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Planning High Quality Motion Paths for Robots, Workshop, Spring 2009

Software Workshop (sadna)


Lecture: Wed 16-18, Schreiber 309

Instructor: Dan Halperin

Teaching AssistantsBarak Raveh & Naama Mayer

General Information

Motion-planing algorithms compute collision-free motion paths for objects that move among obstacles.  They arise in robotics, graphical animation, surgical planning, navigation systems, computational biology and computer games, among other domains. In this workshop we will explore and apply algorithms for planning high-quality motion paths. The quality of a motion path may be measured by the path length, smoothness, clearance from obstacles or even its physical energy. The students will apply motion-planning techniques to virtual or physical robots.

Project Examples

  1. Non holonomic motion planner
  2. Robot motion planning

Useful Resources

Reading Material

  • Chapter 7: Sampling-Based Algorithms in Principles of Robot Motion: Theory, Algorithms, and Implementations
    H. Choset, K.M. Lynch, S. Hutchinson, G. Kantor, W. Burgard, L.E. Kavraki, and S. Thrun, The MIT Press, 2005.
  • Chapter 5: Sampling-Based Motion Planning in Planning Algorithms, S.M. LaValle, Cambridge University Press, 2006
    Web version


04/03—Introduction to Planning High-Quality Motion Paths
11/03—Sampling-Based Motion Planning (following Chapter 7, Sampling-Based Algorithms in Principles of Robot Motion: Theory, Algorithms, and Implementations)
18/03—Details of Projects [link to ppt presentation part I and part II]
25/03—Improving the Quality of Motion Paths [link]

List of Possible Projects

  • Planning high-quality motion path in virtual environments using Google Sketchup
  • Planning high-quality motion paths with a Lego Mindstorms NXT robot
  • Coordinating high-precision motion for multiple polygon robots in 2D

Course Requirements & Grading

  • In the beginning of the workshop, we will present you with the basics of algorithmic motion planning in a series of three lectures.
  • The recommended team size is three. Each group will choose a project among the list of projects, and submit the final project later in the summer – see dates below.
  • Except for doing the project for you, we are here to help you with any question. Please do not hesitate to contact the course’s team.
  • In order to make sure you successfully complete the project, you will be required to the following milestones:
      • By April 1st, 2009—Submitting an initial plan by e-mail:
        An initial description of the project and the workplan (2–3 pages Word document):
        1. Title
        2. Description (~100-200 words) of the project’s main idea.
        3. Brief description of project from a user point of view (input / output, etc.)
        4. Algorithmic details.
        5. The major programming tasks (engine, user interface, etc.)
        6. Milestones towards the final goal.
        7. Tools that are going to help you program / run the project (libraries, programming languages, etc.).
        8. Open questions, conflicts and so on.
        If you are considering a few ideas , you can write more than one option and we can help you decide between those options.
      • By May 6th, 2009—Presenting the project plan:
        On May 6th we will hold a class meeting at the usual time (16:10–18:00). In that meeting you are expected to give a detailed presentation of your project plan in front of the class. Please prepare to present your project and talk about it for 10-15 minutes. In addition, by this time you will need to prepare a written document describing the final plan (3-4 pages). It should include the same subjects as the initial plan (more or less, we hope that there will be less open questions), but we expect more detailed solutions.
      • By June 3rd, 2009—Testing the project basic infrastructure:
        The students will be required to show that the basic technical infrastructure of the project works (e.g. tools or programming libraries that need to be installed, etc.).
      • By July 24th, 2009—Basic prototype:
        At this point in time, we will want to see your initial development, in order to make sure you are working in the right direction. You will show us a basic prototype of the project. The prototype is not expected to be fully functional, but it should give a very good feeling of where you’re heading.
      • August 28th, 2009—Submission of a final project:
        Submitting a fully functional project, including documented code, a detailed user guide and a developer guide. You will present the project to all students of the workshop. Your project will be tested against a set of problems we will design in advance. We will provide more details in the description of each project, to appear soon.

LegoNXT Robot – ABS Motion Planning Project

 This work is part of a High quality Motion Planning Workshop (spring-2009).

Project Goal:

Generate a path from source to target locations while avoiding obstacles, optimized in some aspects, for our constructed robot to follow.

The project included:

  • Designing and constructing a robot based on Lego (TM) parts with the MindStorm controller.
  • Designing an algorithm that calculates an efficient path according to parameters entered by the user.
  • Creating A second algorithm that converts the output of the first algorithm to a set of instructions for our robot to follow.

Project Milestones

  • Construction – we have decided to construct our robot as a Car-like robot. I.e. Forward motion generated in the front and steering generated in the back. This decision stemmed from our desire to make the project more interesting, compared to common robot construction models. Retrospectively this was proven to be harder than we thought, due to unexplained misbehavior by the robot from time to time (inaccuracies while following instructions).
  • Optimization aspects were selected:
    • Clearance – maximum distance to obstacles
    • Distance – minimal path distance
    • Turns – preference for turns that the robot performs well
  • Implementation & Design
    • Development/Final Environment: Our development environment consisted of “Google Sketchup” for designing the problem to be solved, “OOPSMP” libraries for existing motion planning algorithms and framework, “Microsoft Visual Studio” for coding, and “Bram NXT” library for controlling the robot.
    • Motion planning: Our approach was to use existing algorithms for motion planning, and hybridize their solution paths to a single path optimized for the aspects we selected, while prioritizing these aspects using weights given by the user.
    • Translation to robot control: We decided to address the issue of control by regarding the solution path as a path to follow, rather than a description of the robot’s exact state at a given time (which is the broadly accepted convention).


Video of our robot in action

Installing CGAL and related programs on Windows operating system

This page explains how to install CGAL 4.9 with Boost 1.59.0 and Qt5 5.7.1 on Windows 8 using Visual Studio 12 (2013) generating 64 bit binaries. The same procedure should apply to earlier versions of Windows.

Note that during the entire setup you need Internet connection!

Note that the installation requires significant disk space. Make sure to free enough disk space before the installation.

Instructions on adding Environment Variables in Windows are at the end.


IMPORTANT: make sure that you install everything in 64-bit.

  1. Visual Studio 12 Professional (recommended) or Express.
    Professional – Students can get a free version here
  2. Boost 1.59.0: here
  3. CMake 3.7.1
  4. CGAL 4.9.0
  5. Qt5 5.7.1
In parentheses are the paths on my computer.
1) Visual C++ 2013:
  •  If you use the offline version, choose to install Visual C++.
  •  Accept the license terms.
  •  You may select a custom installation (instead of full) and select only Visual C++ (unselect other features).
  •  You don’t need to install “SQL Server” & “Silverlight Runtime” although you may.
  •  There is a chance that it is recommended to reboot now.
2) Boost

Versions earlier than 1.55 used to include a binary installer. Such an installer is no longer available. However, the procedure is fairly simple. There are several ways to build boost; the following is referred to as “build from source”.

  • Open a command-line terminal, such as ‘cmd’.
  • Make the compiler known by running the following batch file:
c:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\bin\vcvars32.bat
  • Download the boost archive, unpack it to a target directory of your choice (e.g., C:\boost\boost_1_55_0), and change directory to target directory.
  • Run:
  • Then, build the static, shared, single and multi threaded boost libraries:
.\b2 link=static,shared threading=single,multi variant=debug,release
  • Make sure the subdirectory stage\lib\ has been populated with the compiled libraries (both .lib and .dll files).
3) CMake
  •  -Agree to the license.
  •  Check “Add CMake to the system PATH for all users”.
  • Check “create desktop icon”.
  •  Next, Next, Next.
  •  Finish
4) QT
  •  Agree to the license.
  •  Next, Next, Next, Install.
  •  Add QTDIR variable with the value C:\Qt\5.7.1 to the environment variables (if it’s not already there).
  •  Add <QT>\bin to the system PATH. (C:\Qt\5.7.1\bin)
4.1) QT Visual Studio 2013 addin:
  •  install the addin (Is it still necessary in VC 12?)
  •  CGAL installation will need to connect to the internet for GMP and MPFR.
  •  Be amazed by the splash screen.
  •  Agree to the license.
  •  Just choose the default: with GMP and MPFR, and with examples and demos.
  •  64-bit (for me).
  •  In the “Setting Environment Variables” screen, choose all users and make sure that CGAL_DIR is checked.
  •  Install.
  •  Add <CGAL_DIR >\auxiliary\gmp\lib to the system PATH. (C:\Program Files\CGAL-4.9\auxiliary\gmp\lib)
Now you need to compile CGAL
  •  Open CMake – cmake-gui (on the Desktop) – if you are using win7 make sure you open the program in administrator mode – right click on the icon and click on “run as administrator”.
  •  For both “Where is the source code” and “Where to build the binaries” specify the CGAL Installation folder (C:\Program Files\CGAL-4.9)
  •  Click Configure.
  •  Choose “Visual Studio 12 2013” and click “Finish”
  •  Click Generate
  •  A solution named CGAL was created in the directory.
  •  Compile ALL_BUILD project both in Debug and Release (ignore the compilation error in CGAL_imageIO).
  •  All CGAL libraries should be under the lib directory.
6) Sanity check (optional)
  •  Open CMake (cmake-gui, can be found on the desktop) – (for win7 users, use “Run as admin”)
  •  Choose “Where is the source code:” to be the Triangulation_2 demo directory under the CGAL installation. Namely, <CGAL>/demo/Triangulation_2 (C:\Program Files\CGAL-4.9/demo/Triangulation_2).
  •  Choose “Where to build the binaries:” to the same directory.
  •  Click Configure
  •  Click Generate
  •  Go to the directory (C:\Program Files\CGAL-4.9) and open the solution and compile. Run the Delaunay_triangulation project for check (in debug and release)
7) Customizing env – If you are not using CMake to create new VS projects
 Note: the following operations should be repeated for the Debug and Release modes
  •  Right-click on the selected project and select “Properties”.
   Go to C/C++ -> General . Add the following to “Additional Include Directories” (include)
   * include: <Boost> (C:\Program Files\boost\boost_1_59)
   * include: <CGAL>\include (C:\Program Files\CGAL-4.9\include)
   * include: <CGAL>\auxiliary\gmp\include (C:\Program Files\CGAL-4.9\auxiliary\gmp\include)
   * include: <QT>\include\Qt (C:\Qt\5.7.1\include\Qt)
   * include: <QT>\include\QtCore (C:\Qt\5.7.1\include\QtCore)
   * include: <QT>\include\QtGui (C:\Qt\5.7.1\include\QtGui)
  Go to Linker -> General. Add the following to “Additional Dependencies” (include)
   * library: <CGAL>\lib (C:\Program Files\CGAL-4.9\lib)
   * library: <QT>\lib (C:\Qt\5.7.1\lib)
   * library: <Boost>\lib (C:\Program Files\boost\boost_1_59\lib)
   * library: <CGAL>\auxiliary\gmp\lib (C:\Program Files\CGAL-4.9\auxiliary\gmp\lib)
For a specific project using CGAL you need to ignore the auto-link of gmp and mpfr. The names below are for Debug.
 – Linker -> Input
   * Add libgmp-10.lib and libmpfr-4.lib to “Additional Dependencies”
   * Add gmp-vc100-mt-gd.lib and mpfr-vc100-mt-gd.lib to “Ignore Specific Library” (gmp-vc100-mt.lib and mpfr-vc100-mt.lib in release mode).
For a specific project using QT:
 – Linker -> Input
   * Add qtmaind.lib, QtGuid4.lib, and QtCored4.lib to “Additional Dependencies” (qtmain.lib;QtCore4.lib;QtGui4.lib in release).
Important: In case that the compilation succeeds but the linker is unable to find cgal-related dlls (“the program can’t start because cgal-vc100-mt-gd-4.2.dl is missing”)
find these files in the CGAL directory and copy them either to the system32 folder of windows, or the folder of the visual studio project.
Try to compile this programs:
Hello CGAL:

Setting up PATH variable or other Environment variables on windows systems

    1. From the desktop, right-click My Computer and click properties.
    2. (on Vista/Win7/Win8 click Advanced system settings on the left side)
    3. In the System Properties window, click on the Advanced tab.
    4. In the Advanced section, click the Environment Variables button.
    5. Finally, in the Environment Variables window, highlight the path variable in the Systems Variable section and click edit. Add or modify the path lines with the paths you wish the computer to access. Each different directory is separated with a semicolon as shown below.C:\Program Files;C:\Winnt;C:\Winnt\System32

Non holonomic motion planner project

Authors : Bosmat Eldar, Itamar Berger, Gal Zohar
This project is part of the high-quality motion paths for robots workshop, Spring 2009

Project Goal

Generating high-quality paths for non-holonomic robots.

In 2D worlds, finding a path from point A to point B is an interesting problem which can easily be solved. However, when there are limitations on the robot’s movement, the problem may become difficult. In this project we’ve tried to deal with the limitations of cars’ movement. Cars are non-holonomic, so actions such as parking or making a sharp turn are not always trivial. A typical GPS doesn’t take these limitations into account.

In order to make high quality paths, we’ve defined several criteria for path quality: length, smoothness, clearance and minimizing reverse and steering amount.

The resulting project

We’ve examined the solutions currently suggested for this problem over the net, and a particular article appeared to be a good start for our basic demands –  “Randomized Motion Planning for Car-like Robots with C-PRM” by Guang Song and Nancy M. Amato from Texas A&M University. [PDF]

The C-PRM algorithm provides us the ability to control the preferred paths procedure. We used its basic structure to achieve our quality criteria.

The results were encouraging, however, we thought the Hybrydization method we’d learned in the workshop might improve the path quality. Merging the methods wasn’t trivial. The combination of the paths required some creativity because the C-PRM algorithm wasn’t meant to support it.
This optimization improved the results in every quality measure, but, as expected,
solving the problem multiple times reqiured that much more time.

We noticed that custom optimizations can assist in specific situations,
so we’ve added some more optimizations for situations such as parking and narrow passage.

Finally , the resulting project is a fully GUI standalone application which contains a
“Scene Creator” – a painter program for creating 2d worlds ( and saving as XML files)
made from polygons, and the main program – an impressive non-holonomic motion planner.

Visual results

green: start point
red: end point


The project was written in C++ with support of the following software packages:

  • OOPSMP – we used this package as a basic framework for our project.
    This package contains some useful tools such as Graph structures,
    Search Algorithms, State Sampler ,XML reader, basic GUI etc.
  • PQP – Collision Detector , assisted in finding collision and distance measurements between polygons.
  • Triangulate – used for triangulate the polygons for the collision detector.
  • QT – used for 2D GUI implementation.
  • OpenGL – used to draw the problem.

We’ve implemented and modified the C-PRM algorithm.

More Details regarding implantation can be found in our Developer Guide Manual.


We’ve learned a lot in this workshop. We’ve been introduced to the interesting field of MotionPlanning –
A broad field with much room for innovation.
In this project we were required to deal with a large software package and a lot of self learning.

We were given a great deal of freedom and support throughout the project.
We believe our final results are interesting and perhaps even innovative in the field of car motion planning.


Press here to watch the movie

Yair Oz - Webcreator


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