[Question] I want my robot slow down.

[Holiclife-KTH]

Hi,
I'm training a UR5e equipped with a Robotiq 2F-85 gripper using RSL_RL.

However, I'm facing an issue where the manipulator moves too quickly.

I tried lowering the joint velocity limits, but doing so makes the robot's movement look unnatural.

What would be the best way to address this?

Should I modify the reward function?

I've included my current reward functions below.
"# action penalty
action_rate = RewTerm(func=mdp.action_rate_l2, weight=-1e-4)
joint_vel = RewTerm(
func=mdp.rewards_sweep_ur5e.joint_vel_l2,
weight=-1e-4,
params={"asset_cfg": SceneEntityCfg("robot")},
)

reaching = RewTerm(
    func=mdp.rewards_sweep_ur5e.reward_for_hand_reaching,
    weight=3.0,
    params={"object_id_dict_rev": MISSING}
)

orientation = RewTerm(
    func=mdp.rewards_sweep_ur5e.ee_Align,
    weight=3.0,
    params={},
)

sweeping_object = RewTerm(func=mdp.rewards_sweep_ur5e.pushing_target, 
                          params={"command_name": "target_goal_pos"}, 
                          weight=5.0)"

[RandomOakForest]

Thank you for posting this. Will move the post into our Discussions section for the team to follow up.

[ZachAtkins0n]

Hi,
I think I had the same issue as you except for a UR3 and Robotiq 2F_140 gripper. What worked for me was setting the velocity limits to these:

 "arm": ImplicitActuatorCfg(
        joint_names_expr=["shoulder_pan_joint","shoulder_lift_joint", "elbow_joint", "wrist_1_joint","wrist_2_joint", "wrist_3_joint"],
        velocity_limit=50,
        effort_limit=80.0,
        stiffness=800.0,
        damping=40,
    ),
   
"finger": ImplicitActuatorCfg(
        joint_names_expr=["finger_joint"],
        velocity_limit = 40,
        effort_limit=60.0,
        stiffness=2e2,
        damping=10,
        friction = 0.8,

    ),

I also have the finger joint to be closed slighty at 0.2 to prevent itself from folding into itself in a weird way.

If that doesn't work you may need to set the joint velocity values in the robot's .usd file as well.