Challenge

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

SShibnu Rahman Kp21 Jan 2023

EMB LIVE BATCH : ABHINAYA

AIM:-

Implement the code for controlling the retraction and extensioin of Airplane's Landing gear

Introduction:-

An airplne has three gears for landing:

Nose Gear
Left Gear
Right Gear

The hydraulic pump are used for exerting pressure to the gears to bring it down or pull it up and that pump is electrically driven.

Limit switches: Every leg of the gear has one limit switch.

Squat switch: only nose gear have squat switch to determine whether the airplan is in ground or not.

Switch state	State of Gears
Limit Switch CLOSED	Gear is UP
Limit Switch OPENED	Gear is DOWN

Switch State	State of Airplane
Squat Switch CLOSED	Airplane is grounded and gears are locked
Squat Switch OPENED	Airplane is taking off/ landing/ airborne

A direction valve is controlled by software to allow the hydraulic pressure to either raise or lower the landing gear

Status of Direction Valve	States of landing gear
Direction valve = Down	(Gear Down) (Parked at bay or Landed)
Direction valve = Up	Raising Gear (Taking Off)
Control of hydraulic pump for the landing gear part is disabled	Gear up (Airborne)
Direction valve = down	Lowering Gear (Landing)

Input for the direction valve :

Pilot's Lever State	Direction Valve State
Lever UP	Direction valve = Up
Lever Down	Direction valve = Down

Pilot's Lever State	Light Status
Lever Rising Edge	Red
Lever Falling Edge	Red

Every gear has one light. According to the state of the gear, color of the light is changing.

Landing Gear State	Light Status
Gear is up	OFF
Gear is down	Green
Gear in transit	Red

By incorperating all these constraints we can come to result as shown below.

PROGRAMS:-

Project2.c(main.c)

#include
#include "States.h"        //User defined library

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


int main()
{
	Init_State_Machine();
	while(1)
	{
		state_table[current_state](); //calling each state functions
	}
}

States.h

#ifndef STATES_H_
#define STATES_H_


/*.......Functions.......*/
void Init_State_Machine();
void Gear_Down();
void Checking_Before_Takeoff();
void Raising_Gear();
void Gear_Up();
void Checking_Before_Landing();
void Lowering_Gear();

typedef enum State
{
	GEAR_DOWN,
	CHECKING_BEFORE_TAKEOFF,
	RAISING_GEAR,
	GEAR_UP,
	CHECKING_BEFORE_LANDING,
	LOWERING_GEAR,
}State_Type;

typedef enum Switch        //switch states
{
	Open,
	Close    //plane is in ground
}Switch_Status;

typedef enum Pilot_Lever     //pilot lever states
{
	Rising,
	Falling,
	UP,
	DOWN
}Pilot_Lever_Status;

typedef enum Hydraulic_Mechanism   //hydraulic control states
{
	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;

//state table elements
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;

//creating state table
static State_Table State_Machine[6]={
		{"Gear Down", "Green", "Down", "Enabled", {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"}}
};


#endif /* STATES_H_ */

Init_State_Machine.c

#include "States.h"    //User defined library

void Init_State_Machine()
{
	current_state = GEAR_DOWN;
	printf("\nState Machine is initialized and program is in Gear_Down state & Light Status : %s\n",State_Machine[current_state].light_status);
}

Gear_Down.c

#include "States.h"              //User defined library
#include

void Gear_Down()
{
	current_state = GEAR_DOWN;

	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 = CHECKING_BEFORE_TAKEOFF;

		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();
	}
}

Checking_Before_Takeoff.c

#include "States.h"           //User defined library
#include

void Checking_Before_Takeoff()
{
	current_state = CHECKING_BEFORE_TAKEOFF;

	printf("\nEnter the pilot's lever position and squat switch status and Hydraulic Mechanism Status: ");
	fflush(stdout);
	scanf("%d %d %d", &pilot_lever, &squat_switch, &hydraulic_mechanism );
	printf("\nWait for 2 sec\n");

	if(pilot_lever == Falling || squat_switch == Close)
	{
		Gear_Down();
	}
	else if(pilot_lever == UP && squat_switch == Open && hydraulic_mechanism == Working)
	{
		current_state = RAISING_GEAR;

		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 = RAISING_GEAR;

		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 status : %s\n",State_Machine[current_state].gas_pressurized_spring_status[hydraulic_mechanism]);
	}
}

Raising_Gear.c

#include "States.h"                 //User defined library
#include

void Raising_Gear()
{
	current_state = RAISING_GEAR;

	printf("\nEnter the Limit switch status, Pilot's lever 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 = CHECKING_BEFORE_LANDING;

		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(pilot_lever == UP && limit_switch == Close)
	{
		current_state = GEAR_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();
	}
}

Gear_Up.c

#include "States.h"                   //User defined library
#include

void Gear_Up()
{
	current_state = GEAR_UP;

	printf("\nEnter the Pilot's lever Position: ");
	fflush(stdout);
	scanf("%d",&pilot_lever);

	if(pilot_lever == Falling)
	{
	current_state = CHECKING_BEFORE_LANDING;

	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();
	}
}

Checking_Before_Landing.c

#include "States.h"                   //User defined library
#include

void Checking_Before_Landing()
{
	current_state = CHECKING_BEFORE_LANDING;

	printf("\nEnter the Pilot's lever status and status OF Hydraulic Mechanism: ");
	fflush(stdout);
	scanf("%d %d", &pilot_lever, &hydraulic_mechanism);

	if(pilot_lever == DOWN && hydraulic_mechanism == Working)
	{
		current_state = LOWERING_GEAR;

		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 = LOWERING_GEAR;

		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 status : %s\n",State_Machine[current_state].gas_pressurized_spring_status[hydraulic_mechanism]);
	}

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

Lowering_Gear.c

#include "States.h"                  //User defined library
#include

void Lowering_Gear()
{
	current_state = LOWERING_GEAR;

	printf("\nEnter the limit switch status and pilot's lever status: ");
	fflush(stdout);
	scanf("%d %d", &limit_switch, &pilot_lever);

	if(limit_switch == Close && pilot_lever == Rising)
	{
		current_state = CHECKING_BEFORE_TAKEOFF;

		printf("\nCurrent state          : %s\n",State_Machine[current_state].current_state_indication);
		printf("Light status             : %s\n",State_Machine[current_state].light_status);

	}
	else if(limit_switch == Open && pilot_lever == DOWN)
	{
		current_state = GEAR_DOWN;

		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();
	}
}

OUTPUT

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

Ship work like this
in your own course.

Talk to a career counsellor

Ship work like thisin your own course.

Talk to a career counsellor

Ship work like this
in your own course.