README.md

Vector Quantized - Motion Planning Transformers

This github repo contains the models, and helper functions for generating sampling distributions using VQ-MPT.

Installing the package

To install the package, clone this repo to your local machine.

git clone https://github.com/jacobjj/vqmpt.git

To install the package, go to cloned repo, and run the following command.

pip install -e .

Runing inside a container

We provide the dockerfiles to run our models. But you need to have our base image downloaded and loaded on your system before you build the container. Afterwards, either clone or attach this repo inside the container to get started with using our models.

Loading models

You can get the pre-trained models for the panda robot from here - Panda Models

To load the models, use the following:

from vqmpt import utils
import torch

device = torch.device('cuda') if torch.cuda.is_available() else torch.device('cpu')
quantizer_model, decoder_model, context_env_encoder, ar_model = utils.get_inference_models(
    decoder_model_folder,
    ar_model_folder,
    device,
    n_e=2048,
    e_dim=8,
)

Getting distributions

To get the distribution, you can use the get_search_dist in utils.py. Normalize the start and goal configurations between [0, 1], and stack them together to form a 2*n_dim.

search_dist_mu, search_dist_sigma = utils.get_search_dist(
    norm_start_n_goal,
    depth_points,
    context_encoder,
    decoder_model,
    ar_model,
    quantizer_model,
    num_keys=2048,
    device=device,
)

Sampling from the distribution

If you are using the distribution with OMPL, here is an example of writing a custom sampling function.

from ompl import base as ob

class StateSamplerRegion(ob.StateSampler):
    '''A class to sample robot joints from a given joint configuration.
    '''
    def __init__(self, space, qMin=None, qMax=None, dist_mu=None, dist_sigma=None):
        '''
        If dist_mu is None, then set the sampler as a uniform sampler.
        :param space: an object of type ompl.base.Space
        :param qMin: np.array of minimum joint bound
        :param qMax: np.array of maximum joint bound
        :param region: np.array of points to sample from
        '''
        super(StateSamplerRegion, self).__init__(space)
        self.name_ ='region'
        self.q_min = qMin
        self.q_max = qMax
        if dist_mu is None:
            self.X = None
            self.U = stats.uniform(np.zeros_like(qMin), np.ones_like(qMax))
        else:
            self.seq_num = dist_mu.shape[0]
            self.X = MultivariateNormal(dist_mu, dist_sigma)

                       
    def get_random_samples(self):
        '''Generates a random sample from the list of points
        '''
        index = 0
        random_samples = np.random.permutation(self.X.sample()*(self.q_max-self.q_min)+self.q_min)

        while True:
            yield random_samples[index, :]
            index += 1
            if index==self.seq_num:
                random_samples = np.random.permutation(self.X.sample()*(self.q_max-self.q_min)+self.q_min)
                index = 0
                
    def sampleUniform(self, state):
        '''Generate a sample from uniform distribution or key-points
        :param state: ompl.base.Space object
        '''
        if self.X is None:
            sample_pos = ((self.q_max-self.q_min)*self.U.rvs()+self.q_min)[0]
        else:
            sample_pos = next(self.get_random_samples())
        for i, val in enumerate(sample_pos):
            state[i] = float(val)
        return True