Self-Driving Car Engineer Nanodegree Program

Per the suggestion within the code, two PID controllers are used to control both the Steering and augmented by Throttle Speed.

To start finding the optimal parameters for Steering, through a continual process of trial and error and visually inspecting the results on the Simuulator, I applied the following methodology:

• Initially set the P (Proportional Control), I (Integral Control) and D (Derivative Control) PID components to 0.
• Increasing the proportional gain which increases the degree of vehicle oscillation.
• To offset this, increase the derivative gain and in turn decreasing the proportional gain to reduce the overall vehicle oscillation. It was noted that a too high an increase in the derivative gain causes the vehicle to over-steer. To reduce this this, without compromising the proportional gain, I gradually introduced integral gain to compensate for this and keep the vehicle toward the center.

Note: This tuning methodology does not apply high speeds above 52, therefore the values are lowered and constrained by the Throttle Speed.

The Throttle Speed is indirectly proportional to the cte (cross track error), which is the error from the desired position on the track. Basically, if the cte is high, then there is drift from the desired position. It was observed that a high cte occurred when the vehicle accelerated beyond 52 and thus the Throttle Speed PID constrains the vehicle and slows it down in order for the Steering parameters to have an optimal effect. Additionally, it was noted that the optimal Throttle Speed value for the Steering parameters to have a full effect, was 40.

• 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
  • Run either ./install-mac.sh or ./install-ubuntu.sh.
  • If you install from source, checkout to commit e94b6e1, i.e.

    git clone https://github.com/uWebSockets/uWebSockets 
    cd uWebSockets
    git checkout e94b6e1
    

    Some function signatures have changed in v0.14.x. See this PR for more details.
• Simulator. You can download these from the project intro page in the classroom.

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

We've purposefully kept editor configuration files out of this repo in order to keep it as simple and environment agnostic as possible. However, we recommend using the following settings:

• indent using spaces
• set tab width to 2 spaces (keeps the matrices in source code aligned)

Please (do your best to) stick to Google's C++ style guide.

Note: regardless of the changes you make, your project must be buildable using cmake and make!

More information is only accessible by people who are already enrolled in Term 2 of CarND. If you are enrolled, see the project page for instructions and the project rubric.

• You don't have to follow this directory structure, but if you do, your work will span all of the .cpp files here. Keep an eye out for TODOs.

Help your fellow students!

We decided to create Makefiles with cmake to keep this project as platform agnostic as possible. Similarly, we omitted IDE profiles in order to we ensure that students don't feel pressured to use one IDE or another.

However! I'd love to help people get up and running with their IDEs of choice. If you've created a profile for an IDE that you think other students would appreciate, we'd love to have you add the requisite profile files and instructions to ide_profiles/. For example if you wanted to add a VS Code profile, you'd add:

• /ide_profiles/vscode/.vscode
• /ide_profiles/vscode/README.md

The README should explain what the profile does, how to take advantage of it, and how to install it.

Frankly, I've never been involved in a project with multiple IDE profiles before. I believe the best way to handle this would be to keep them out of the repo root to avoid clutter. My expectation is that most profiles will include instructions to copy files to a new location to get picked up by the IDE, but that's just a guess.

One last note here: regardless of the IDE used, every submitted project must still be compilable with cmake and make./