AeroQuest

Intro

Developed a drone simulation system using the provided ARM based board to replicate the intricacies of controlling a drone during a search operation in mountainous terrains. The program simulates the navigation of a drone over a 2D matrix representing a mountain landscape. The simulation provides real-time updates of the drone as it navigates the terrain such as the drone states, speed, altitude, position on the map and whether the drone has identified the crash location or crashed. Users define the accident location, introducing variability to the simulation.

Input mechanisms include a reset button, push buttons for speed adjustment, a keypad for flight direction and state changes, and an LED bar indicating simulation status.

Design assumptions

1. given valid inputs, where required. For, we will not be provided an accident location outside of the map
2. The drone automatically increases its altitude by 1 at each tick, unless a higher value is set whilst in hover mode during the prior one-second interval.
3. A crash event occurs when the difference between the drone’s altitude and the altitude at the current position is greater than 1.
4. Going up and down will not cause a crash
5. A drone will not move out of the grid. If a move like this is performed, it will remain at the border of the map.
6. Search is only done in the direction that the drone is facing and Manhattan distance is used for visibility.
7. Top speed is 9m/s.

Execution Flow

• Accident Input: The program starts with input of the x and y positions for the accident. It will then automatically calculate the z position of the accident.

• Main: Continuous looping of main until it polls for input or goes to the timer interrupt every 1 microsecond.

• Check Input: Loops through checking of input of button press and keyboard. If no input is detected then return to main. If detected then handle the relevant input separately

• Handle Push Button: If the push button is pressed, Check whether states should be changed according to the button pushed (Cannot change speed for N, S, E, W when in hover mode, speed cannot go over 9, etc.)

• Button Debounce: Poll the push button until the counter is either 0 or 40. 0 meaning no button is being pressed and 40 meaning the button is still pressed.

• Keypad debounce Delay keypad input after keypad entry for 256ms.

• Timer interrupt: The OVF2 interrupt rate depends on the speed of the drone. The OVF1 condition refreshes the LCD around every 100ms and the OVF2 condition is achieved every 10 times OVF1 condition is achieved when the drone is moving at a speed of 1m/s, which is around once every second. The number of times OVF1 is achieved before OVF2 is inversely proportional to the speed. For example at the speed of 2, OVF2 will be achieved every 5 times OVF1 is achieved, which is around 500ms. This means that the handle speed state only increments the position by at most once and it has the effect of changing the state faster when speed is faster, which makes the drone seem like it’s flying faster..

• Handle Speed: Handles how the speed and direction change the position of the drone. Only increment or decrement by 1 as mentioned previously.

• Crash Check: Check if the current altitude of the mountain is higher than the current position of the drone by 2. If only by one the drone automatically adjusts height. If not, the drone crashes.

• Crashed: Return a display on LCD that shows the drone has crashed and the location of the crash is displayed

• Search: Search in the direction where the drone is heading only. Loop through each position ahead of the drone in the direction that it is facing. If visibility reaches 0 then the accident is not found and goes to the next state. If the current loop’s altitude of the map is higher than the drone then the accident is not found and goes to the next state. If the drone's position is above the ground by more than the visibility level then go to the next loop (This prevents early exiting when there is a huge pit one step ahead of the drone but accident on the next location level with the drone which should still be visible). If the accident location is found then go to the state of return. The next loop starts with the next position in the direction the drone is facing with 1 lower visibility level (Since we are using Manhattan’s distance).

• Return: Return a display on LCD that shows the drone has returned and the location of the accident is displayed.

• Load state on LCD: Displays the states of the drone: the map in the direction the drone is facing, a cursor underneath the drone’s current position on the map, the state of the drone, the x,y, and z coordinate of the drone, and the speed of the drone.

Components

Registers

Name	Register	Description
flightDirection	R3	Stores the flight direction of the drone
hfState	R4	Stores whether the drone is in hover or flight state
pos_x	R5	Stores the drone's x position
pos_y	R6	Stores the drone's y position
pos_z	R7	Stores the drone's altitude
counter_speed	R8	Used for determining timing intervals in the Timer interrupt
func_return	R9	Used to store return values from function calls
func_return2	R10	Used to store return values from function calls
acci_loc_x	R11	Stores the x coordinate of the accident location
acci_loc_y	R12	Stores the y coordinate of the accident location
acci_loc_z	R13	Stores the altitude of the accident location
visibility	R14	Stores visibility level of the drone
row	R16	Used to store the current row when polling keypad input
col	R17	Used to store the current column when polling keypad input
rmask	R18	Mask used for determining the current row
cmask	R19	Mask used for determining the current column
speed	R20	Stores the speed that the drone travels each second
temp1	R21	Used as a working register
temp2	R22	Used as a working register
temp3	R23	Used as a working register
iL	R24	Used for counting in the supporting functions
iH	R25	Used for counting in the supporting functions

Hardware

Port Group	Pin	Port Group	Pin
PORT L	PL7	KEYPAD	R0
PORT L	PL6	KEYPAD	R1
PORT L	PL5	KEYPAD	R2
PORT L	PL4	KEYPAD	R3
PORT L	PL3	KEYPAD	C0
PORT L	PL2	KEYPAD	C1
PORT L	PL1	KEYPAD	C2
PORT L	PL0	KEYPAD	C3
PORT D	RDX3	INPUTS	PB1
PORT D	RDX4	INPUTS	PB0
PORT C	PC0	LED BAR	LED2
PORT C	PC1	LED BAR	LED3
PORT C	PC2	LED BAR	LED4
PORT C	PC3	LED BAR	LED5
PORT C	PC4	LED BAR	LED6
PORT C	PC5	LED BAR	LED7
PORT C	PC6	LED BAR	LED8
PORT C	PC7	LED BAR	LED9
PORT G	PG2	LED BAR	LED0
PORT G	PG3	LED BAR	LED1
PORT F	PF0	LCD DATA	D0
PORT F	PF1	LCD DATA	D1
PORT F	PF2	LCD DATA	D2
PORT F	PF3	LCD DATA	D3
PORT F	PF4	LCD DATA	D4
PORT F	PF5	LCD DATA	D5
PORT F	PF6	LCD DATA	D6
PORT F	PF7	LCD DATA	D7
PORT A	PA4	LCD CTRL	BE
PORT A	PA5	LCD CTRL	RW
PORT A	PA6	LCD CTRL	E
PORT D	RDX4	INPUTS	PB0
PORT D	RDX3	INPUTS	PB1