Project 2 - Implement the Code for controlling the retraction and extension of Airplane’s landing gear

Abhinaya Batch

#include<stdio.h>
#include<stdlib.h>

void Initial_state_machine();//function declaration
void Gear_down();
void Checking_before_takeoff();
void Raising_gear();
void Gear_up();
void Checking_before_landing();
void Lowering_gear();

typedef enum states
{
GEAR_DOWN ,
CHECK_BEFORE_TAKEOFF ,
RAISING_GEAR ,
GEAR_UP ,
CHECK_BEFORE_LANDING ,
LOWERING_GEAR
}state_type;

typedef enum Switch
{
open ,
close //open=0,close=1;.Plane is in ground
}Switch_status;

typedef enum pilot_lever
{
raising ,
falling ,
up ,
down
}pilot_lever_status;

typedef enum hydraulic_mechanism
{
working ,
malfunctioning //here 0 for working and 1 for malfunction
}hydraulic_mechanism_status;
/*inputs used in order to change the state*/

static volatile Switch_status squat_switch;
static volatile Switch_status limit_switch;
static volatile pilot_lever_status pilot_lever;
static volatile pilot_lever_status hydraulic_mechanism;

state_type current_state;

typedef struct //structure is used to have different types of data types
{
char* current_state_status; //output which we want to visualize are given under structure as stucture member
char* light_status;
char* direction_value_status;
char* hydraulic_pump_ctrl_status;
char* gas_pressurized_spring_status[2];
}state_table;

/*State table of the require system*/
static state_table state_machine[6] = {
{"gear down","green","down","enables",{0,0}},
{"checking before take off","green", "down","enabled",{0,0}},
{"raising gear","red","up","enabled",{"disabled","enabled"}},
{"gear up","off","NULL","disabled",{0,0}},
{"checking before landing","red","down","enabled",{0,0}},
{"lowering gear","green","down","enabled",{"disabled","enabled"}}
};

static void(*State_Table[])(void)={Gear_down,Checking_before_takeoff,
Raising_gear,Gear_up,Checking_before_landing,Lowering_gear};

//initial state machine//

void Initial_state_machine()
{
current_state = GEAR_DOWN;//during initialization, system is at gear down
printf("\n state machine is initials and at first program is in gear down and its light status is:%s\n",state_machine[current_state].light_status);
}

//Gear down//

void Gear_down(void)
{
current_state = GEAR_DOWN;
printf("\n Enter the pilot's lever and squat switch status:\n");
fflush(stdout);
scanf("%d %d", &pilot_lever, &squat_switch);
if(pilot_lever == raising && squat_switch == open)
{
current_state = CHECK_BEFORE_TAKEOFF;
printf("\n The current state of the machine is: %s\n",state_machine[current_state].current_state_status);
printf("\n Light status of the current machine state is: %s\n",state_machine[current_state].light_status);
}
else
{
Gear_down();
}
}

//checking before takeoff//

void Checking_before_takeoff()
{
current_state = CHECK_BEFORE_TAKEOFF;
printf("\n Enter the pilot lever position,squat switch and hydraulic mechanism:\n");//getting pilot lever,squat switch and hydraulic mechanism//
fflush(stdout);
scanf("%d %d %d",&pilot_lever,&squat_switch,&hydraulic_mechanism);
printf("\n just wait 2secs\n");
if(pilot_lever == up && squat_switch == close)
{
Gear_down(); //gear function is called
}
else if (pilot_lever == up && squat_switch ==open && hydraulic_mechanism == working);
{
current_state = RAISING_GEAR;
printf("\n Current state: %s\n",state_machine[current_state].current_state_status);
printf("light status : %s\n", state_machine[current_state].light_status);
printf("\n direction status:%s\n\n",state_machine[current_state].direction_value_status);
}

if (pilot_lever == up && squat_switch == open && hydraulic_mechanism == malfunctioning);
{
current_state = RAISING_GEAR;
printf("\n Current state: %s\n",state_machine[current_state].current_state_status);
printf("\nlight status : %s\n", state_machine[current_state].light_status);
printf("\n direction status:%s\n\n",state_machine[current_state].direction_value_status);
printf("\n Gas pressurised spring status:%s\n",state_machine[current_state].gas_pressurized_spring_status[hydraulic_mechanism]);
}

}

//raising gear//

void Raising_gear()
{
current_state = RAISING_GEAR;
printf("\n Enter the switch status and pilot lever status:\n");
fflush(stdout);
scanf("%d %d",&limit_switch,&pilot_lever);
printf("\n wait for 1 sec\n");
if(pilot_lever == falling && limit_switch == open)
{
current_state = CHECK_BEFORE_LANDING;
printf(" \n current state is:%s\n",state_machine[current_state].current_state_status);
printf("\n Light status:%s\n",state_machine[current_state].light_status);
printf("\nHydraulic condition for landing gear status is %s\n",state_machine[current_state].hydraulic_pump_ctrl_status);
}
else if(limit_switch == close && pilot_lever == up)
{
current_state = GEAR_UP;
printf(" \n current state is:%s\n",state_machine[current_state].current_state_status);
printf("\n Light status:%s\n",state_machine[current_state].light_status);
printf("\nHydraulic condition for landing gear status is %s\n",state_machine[current_state].hydraulic_pump_ctrl_status);

}
else
{
Raising_gear();
}
}

//gear up//

void Gear_up()

{
current_state = GEAR_UP;
printf("\n Enter the pilot lever position: \n");
fflush(stdout);
scanf("%d",&pilot_lever);
if(pilot_lever == falling)
{
current_state = CHECK_BEFORE_LANDING;
printf("\n Current state: %s\n", state_machine[current_state].current_state_status);
printf("\nlight status: %s\n",state_machine[current_state].light_status);
printf("\nHydraulic condition for landing gear status is %s\n",state_machine[current_state].hydraulic_pump_ctrl_status);
}
else
{
Gear_up();
}
}

//check before landing//

void Checking_before_landing()
{
current_state = CHECK_BEFORE_LANDING;
printf("\n Enter the pilot lever positon,status of hydraulic mechanism :\n");
fflush(stdout);
scanf("%d %d",&pilot_lever,&hydraulic_mechanism);

if(pilot_lever == down && hydraulic_mechanism == working)
{
current_state=LOWERING_GEAR;
printf("\n Current state: %s\n",state_machine[current_state].current_state_status);
printf("\nlight status: %s\n",state_machine[current_state].light_status);
printf("\n direction status:%s\n\n",state_machine[current_state].direction_value_status);
}
else if(pilot_lever == down && hydraulic_mechanism == malfunctioning)
{
current_state = LOWERING_GEAR;
printf("\n Current state: %s\n", state_machine[current_state].current_state_status);
printf("light status:%s\n",state_machine[current_state].light_status);
printf("\n direction status:%s\n\n",state_machine[current_state].direction_value_status);
printf("\n Gas pressurised spring status:%s\n",state_machine[current_state].gas_pressurized_spring_status[hydraulic_mechanism]);
}
if(pilot_lever == (up || raising || falling))
{
Checking_before_landing();
}
}

//lowering gear//

void Lowering_gear()
{
current_state = LOWERING_GEAR;
printf("\n Enter the pilot lever position, limit switch :");
fflush(stdout);
scanf("%d %d",&pilot_lever,&limit_switch);
if(pilot_lever == raising && limit_switch == close)
{
current_state = CHECK_BEFORE_TAKEOFF;
printf("\n Current state: %s\n",state_machine[current_state].current_state_status);
printf("\nlight status: %s\n", state_machine[current_state].light_status);
}
if(pilot_lever == down && limit_switch == open)
{
if(pilot_lever == down && limit_switch == open)
{
current_state = GEAR_DOWN;
printf("\n Currentstate: %s\n",state_machine[current_state].current_state_status);
printf("\n light status: %s\n",state_machine[current_state].light_status);
printf("\n Hydraulic contion for landing gear status is %s\n",state_machine[current_state].hydraulic_pump_ctrl_status);
}
else
{
Lowering_gear();
}
}
}

//main function//
int main()
{
Initial_state_machine();
while(1)
{
State_Table[current_state]();
}
}