bdschrisk/carnd-mpc-project-p5

Model Predictive Controller for use in waypoint navigation to drive a vehicle

CarND-Controls-MPC

Self-Driving Car Engineer Nanodegree Program

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Overview

This project uses a Model-Predictive-Controller to drive a vehicle around a track using waypoint navigation. The MPC model uses inference over a discrete number of timesteps to accurately (and smoothly) drive the vehicle around the track. To account for latency in the solvers' computation time, the current state is forward projected using a global kinematic motion model to update the state prior to differentiation.

Optimisation

The model is optimised using automatic-differentiation (IpOpt library) using the following cost function:

• Interpolation of states (i.e. state[t+1] - state[t])
• Actuator loss (acceleration and throttle)
• Reference state loss (cross-track, orientation and velocity errors)

The number of discrete timesteps used in optimisation is 2N + 1, which in this case is 11. This accounts for the forward projection of the initial state and the number of datapoints available at each prediction step.

Dependencies

• cmake >= 3.5
• All OSes: click here for installation instructions
• make >= 4.1
  • Linux: make is installed by default on most Linux distros
  • Mac: install Xcode command line tools to get make
  • Windows: Click here for installation instructions
• gcc/g++ >= 5.4
  • Linux: gcc / g++ is installed by default on most Linux distros
  • Mac: same deal as make - [install Xcode command line tools]((https://developer.apple.com/xcode/features/)
  • Windows: recommend using MinGW
• uWebSockets == 0.14, but the master branch will probably work just fine
  • Follow the instructions in the uWebSockets README to get setup for your platform. You can download the zip of the appropriate version from the releases page. Here's a link to the v0.14 zip.
  • If you have MacOS and have Homebrew installed you can just run the ./install-mac.sh script to install this.
• Ipopt
  • Mac: brew install ipopt --with-openblas
  • Linux
    • You will need a version of Ipopt 3.12.1 or higher. The version available through apt-get is 3.11.x. If you can get that version to work great but if not there's a script install_ipopt.sh that will install Ipopt. You just need to download the source from the Ipopt releases page or the Github releases page.
    • Then call install_ipopt.sh with the source directory as the first argument, ex: bash install_ipopt.sh Ipopt-3.12.1.
  • Windows: TODO. If you can use the Linux subsystem and follow the Linux instructions.
• CppAD
  • Mac: brew install cppad
  • Linux sudo apt-get install cppad or equivalent.
  • Windows: TODO. If you can use the Linux subsystem and follow the Linux instructions.
• Eigen. This is already part of the repo so you shouldn't have to worry about it.
• Simulator. You can download these from the releases tab.

Basic Build Instructions

1. Clone this repo.
2. Make a build directory: mkdir build && cd build
3. Compile: cmake .. && make
4. Run it: ./mpc.