Improves Spot gait reward (#451)

Adds a new reward for Spot's gait, which is based on the foot body name

## 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
`./isaaclab.sh --format`
- [x] 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 run all the tests with `./isaaclab.sh --test` and they pass
- [ ] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [ ] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

source/extensions/omni.isaac.lab_tasks/omni/isaac/lab_tasks/manager_based/locomotion/velocity/config/spot/agents/rsl_rl_cfg.py

@@ -15,7 +15,7 @@ from omni.isaac.lab_tasks.utils.wrappers.rsl_rl import (
 @configclass
 class SpotFlatPPORunnerCfg(RslRlOnPolicyRunnerCfg):
     num_steps_per_env = 24
-    max_iterations = 35000
+    max_iterations = 20000
     save_interval = 50
     experiment_name = "spot_flat"
     empirical_normalization = False

source/extensions/omni.isaac.lab_tasks/omni/isaac/lab_tasks/manager_based/locomotion/velocity/config/spot/flat_env_cfg.py

@@ -64,7 +64,7 @@ class SpotCommandsCfg:
         heading_command=False,
         debug_vis=True,
         ranges=mdp.UniformVelocityCommandCfg.Ranges(
-            lin_vel_x=(-2.0, 4.0), lin_vel_y=(-1.5, 1.5), ang_vel_z=(-2.0, 2.0)
+            lin_vel_x=(-2.0, 3.0), lin_vel_y=(-1.5, 1.5), ang_vel_z=(-2.0, 2.0)
         ),
     )
 
@@ -189,7 +189,12 @@ class SpotRewardsCfg:
     air_time = RewardTermCfg(
         func=spot_mdp.air_time_reward,
         weight=5.0,
-        params={"mode_time": 0.3, "sensor_cfg": SceneEntityCfg("contact_forces", body_names=".*_foot")},
+        params={
+            "mode_time": 0.3,
+            "velocity_threshold": 0.5,
+            "asset_cfg": SceneEntityCfg("robot"),
+            "sensor_cfg": SceneEntityCfg("contact_forces", body_names=".*_foot"),
+        },
     )
     base_angular_velocity = RewardTermCfg(
         func=spot_mdp.base_angular_velocity_reward,
@@ -212,9 +217,16 @@ class SpotRewardsCfg:
         },
     )
     gait = RewardTermCfg(
-        func=spot_mdp.gait_reward,
+        func=spot_mdp.GaitReward,
         weight=10.0,
-        params={"std": 0.1, "sensor_cfg": SceneEntityCfg("contact_forces", body_names=".*_foot")},
+        params={
+            "std": 0.1,
+            "max_err": 0.2,
+            "velocity_threshold": 0.5,
+            "synced_feet_pair_names": (("fl_foot", "hr_foot"), ("fr_foot", "hl_foot")),
+            "asset_cfg": SceneEntityCfg("robot"),
+            "sensor_cfg": SceneEntityCfg("contact_forces"),
+        },
     )
 
     # -- penalties
@@ -247,7 +259,11 @@ class SpotRewardsCfg:
     joint_pos = RewardTermCfg(
         func=spot_mdp.joint_position_penalty,
         weight=-0.7,
-        params={"asset_cfg": SceneEntityCfg("robot", joint_names=".*"), "stand_still_scale": 5.0},
+        params={
+            "asset_cfg": SceneEntityCfg("robot", joint_names=".*"),
+            "stand_still_scale": 5.0,
+            "velocity_threshold": 0.5,
+        },
     )
     joint_torques = RewardTermCfg(
         func=spot_mdp.joint_torques_penalty,