Automatic Pneumatic Bumper System for Four Wheeler

Published on May 2016 | Categories: Types, Presentations | Downloads: 349 | Comments: 0 | Views: 296
of 33
Download PDF   Embed   Report

about the pneumatic system and sensors used

Comments

Content

AUTOMATIC PNEUMATIC BUMPER AND BRAKING SYSTEM FOR FOUR WHEELER
SYNOPSIS
The technology of pneumatics has gained tremendous importance in the field of workplace rationalization and automation from old-fashioned timber works and coal mines to modern machine shops and space robots. It is therefore important that technicians and engineers should have a good knowledge of pneumatic system, air operated valves and accessories. The aim is to design and develop a control system based
PNEUMATIC BUMPER AND BRAKING SYSTEM”.

intelligent electronically

controlled automotive bumper activation and automatic braking system is called “ AUTOMATIC

This system is consists of IR transmitter and

Receiver circuit, Control

nit, !neumatic bumper system and pneumatic braking system.

The IR sensor is used to detect the obstacle. There is any obstacle closer to the vehicle "with in #-$ feet%, the control signal is given to the bumper activation system and also pneumatic braking system simultaneously. The pneumatic bumper and braking system is used to product the man and vehicle. This bumper and braking activation system is only activated the vehicle speed above #&-$& km per hour. This vehicle speed is sensed by the pro'imity sensor and this signal is given to the control unit and pneumatic bumper and braking activation system.

INTRODUCTION
(e have pleasure in introducing our new pro)ect * AUTOMATIC PNEUMATIC BUMPER AND BRAKING SYSTEM”, which is fully e+uipped by IR sensors circuit and !neumatic bumper and braking activation circuit.

It is a genuine pro)ect which is fully e+uipped and designed for ,utomobile vehicles. This forms an integral part of best +uality. This product underwent strenuous test in our ,utomobile vehicles and it is good.

BLOCK DIAGRAM

WHEEL SPEED SENSING ARRANGEMENT
IR TRANSMITTER

POWER SUPPLY

CONTROL UNIT

IR RECEIVER

FLOW CONTROL VANVE

SOLINOID VALVE

PNEUMATIC CYLINDER -1 AIR TANK (COMPRESSOR) PNEUMATIC CYLINDER -2 BRAKING ARRANGEMENT

BUMPER ANGEMENT

WORKING OPERATION
The vehicle speed is sensed by the pro'imity sensor. The vehicle speed is above the #&-$& -m per hour, the control unit will activate the IR sensor nit. The IR TRANSMITTER circuit is to transmite the Infra-Red rays. If any obstacle is there in a path, the Infra-Red rays reflected. This reflected Infra-Red rays are received by the receiver circuit is called * IR RECEIVER”. The IR receiver circuir receives the reflected IR rays and giving the control signal to the control circuit. The control circuit is used to activate the solenoid valve. If the solenoid valve is activated, the compressed air passes to the !neumatic Cylinder. The compressed air activates the pneumatic cylinder and moves the piston rod. If the piston moves forward, then the bumper arrangement and braking arrangements are activated. The piston speed is varied by ad)esting the valve is called FLOW CONTROL VALVE”. In our pro)ect, we have to apply this arrangement in one wheel as a model. The compressed air is drawn from the compressor in our pro)ect. The compressed air is flow through the !olyurethene tube to the flow control valve. The flow control valve is connected to the solenoid valve as mentioned in the diagram.

APPLICATIONS
• .or automobile application • Industrial application • .our wheeler application • Two wheeler applications

ADVANTAGES
• .ree from wear ad)ustment. • /ess power consumption • It gives simplified very operation. • Installation is simplified very much. • To minimize the accident • 0afe the vehicle and human being

DISADVANTAGES
• ,dditional cost is re+uired to install this arrangement in the vehicle.

LITERATURE SURVEY

SAFETY SYSTEM!

The aim is to design and develop a control system based on pneumatic breaking system of an intelligent electronically controlled automotive braking system. 1ased on this model, control strategies such as an 2antilock braking system2 ",10% and improved maneuverability via individual wheel braking are to be developed and evaluated.

There have been considerable advances in modern vehicle braking systems in recent years. .or e'ample, electronically controlled ,10 for emergency braking, electronically controlled hydraulically actuated individual brake-by-wire "11(% systems for saloon cars and electronically controlled pneumatically actuated systems for heavy goods vehicles. The work of recent years shall form the basis of a system design approach to be implemented. The novelty of the proposed research programmed shall lie in the design and evaluation of control systems for achieving individual wheel motion control facilitated by 11(. In the case of 11( the brake pedal is detached from the hydraulic system and replaced by a 2brake pedal simulator2. The simulator provides an electrical signal for the electronic control system.

!reliminary modeling and simulation work considers a +uarter cars initially followed by a natural progression to the half car and full four wheel station cases. The model is to be constructed in modular form thus allowing the replacement 3 interchange of the various blocks and their associated technologies. pon completion of the full

vehicle braking model, sensitivity analyses will be carried out. 4nce the preliminary simulation model has been thoroughly benchmarked and e'isting control system strategies evaluated, an audit of the technology used is to take place and this will provide a basis for comparison of iterative technologies 3 techni+ues.

The final phase of the new modern vehicle shall include5

• • • • • •

6evelopment of improved ,10 control systems 6evelopment and assessment of an electro-hydraulic-11( "78-11(% system Individual wheel braking combined with traction control ,ssessing sensor failure and fault tolerant control system design !reliminary studies into an electrically actuated system Re-engineering using simplified models.

PNEUMATICS

The word 9pneuma: comes from ;reek and means breather wind. The word pneumatics is the study of air movement and its phenomena is derived from the word pneuma. Today pneumatics is mainly understood to means the application of air as a working medium in industry especially the driving and controlling of machines and e+uipment.

!neumatics has for some considerable time between used for carrying out the simplest mechanical tasks in more recent times has played a more important role in the development of pneumatic technology for automation. !neumatic systems operate on a supply of compressed air which must be made available in sufficient +uantity and at a pressure to suit the capacity of the system. (hen the pneumatic system is being adopted for the first time, however it wills indeed the necessary to deal with the +uestion of compressed air supply.

The key part of any facility for supply of compressed air is by means using reciprocating compressor. , compressor is a machine that takes in air, gas at a certain pressure and delivered the air at a high pressure.

Compressor capacity is the actual +uantity of air compressed and delivered and the volume e'pressed is that of the air at intake conditions namely at atmosphere pressure and normal ambient temperature.

The compressibility of the air was first investigated by Robert 1oyle in <=>? and that found that the product of pressure and volume of a particular +uantity of gas. The usual written as !@ A C "or% !B@B A !?@?

In this e+uation the pressure is the absolute pressured which for free is about <$.C !si and is of courage capable of maintaining a column of mercury, nearly #& inches high in an ordinary barometer. ,ny gas can be used in pneumatic system but air is the mostly used system now a days.

TYPES OF BRAKING
The brakes for automotive use may be classified according the following considerations.

<. ?. #. $. F.

! R!407 /4C,TI4D C4D0TR CTI4D E7T846 4. ,CT ,TI4D 7GTR, 1R,-ID; 7..4RT

IR SENSOR

SENSORS , sensor is a transducer used to make a measurement of a physical variable. ,ny sensor re+uires calibration in order to be useful as a measuring device. Calibration is the procedure by which the relationship between the measured variable and the converted output signal is established.

Care should be taken in the choice of sensory devices for particular tasks. The operating characteristics of each device should be closely matched to the task for which it is being utilized. 6ifferent sensors can be used in different ways to sense same

conditions and the same sensors can be used in different ways to sense different conditions.

TYPES OF SENSOR! P"##$%& #&'#()# detect the reflected or emitted electro-magnetic radiation from natural sources, while "*+$%& #&'#()# detect reflected responses from ob)ects which are irradiated from artificially generated energy sources, such as radar. 7ach is divided further in to '('-#*"''$', and #*"''$', #-#+&.#.

SELECTION OF PNEUMATICS! Eechanization is broadly defined as the replacement of manual effort by mechanical power. !neumatics is an attractive medium for low cost mechanization particularly for se+uential or repetitive operations. Eany factories and plants already have a compressed air system, which is capable of providing both the power or energy re+uirements and the control system "although e+ually pneumatic control systems may be economic and can be advantageously applied to other forms of power%.

The main advantages of an all-pneumatic system are usually economy and simplicity, the latter reducing maintenance to a low level. It can also have out standing advantages in terms of safety.

i. ii. iii. iv.

0ingle acting !neumatic cylinder 0olenoid valve .low control value Connectors

<% PNEUMATIC SINGLE ACTING CYLINDER5

!neumatic cylinder consist of

,% !I0T4D

1% CH/ID67R

The cylinder is a 0ingle acting cylinder one, which means that the air pressure operates forward and spring returns backward. The air from the compressor is passed through the regulator which controls the pressure to re+uired amount by ad)usting its knob.

, pressure gauge is attached to the regulator for showing the line pressure. Then the compressed air is passed through the single acting #3? solenoid valve for supplying the air to one side of the cylinder.

4ne hose take the output of the directional Control "0olenoid% valve and they are attached to one end of the cylinder by means of connectors. 4ne of the outputs from the directional control valve is taken to the flow control valve from taken to the cylinder. The hose is attached to each component of pneumatic system only by connectors.

CYLINDER TECHNICAL DATA! P$#+(' R(/! E.0. hard Chrome plated S&"0#! Ditrile "1una I D% 7lastomer E'/ C(%&)#!

Cast iron graded fine grained from ?Fmm to #&&mm P$#+('! -,luminium. M&/$"! -,ir. T&.1&)"+2)& R"',&! &Jc to KFJc

2. SOLENOID VALVE WITH CONTROL UNIT!

The directional valve is one of the important parts of a pneumatic system. Commonly known as 6C@, this valve is used to control the direction of air flow in the pneumatic system. The directional valve does this by changing the position of its internal movable parts.

This valve was selected for speedy operation and to reduce the manual effort and also for the modification of the machine into automatic machine by means of using a solenoid valve. , solenoid is an electrical device that converts electrical energy into straight line motion and force. These are also used to operate a mechanical operation which in turn operates the valve mechanism. 0olenoids may be push type or pull type.

The push type solenoid is one in which the plunger is pushed when the solenoid is energized electrically. The pull type solenoid is one is which the plunger is pulled when the solenoid is energized.

The name of the parts of the solenoid should be learned so that they can be recognized when called upon to make repairs, to do service work or to install them.

P")+# (3 " S(0&'($/ V"0%& 1. C($0 The solenoid coil is made of copper wire. The layers of wire are separated by insulating layer. The entire solenoid coil is covered with an varnish that is not affected by solvents, moisture, cutting oil or often fluids. Coils are rated in various voltages such as <<F volts ,C, ?#& volts ,C, $>& volts ,C, FCF @olts ,C, > @olts 6C, <? @olts 6C, ?$ @olts 6C, <<F @olts 6C L ?#& @olts 6C. They are designed for such fre+uencies as F& 8z to >& 8z.

2. F)".& The solenoid frame serves several purposes. 0ince it is made of laminated sheets, it is magnetized when the current passes through the coil. The magnetized coil attracts the metal plunger to move. The frame has provisions for attaching the mounting. They are usually bolted or welded to the frame. The frame has provisions for receivers, the

plunger. The wear strips are mounted to the solenoid frame, and are made of materials such as metal or impregnated less fiber cloth.

4. S(0&'($/ P02',&) The 0olenoid plunger is the mover mechanism of the solenoid. The plunger is made of steel laminations which are riveted together under high pressure, so that there will be no movement of the lamination with respect to one another. ,t the top of the plunger a pin hole is placed for making a connection to some device.

The solenoid plunger is moved by a magnetic force in one direction and is usually returned by spring action. 0olenoid operated valves are usually provided with cover over either the solenoid or the entire valve. This protects the solenoid from dirt and other foreign matter, and protects the actuator. In many applications it is necessary to use e'plosion proof solenoids.

WORKING OF 452 SINGLE ACTING SOLENOID (OR) CUT OFF VALVE!

The control valve is used to control the flow direction is called cut off valve or solenoid valve. This solenoid cut off valve is controlled by the emergency push button. The #3? 0ingle acting solenoid valve is having one inlet port, one outlet port and one e'haust port. The solenoid valve consists of electromagnetic coil, stem and spring. The

air enters to the pneumatic single acting solenoid valve when the push button is in 4D position.

T&*6'$*"0 D"+"! 0ize !ressure Eedia Type ,pplied @oltage .re+uency 5 MN 5 & to C kg 3 cm? 5 ,ir 5 #3? 5 ?#&@ ,.C 5 F& 8z

4. FLOW CONTROL VALVE! 1. T&*6'$*"0 D"+"! 0ize !ressure Eedia 5 MN 5 & to <& kg 3 cm? 5 ,ir (7) P2)1(#&! This valve is used to speed up the piston movement and also it acts as an one I way restriction valve which means that the air can pass through only one way and it can:t return back. 1y using this valve the time consumption is reduced because of the faster movement of the piston.

<. IR SENSOR UNIT!-

The IR transmitter and IR receiver circuit is used to sense the obstacle. It is fi'ed to the back side of the frame stand with a suitable arrangement. The pneumatic cylinder is controlled by the flow control valve, single acting solenoid valve and control unit.

IR TRANSMITTER CIRCUIT!

=V** R< (<9Ω) 4 T1 (BD1<>) 1 1:>K 1 8 9

2 C4 (1>>µ52:V) R2 (<9Ω) R: L1 <.9Ω IR LED

2 4

IC :::
; :

R1 1.:K

C2 >.>11F

<

C1 >.11F

IR RECEIVER CIRCUIT!

1K =12V RELAY R12 (;8>Ω) RL1 L4 (LED) D2 1N<>>9 R1> <.9K C4 (1>> µ) R9 (1>>K) C2 (1>>µ) <.9K R4 R2 <.9K R1 (<.9K) L1 (IR SENSOR) L2 (IR SENSOR)

D1 (1N <>>9) T: (BC:<9B) T< (BC :<9B) 12>Ω R11 22K R? (<.9K) R8

T4 BC ::9

C< (>.11F) T2 (BC:<?C)

C1 (>.>1 1F) C8 (<9 1F) R: T1 (BC :<?C) R14 12> Ω

C9 22µF (:>V)

R; 2.2K

C: (>.11F)

AT NORMAL CONDITION!

The IR transmitter sensor is transmitting the infrared rays with the help of FFF IC timer circuit. These infrared rays are received by the IR receiver sensor. The Transistor T<, T? and T# are used as an amplifier section. ,t normal condition Transistor TF is 4.. condition. ,t that time relay is 4.., so that the vehicle running continuously.

AT OBSTACLE CONDITION!

,t 4bstacle conditions the IR transmitter and IR receiver, the resistance across the Transmitter and receiver is high due to the non-conductivity of the IR waves. 0o the output of transistor TF goes from 4.. condition to 4D stage. In that time the relay is 4D position. In that time, the solenoid valve is on so that the vehicle stops.

CONTROL UNIT -8?C:2

In our pro)ect K=CF? Eicrocontroller is used as a control unit.

INTRODUCTION ABOUT MICRO CONTROLLER!

, microcontroller consists of a powerful CPU tightly coupled with memory "R,E, R4E or 7!R4E%, various I34 features such as serial port"s%, parallel port"s%, Timer3Counter"s%, Interrupt controller, 6ata ,c+uisition interfaces-,nalog to 6igital Converter ",6C%, 6igital to ,nalog Converter "6,C%, everything integrated onto a single silicon chip.

It does not mean that any micro controller should have above said features on-chip. 6epending on the need and area of application for which it is designed, the on-chip features present in it may or may not include all the individual sections said above. ,ny micro computer system re+uires memory to store a se+uence of instructions making up a program, parallel port or serial port for communicating with an e'ternal system, timer3counter for control purposes like generating time delays, baud rate for the serial port, apart from the controlling unit called the Central !rocessing nit.

MEMORY ASSOCIATED WITH AT-8?C:2!

PROGRAM MEMORY!

, program memory is a block of memory, which can be used to store a se+uence of program codes "by using special EPROM 5 PROM programmers%. It can only be read from and not written into, under normal operating conditions.

There can be up to >$ k bytes of program memory in ,T-K=CF?. in ROM and EPROM versions of the MCS-#F< family of devices, the lower $- are provided on-chip whereas in ROM fewer versions, all program memory is e'ternal.

In ROM and EPROM versions of this device, if the special control signals EA "7'ternal ,ccess enable% is strapped off @cc, and then program fetches to addresses &&&& to &... are directed to the internal ROM. The program fetch will be from e'ternal memory, where 7,O is grounded.

,fter reset, the CPU begins e'ecution from address location &&&& of the program memory.

F$,2)& #6(@# " ."1 (3 +6& AT-8?C:2-1)(,)". .&.()-

FFFF ;>K B-+&# I'+&)'"0 1>>> >FFF < K B-+&# I'+&)'"0 >>>> FFFF OR ;< K B-+&# EA+&)'"0

>>>>

DATA MEMORY!

6ata memory is the Read3(rite memory. 8ence, it can be both read from and written into. ,T-K=CF? has got <?K bytes of internal data memory and >$of e'ternal data memory.

FF 8> 9F

SFRS DIRECT ADDRESS SING ONLY

FFFF AND >>>> ;< K B-+&# EA+&)'"0

6IR7CT ,D6 ID6IR7CT ,66R700 >> ID;

INTERNAL DATA MEMORY:

Internal data memory addresses are one byte wide, which includes <?K bytes of on-chip RAM plus a number of special .unction Registers. The <?K bytes of RAM can be accessed either by direct addressing " MOV data address% or by indirect addressing "MOV PRi%.

The lowest #?bytes "&&-<.% of on-chip RAM are grouped into $ banks of K registers each. !rogram instructions call out these registers as R& through RC Q 1its # and $ "PSW.4 and PSW.$% in register program status word " PSW% select which register bank is n use. This allows more efficient use of code space, since register instructions are shorter than instructions that use direct addressing.

Reset initializes the stack pointer register to C and its incremented once to start from locating &K, which is register R& of second register bank. 8ence, in order to use more than one register bank, the stack pointer should be initialized to a different location of RAM if it is not used for data storage.

The ne't <> bytes "?&-?.% from a block of bit addressable memory space, which can also byte addressed.

1ytes #& through C. are available to the user as data RAM. 8owever, is the stack pointer has been initialized to this area, enough number of bytes should be left a side to prevent stack overflow.

I/O STRUCTURE OF AT-89C52:

,T-K=CF? has four K-bit parallel ports "hence KO$A#? I34 lines are available%. ,ll four parallel ports are bi-directional. 7ach line consists of a latch, an output driver and an input buffer.

The four ports are named as port & "po%, port < "p<%, port ? "p?% and port #"p#%. They are bit addressable and has to be represented in the form PB.Y is i.e. bit H of port G while using bit addressing mode. !G.& is the LSB "least significant 1it% of port ' and p'.C is the MSB "Eost 0ignificant 1it% of that port.

4ut of the four ports, port & and port ? are used in accesses to e'ternal memory. ,ll the port # pins are multifunctional. !ort # is an K-bit bidirectional with internal pullups.

!ort pin !#.& !#.< !#.? !#.# !#.$ !#.F !#.>

,lternate .unctions RG6 "0erial input port% TG6 "0erial output port% IDT4 "7'ternal Interrupt &% IDT< "7'ternal Interrupt <% T& "Timer & 7'ternal input% T< "Timer < 7'ternal Input% (R "7'ternal 6ata memory write strobe%

!#.C

R6 "7'ternal 6ata memory Read 0trobe%

PORT >! !ort & is an K-bit open drain bi-directional I34 port. It is also the multiple'ed low order address and data bus during access to e'ternal memory.

It also receives the instruction bytes during 7!R4E programming and outputs instruction bytes during program verification. "7'ternal pull-ups are re+uired during verification%. !ort & can sink "and operation and source% eight /0 TT/ input.

PORT 1! !ort < is an K-bit bi-directional with internal pull-ups. It receives the low order address byte during 7!R4E program verification. The port-< output buffers can sink3source four /0 TT/ inputs.

PORT 2! !ort ? is an K-bit bi-directional with e'ternal pull-ups. It emits the high order address byte during accesses to e'ternal memory. It also receives, these high-order address bits during 7!R4E programming @erification. !ort ? can sink3source four /0 TT/ inputs.

RST! (hile the oscillator is running a high on this pin for two machine cycles resets the device. , small e'ternal pull down resistor "K.?k% from R0T to @ss permits power on reset when a capacitor "<& micro fre+uencies% also connected from this pin to @cc.

ALE5PROG! ,ddress latch enable is the output for latching low byte of the address, during access <& e'ternal memory. ,/7 is activated at a constant rate of <3> the oscillator fre+uency e'cept during an e'ternal data memory access at which time one ,/7 pulse is skipped. ,/7 can sink3source eight /0 TT/ inputs. This pin is also the program pulse input "!R4;% during 7!R4E programming.

PSEN! !rogram 0tore 7nable is the read strobe to e'ternal program memory. !07D is activated twice each machine cycle, during fetches form e'ternal program memory. !07D is not activated during fetches from internal program memory. !07D can sink3source K /0 TT/ inputs.

EA5V11! (hen e'ternal access enable "7,% is held high, the ,T-K=CF? e'ecute out of internal program memory " nless the program counter e'ceeds 4.. "8%%. (hen 7, is held low, the ,T-K=CF? 8 e'ecutes only out of e'ternal program memory. This pin also receives the ?< @olts programming. 0upply @oltage "@pp% during 7!R4E programming. This pin should not be floated during normal.

BTAL1! It is inputs to the inverting amplifier that forms the oscillator. GT,/< should be grounded when an e'ternal oscillator is used.

BTAL 2! It is 4utputs to the inverting amplifier that forms the oscillator, and input to the internal clock generator, receives the e'ternal oscillator signal when an e'ternal oscillator is used.

@ss @cc normal 4peration.

-

Circuit ground potential 0upply @oltage during !rogramming @erification and

TIMERS5COUNTERS! ,T-K=CF? has two <>-bit timer3counter &, and timer3counter <. They can be configured in any of the four operating modes, which are selected by bit-pars "m<, &% in register TE46 "Timer3counter Eode control%. Eodes &, < and ? are the same for the timer3counters. Eode # is different. 1 2 FEATURES OF AT-8?C:2! 4

<> 4? 48

< 49 Dow a days an K-bit ,T-K=CF?3K&#<3KCF< and <> bit K&=C micro controllers : 4; available in the form of kits. Its special features are summarized as5; 4: • • • • • • $k 1ytes of 9 .lash 8 <?K 1ytes of R,E ? #? I34 lines 1> 11 4< 44 42 41 4>

, five vector two level interrupt architecture. 12 2? 14 , full duple' serial port 1< 28 29

4n chip 4scillator and clock circuitry. 2; 1: 2: 2<

1; PIN DIAGRAM OF AT8?C:2! 19 18 1? 2>

PDIP

24 22 21

P1.> P1.1 P1.2 P1.4 P1.<
RAM ADDR RESISTOR PORT > DRIVERS

V** P >.>(AD >) P >.1 (AD 1) P >.2 (AD 2)
PORT 2 DRIVERS

P >.4 (AD 4) P >.< (AD <) FLASH P >.: (AD :) P >.; (AD ;) P >.9 (AD 9)

P1.: RAM P1.; P1.9 RST

PORT > LATCH

PORT 2 LATCH

B REGISTER

(R B D) P4.> ACC (T B D) P4.1 (INT >) P4.2 (INT 1) P4.4 TMP 2 (T >) P4.< (T1) P4.: (WR) P4.; TMP 1

STACK POINTER

EA 5 VPP ALE5PROG PSEN

PROGRAM ADDRESS REGISTER

P2.9 (A 1:) BUFFER P2.; (A 1<) P2.: (A 14) P2.<
PC INCREME (AN-TER

12) (RD) P4.9 BTAL 2 BTAL 1
TIMING AND CONTROL INSTRUCT -ION REGISTER PSW INTERRUPT SERIAL PORT AND TIMER BLOCKS P2.4

(A 11)
PROGRAM

P2.2 (A 1>) COUNTER P2.1 (A ?) P2.> (A 8)
DPTR

GND

PLCC
PORT 1 LATCH PORT 4 LATCH P2.> C P2.9

P >. > C P > . 9 V**

OSC

PORT 1 DRIVERS

PORT 4 DRIVERS

GND

ALU

PSEN ALE5 PROG EA5V11 RST

P1.> C P1.9

P4.> C P4.9

Sponsor Documents

Or use your account on DocShare.tips

Hide

Forgot your password?

Or register your new account on DocShare.tips

Hide

Lost your password? Please enter your email address. You will receive a link to create a new password.

Back to log-in

Close