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

Project2:

• Implementation of the code for controlling the retraction and extension of airplane’s landing gear

Aim:

• To implement the code for control retraction and extension of airplanes landing gear implementation using Finite State Machine (FSM).

Objective:

• Controlling the direction of valve.
• Controlling the retraction and extension of airplane’s 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.

Principle:

• The airplane has three gears for landing such as nose gear, left gear and right gear.
• There is a hydraulic pump which is exerting pressure tothe gears to bring it down or pull it up using electrical driven pump.
• When the direction of the valve is down then it is landed or gear down position.
• Similarly when the direction of valve is up then it is in rising gear or taking off.
• When gear is up then light status is off.
• Gear is down then the light status is green.
• Gear is raising or lowering then the color of light is red.

Implementation of problem:

• • To carry out the problem we need the states with their respective functions.
  • Here we are using the switch states, Direction of valves with respect to gear.

• 
• 
  
• 
  
• 

• From the above input we are creating six differernt conditions and function.In this function we are determing or controlling the land gear in diffferent conditions.

• 
• This flow chart represent condition of the state and condition required to jump into next state.
  

Code:

^/*

^{* PROJECT 2.c}

^*

^{* Created on: Jul 8, 2024}

^{* Author: mages}

^*/

^{#include <stdio.h>}

^{//we have define the function based on the conditions}

^{void Initiate_State_Machine();}

^{void GearDown();}

^{void CheckingBeforeTakeOFF();}

^{void RaisingGear();}

^{void GearUp();}

^{void CheckBeforeLanding();}

^{void LoweringGear();}

^{static void(*statetable[])(void)={GearDown, CheckingBeforeTakeOFF, RaisingGear, GearUp, CheckBeforeLanding, LoweringGear}; // Entering the function into the array}

^{typedef enum State}

^{

^GEAR_DOWN,

^{CHECKING_BEFORE_TAKEOFF,}

^{RAISING_GEAR,}

^GEAR_UP,

^{CHECK_BEFORE_LANDING,}

^{LOWERING_GEAR,}

^}State_Type;

^{typedef enum Switch}

^{

^on,

^{off//plane is on ground}

^{}Switch_status;}

^{typedef enum pilot_lever}

^{

^Raising,

^falling

^{}pilot_lever;}

^{typedef enum hydraulic_mechanism}

^{

^working,

^not_working

^{}hydraulic_mechanism;}

^{static volatile Switch_status squat_switch;}

^{static volatile Switch_status squat_switch;}

^{static volatile Switch_status limit_switch;}

^{static volatile pilot_lever pl;}

^{static volatile hydraulic_mechanism hm;}

^{State_Type current_state;}

^{typedef struct}

^{

^{char* current_state_indication;}

^{char* light;}

^{char* direction_valve_status;}

^{char* landing_gear_hydraulic_control;}

^{char* Gas_Pressurized_Spring_system_status[2];}

^{}State_Table;}

^{static State_Table State_Machine[6]={{"GearDown","Green","Down","Enabled",{NULL,NULL}},}

^{{"CheckingBeforeTakeOFF","Green","Down","Enabled",{NULL,NULL}},}

^{{"RaisingGear","Red","Up","Enabled",{NULL,NULL}},}

^{{"GearUp","Off","NULL","Disabled",{NULL,NULL}},}

^{{"CheckBeforeLanding","Red","Down","Enabled",{NULL,NULL}},}

^{{"LoweringGear","Green","Down","Enabled",{"Disabled","Enabled"}}}

^};

^{int main()}

^{

^{Initiate_State_Machine();}

^while(1)

^{

^{statetable[current_state]();}

^}

^}

^{void GearDown(void)}

^{

^{current_state=GEAR_DOWN;}

^{printf("Enter the status of pilot's lever and squat switch:");}

^{fflush(stdout);}

^{scanf("%d %d",&pl,&squat_switch);}

^{if(pl==Raising && squat_switch==on)}

^{

^{current_state=CHECKING_BEFORE_TAKEOFF;}

^{printf("current state:%s\n",State_Machine[current_state].current_state_indication);}

^{printf("Light is :%s\n", State_Machine[current_state].light);}

^}

^else

^{

^GearDown();

^}

^}

^{//CheckingBeforeTakeOFF}

^{void CheckingBeforeTakeOFF(void)}

^{

^{current_state=CHECKING_BEFORE_TAKEOFF;}

^{printf("Enter the status of pilot's lever and squat switch and hydraulic mechanism:");}

^{fflush(stdout);}

^{scanf("%d %d",&pl,&squat_switch,&hm);}

^{if(pl==falling&&squat_switch==off)}

^{

^GearDown();

^}

^{else if(pl==Raising && squat_switch==on && hm==working)}

^{

^{current_state=RAISING_GEAR;}

^{printf("Current State:%s\n",State_Machine[current_state].current_state_indication);}

^{printf("Light is:%s\n",State_Machine[current_state].light);}

^{printf("Status of Direction valve:%s\n",State_Machine[current_state].direction_valve_status);}

^}

^{else if(pl==Raising && squat_switch==on && hm==not_working)}

^{

^{current_state=RAISING_GEAR;}

^{printf("Current State:%s\n",State_Machine[current_state].current_state_indication);}

^{printf("Light is:%s\n",State_Machine[current_state].light);}

^{printf("Status of Direction valve:%s\n",State_Machine[current_state].direction_valve_status);}

^{printf("Status of gas pressurised Spring System:%s\n",State_Machine[current_state].Gas_Pressurized_Spring_system_status);}

^}

^}

^{//RaisingGear}

^{void RaisingGear(void)}

^{

^{current_state=RAISING_GEAR;}

^{printf("Enter the status of pilot's lever and limit switch:");}

^{fflush(stdout);}

^{scanf("%d %d",&pl,&limit_switch);}

^{if(pl==falling && limit_switch==on)}

^{

^{current_state=CHECK_BEFORE_LANDING;}

^{printf("Current State:%s\n",State_Machine[current_state].current_state_indication);}

^{printf("Light is:%s\n",State_Machine[current_state].light);}

^{printf("Landing Gear Hydraulic Control:%s\n",State_Machine[current_state].landing_gear_hydraulic_control);}

^}

^{else if(pl==Raising && limit_switch==off)}

^{

^{current_state=GEAR_UP;}

^{printf("Current State:%s\n",State_Machine[current_state].current_state_indication);}

^{printf("Light is:%s\n",State_Machine[current_state].light);}

^{printf("Landing Gear Hydraulic Control:%s\n",State_Machine[current_state].landing_gear_hydraulic_control);}

^}

^else

^{

^{RaisingGear();}

^}

^}

^//GearUp

^{void GearUp(void)}

^{

^{current_state=GEAR_UP;}

^{printf("Enter the status of pilot's lever:");}

^{fflush(stdout);}

^{scanf("%d",&pl);}

^{if(pl==falling)}

^{

^{current_state=CHECK_BEFORE_LANDING;}

^{printf("Current State:%s\n",State_Machine[current_state].current_state_indication);}

^{printf("Light is:%s\n",State_Machine[current_state].light);}

^{printf("Landing Gear Hydraulic Control:%s\n",State_Machine[current_state].landing_gear_hydraulic_control);}

^}

^else

^{

^GearUp();

^}

^}

^{//CheckBeforeLanding}

^{void CheckBeforeLanding(void)}

^{

^{current_state=CHECK_BEFORE_LANDING;}

^{printf("Enter the status of pilot's lever and hydraulic mechanism status:");}

^{fflush(stdout);}

^{scanf("%d %d",&pl,&hm);}

^{if(pl==falling && hm==working)}

^{

^{current_state=LOWERING_GEAR;}

^{printf("Current State:%s\n",State_Machine[current_state].current_state_indication);}

^{printf("Light is:%s\n",State_Machine[current_state].light);}

^{printf("Status of Direction valve:%s\n",State_Machine[current_state].direction_valve_status);}

^}

^{else if(pl==falling && hm==not_working)}

^{

^{current_state=LOWERING_GEAR;}

^{printf("Current State:%s\n",State_Machine[current_state].current_state_indication);}

^{printf("Light is:%s\n",State_Machine[current_state].light);}

^{printf("Status of Direction valve:%s\n",State_Machine[current_state].direction_valve_status);}

^{printf("Status of gas pressurised Spring System:%s\n",State_Machine[current_state].Gas_Pressurized_Spring_system_status);}

^}

^{else if(pl==(Raising))}

^{

^{CheckBeforeLanding();}

^}

^}

^{//LoweringGear.}

^{void LoweringGear(void)}

^{

^{current_state=LOWERING_GEAR;}

^{printf("Enter the status of pilot's lever and limit switch:");}

^{fflush(stdout);}

^{scanf("%d %d",&pl,&limit_switch);}

^{if(pl==falling && limit_switch==on)}

^{

^{current_state=CHECKING_BEFORE_TAKEOFF;}

^{printf("Current State:%s\n",State_Machine[current_state].current_state_indication);}

^{printf("Light is:%s\n",State_Machine[current_state].light);}

^}

^{else if(pl==Raising && limit_switch==off)}

^{

^{current_state=GEAR_DOWN;}

^{printf("Current State:%s\n",State_Machine[current_state].current_state_indication);}

^{printf("Light is:%s\n",State_Machine[current_state].light);}

^{printf("Landing Gear Hydraulic Control:%s\n",State_Machine[current_state].landing_gear_hydraulic_control);}

^}

^{if(limit_switch==off)}

^{

^{LoweringGear();}

^}

^}

^{//Initiate_State_Machine}

^{void Initiate_State_Machine()}

^{

^{current_state==GEAR_DOWN;}

^{printf("The Finite State Machine is Initialized and current the program is in""GearDown State & Light is:%s\n",State_Machine[current_state].light);}

^}

SCREENSHOTS OF THE CODE:

OUTPUT OF THE CODE:

RESULT:

• Thus a program code is created to control retraction and extension of airplanes landing gear implementation using Finite State Machine (FSM).

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