Self-Driving Car Engineer Nanodegree Program
The project consisted of developing and tuning a PID controller for the steering given a simulation. The PID parameters were manually tuned then adjusted using gradient ascent.
Gradient ascent was implemented by timing approximately how long it took to go around the track and tracking the error along one full lap of the track. Using a full lap made it easier to judge the best parameters as the controller had to deal with the same terrain for all sets of parameters. Parameters were adjusted up and down on each lap of the track. The tuning script was allowed to run over night to ensure the (locally) optimal parameters were reached.
Throttle was arbitrarily set to 0.5 because it was faster than most other projects (steady state around 50 mph), but not too fast to do the inital manually tuning.
- P is the tendency of the vehicle to return to the center. When it is too high it will oscillate but will reach the control value faster. When it is too low it will fail to return to the center of the lane.
- I is useful for correcting small offsets when a signal is approaching a control value asymptotically.
- D is useful for making the vehicle approach the center line more smoothly, but if it is too high it will lead to overshoot and instability.
Given the above, the most common approach for manually tuning is to get the P value correct and adjust the I and D from 0 to smooth the trajectory of the vehicle.
- 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.Some function signatures have changed in v0.14.x. See this PR for more details.git clone https://github.com/uWebSockets/uWebSockets cd uWebSockets git checkout e94b6e1
- Run either
- Simulator. You can download these from the project intro page in the classroom.
There's an experimental patch for windows in this PR
- Clone this repo.
- Make a build directory:
mkdir build && cd build
- Compile:
cmake .. && make
- Run it:
./pid
.
Tips for setting up your environment can be found here
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./
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