Briefing

Sample Based Motion Planning.

This project is intended as educational replication of several general ideas:

• Sparseness
• Motion Primitives
• Importance Sampling

A sub-goal of this project is to integrate and leverage benefits of several of these ideas in a hybrid solution.

Inputs to program

• system dynamics and various constraints are supplied as functions
• environment obstacles

What's in it:

• Sparseness
  • Stable Sparse RRT (https://www.cs.rutgers.edu/~kb572/pubs/stable_sparse_rrt_WAFR14_LLB.pdf)
  • approximate nearest neighbour with stochastic search
• Motion Primitives:
  • lookup for feasible control for steering toward a direction (https://arxiv.org/pdf/1809.02399.pdf)
  • compile flag for enabling its use
  • adapted for run-time lookup filling
  • non-grid based greedy goal-neighbourhood search
• Importance Sampling:
  • adaptive sampling (https://journals.sagepub.com/doi/pdf/10.1177/0278364912444543)
  • used for trajectory optimization with a given fitness function

Writeups, Benchmarks, etc..

project

Running Planner

• prerequisites
  • install Rust: https://rustup.rs/
  • internet connection (building project pulls in software dependencies)
  • Make (to build triangulation tool if using custom maps, or obtain executable at: https://www.cs.cmu.edu/~quake/triangle.html)
• build and run in release mode
  • Either:
    • have custom maps already generated (see Generating Custom Maps section)
    • cargo run --release --bin planner -- -p <problem_instance_name> (other program arguments...)
    • see prob_instances.rs for predefined problem domain list
  • Or:
    • cargo run --release --bin planner -- -o <file_obstacle> (other program arguments...)
    • sample obstacle file: obstacles/obs3.txt (randomly generated boxes)
  • Or:
    • have custom maps already generated (see Generating Custom Maps section)
    • cargo run --release --bin planner -- -e <.ele file path> -n <.node file path> (other program arguments...)
      • eg: cargo run --release --bin planner -- -e maps_custom/dragon_age/poly/ost100d.1.ele -n maps_custom/dragon_age/poly/ost100d.1.node -p orz000d -i 1000000 -b 300 -m dubins
    • would need to modify dynamics model file to change goal states, etc.
    • see custom maps section for .ele and .node details
• optional arguments:
  • -w: show witness node and witness representative pairs
    • drawn as a line(red) with end points (purple: witness), (blue: witness representative)
  • -i <N>: max iterations
  • -m <model>: dynamical model selection (see src/dynamics_* files)
    • variants: dubins, airplane (defaults to dubins)
  • -b <N>: batch N iterations in between rendering calls
  • -h: help
• optional compile-time features:
  • usage:
    • cargo run --release --bin planner --features nn_naive,disable_pruning,(other features...) -- -p <problem_instance_name> (other program arguments...)
  • variants: see [features] section of Cargo.toml for the list
• sample program:
  • cargo run --release --bin planner --features nn_sample_log,state_propagate_sample,path_optimize -- -p obs3 -m dubins -i 1000000 -b 200

Generating Random Obstacles (a couple obstacles exists in obstacles/ folder)

• build and run in release mode with: cargo run --release --bin gen_obs -- -f <output_file_path>
• required arguments:
  • -f <output_file_path> (eg: cargo run --release --bin gen_obs -- -f obstacles/obs99.txt)
• optional arguments:
  • -n <N>: number of obstacles to be generated (default: 30)
• optional features:
  • gen_obs_3d: generate boxes for in 3D domain (defaults to planar domain)

Using Random Obstacles

• cargo run --release --bin planner -- -o <file_obstacle>
  • -o <file_obstacle>: obstacle file path (eg: -o obstacles/obs2.txt)

Generating Custom Maps (need to run this once in order to use custom maps):

• a set of maps that is mainly used for benchmarking purposes obtainable from https://www.movingai.com/benchmarks/grids.html can be used, these are located in the /maps_custom folder
• character movable space within a map are triangulated for use in the planner as the configuration free space
• triangulation is done using the awesome Triangle software from http://www.cs.cmu.edu/~quake/triangle.html
• the maps are converted into a format for Triangle to process and output is loadable into our planner and further extruded as triangular prisms for use with a general purpose 3D obstacle detector, these intermediate files are stored at /maps_custom//poly
• some maps might have bad triangulation not useable for the planner (I aimed for working with Dragon Age maps)
• generating intermediate files and map assets for our planner
  • 1st, compile Triangle
    • cd Triangle_v1_6
    • make
  • 2nd, run ./script_map2poly.sh (generates formatted file for Triangle, may take a while)
  • 3rd, run ./script_triangulate_poly.sh (outputs 2D triangulation result as .ele and .node files)
  • all set for use...

Screenshots

Simple Environments

Hard Game Maps