velocity_limit_sim, joint_ids=actuator.joint_indices)
                 self.write_joint_armature_to_sim(actuator.armature, joint_ids=actuator.joint_indices)
                 self.write_joint_friction_to_sim(actuator.friction, joint_ids=actuator.joint_indices)
             else:
                 # the gains and limits are processed by the actuator model
                 # we set gains to zero, and torque limit to a high value in simulation to avoid any interference
                 self.write_joint_stiffness_to_sim(0.0, joint_ids=actuator.joint_indices)
                 self.write_joint_damping_to_sim(0.0, joint_ids=actuator.joint_indices)
-                self.write_joint_effort_limit_to_sim(1.0e9, joint_ids=actuator.joint_indices)
-                self.write_joint_velocity_limit_to_sim(actuator.velocity_limit, joint_ids=actuator.joint_indices)
+                self.write_joint_effort_limit_to_sim(actuator.effort_limit_sim, joint_ids=actuator.joint_indices)
+                self.write_joint_velocity_limit_to_sim(actuator.velocity_limit_sim, joint_ids=actuator.joint_indices)
                 self.write_joint_armature_to_sim(actuator.armature, joint_ids=actuator.joint_indices)
                 self.write_joint_friction_to_sim(actuator.friction, joint_ids=actuator.joint_indices)
             # Store the actual default stiffness and damping values for explicit and implicit actuators (not written the sim)

Diff for: source/isaaclab/test/assets/test_articulation.py

@@ -45,6 +45,8 @@ def generate_articulation_cfg(
     damping: float | None = 2.0,
     vel_limit: float | None = 100.0,
     effort_limit: float | None = 400.0,
+    vel_limit_sim: float | None = None,
+    effort_limit_sim: float | None = None,
 ) -> ArticulationCfg:
     """Generate an articulation configuration.
 
@@ -77,6 +79,8 @@ def generate_articulation_cfg(
                     joint_names_expr=[".*"],
                     effort_limit=effort_limit,
                     velocity_limit=vel_limit,
+                    effort_limit_sim=effort_limit_sim,
+                    velocity_limit_sim=vel_limit_sim,
                     stiffness=0.0,
                     damping=10.0,
                 ),
@@ -900,7 +904,7 @@ def test_setting_gains_from_cfg_dict(self):
                         torch.testing.assert_close(articulation.actuators["body"].stiffness, expected_stiffness)
                         torch.testing.assert_close(articulation.actuators["body"].damping, expected_damping)
 
-    def test_setting_velocity_limits(self):
+    def test_setting_velocity_sim_limits(self):
         """Test that velocity limits are loaded form the configuration correctly."""
         for num_articulations in (1, 2):
             for device in ("cuda:0", "cpu"):
@@ -911,7 +915,7 @@ def test_setting_velocity_limits(self):
                         ) as sim:
                             sim._app_control_on_stop_handle = None
                             articulation_cfg = generate_articulation_cfg(
-                                articulation_type="single_joint", vel_limit=limit, effort_limit=limit
+                                articulation_type="single_joint", vel_limit_sim=limit, effort_limit_sim=limit
                             )
                             articulation, _ = generate_articulation(
                                 articulation_cfg=articulation_cfg, num_articulations=num_articulations, device=device
@@ -928,7 +932,7 @@ def test_setting_velocity_limits(self):
                                 )
                                 # Check that gains are loaded from USD file
                                 torch.testing.assert_close(
-                                    articulation.actuators["joint"].velocity_limit, expected_velocity_limit
+                                    articulation.actuators["joint"].velocity_limit_sim, expected_velocity_limit
                                 )
                                 torch.testing.assert_close(
                                     articulation.data.joint_velocity_limits, expected_velocity_limit