This ROS package allows generation of motion-profiled spline path trajectories, supporting constraints on velocity, acceleration, and jerk (time derivative of acceleration).
For spline interpolation, this package uses a build of the Pathfinder library and creates ROS bindings and utility scripts for usage with ROS.
This package publishes data in various message formats including nav_msgs/Path, geometry_msgs/PoseArray, and the custom trajectory datatype pathfinder_ros/Path
pathfinder_node is the main node for running Pathfinder ROS. It generates and publishes a new path every time it receives updated waypoint information.
/pathfinder_ros/path (nav_msgs/Path)
Publishes a path object representing the spline path. Primarily for visualization and debugging.
/pathfinder_ros/segments (geometry_msgs/PoseArray)
Publishes a pose array representing the segments of the spline path (position and heading for each point)
/pathfinder_ros/path_references (pathfinder_ros/Path)
Publishes a trajectory containing the segments of the path along with followable references for each point (coordinates, position and it's time derivatives, heading, and angular velocity).
/pathfinder_ros/waypoints (geometry_msgs/PoseArray)
Waypoints (knot points) for the spline path. Note that having too many knot points or having heavily varying direction between the knot points may create a very high-curvature path with high change in curvature, which may be difficult for a robot to follow smoothly. Additionally, in some cases the spline interpolation can create a path that strays extremely far from the waypoints if they are not aligned well.
sample_count (int, default: 10000)
Number of samples to use for the trajectory generator. Higher numbers will create a more precise trajectory at the expense of higher computational time.
time_step (float, default: 0.05)
Length of time, in seconds, for each segment in the trajectory. A smaller value will create a more precise trajectory at the cost of higher computational time. This value should be greater than the minimum control loop time for the robot to prevent the trajectory-following loop from getting behind on the path.
max_velocity (float, default: 0.8)
Maximum robot velocity to use in the trajectory, in meters per second. Warning: This applies only for the generated trajectory, the trajectory-following code may cause the robot to drive at higher velocities if it does not have its own constraints on velocity.
max_acceleration (float, default: 100000.0)
Maximum robot acceleration to use in the trajectory, in meters per second squared. Warning: This applies only for the generated trajectory, the trajectory-following code may cause the robot to drive with higher acceleration if it does not have its own constraints on acceleration.
max_jerk (float, default: 0.8)
Maximum robot jerk (time derivative of acceleration) to use in the trajectory, in meters per second cubed. Warning: This applies only for the generated trajectory, the trajectory-following code may cause the robot to drive with higher jerk if it does not have its own constraints on jerk.
simple_path_to_nav_goal.py is a simple node for publishing a path to be used by pathfinder_node with only 2 waypoints, one being the robot's current position and the other being a goal point (which can be selected through RViz or through the move_base goal topic)
/pathfinder_ros/waypoints (geometry_msgs/PoseArray)
Waypoints for the spline path (to be used by pathfinder_node). This will include the robot's current pose as well as the goal pose.
/move_base_simple/goal (geometry_msgs/PoseStamped)
Goal pose for the robot. This can be sent using RViz "Set 2D Nav Goal" tool or manually through a node or rostopic pub. This is used as the second waypoint for the generated waypoints.