Tunes rewards for A1 locomotion environment (#271)

# Description

This MR tunes the A1 locomotion environment.

Fixes # (issue)

## Type of change

- New feature (non-breaking change which adds functionality)

## 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

source/extensions/omni.isaac.orbit/omni/isaac/orbit/assets/config/unitree.py

@@ -60,6 +60,7 @@ UNITREE_A1_CFG = ArticulationCfg(
             velocity_limit=21.0,
             stiffness=25.0,
             damping=0.5,
+            friction=0.0,
         ),
     },
 )

source/extensions/omni.isaac.orbit_tasks/omni/isaac/orbit_tasks/locomotion/velocity/config/unitree_a1/flat_env_cfg.py

@@ -5,29 +5,18 @@
 
 from omni.isaac.orbit.utils import configclass
 
-from omni.isaac.orbit_tasks.locomotion.velocity.velocity_env_cfg import LocomotionVelocityRoughEnvCfg
-
-##
-# Pre-defined configs
-##
-from omni.isaac.orbit.assets.config.unitree import UNITREE_A1_CFG  # isort: skip
+from .rough_env_cfg import UnitreeA1RoughEnvCfg
 
 
 @configclass
-class UnitreeA1FlatEnvCfg(LocomotionVelocityRoughEnvCfg):
+class UnitreeA1FlatEnvCfg(UnitreeA1RoughEnvCfg):
     def __post_init__(self):
         # post init of parent
         super().__post_init__()
 
-        # switch robot to unitree a1
-        self.scene.robot = UNITREE_A1_CFG.replace(prim_path="{ENV_REGEX_NS}/Robot")
-        # reduce action scale
-        self.actions.joint_pos.scale = 0.25
         # override rewards
         self.rewards.flat_orientation_l2.weight = -2.5
         self.rewards.feet_air_time.weight = 1.0
-        # self.rewards.dof_torques_l2.weight = -2.0e-4
-        # self.rewards.dof_pos_limits.weight = -10.0
 
         # change terrain to flat
         self.scene.terrain.terrain_type = "plane"
@@ -37,14 +26,6 @@ class UnitreeA1FlatEnvCfg(LocomotionVelocityRoughEnvCfg):
         self.observations.policy.height_scan = None
         # no terrain curriculum
         self.curriculum.terrain_levels = None
-        # disable pushing for now
-        self.randomization.push_robot = None
-        self.randomization.add_base_mass = None
-
-        # change body and joint names
-        # TODO: Change to .*foot once we make a new USD for the robot
-        self.rewards.feet_air_time.params["sensor_cfg"].body_names = ".*calf"
-        self.rewards.undesired_contacts.params["sensor_cfg"].body_names = [".*thigh", ".*hip"]
 
 
 class UnitreeA1FlatEnvCfg_PLAY(UnitreeA1FlatEnvCfg):

source/extensions/omni.isaac.orbit_tasks/omni/isaac/orbit_tasks/locomotion/velocity/config/unitree_a1/rough_env_cfg.py

@@ -18,22 +18,40 @@ class UnitreeA1RoughEnvCfg(LocomotionVelocityRoughEnvCfg):
     def __post_init__(self):
         # post init of parent
         super().__post_init__()
-        # switch robot to unitree-a1
+
         self.scene.robot = UNITREE_A1_CFG.replace(prim_path="{ENV_REGEX_NS}/Robot")
+        # scale down the terrains because the robot is small
+        self.scene.terrain.terrain_generator.sub_terrains["boxes"].grid_height_range = (0.025, 0.1)
+        self.scene.terrain.terrain_generator.sub_terrains["random_rough"].noise_range = (0.01, 0.06)
+        self.scene.terrain.terrain_generator.sub_terrains["random_rough"].noise_step = 0.01
+
         # reduce action scale
         self.actions.joint_pos.scale = 0.25
-        # override rewards
-        # self.rewards.dof_torques_l2.weight = -2.0e-4
-        # self.rewards.dof_pos_limits.weight = -10.0
 
-        # disable pushing for now
+        # randomization
         self.randomization.push_robot = None
         self.randomization.add_base_mass = None
+        self.randomization.reset_robot_joints.params["position_range"] = (1.0, 1.0)
+        self.randomization.reset_base.params = {
+            "pose_range": {"x": (-0.5, 0.5), "y": (-0.5, 0.5), "yaw": (-3.14, 3.14)},
+            "velocity_range": {
+                "x": (0.0, 0.0),
+                "y": (0.0, 0.0),
+                "z": (0.0, 0.0),
+                "roll": (0.0, 0.0),
+                "pitch": (0.0, 0.0),
+                "yaw": (0.0, 0.0),
+            },
+        }
 
-        # change body and joint names
-        # TODO: Change to .*foot once we make a new USD for the robot
-        self.rewards.feet_air_time.params["sensor_cfg"].body_names = ".*calf"
-        self.rewards.undesired_contacts.params["sensor_cfg"].body_names = [".*thigh", ".*hip"]
+        # rewards
+        self.rewards.feet_air_time.params["sensor_cfg"].body_names = ".*_calf"
+        self.rewards.feet_air_time.weight = 0.01
+        self.rewards.undesired_contacts = None
+        self.rewards.dof_torques_l2.weight = -0.0002
+        self.rewards.track_lin_vel_xy_exp.weight = 1.5
+        self.rewards.track_ang_vel_z_exp.weight = 0.75
+        self.rewards.dof_acc_l2.weight = -2.5e-7
 
 
 @configclass