validatorVehicleCostmap

State validator based on 2-D costmap

Description

The validatorOccupancyMap object validates states and discretized motions based on the value in a 2-D costmap. An occupied map location is interpreted as an invalid state.

Creation

Syntax

Description

validator = validatorVehicleCostmap creates a vehicle cost map validator associated with an SE2 state space with default settings.

validator = validatorVehicleCostmap(stateSpace) creates a validator in the given state space definition derived from nav.StateSpace.

validator = validatorVehicleCostmap(stateSpace,xyIndices)sets the XYIndices property to specify which variables in the state vector define the xy-coordinates.

validator = validatorVehicleCostmap(stateSpace,Name,Value) specifies the Map or XYIndices properties using Name,Value pair arguments.

Properties

StateSpace — State space for validating states

stateSpaceSE2 (default) | subclass of nav.StateSpace

State space for validating states, specified as a subclass of nav.StateSpace. Provided state space objects include:

• stateSpaceSE2

• stateSpaceDubins

• stateSpaceReedsShepp

Map — Map used for validating states

vehicleCostMap(10,10) (default) | vehicleCostMap object

Map used for validating states, specified as a vehicleCostMap object.

ValidationDistance — Interval for checking state validity

Inf (default) | positive numeric scalar

Interval for sampling between states and checking state validity, specified as a positive numeric scalar.

XYIndices — State variable mapping for xy-coordinates

[1 2] (default) | [xIdx yIdx]

State variable mapping for xy-coordinates in state vector, specified as a two-element vector, [xIdx yIdx]. For example, if a state vector is given as [r p y x y z], the xy-coordinates are [4 5].

ThetaIndex — State variable mapping for theta coordinate

NaN (default) | positive integer

State variable mapping for theta coordinate in state vector, specified as a positive integer. For example, if a state vector is given as [x y theta], the theta coordinate is 3.

Object Functions

copy	Create deep copy of state validator object
isStateValid	Check if state is valid
isMotionValid	Check if path between states is valid

Examples

Validate Path Through Vehicle Costmap Environment

This example shows how to validate paths through an evironment.

Load example maps. Use the simple map to create a vehicle cost map. Specify an inflation raidus of 1 meter.

load exampleMaps.mat
map = vehicleCostmap(double(simpleMap));
map.CollisionChecker = inflationCollisionChecker("InflationRadius",1);
plot(map)

Specify a coarse path through the map.

path = [3 3 pi/2; 8 15 0; 17 8 -pi/2];
hold on
plot(path(:,1),path(:,2),"--o")

Create a state validator using the stateSpaceSE2 definition. Specify the map and the distance for interpolating and validating path segments.

validator = validatorVehicleCostmap(stateSpaceSE2);
validator.Map = map;
validator.ValidationDistance = 0.1;

Check the points of the path are valid states. All three points are in free space, so are considered valid.

isValid = isStateValid(validator,path)

isValid = 3x1 logical array

   1
   1
   1

Check the motion between each sequential path states. The isMotionValid function interpolates along the path between states. If a path segment is invalid, plot the last valid point along the path.

startStates = [path(1,:);path(2,:)];
endStates = [path(2,:);path(3,:)];
    for i = 1:2
        [isPathValid, lastValid] = isMotionValid(validator,startStates(i,:),endStates(i,:));
        if ~isPathValid
            plot(lastValid(1),lastValid(2),'or')
        end
    end
hold off

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

For code generation, the map used inside the object must remain constant.