gennav.envs package

Submodules

gennav.envs.base module

class gennav.envs.base.Environment

Bases: object

Base class for an envrionment.

An environment object should encapsulate all data processing related to a specific environment representation and should provide the ability to check for collision using this API

get_status(state)

Get whether a given state is valid within the environment.

This method needs to be implemented in the specific env implementation.

Parameters:state (gennav.utils.RobotState) – State to be checked
Returns:True if state is valid otherwise False
Return type:bool
get_traj_status(traj)

Get whether a given trajectory is valid within the environment.

This method needs to be implemented in the specific env implementation.

Parameters:state (gennav.utils.Trajectory) – Trajectory to be checked
Returns:True if state is valid otherwise False
Return type:bool
minimum_distance(state, *args, **kwargs)

Gives a list of minimum distance of each obstacle from the robot state.

This method needs to be implemented in the specific env implementation.

Parameters:
  • state (gennav.utils.RobotState) – The current state of the robot.
  • *args – Variable length argument list.
  • **kwargs – Variable length keyword arguments.
nearest_obstacle_distance(state, *args, **kwargs)

Get the distance to nearest obstacle.

This method needs to be implemented in the specific env implementation

Parameters:
  • state (gennav.utils.RobotState) – The current state of the robot.
  • *args – Variable length argument list.
  • **kwargs – Variable length keyword arguments.
update(*args, **kwargs)

Update the environment.

This method needs to be implemented in the specific env implementation.

Parameters:
  • *args – Variable length argument list.
  • **kwargs – Arbitrary keyword arguments.

gennav.envs.binaryOccupancyGrid2D_env module

class gennav.envs.binaryOccupancyGrid2D_env.BinaryOccupancyGrid2DEnv(X=10, Y=10, *args, **kwargs)

Bases: gennav.envs.base.Environment

Base class for a Binary Occupancy Grid 2D envrionment.

Parameters:
  • X (unsigned int) – The number of grid cells in the x-direction
  • Y (unsigned int) – the number of grid cells in the y-direction
check_line_segment(state1, state2)

Checks whether a line segment is collision free in the environent

Computes a line segment from the start point to the end point and parametrically checks if the grid cells they occupy are occupied.

Parameters:
compute_transforms()

Computes transforms between frames

Uses robot pose to compute transform between the world frame and the bot frame

fillOccupancy()

Function that fill the occupnacy grid on every update Assumptions:

  1. RobotPose is considered (0, 0, 0) to accomodate the laser scan, which produces ranges wrt to the bot
  2. The RobotPose in the occupancy grid is (X * scale_factor/2, Y * scale_factor /2, 0)
  3. The attribute robotPose is the real pose of the robot wrt to the world Frame,
    thus it helps us to calculate the transform for trajectory and pose validity queries
get_status(state)

Get whether a given state is valid within the environment.

Method for checking the validity of a given RobotPose in the environment.

Parameters:state (gennav.utils.RobotState) – State to be checked
Returns:True if state is valid otherwise False
Return type:bool
get_traj_status(traj)

Get whether a given trajectory is valid within the environment.

Method for checking the validity of a trajectory in the given environment.

Parameters:state (gennav.utils.Trajectory) – Trajectory to be checked
Returns:True if state is valid otherwise False
Return type:bool
transform(frame1, frame2, rsf1)

Transform robotPose from one pose to the other

Parameters:
  • frame1 (string) – from the frame (world, bot, map)
  • frame2 (string) – to the frame (world, bot, map)
  • rsf1 (gennav.utils.common.RobotState) – RobotState in frame1
Returns:

RobotState in frame2
Return type:

rsf2 (gennav.utils.common.RobotState)
update(scan, robotPose)

Function to update the environment :param scan: List of ang_min, ang_max, ranges :type scan: list :param robotPose: Current RobotPose :type robotPose: gennav.utils.RobotPose

visualise_grid()

Helper function to visualise grid

gennav.envs.common module

gennav.envs.common.visualize_path(traj, env)

Draw the path along with environment obstacles.

Parameters:
  • traj (gennav.utils.Trajectory) – list of points in the path as tuples.
  • env (gennav.envs.Environment) – list of obtacles.

gennav.envs.polygon_env module

Polygon Environment Class

class gennav.envs.polygon_env.PolygonEnv(buffer_dist=0.0, *args, **kwargs)

Bases: gennav.envs.base.Environment

PolygonEnvironment Class .. attribute:: obstacles

type:list of Coordinates
buffer_dist

distance passed to shapely.buffer()

Type:float
collision(points, obstacles)

A helper function that checks for Collision between the given obstacles and a set of points using shapely

Parameters:
  • points (list of coordinates (x, y)) –
  • obstacles (list of list of cooridnates(x,y)) –
Returns:

True if collision is detected
Return type:

bool
get_status(state)

Get whether a given state is valid within the given environment

Checks whether the position given is not within any obstacle

Parameters:state (gennav.utils.RobotState) – State to be checked for
Returns:True if the state is valid, False otherwise
Return type:bool
get_traj_status(traj)

Get whether a given trajectory is valid within the given environment

Checks whether the given trajectory intersects with any obstacles or not

Parameters:traj (gennav.utils.common.Trajectory) – Trajectory to be checked for
Returns:True if the trajctory is valid, False otherwise
Return type:bool
minimum_distances(state, sort=False)

Function to get the minimum distance of each obstacle form the robot state

Uses shapely Point’s distance method to obtain the minimum distances

Parameters:
  • state (gennav.utils.RobotState) – present state of the robot
  • sort (bool default = False) – returns the distances in ascending form when set true
Returns :
min_dist (list) : list containing minimum distances(float) of each obstacle from the robot state
nearest_obstacle_distance(state, return_object=True)

Function to get the nearest obstacle to the robot state

Uses shapely Point’s distance method to obtain the distance

Parameters:
  • state (gennav.utils.RobotState) – present state of the robot
  • return_object (bool default=True) – returns nearest obstacle also
Returns:

distance to the nearest obstacle obj (shapely.Polygon) : nearest obstacle
Return type:

dist (float)
update(obstacles)

Function call to update environment variables

Updates the obstacles in the environment

Parameters:obstacles – list of list of points (x, y) that make an obstacle Example of argument: [ [(1, 1), (2, 1), (2, 2), (1, 2)], [(3, 4), (3.3, 4), (3.3, 4.2), (3, 4.2)] ] The above list contains a list of points that constitute an obstacle. There can be arbitrary number of obstacles, which each obstacle having an arbitrary number of points

gennav.envs.scan_env module

class gennav.envs.scan_env.ScanEnv(scan_=None, bot_size=0.4, ang_range=[0, 6.283185307179586], viz=False, *args, **kwargs)

Bases: gennav.envs.base.Environment

get_status(state)

Get whether a given state is valid within the environment.

Checks whether position of given state is clear of all points in the scan by a certain threshold given as the robot size.

Parameters:state (gennav.utils.RoboState) – State to be checked
Returns:True if state is valid otherwise False
Return type:bool
get_traj_status(traj)

Get whether a given trajectory is valid within the environment.

Checks if the path is clear of all obstacles by a certain threshold given as the robot size.

Parameters:state (gennav.utils.Trajectory) – Trajectory to be checked
Returns:True if state is valid otherwise False
Return type:bool
scan
update(data)

Update the environment.

Updates internal representation with new scan data.

Parameters:data – The updated scan data.

Module contents