Recruitment Sim

Your task is to write a simple race simulation that will output the optimal constant speed for the World Solar Challenge, a ~3000km race starting in Darwin, Australia and ending in Adelaide, Australia. Your primary goal is to fill in the code and complete the Sim class and the Car class.

Description of the World Solar Challenge

The world solar challenge is a seven day event starting on October 22nd, 2023 and ending on October 28th, 2023. The race day begins at 9am and ends at 5pm from the second day (October 23rd) onwards. On the first day, the race day begins at 10am and ends at 6pm. During this time, the car is able to drive and make progress towards the finish line. Outside of race hours, the car can be charged in a stationary position as long as the sun is above the horizon. There are also 9 control stops at specific places throughout the race where you must stop for 30 minutes, allowing you to charge and check in with the race officials to ensure that you are staying on the route. The goal is to make it to the finish line in Adelaide as quickly as possible.

Your Task

You have been given starter code for completing this assignment that can be found in the include/ and src/ folders. You will first need to complete the Car class which will model the energy state of the car when travelling at a constant speed between two points. At minimum, you will need to model aerodynamic energy loss, rolling resistance loss, gravitational loss, and passive electric loss. You'll be able to find equations for these from a quick google search. A list of constants are given below to aid in the formulation of those equations:

• Passive Electric Loss: 20 W
• Rolling Resistance Constant: 0.0026
• cda: 0.15
• Array Efficiency: 0.252
• Car Mass: 283kg
• Battery Efficiency: 0.98
• Motor Efficiency: 0.8
• Array Area: 4 m^2
• Maximum Battery Capacity: 5.2 kWh

You will also have to complete the Sim class which will take a Car object as input along with an array of route coordinates, and control stop locations. The sim class has one primary function called run_sim that will simulate whether a proposed constant speed is a viable solution for the race. It is viable if the energy level of the car never drops below 0.0 and if the car can make it to the end of the race by October 28th, 2023, 5pm. Your run_sim function should be calling functions from your Car class to calculate energy changes throughout the race. The Sim.hpp file already defines the series of constants e.g. race day start/end times that you can use.

There are two .csv files located in the data/ folder - baseroute.csv and dni.csv

The baseroute.csv is the series of points in the route formatted into |latitude(deg) | longitude(deg) | altitude(m)| columns.

The dni.csv is a lookup table that holds irradiance values (W/m^2) from the sun throughout the route. In this lookup table, you can access the irradiance value using a latitude/longitude and a timestamp combination where the latitude/longitude index the rows and the timestamps index the columns. The timestamps are formatted in a single string YYMMDDHHMMSS.

For example, if you want to know the irradiance value at a lat/long coordinate of -12.51163,131.02239 and timestamp of 2023-10-21 22:00:00, it would be 187 W/m^2 (highlighted in red). The coordinate indexes the 12th row and the timestamp indexes the 10th column. For timestamps or latitude/longitude values that aren't directly on the lookup table, linearly interpolate to the nearest row/column.

WARNING: All times in dni.csv are in UTC time, which is 9.5 hours behind Australian central time zone. Therefore, 2023/10/23 21:30:00 (231023213000 in dni.csv) actually means 2023/10/24 09:00:00 LOCAL Australian time. You will notice that in every instantiation of the Time class, there is a -9.5 argument to account for this UTC adjustment.

The main.cpp file is the entry point of your program. It loads in the series of route points from baseroute.csv, sets up a set of indices where control stops are located and loads the dni.csv . You should NOT modify these lines. Then, it instantiates an object of Car type which you will write, sets the starting time and starting coordinate of the simulation. Finally, it loops through speeds from 1 to 100 to determine which speeds allow the race to be completed by repeatedly calling the run_sim() function that you will write. You should not need to modify the Luts.hpp file and date.h files at all. You should not have to read the date.h file at all; it is a third party package written by other people. You should not have to modify anything in main.cpp.

You will have to take a read through the code to understand how it interacts before beginning your implementation. The instructions are kept vague to encourage you to think critically about your implementation. I recommend starting with the Car class and specifically listing out the equations that will model energy losses and energy gains.

Toolchain

The below download are for those who don't already have the necessary dependencies for this project (CMake, git, make, gcc). If you already have those, you can ignore the stuff below

Getting a Windows Compiler

• Download Git (https://git-scm.com/downloads/win) which will also install the git bash terminal
• Download CMake windows installer (https://cmake.org/download/)
• Download Msys2 (https://www.msys2.org/)
• Follow the instructions on the Msys2 home page with the following modifications to the steps:
  • In step 5, instead of launching the UCRT64 environment which has proven to be buggy, use the MinGW64 environment. You can find this as one of the applications in the downloaded msys2/ folder.
  • In step 6, run pacman -S mingw-w64-x86_64-gcc inside the MinGW64 terminal. Then install make with pacman -S mingw-w64-x86_64-make inside the same MinGW64 terminal. After installing make, re-name the mingw32-make file in msys2/mingw64/bin to make.
• Add the absolute path to msys2/mingw64/bin to your PATH environment variable
• Open git bash and ensure that make --version gcc --version run without error. If you get a command not found error.

Getting a Linux Compiler

• sudo apt-get install build-essential gdb cmake

Build

Run these from a terminal

• mkdir build
• cd build
• cmake ..
• make
• ./sim.exe [relative baseroute.csv location] [relative dni.csv location]

After building for the first time with nothing written, you should get the output:

Speed 0 is not viable
Speed 1 is not viable
Speed 2 is not viable
Speed 3 is not viable
Speed 4 is not viable
Speed 5 is not viable
Speed 6 is not viable
Speed 7 is not viable
Speed 8 is not viable
Speed 9 is not viable
Speed 10 is not viable
...