Theta Star Planner¶
Theta Star Planner implements the Theta* path planner meant to plan any-angled paths using A*.
For the below example the planner took ~46ms (averaged value) to compute the path of 87.5m -
<name> is the corresponding planner plugin ID selected for this type.
The parameters of the planner are:
To choose between 4-connected (up, down, left, right) and 8-connected (all the adjacent cells) graph expansions, the accepted values are 4 and 8
Weight applied on the length of the path.
It tunes how harshly the nodes of high cost are penalised. From the above g(neigh) equation you can see that the cost-aware component of the cost function forms a parabolic curve, thus this parameter would, on increasing its value, make that curve steeper allowing for a greater differentiation (as the delta of costs would increase, when the graph becomes steep) among the nodes of different costs.
If true, the last pose of the path generated by the planner will have its orientation set to the approach orientation, i.e. the orientation of the vector connecting the last two points of the path
Do go through the README file available on this repo’s link to develop a better understanding of how you could tune this planner. This planner requires you to tune the cost_scaling_factor parameter of your costmap too, to get good results.
planner_server: ros__parameters: expected_planner_frequency: 20.0 use_sim_time: True planner_plugins: ["GridBased"] GridBased: plugin: "nav2_theta_star_planner/ThetaStarPlanner" how_many_corners: 8 w_euc_cost: 1.0 w_traversal_cost: 2.0 w_heuristic_cost: 1.0