Animations

These classes create a graphical object that can be animated to show vehicle position or pose.

class roboticstoolbox.mobile.VehicleAnimationBase

Abstract base class to support animation of a vehicle in a Matplotlib plot

There are three concrete subclasses:

• VehicleMarker animates a Matplotlib marker (shows position only)

• VehiclePolygon animates a polygon shape (outline or filled), including predefined shapes (shows position and orientation)

• VehicleIcon animates an image (shows position and orientation)

An instance a of these classes can be used in three different ways, firstly:

a = VehiclePolygon("car", color="red")
a.add()

adds an instance of the animation shape to the plot and subsequent calls to:

a.update(q)

will animate it with the configuration given by q.

Secondly, an instance can be passed to a Vehicle subclass object to make an animation during simulation:

a = VehiclePolygon("car", color="red")
veh = Bicycle(animation=a)

Thirdly:

a = VehiclePolygon("car", color="red")
a.plot(q)

adds an instance of the animation shape to the plot with the specified configuration. It cannot be moved, but the method does return a reference to the Matplotlib object added to the plot.

Simple marker

class roboticstoolbox.mobile.VehicleMarker(**kwargs)

Bases: VehicleAnimationBase

__init__(**kwargs)

Create graphical animation of vehicle as a Matplotlib marker

Parameters:

kwargs – additional arguments passed to Matplotlib plot().

Returns:

animation object

Return type:

VehicleAnimation

Creates an object that can be passed to a Vehicle subclass to depict the moving robot as a simple Matplotlib marker during simulation.

The default marker is a red filled circle with a white outline.

For example, to animate a simulation with a blue square marker:

a = VehicleMarker(marker="s", markerfacecolor="b")
veh = Bicycle(driver=RandomPath(10), animation=a)
veh.run()

Note

A marker can only indicate vehicle position, not orientation.

Seealso:

Vehicle()

add(ax=None, **kwargs)

Add vehicle animation to the current plot

Parameters:

• ax (Axes, optional) – Axis to add to, defaults to current axis

• kwargs – additional arguments passed to Matplotlib plot(), which override arguments given to the constructor.

A reference to the animation object is kept, and it will be deleted from the plot when the VehicleAnimation object is garbage collected.

The animation is not displayed until update() is called.

Seealso:

update()

plot(q, **kwargs)

Add vehicle to the current plot (superclass)

Parameters:

• q (array_like(2) or array_like(3)) – vehicle position or configuration

• kwargs – additional arguments passed to Matplotlib plot(), which override arguments given to the constructor.

Returns:

reference to Matplotlib object

The animation object is rendered into the current axes.

update(q)

Update the vehicle animation (superclass)

Parameters:

q (array_like(2) or array_like(3)) – vehicle position or configuration

The graphical depiction of the vehicle position or configuration is updated.

Seealso:

add()

Polygon shape

class roboticstoolbox.mobile.VehiclePolygon(shape='car', scale=1, **kwargs)

Bases: VehicleAnimationBase

__init__(shape='car', scale=1, **kwargs)

Create graphical animation of vehicle as a polygon

Parameters:

• shape (ndarray(2,n) or str) – polygon shape as vertices or a predefined shape, defaults to “car”

• scale (float) – Length of the vehicle on the plot, defaults to 1

• kwargs – additional arguments passed to Matplotlib Polygon such as color (face+edge), alpha, facecolor, edgecolor, linewidth etc.

Raises:

• ValueError – unknown shape name

• TypeError – bad shape argument

Returns:

animation object

Return type:

VehiclePolygon

Creates an object that can be passed to a Vehicle subclass to depict the moving robot as a polygon during simulation.

For example, to animate a simulation with a red filled car-shaped polygon:

a = VehiclePolygon("car", color="r")
veh = Bicycle(driver=RandomPath(10), animation=a)
veh.run()

shape can be:

• "car" a rectangle with chamfered front corners

• "triangle" an isocles triangle pointing in the forward direction

• an 2xN NumPy array of vertices, does not have to be closed.

The polygon is scaled to an image with a length of scale in the vehicle x-direction, in the units of the plot.

Seealso:

Vehicle() matplotlib.patches.Polygon

add(ax=None, **kwargs)

Add vehicle animation to the current plot

Parameters:

• ax (Axes, optional) – Axis to add to, defaults to current axis

• kwargs – additional arguments passed to Matplotlib plot(), which override arguments given to the constructor.

A reference to the animation object is kept, and it will be deleted from the plot when the VehicleAnimation object is garbage collected.

The animation is not displayed until update() is called.

Seealso:

update()

plot(q, **kwargs)

Add vehicle to the current plot (superclass)

Parameters:

• q (array_like(2) or array_like(3)) – vehicle position or configuration

• kwargs – additional arguments passed to Matplotlib plot(), which override arguments given to the constructor.

Returns:

reference to Matplotlib object

The animation object is rendered into the current axes.

update(q)

Update the vehicle animation (superclass)

Parameters:

q (array_like(2) or array_like(3)) – vehicle position or configuration

The graphical depiction of the vehicle position or configuration is updated.

Seealso:

add()

Image icon

class roboticstoolbox.mobile.VehicleIcon(filename, origin=None, scale=1, rotation=0)

Bases: VehicleAnimationBase

__init__(filename, origin=None, scale=1, rotation=0)

Create graphical animation of vehicle as an image icon

Parameters:

• filename (str) – Standard icon name or a path to an image

• origin (array_like(2)) – Origin of the vehicle coordinate frame, defaults to centre

• scale (float) – Length of the vehicle on the plot, defaults to 1

• rotation (float) – Vehicle icon heading in degrees, defaults to 0

Raises:

ValueError – Icon file not found

Returns:

animation object

Return type:

VehicleAnimation

Creates an object that can be passed to a Vehicle subclass to depict the moving robot as an image icon during simulation. The image is translated and rotated to represent the vehicle configuration.

The car is scaled to an image with a horizontal length (width) of scale in the units of the plot. By default the image is assumed to contain a car parallel to the x-axis and facing right. If the vehicle is facing upward set rotation to 90.

The vehicle rotates about its origin which is expressed in terms of normalized coordinates in the range 0 to 1. By default it is in the middle of the icon image, (0.2, 0.5) moves it toward the back of the vehicle, (0.8, 0.5) moves it toward the front of the vehicle.

filename can be an included image:

• "greycar" a grey and white car (top view)

• "redcar" a red car (top view)

• "piano" a piano (top view)

or the path to an image file, including extension.

The included images are:

For example, to animate a simulation with the red car icon:

a = VehicleIcon("redcar", scale=2)
veh = Bicycle(driver=RandomPath(10), animation=a)
veh.run(animation=a)

Note

The standard icons are provided in the package rtb-data

Seealso:

Vehicle

add(ax=None, **kwargs)

Add vehicle animation to the current plot

Parameters:

• ax (Axes, optional) – Axis to add to, defaults to current axis

• kwargs – additional arguments passed to Matplotlib plot(), which override arguments given to the constructor.

A reference to the animation object is kept, and it will be deleted from the plot when the VehicleAnimation object is garbage collected.

The animation is not displayed until update() is called.

Seealso:

update()

plot(q, **kwargs)

Add vehicle to the current plot (superclass)

Parameters:

• q (array_like(2) or array_like(3)) – vehicle position or configuration

• kwargs – additional arguments passed to Matplotlib plot(), which override arguments given to the constructor.

Returns:

reference to Matplotlib object

The animation object is rendered into the current axes.

update(q)

Update the vehicle animation (superclass)

Parameters:

q (array_like(2) or array_like(3)) – vehicle position or configuration

The graphical depiction of the vehicle position or configuration is updated.

Seealso:

add()