Self-Driving Car Engineer Nanodegree Program
The x and y position, psi orientation, velocity, cross track error and psi error denotes the state of a car in this model. The actuators are driven by the output of the model which is steering angle(+-25 degrees) and the throttle(+1 denotes full throttle and -1 denotes full breaking). Update Equations are as follows for the given kinematic model.
N is the total number of points we are considering to calculate the future state of the vehicle. dt is the time interval between the two consecutive future states.
dt is the interval between two consecutive future states. So if dt is smaller we will be able to predict the states of the vehicle very accurately in near future.
N is the number of future states we are predicting. N will be directly proportional to the computation time. So larger value of N can cost a lot of computation.
As discussed above increasing N and decreasing dt can increase the accuracy of future predicted states but this could also affect the overall performance of the MPC algorithm. If the car is at high speeds and we have a Large N and very small dt then the computation could take a larger time and the car could be moving ahead of the predicted state.
The most popular choice is N=10, dt=0.1 which worked well for this project too.
Prior to MPC I am converting the global coordinates ptsx and ptsy to vehicle's local coordinate waypoints_x and waypoints_y. Later I ran polyfit on waypoints to calculate coefficients of the 3rd-degree curve in which the car will be moving. Using these coefficients I calculated the cross track error and the psi error. These errors are used to denote the state of the car ie (x, y, psi, v, cte, psi error)
For dealing with latency I am predicting the future state of the vehicle using the velocity of the car with the MPC equations. I added this logic at line 109 - 116 in main.cpp
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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.shorinstall-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.csvfile 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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