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

AIM:

To implement the code of controlling the retraction and extension of airplane's landing gear.

Project:

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

/* Functions used in our projects*/
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,									//ENUM IS USED TO GIVING SUBSEQUENT VALUE FOR EACH STATES
	CHECK_BEFORE_TAKEOFF,
	RAISING_GEAR,
	GEAR_UP,
	CHECK_BEFORE_LANDING,
	LOWERING_GEAR
}state_type;


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

typedef enum pilot_lever
{
	raising,										//by using enum rising =0,falling=1,up=3and down=4 is assumed
	falling,
	up,
	down
}pilot_lever_status;

typedef enum hydraulic_mechanism
{
	working,									//here 0 means for working and 1 means for malfunction
	malfunctioning

}hydraulic_mechanism_status;

/* input 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 type
{
	char* current_state_status;					//output which we want to visualize are given under structure as structure 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 position and squat switch status:\n");// getting pilot lever and squat switch value from input
	fflush(stdout);
	scanf("%d %d",&pilot_lever,&squat_switch);
	if(pilot_lever == raising && squat_switch == open)  // if pilot lever raising(0) and squar switch is open(0)
	{
		current_state = CHECK_BEFORE_TAKEOFF;
		printf("\n The current state of the machine is: %s\n",state_machine[current_state].current_state_status);// current status value is printed from the state table
		printf("\n Light status of the current machine state is:%s\n",state_machine[current_state].light_status);// light status value is taken from state table  current state
	}
	else
	{
		Gear_down();									//gear down function is called
	}
}

//checking before takeoff//

void Checking_before_takeoff()
{
 current_state= CHECK_BEFORE_TAKEOFF;					//current state is check before takeoff
 printf("\n Enter the pilot lever position, squat switch and hydraulic mechancism:\n");// getting pilot liver, squat switch and hydraulic mechanism as input
 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)			//pilot lever is up and squat switch is closed it get into the if loop
 {
	 Gear_down();										//gear down 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);
		}
		else 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("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]);
		}
}

//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();
 }
}

//checking before landing//
void Checking_before_landing()
{
 current_state= CHECK_BEFORE_LANDING;
 printf("\n Enter the pilot lever position, 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("light 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)
		{
			current_state= GEAR_DOWN;
			printf("\n Current state: %s\n", state_machine[current_state].current_state_status);
			printf("\n light status: %s\n", state_machine[current_state].light_status);
			printf("\n Hydraulic condition 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]();
	}
}

Output:

snap of the code:

Conclusion:

Hence we implement the airplane's landing gear for controlling and retraction.