enienws / carnd-pid-control-project

CarND-Controls-PID

Self-Driving Car Engineer Nanodegree Program

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##What is a PID Controller PID controller is a control loop feedback controller. This type of controller is used widely among different control problems.

PID controller consists of three components named as Proportional, Integrative, Derivative.

Proportional error is proportional to systems overall error. Derivative error is propportional to how fast the error increasing or decreasing. Integrative error is proportional to cumulative error that depends to system run before.

Three errors are implemented by using the following code block:

d_error = cte - p_error;
p_error = cte;
i_error += cte;

Each kind of error types are used to provide a smooth system act. Not all the systems need to have all the components simple P controllers or PD controllers may be implemented as well.

##PID Controller Implementation In the project source code we have PID.cpp and PID.h files. These files define the PID class which implements a simple PID controller.

In UpdateError method, three different errors are defined. In TotalError method, total error of the system is calculated using three types of error. This result is given as a steering value to the simulator.

##Tuning PID Parameters I have chosen to tune PID parameters by a manual try and error way. Since P error affects the overall system a lot, I first start to tune P value by setting I and D values to 0. In other words, I started by a simple P controller as a first step. I started to tune D parameter as the P controller performs well and finally I parameter is tuned.

Below you can find different videos related to different steps of tuning:

Tuning the P controller, Kp = 5 Link to video file

Tuning the P controller, Kp = 2.5 Link to video file

Tuning the P controller, Kp = 0.5 Link to video file

Tuning the P controller, Kp = 0.25 Link to video file

It seems P controller works well with Kp=0.25. After this step I started to work on Derivative term.

Tuning the PD controller, Kp = 0.25, Kd = Link to video file

And finally the PID controller: Kp = 0.25, Kd = 1.5, Ki = 0.003 Link to video file

The final PID Controller: Kp = 0.25, Kd = 1.5, Ki = 0.0003 Link to video file

Dependencies

• cmake >= 3.5
• All OSes: click here for installation instructions
• make >= 4.1(mac, linux), 3.81(Windows)
  • 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.

Fellow students have put together a guide to Windows set-up for the project here if the environment you have set up for the Sensor Fusion projects does not work for this project. There's also 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.

Tips for setting up your environment can be found here

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./

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