CarND-Controls-PID

Self-Driving Car Engineer Nanodegree Program

---

Parameter Selection (steering angle only)

Proportional Constant (Kp) - 0.15 I started with 0.3 (Ki and Kd set to zero) and then slowly decreased the value and finally settled at 0.15 to achieve near equal amplitude assuming vehicle is driven on straight road.

Differential Constant (Kd) - 2.5* The parameter was set to 3 (Kp set to 0.15 and Ki set to zero) and was slowing decreased to 2.5 to achieve dampening for overshoot due to proportional factor.

Integral Constant (Ki) - 0.001 The vehicle in the simulator did not seem to have a systematic bias and I therefore started with 0 (Kp as 0.15 and Kd as as 2.5) and slowly increased it. Increasing the value over 0.003 increased the oscillations and therefore I settle for 0.001.

Parameter Selection (steering angle and throttle)

The throttle should be decreased if cross track error (cte) is high. Therefore, the hyperparameters for throttle is decreased or increased only when the rate of change of cte cross track error (cte) is high. Therefore, only Kd for throttle is being tuned. After trial and error, I selected 10 for the Kd of the throttle pid controller.

Once the throttle controller was set, I again tuned the parameters for steering controller similar to steps in previous section and finally set the Kp, Kd and Ki to 0.3, 2.7 and 0.001 respectively.

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
  • 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.

There's an experimental patch for windows in this PR

Basic Build Instructions

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

Editor Settings

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)

Code Style

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

Project Instructions and Rubric

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.

Hints!

• 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.

Call for IDE Profiles Pull Requests

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./