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

#include<stdio.h>

void Init_State_Machine();
void Gear_Down();
void Checking_Before_Takeoff();
void Raising_Gear();
void Gear_Up();
void Checking_Before_Landing();
void Lowering_Gear();

static void (*state_table[])(void) = {Gear_Down, Checking_Before_Takeoff, Raising_Gear,
Gear_Up, Checking_Before_Landing, Lowering_Gear};// syntax

typedef enum State
{

GR_DWN,
CHK_BFR_TKFF,
RSING_GR,
GR_UP,
CHK_BFR_LND,
LWRNG_GR

}State_Type;

typedef enum Switch
{

Open,
Close//Plane is in ground

}Switch_Status;

typedef enum Pilot_Lever
{

Rising,
Falling,
UP,
DOWN

}Pilot_Lever_Status;

typedef enum Hydraulic_Mechanism
{

Working,
Malfunctioning

}Hydraulic_Mechanism_Status;

/* -----input for changing the State----- */
static volatile Switch_Status squat_switch;
static volatile Switch_Status limit_switch;
static volatile Pilot_Lever_Status pilot_lever;
static volatile Hydraulic_Mechanism_Status hydraulic_mechanism;

State_Type current_state;

typedef struct
{
char* current_state_indication;
char* light_status;
char* direction_valve_status;
char* hydraulic_pump_control_status;
char* gas_pressurized_spring_status[2];
}State_Table;

static State_Table State_Machine[6] = {
{"Gear Down","Green","Down","Enabled",{NULL,NULL}},
{"Checking Before Take Off","Green","Down","Enabled",{NULL,NULL}},
{"Raising Gear","Red","Up","Enabled",{"Disabled","Enabled"}},
{"Gear Up","Off","Null","Disabled",{NULL,NULL}},
{"Checking Before Landing","Red","Down","Enabled",{NULL,NULL}},
{"Lowering Gear","Green","Down","Enabled",{"Disabled","Enabled"}}
};
int main()
{
Init_State_Machine();
while(1)
{
state_table[current_state]();
}
}

void Raising_Gear()
{
current_state = RSING_GR;
//printf("\nCurrent State : %s\n",State_Machine[current_state].current_state_indication);
printf("\nEnter the Limit Switch Status,Pilots Leaver Status:");
fflush(stdout);
scanf("%d %d",&limit_switch,&pilot_lever);
printf("\nWait for 1 sec\n");
if(pilot_lever == Falling && limit_switch == Open)
{
current_state = CHK_BFR_LND;
printf("\nCurrent State : %s\n",State_Machine[current_state].current_state_indication);
printf("Light Status:%s\n",State_Machine[current_state].light_status);
printf("Hydraulic Control for Landing Gear Status:%s\n",State_Machine[current_state].hydraulic_pump_control_status);

}
else if(limit_switch == Close && pilot_lever == UP)
{
current_state = GR_UP;
printf("\nCurrent State : %s\n",State_Machine[current_state].current_state_indication);
printf("Light Status:%s\n",State_Machine[current_state].light_status);
printf("Hydraulic Control for Landing Gear Status:%s\n",State_Machine[current_state].hydraulic_pump_control_status);
}

else
{
Raising_Gear();
}
}

void Checking_Before_Takeoff()
{
current_state = CHK_BFR_TKFF;
//printf("\nCurrent State : %s\n",State_Machine[current_state].current_state_indication);
printf("\nEnter the Pilot's Lever Position,Squat Switch Status and Hydraulic Mechanism Status:");
fflush(stdout);
scanf("%d %d %d",&pilot_lever,&squat_switch,&hydraulic_mechanism);
printf("\nWait for 2 secs\n");
if(pilot_lever == Falling || squat_switch == Close)
{
Gear_Down();
}

else if(pilot_lever == UP && squat_switch == Open && hydraulic_mechanism == Working)
{
current_state = RSING_GR;
printf("\nCurrent State : %s\n",State_Machine[current_state].current_state_indication);
printf("Light Status:%s\n",State_Machine[current_state].light_status);
printf("Direction Valve Status:%s\n\n",State_Machine[current_state].direction_valve_status);
}

else if(pilot_lever == UP && squat_switch == Open && hydraulic_mechanism == Malfunctioning)
{
current_state = RSING_GR;
printf("\nCurrent State : %s\n",State_Machine[current_state].current_state_indication);
printf("Light Status:%s\n",State_Machine[current_state].light_status);
printf("Direction Valve Status:%s\n",State_Machine[current_state].direction_valve_status);
printf("Gas Pressurized Spring System Status:%s\n",State_Machine[current_state].gas_pressurized_spring_status[hydraulic_mechanism]);
}
}
void Lowering_Gear()
{
current_state = LWRNG_GR;
//printf("\nCurrent State : %s\n",State_Machine[current_state].current_state_indication);
printf("\nEnter the Limit Switch Status,Pilots Leaver Status::");
fflush(stdout);
scanf("%d %d",&limit_switch,&pilot_lever);
if( limit_switch == Close && pilot_lever == Rising )
{
current_state = CHK_BFR_TKFF;
printf("\nCurrent State : %s\n",State_Machine[current_state].current_state_indication);
printf("Light Status:%s\n",State_Machine[current_state].light_status);
}
if(limit_switch == Open && pilot_lever == DOWN)
{
current_state = GR_DWN;
printf("\nCurrent State : %s\n",State_Machine[current_state].current_state_indication);
printf("Light Status:%s\n",State_Machine[current_state].light_status);
printf("Hydraulic Control for Landing Gear Status:%s\n",State_Machine[current_state].hydraulic_pump_control_status);
}

else
{
Lowering_Gear();
}
}
void Init_State_Machine()
{
//System Initialized and its in State_A
current_state = GR_DWN;
printf("\nState Machine is initialized & Program is in Gear_Down State & Light Status : %s\n"
,State_Machine[current_state].light_status);
}
void Gear_Up()
{
current_state = GR_UP;
//printf("Current State : %s\n",State_Machine[current_state].current_state_indication);
printf("\nEnter the Pilot's Lever Position:");
fflush(stdout);
scanf("%d",&pilot_lever);
if(pilot_lever == Falling)
{
current_state = CHK_BFR_LND;
printf("\nCurrent State : %s\n",State_Machine[current_state].current_state_indication);
printf("Light Status:%s\n",State_Machine[current_state].light_status);
printf("Hydraulic Control for Landing Gear Status:%s\n",State_Machine[current_state].hydraulic_pump_control_status);
}
else
{
Gear_Up();
}
}
void Gear_Down(void)
{
current_state = GR_DWN;
//printf("\nCurrent State : %s\n",State_Machine[current_state].current_state_indication);
printf("\nEnter the Pilot's Lever Position and Squat Switch Status:");
fflush(stdout);
scanf("%d %d",&pilot_lever,&squat_switch);
if(pilot_lever == Rising && squat_switch == Open)
{
current_state = CHK_BFR_TKFF;
printf("\nCurrent State : %s\n",State_Machine[current_state].current_state_indication);
printf("Light Status:%s\n",State_Machine[current_state].light_status);
}
else
{
Gear_Down();
}

}

void Checking_Before_Landing()
{
current_state = CHK_BFR_LND;
//printf("\nCurrent State : %s\n",State_Machine[current_state].current_state_indication);
printf("\nEnter the Pilot's Lever Position and Status of Hydraulic Mechanism:");
fflush(stdout);
scanf("%d %d",&pilot_lever,&hydraulic_mechanism);
if(pilot_lever == DOWN && hydraulic_mechanism == Working)
{
current_state = LWRNG_GR;
printf("\nCurrent State : %s\n",State_Machine[current_state].current_state_indication);
printf("Light Status:%s\n",State_Machine[current_state].light_status);
printf("Direction Valve Status:%s\n",State_Machine[current_state].direction_valve_status);
}
else if(pilot_lever == DOWN && hydraulic_mechanism == Malfunctioning)
{
current_state = LWRNG_GR;
printf("\nCurrent State : %s\n",State_Machine[current_state].current_state_indication);
printf("Light Status:%s\n",State_Machine[current_state].light_status);
printf("Direction Valve Status:%s\n",State_Machine[current_state].direction_valve_status);
printf("Gas Pressurized Spring System Status:%s\n",State_Machine[current_state].gas_pressurized_spring_status[hydraulic_mechanism]);
}

if(pilot_lever == (UP || Rising || Falling))
{
Checking_Before_Landing();
}

}

Explanation:

In this project, a Finite State Machine is used to manage the retraction and extension of an airplane's landing gear (FSM). The most efficient algorithm is the FSM, which is a mathematical processing model.

Actually an airplane has 3 gears for landing: Nose gear, Left gear, Right gear.

There is an electrically powered hydraulic pump that applies pressure to the gears to bring it down or pull it up.

There is a limit switch on each leg of the gear. One extra squat switch is installed in the nose gear to assess whether the plane is on the ground or not.In this project, controlling the retraction and extension of Airplane’s landing gear can be implemented using Finite State Machine (FSM). FSM is the most efficient algorithm which is mathematical model of computation.

Objective:

Here we are going to control the Airplanes landing gear.

What is Finite state Machine:A finite state machine (sometimes called a finite state automaton) is a computation model that can be implemented with hardware or software and can be used to simulate sequential logic and some computer programs. Finite state automata generate regular languages. Finite state machines can be used to model problems in many fields including mathematics, artificial intelligence, games, and linguistics.A system where particular inputs cause particular changes in state can be represented using finite state machines. This example describes the various states of a turnstile. Inserting a coin into a turnstile will unlock it, and after the turnstile has been pushed, it locks again. Inserting a coin into an unlocked turnstile, or pushing against a locked turnstile will not change its state.