timout/carnd-pid-control

CarND-Controls-PID

Self-Driving Car Engineer Nanodegree Program

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Objective

This project is to use PID controllers to control the steering angle and the throttle for driving a car in a game simulator. The simulator provides cross-track error (CTE) via websocket. The PID (proportional-integral-differential) controllers give steering and throttle commands to drive the car reliably around the simulator track.

Basic Build Instructions

1. Clone this repo.
2. Make a build directory: mkdir build && cd build
3. Compile: cmake .. && make
4. Run it: ./pid.

Parameters of PID controller

Description of PID values in PID control

• P (proportional) accounts for present values of the error.
• I (integral) accounts for all past values of the error.
• D (differential) accounts for possible future trends of the error, based on its current rate of change.

PID parameters used for steering angles:

• P = 0.195138, -7.286e-13,
• I = value: -7.286e-13
• D = value: 2.9994

Parameter tuning

I have implemented 2 algorithms:

• Gradient Descent with Backpropagation
• Twiddle

Thoughts and improvents

• Tuning with Twiddle takes more time so it was implemented limited number of iterations. Reset every epoch_size iterations. Than need some improvement, probably any way to avoid it.
• SG implementation depends on initial parameters so with poor choice the car often goes out of the road. So reset function was implemented and requires some improvement.
• Only steering controller was implemented. Next step will speed contoller.

Result

Result video: