deep-rl-class/units/en/unit6/hands-on.mdx

# Advantage Actor Critic (A2C) using Robotics Simulations with PyBullet and Panda-Gym 🤖 [[hands-on]]


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Now that you've studied the theory behind Advantage Actor Critic (A2C), **you're ready to train your A2C agent** using Stable-Baselines3 in robotic environments. And train two robots:

- A spider 🕷️ to learn to move.
- A robotic arm 🦾 to move in the correct position.

We're going to use two Robotics environments:

- [PyBullet](https://github.com/bulletphysics/bullet3)
- [panda-gym](https://github.com/qgallouedec/panda-gym)

<img src="https://huggingface.co/datasets/huggingface-deep-rl-course/course-images/resolve/main/en/unit8/environments.gif" alt="Environments"/>


To validate this hands-on for the certification process, you need to push your three trained model to the Hub and get:

- `AntBulletEnv-v0` get a result of >= 650.
- `PandaReachDense-v2` get a result of >= -3.5.

To find your result, [go to the leaderboard](https://huggingface.co/spaces/huggingface-projects/Deep-Reinforcement-Learning-Leaderboard) and find your model, **the result = mean_reward - std of reward**

For more information about the certification process, check this section 👉 https://huggingface.co/deep-rl-course/en/unit0/introduction#certification-process

**To start the hands-on click on Open In Colab button** 👇 :

[![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/github/huggingface/deep-rl-class/blob/master/notebooks/unit6/unit6.ipynb)


# Unit 6: Advantage Actor Critic (A2C) using Robotics Simulations with PyBullet and Panda-Gym 🤖

### 🎮 Environments:

- [PyBullet](https://github.com/bulletphysics/bullet3)
- [Panda-Gym](https://github.com/qgallouedec/panda-gym)

### 📚 RL-Library:

- [Stable-Baselines3](https://stable-baselines3.readthedocs.io/)

We're constantly trying to improve our tutorials, so **if you find some issues in this notebook**, please [open an issue on the GitHub Repo](https://github.com/huggingface/deep-rl-class/issues).

## Objectives of this notebook 🏆

At the end of the notebook, you will:

- Be able to use **PyBullet** and **Panda-Gym**, the environment libraries.
- Be able to **train robots using A2C**.
- Understand why **we need to normalize the input**.
- Be able to **push your trained agent and the code to the Hub** with a nice video replay and an evaluation score 🔥.

## Prerequisites 🏗️
Before diving into the notebook, you need to:

🔲 📚 Study [Actor-Critic methods by reading Unit 6](https://huggingface.co/deep-rl-course/unit6/introduction) 🤗

# Let's train our first robots 🤖

## Set the GPU 💪

- To **accelerate the agent's training, we'll use a GPU**. To do that, go to `Runtime > Change Runtime type`

<img src="https://huggingface.co/datasets/huggingface-deep-rl-course/course-images/resolve/main/en/notebooks/gpu-step1.jpg" alt="GPU Step 1">

- `Hardware Accelerator > GPU`

<img src="https://huggingface.co/datasets/huggingface-deep-rl-course/course-images/resolve/main/en/notebooks/gpu-step2.jpg" alt="GPU Step 2">

## Create a virtual display 🔽

During the notebook, we'll need to generate a replay video. To do so, with colab, **we need to have a virtual screen to be able to render the environment** (and thus record the frames).

Hence the following cell will install the librairies and create and run a virtual screen 🖥

```python
%%capture
!apt install python-opengl
!apt install ffmpeg
!apt install xvfb
!pip3 install pyvirtualdisplay
```

```python
# Virtual display
from pyvirtualdisplay import Display

virtual_display = Display(visible=0, size=(1400, 900))
virtual_display.start()
```

### Install dependencies 🔽
The first step is to install the dependencies, we’ll install multiple ones:

- `pybullet`: Contains the walking robots environments.
- `panda-gym`: Contains the robotics arm environments.
- `stable-baselines3[extra]`: The SB3 deep reinforcement learning library.
- `huggingface_sb3`: Additional code for Stable-baselines3 to load and upload models from the Hugging Face 🤗 Hub.
- `huggingface_hub`: Library allowing anyone to work with the Hub repositories.

```bash
!pip install -r https://raw.githubusercontent.com/huggingface/deep-rl-class/main/notebooks/unit6/requirements-unit6.txt
```

## Import the packages 📦

```python
import pybullet_envs
import panda_gym
import gym

import os

from huggingface_sb3 import load_from_hub, package_to_hub

from stable_baselines3 import A2C
from stable_baselines3.common.evaluation import evaluate_policy
from stable_baselines3.common.vec_env import DummyVecEnv, VecNormalize
from stable_baselines3.common.env_util import make_vec_env

from huggingface_hub import notebook_login
```

## Environment 1: AntBulletEnv-v0 🕸

### Create the AntBulletEnv-v0
#### The environment 🎮

In this environment, the agent needs to use correctly its different joints to walk correctly.
You can find a detailled explanation of this environment here: https://hackmd.io/@jeffreymo/SJJrSJh5_#PyBullet

```python
env_id = "AntBulletEnv-v0"
# Create the env
env = gym.make(env_id)

# Get the state space and action space
s_size = env.observation_space.shape[0]
a_size = env.action_space
```

```python
print("_____OBSERVATION SPACE_____ \n")
print("The State Space is: ", s_size)
print("Sample observation", env.observation_space.sample())  # Get a random observation
```

The observation Space (from [Jeffrey Y Mo](https://hackmd.io/@jeffreymo/SJJrSJh5_#PyBullet)):

<img src="https://huggingface.co/datasets/huggingface-deep-rl-course/course-images/resolve/main/en/unit8/obs_space.png" alt="PyBullet Ant Obs space"/>


```python
print("\n _____ACTION SPACE_____ \n")
print("The Action Space is: ", a_size)
print("Action Space Sample", env.action_space.sample())  # Take a random action
```

The action Space (from [Jeffrey Y Mo](https://hackmd.io/@jeffreymo/SJJrSJh5_#PyBullet)):

<img src="https://huggingface.co/datasets/huggingface-deep-rl-course/course-images/resolve/main/en/unit8/action_space.png" alt="PyBullet Ant Obs space"/>


### Normalize observation and rewards

A good practice in reinforcement learning is to [normalize input features](https://stable-baselines3.readthedocs.io/en/master/guide/rl_tips.html).

For that, a wrapper exists and will compute a running average and standard deviation of input features.

We also normalize rewards with this same wrapper by adding `norm_reward = True`

[You should check the documentation to fill this cell](https://stable-baselines3.readthedocs.io/en/master/guide/vec_envs.html#vecnormalize)

```python
env = make_vec_env(env_id, n_envs=4)

# Adding this wrapper to normalize the observation and the reward
env = # TODO: Add the wrapper
```

#### Solution

```python
env = make_vec_env(env_id, n_envs=4)

env = VecNormalize(env, norm_obs=True, norm_reward=False, clip_obs=10.0)
```

### Create the A2C Model 🤖

In this case, because we have a vector of 28 values as input, we'll use an MLP (multi-layer perceptron) as policy.

For more information about A2C implementation with StableBaselines3 check: https://stable-baselines3.readthedocs.io/en/master/modules/a2c.html#notes

To find the best parameters I checked the [official trained agents by Stable-Baselines3 team](https://huggingface.co/sb3).

```python
model = # Create the A2C model and try to find the best parameters
```

#### Solution

```python
model = A2C(
    policy="MlpPolicy",
    env=env,
    gae_lambda=0.9,
    gamma=0.99,
    learning_rate=0.00096,
    max_grad_norm=0.5,
    n_steps=8,
    vf_coef=0.4,
    ent_coef=0.0,
    policy_kwargs=dict(log_std_init=-2, ortho_init=False),
    normalize_advantage=False,
    use_rms_prop=True,
    use_sde=True,
    verbose=1,
)
```

### Train the A2C agent 🏃

- Let's train our agent for 2,000,000 timesteps, don't forget to use GPU on Colab. It will take approximately ~25-40min

```python
model.learn(2_000_000)
```

```python
# Save the model and  VecNormalize statistics when saving the agent
model.save("a2c-AntBulletEnv-v0")
env.save("vec_normalize.pkl")
```

### Evaluate the agent 📈
- Now that's our  agent is trained, we need to **check its performance**.
- Stable-Baselines3 provides a method to do that `evaluate_policy`
- In my case, I've got a mean reward of `2371.90 +/- 16.50`

```python
from stable_baselines3.common.vec_env import DummyVecEnv, VecNormalize

# Load the saved statistics
eval_env = DummyVecEnv([lambda: gym.make("AntBulletEnv-v0")])
eval_env = VecNormalize.load("vec_normalize.pkl", eval_env)

#  do not update them at test time
eval_env.training = False
# reward normalization is not needed at test time
eval_env.norm_reward = False

# Load the agent
model = A2C.load("a2c-AntBulletEnv-v0")

mean_reward, std_reward = evaluate_policy(model, env)

print(f"Mean reward = {mean_reward:.2f} +/- {std_reward:.2f}")
```

### Publish your trained model on the Hub 🔥
Now that we saw we got good results after the training, we can publish our trained model on the hub 🤗 with one line of code.

📚 The libraries documentation 👉 https://github.com/huggingface/huggingface_sb3/tree/main#hugging-face--x-stable-baselines3-v20

Here's an example of a Model Card (with a PyBullet environment):

<img src="https://huggingface.co/datasets/huggingface-deep-rl-course/course-images/resolve/main/en/unit8/modelcardpybullet.png" alt="Model Card Pybullet"/>

By using `package_to_hub`, as we already mentionned in the former units, **you evaluate, record a replay, generate a model card of your agent and push it to the hub**.

This way:
- You can **showcase our work** 🔥
- You can **visualize your agent playing** 👀
- You can **share with the community an agent that others can use** 💾
- You can **access a leaderboard 🏆 to see how well your agent is performing compared to your classmates** 👉 https://huggingface.co/spaces/huggingface-projects/Deep-Reinforcement-Learning-Leaderboard


To be able to share your model with the community there are three more steps to follow:

1️⃣ (If it's not already done) create an account to HF ➡ https://huggingface.co/join

2️⃣ Sign in and then, you need to store your authentication token from the Hugging Face website.
- Create a new token (https://huggingface.co/settings/tokens) **with write role**

<img src="https://huggingface.co/datasets/huggingface-deep-rl-course/course-images/resolve/main/en/notebooks/create-token.jpg" alt="Create HF Token">

- Copy the token
- Run the cell below and paste the token

```python
notebook_login()
!git config --global credential.helper store
```

If you don't want to use a Google Colab or a Jupyter Notebook, you need to use this command instead: `huggingface-cli login`

3️⃣ We're now ready to push our trained agent to the 🤗 Hub 🔥 using `package_to_hub()` function

```python
package_to_hub(
    model=model,
    model_name=f"a2c-{env_id}",
    model_architecture="A2C",
    env_id=env_id,
    eval_env=eval_env,
    repo_id=f"ThomasSimonini/a2c-{env_id}",  # Change the username
    commit_message="Initial commit",
)
```

## Take a coffee break ☕
- You already trained your first robot that learned to move congratutlations 🥳!
- It's **time to take a break**. Don't hesitate to **save this notebook** `File > Save a copy to Drive` to work on this second part later.


## Environment 2: PandaReachDense-v2 🦾

The agent we're going to train is a robotic arm that needs to do controls (moving the arm and using the end-effector).

In robotics, the *end-effector* is the device at the end of a robotic arm designed to interact with the environment.

In `PandaReach`, the robot must place its end-effector at a target position (green ball).

We're going to use the dense version of this environment. It means we'll get a *dense reward function* that **will provide a reward at each timestep** (the closer the agent is to completing the task, the higher the reward). Contrary to a *sparse reward function* where the environment **return a reward if and only if the task is completed**.

Also, we're going to use the *End-effector displacement control*, it means the **action corresponds to the displacement of the end-effector**. We don't control the individual motion of each joint (joint control).

<img src="https://huggingface.co/datasets/huggingface-deep-rl-course/course-images/resolve/main/en/unit8/robotics.jpg"  alt="Robotics"/>


This way, **the training will be easier**.



In `PandaReachDense-v2` the robotic arm must place its end-effector at a target position (green ball).



```python
import gym

env_id = "PandaPushDense-v2"

# Create the env
env = gym.make(env_id)

# Get the state space and action space
s_size = env.observation_space.shape
a_size = env.action_space
```

```python
print("_____OBSERVATION SPACE_____ \n")
print("The State Space is: ", s_size)
print("Sample observation", env.observation_space.sample())  # Get a random observation
```

The observation space **is a dictionary with 3 different element**:
- `achieved_goal`: (x,y,z) position of the goal.
- `desired_goal`: (x,y,z) distance between the goal position and the current object position.
- `observation`: position (x,y,z) and velocity of the end-effector (vx, vy, vz).

Given it's a dictionary as observation, **we will need to use a MultiInputPolicy policy instead of MlpPolicy**.

```python
print("\n _____ACTION SPACE_____ \n")
print("The Action Space is: ", a_size)
print("Action Space Sample", env.action_space.sample())  # Take a random action
```

The action space is a vector with 3 values:
- Control x, y, z movement

Now it's your turn:

1. Define the environment called "PandaReachDense-v2"
2. Make a vectorized environment
3. Add a wrapper to normalize the observations and rewards. [Check the documentation](https://stable-baselines3.readthedocs.io/en/master/guide/vec_envs.html#vecnormalize)
4. Create the A2C Model (don't forget verbose=1 to print the training logs).
5. Train it for 2M Timesteps
6. Save the model and  VecNormalize statistics when saving the agent
7. Evaluate your agent
8. Publish your trained model on the Hub 🔥 with `package_to_hub`

### Solution (fill the todo)

```python
# 1 - 2
env_id = "PandaReachDense-v2"
env = make_vec_env(env_id, n_envs=4)

# 3
env = VecNormalize(env, norm_obs=True, norm_reward=False, clip_obs=10.0)

# 4
model = A2C(policy="MultiInputPolicy", env=env, verbose=1)
# 5
model.learn(1_000_000)
```

```python
# 6
model_name = "a2c-PandaReachDense-v2"
model.save(model_name)
env.save("vec_normalize.pkl")

# 7
from stable_baselines3.common.vec_env import DummyVecEnv, VecNormalize

# Load the saved statistics
eval_env = DummyVecEnv([lambda: gym.make("PandaReachDense-v2")])
eval_env = VecNormalize.load("vec_normalize.pkl", eval_env)

#  do not update them at test time
eval_env.training = False
# reward normalization is not needed at test time
eval_env.norm_reward = False

# Load the agent
model = A2C.load(model_name)

mean_reward, std_reward = evaluate_policy(model, env)

print(f"Mean reward = {mean_reward:.2f} +/- {std_reward:.2f}")

# 8
package_to_hub(
    model=model,
    model_name=f"a2c-{env_id}",
    model_architecture="A2C",
    env_id=env_id,
    eval_env=eval_env,
    repo_id=f"ThomasSimonini/a2c-{env_id}",  # TODO: Change the username
    commit_message="Initial commit",
)
```

## Some additional challenges 🏆

The best way to learn **is to try things by your own**! Why not trying  `HalfCheetahBulletEnv-v0` for PyBullet?

If you want to try more advanced tasks for panda-gym you need to check what was done using **TQC or SAC** (a more sample efficient algorithm suited for robotics tasks). In real robotics, you'll use more sample-efficient algorithm for a simple reason: contrary to a simulation **if you move your robotic arm too much you have a risk to break it**.

PandaPickAndPlace-v1: https://huggingface.co/sb3/tqc-PandaPickAndPlace-v1

And don't hesitate to check panda-gym documentation here: https://panda-gym.readthedocs.io/en/latest/usage/train_with_sb3.html

Here are some ideas to achieve so:
* Train more steps
* Try different hyperparameters by looking at what your classmates have done 👉 https://huggingface.co/models?other=https://huggingface.co/models?other=AntBulletEnv-v0
* **Push your new trained model** on the Hub 🔥


See you on Unit 7! 🔥
## Keep learning, stay awesome 🤗