CarND-Controls-PID

Self-Driving Car Engineer Nanodegree Program

Writeup

Student describes the effect of the P, I, D component of the PID algorithm in their implementation. Is it what you expected?

PID stands for proportional–integral–derivative. Its a control mechanism which constantly corrects based on the error value until a desired setpoint is reached.

The P component - proportional - is taken as an inversely proportional to measure how much turn the wheel should make. This means, more the error more turn the wheel should take The I component - Integral - Accounts for the past error values. Its a sum of past erros over time and correction is proportional to that. This means if there is any small error values over long time, we can correct that error The D component - derivative - this projects the future error and corrects the wheel. This means it calculates if we will overshoot the target if coninued in the same path and correct based on that

Yes, in my implementation I see that P, I, D did have a lot of impact. When I switched off the P, it was catestrophic failure for car as it was never able to be in lane. Its the most important. D component is second most important, expecially for long constant turns I component is very imporant in correcting small errors which can become big soon. This happens when car comes out of a curve into a straight road. The error overtime helps the car adjust fast
Student discusses how they chose the final hyperparameters (P, I, D coefficients). This could be have been done through manual tuning, twiddle, SGD, or something else, or a combination!

Initially for PID values (0.3, 0.0005, 20.) was choosen. Twiddle algorithm was used to tune. the twiddle threshold. Also different twiddle threasholds were experiemented upon. Also there is a throttle component which scales speed of the vehicle. Different speeds had different best parameters for twiddle. Running the simulation many times, the parameter of (0.114, 0, 3.24) was choosen for PID for a throttle of 0.5x scale. This is best suited for this track for the speed choosen.

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

Clone this repo.
Make a build directory: mkdir build && cd build
Compile: cmake .. && make
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./

adarshakb/CarND-PID-Control-Project