Lunar Lander Code

 

% Samuel Georgal

% Lunar Lander

% 4/20/22

close all; clear; clc

global f dtheta dx dy mf theta

global Vxbox Vybox Fuelbox Thrustbox Thetabox Dthetabox

% Creates required variables

xmax = 500;

xmin = 0;

ymax = xmax;

f = 0;

Xs = 50;

Ys = 480;

c = 0;

l = 0;

dx = 10;

dy = 0;

ax = 0;

ay = 0;

g = 1.62;

R = 1.738*10^6;

mf = 3500;

m0 = 4900;

m = m0 + mf;

Tmax = 33000;

fdeg = .00328;

theta = -90;

dt = .01;

dtheta = 0;

% Create Figure window

KeyFig = figure('Units','pixels','Position', [0, 0, 1000, 820]);

% formats figure

axes(KeyFig,'Units', 'pixels', 'Position', [0,0,820,820],'color','k');

axis([xmin, xmax, 0, ymax])

axis manual

hold on

% Register KeyPressFcn to allow figure window to respond to keypresses

set(KeyFig, 'WindowKeyPressFcn', @KeyDownListener)

% Graphs lunar surface

y = graph;

% makes ship and thrust shape

ShipShape = [ -5.00, -3.00, -3.00, 3.00, 3.00, 5.00, 3.00, 1.00, 3.00, 3.00, 1.00, ...

-1.00, -3.00, -3.00, -1.00, -3.00; 0.00, 2.00, 1.00, 1.00, 2.00, 0.00, 4.00, ...

4.00, 6.00, 8.00, 10.00, 10.00, 8.00, 6.00, 4.00, 4.00];

ShipThrust = [-3.00,0,3;0,-16,0];

% scales ship and thrust size

ShipScale = 1.2;

SHIP = ShipScale*ShipShape;

Thrust = ShipThrust * f;

% Creates patch for ship and thrust

Ship_Patch = patch(SHIP(1,:)+Xs, SHIP(2,:)+Ys, 'w');

Ship_Thrust = patch(Thrust(1,:)+Xs, Thrust(2,:)+Ys, 'y');

% Creates editable text boxes for code to show important values

Control;

errordlg(['Land on the Moon! Use WASD or arrow keys to control lander. ' ...

'Land slowly and upright to complete. Have fun!!']);

% Runs Game

while (c == 0) && (l == 0)

% Calculates ship movement and position

ay = ((f*Tmax*cosd(theta))/m)-(g-((dx^2)/R));

ax = (f*Tmax*sind(theta))/m;

dm = f*Tmax*fdeg;

Xs = Xs + dx*dt;

Ys = Ys + dy*dt;

xint = round(Xs);

dx = dx + ax*dt;

dy = dy + ay*dt;

mf = mf - dm*dt;

m = m0 + mf;

theta = theta + dtheta;

if theta >= 180

theta = -180+(theta-180);

elseif theta <= -180

theta = 180-(theta+180);

end

% Makes required changes to patches and updates the patches

Thrust = ShipThrust * f;

RtnMtrx = [-cosd(-theta), -sind(-theta); -sind(-theta), cosd(-theta)];

Ship_R = RtnMtrx*SHIP;

Thrust_R = RtnMtrx*Thrust;

set(Ship_Patch, 'Xdata', Ship_R(1,:)+Xs, 'Ydata', Ship_R(2,:)+Ys)

set(Ship_Thrust, 'Xdata', Thrust_R(1,:)+Xs, 'Ydata', Thrust_R(2,:)+Ys)

% Updates information boxes

Vxbox.String = num2str(dx,'%.1f');

Vybox.String = num2str(dy,'%.1f');

Fuelbox.String = num2str(mf,'%.0f');

Thrustbox.String = num2str(100*f,'%.0f');

Thetabox.String = num2str(theta,'%.0f');

Dthetabox.String = num2str(100*dtheta,'%.0f');

% Keeps ship inbounds and checks for crashing or landing

if Ys >= ymax

Ys = ymax;

elseif Ys <= y(xint)

if (abs(dx) >= 3) || (abs(dy) >= 10)

c = 1;

elseif (abs(theta) > 10)

c = 1;

else

l = 1;

end

end

if Xs >= xmax

Xs = xmax;

elseif Xs <= xmin

Xs = xmin;

end

% Pauses by required time

pause(dt)

end

% Checks if landed or crashed and responds accordingly

if c == 1

th = 0:pi/50:2*pi;

for r = 5:50

xunit = r * cos(th) + Xs;

yunit = r * sin(th) + Ys+2;

plot(xunit, yunit,'r');

fill(xunit, yunit, 'r');

pause(.03)

end

pause(2);

errordlg('Mission Failed!');

else

set(Ship_Thrust, 'Xdata', 0, 'Ydata', 0)

set(Ship_Patch, 'Xdata', SHIP(1,:)+Xs, 'Ydata', SHIP(2,:)+Ys)

errordlg('Mission Complete!');

end

%% Functions

% Key-press 'listener' function

function KeyDownListener(src, event)

% triggered by pressing a key on the keyboard

global f dtheta

% Updates Keyid so key input is registered

KeyID = event.Key;

% Updates correct paramater depending on key input

switch KeyID

case 'w'

f = f + .04;

if f >1

f = 1;

end

case 's'

f = f- .04;

if f < 0

f = 0;

end

case 'a'

dtheta = dtheta - 0.1;

case 'd'

dtheta = dtheta + 0.1;

case 'uparrow'

f = f + .04;

if f >1

f = 1;

end

case 'downarrow'

f = f- .04;

if f < 0

f = 0;

end

case 'leftarrow'

dtheta = dtheta - 0.1;

case 'rightarrow'

dtheta = dtheta + 0.1;

end

KeyID = ' ';

end

function [y] = graph

% Randomly generates a terrain with different probabilities for each dy

y = NaN(1,500);

x = [1:500];

y(1) = randi(200);

for i = 2:3:500

chg = randi(10);

switch chg

case 1

y(i) = y(i-1)-randi(1)+randi(1);

case 2

y(i) = y(i-1)-randi(1)+randi(1);

case 3

y(i) = y(i-1)-randi(1)+randi(1);

case 4

y(i) = y(i-1)-randi(1)+randi(1);

case 5

y(i) = y(i-1)-randi(1)+randi(1);

case 6

y(i) = y(i-1)-randi(3)+randi(3);

case 7

y(i) = y(i-1)-randi(3)+randi(3);

case 8

y(i) = y(i-1)-randi(5)+randi(5);

case 9

y(i) = y(i-1)-randi(5)+randi(5);

case 10

y(i) = y(i-1)-randi(10)+randi(10);

end

%calculates next 3 points

dy = y(i)-y(i-1);

y(i+1) = y(i)+dy;

y(i+2) = y(i+1)+dy;

% ensures terrain stays within bounds

if y(i+2) <= 0

y(i+2) = 5;

elseif y(i+2) >= 350

y(i+2) = 345;

end

if y(i) <= 0

y(i) = 5;

elseif y(i) >= 350

y(i) = 345;

end

end

yc = y(1,1:500);

% Plots result

plot(x,yc,'w','LineWidth',3)

end

function Control

global dx dy mf f theta dtheta

global Vxbox Vybox Fuelbox Thrustbox Thetabox Dthetabox

% Creates a box for each information type

Vxbox = uicontrol('Style', 'edit', 'String', num2str(dx,'%.1f'), ...

'Position', [880, 460, 80, 20], 'Enable', 'inactive');

uicontrol('Style', 'text', 'String', 'Horizontal Velocity (m/s)', ...

'Position', [845, 480, 150, 20])

Vybox = uicontrol('Style', 'edit', 'String', num2str(dy,'%.1f'), ...

'Position', [880, 510, 80, 20], 'Enable', 'inactive');

uicontrol('Style', 'text', 'String', 'Vertical Velocity (m/s)', ...

'Position', [845, 530, 150, 20])

Fuelbox = uicontrol('Style', 'edit', 'String', num2str(mf,'%.0f'), ...

'Position', [880, 560, 80, 20], 'Enable', 'inactive');

uicontrol('Style', 'text', 'String', 'Fuel (kg)', ...

'Position', [845, 580, 150, 20])

Thrustbox = uicontrol('Style', 'edit', 'String', num2str(f,'%.2f'), ...

'Position', [880, 610, 80, 20], 'Enable', 'inactive');

uicontrol('Style', 'text', 'String', '% maximum thrust', ...

'Position', [845, 630, 150, 20])

Thetabox = uicontrol('Style', 'edit', 'String', num2str(theta,'%.1f'), ...

'Position', [880, 660, 80, 20], 'Enable', 'inactive');

uicontrol('Style', 'text', 'String', 'Angle', ...

'Position', [845, 680, 150, 20])

Dthetabox = uicontrol('Style', 'edit', 'String', num2str(100*dtheta,'%.1f'), ...

'Position', [880, 710, 80, 20], 'Enable', 'inactive');

uicontrol('Style', 'text', 'String', 'Rotation Speed (degrees/s)', ...

'Position', [845, 730, 150, 20])

end