ValidatePath

Checks to see if the global path is valid. If there is an obstacle along the path, it returns FAILURE, otherwise it returns SUCCESS. Optionally checks specific costmap layers and can use a custom footprint for validation.

Input Ports

server_timeout

Type	Default
double	20.0

Description: Service response timeout (ms).

path

Type	Default
nav_msgs::msg::Path	N/A

Description: The global path to check for validity.

max_cost

Type	Default
unsigned int	254

Description: The maximum allowable cost for the path to be considered valid.

consider_unknown_as_obstacle

Type	Default
bool	false

Description: Whether to consider unknown cost (255) as obstacle.

layer_name

Type	Default
string	“”

Description: Name of the specific costmap layer to check against. If empty, checks against the full costmap.

footprint

Type	Default
string	“”

Description: Custom footprint specification as a bracketed array of arrays, e.g., “[[x1,y1],[x2,y2],…]”. If empty, uses the robot’s configured footprint.

stop_at_first_collision

Type	Default
bool	true

Description: Whether to stop validation at the first collision (true) or check all poses in the path (false). When false, all collision poses are reported.

max_lookahead_distance

Type	Default
double	-1.0

Description: Maximum distance ahead of the robot along the path to validate. When set to -1.0 (default), the full path is validated. A positive value limits validation to only the portion of the path within that distance from the robot’s current position.

Output Ports

collision_poses

Type	Default
std::vector<geometry_msgs::msg::PoseStamped>	N/A

Description: Vector of poses in the path that are in collision or invalid. Empty if the path is valid.

Example

<ValidatePath
  server_timeout="10"
  path="{path}"
  max_cost="100"
  consider_unknown_as_obstacle="false"
  layer_name=""
  footprint=""
  stop_at_first_collision="true"
  collision_poses="{collision_poses}" />

With max_lookahead_distance:

<ValidatePath
  path="{path}"
  max_lookahead_distance="5.0"
  collision_poses="{collision_poses}" />

With custom footprint:

<ValidatePath
  path="{path}"
  footprint="[[0.5,0.5],[0.5,-0.5],[-0.5,-0.5],[-0.5,0.5]]"
  collision_poses="{collision_poses}" />

Checking a specific costmap layer:

<ValidatePath
  path="{path}"
  layer_name="obstacle_layer"
  stop_at_first_collision="false"
  collision_poses="{collision_poses}" />