Self-Driving Car Engineer Nanodegree Program
As shown in the above figure, there are 6 states in state:
To describe the kinematic state of the vehicle, we need x, y, v, and the yaw. Be aware that the yaw update formula has relation to the velocity (v) and the half-length of the vehicle (Lf).
In addition, we use the cross track error (cte) and the desired orientation subtracted from the current orientation (eψ) as reference to observe how well the vehicle behaves.
In this project, two important hyperparameters need to be tuned are the number of timestemps (N) and the time elapses between actuations (dt). Their multiple result Tau gives the period of time that the vehicle can foresee.
In the naive perspective, we would like to have Tau as large as possible, which means that we can predict a sufficient period. However, consider the dynamic driving environment and other objects, the value of Tau should be within a reasonable range.
Besides, from the perspective of algorithm complexity, N affects the size of the array. The bigger the size of the array is, the longer time it will take for our solver to find out the optimial solution.
The provided waypoints are in Map Coordinate System (MCS). In order to visualize along the driving, we need to transform the waypoints into Vehicle Coordinate System (VCS). After transformation, the 3rd order of polynomial fitting is implemented. The reason why using 3rd order is driving scenario dependent. If the driving environment is only on the highway, then the 1st/2nd order will be enough. However, in the provided driving track, there is S curve which needs to be fitted with 3rd order polynomial. In the real world, the 3rd polynomial fitting is also a reasonable choice.
In this project, we need to consider the 100ms actuator latency. One solution to handle this is after the ipopt solver conduct the optimal actuator combination (steering angle and acceleration value), instead of directly using this optimal combination, we add the latency on top of that.
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cmake >= 3.5
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All OSes: click here for installation instructions
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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
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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
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- Run either
install-mac.sh
orinstall-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
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Ipopt and CppAD: Please refer to this document for installation instructions.
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Eigen. This is already part of the repo so you shouldn't have to worry about it.
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Simulator. You can download these from the releases tab.
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Not a dependency but read the DATA.md for a description of the data sent back from the simulator.
- Clone this repo.
- Make a build directory:
mkdir build && cd build
- Compile:
cmake .. && make
- Run it:
./mpc
.
- It's recommended to test the MPC on basic examples to see if your implementation behaves as desired. One possible example is the vehicle starting offset of a straight line (reference). If the MPC implementation is correct, after some number of timesteps (not too many) it should find and track the reference line.
- The
lake_track_waypoints.csv
file has the waypoints of the lake track. You could use this to fit polynomials and points and see of how well your model tracks curve. NOTE: This file might be not completely in sync with the simulator so your solution should NOT depend on it. - For visualization this C++ matplotlib wrapper could be helpful.)
- Tips for setting up your environment are available here
- VM Latency: Some students have reported differences in behavior using VM's ostensibly a result of latency. Please let us know if issues arise as a result of a VM environment.
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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