Pneumatic Crane New f3h1h

CONTENTS

CHAPTER NO

TITLE SYNOPSIS CONSTRUCTION WORKING PRINCIPLE ELECTRICAL CIRCUIT DETAILS MECHANIAL ASSEMBLY DIAGRAM PNEUMATIC COMPONENTS DETAILS ELECTRICAL WIRING DIAGRAM COST ESTIMATION CONCLUSION BIBLIOGRAPHY

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SYNOPSIS MICROCONTROLLER is playing a major role in the field of industrial automation.

The main aim for us to select this project work is to acquire

practical knowledge in the field of automation using PNEUMATICS. We selected “MATERIAL ELEVATING CONTROL SYSTEM USING PNEUMATIC CYLINDER ” as our project work and we have used principles of Mechatronics in developing this project work.. In this project the materials are placed on a platform and transported from the ground floor to upstairs using a Pneumatic cylinder . This cylinder is controlled through the 5/3 solenoid operated directional controlled valve which is ON/OFF by the controller. There are three magnetic reed sensors placed at each floor for the purpose of stopping the platform. The materials are transmitted from one floor to another floor by pressing the switch in the keyboard.

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CONSTRUCTION This project consists of following parts 1. MICROCONTROLLER based control system 2. Air cylinder. 3. Magnetic reed sensor unit 4. 5/3 Directional controlled solenoid valve.

PNEUMATIC ELEVATOR

DOUBLE ACTING CYLINDER

M.S.STAND

BASE

AIR CYLINDER AIR cylinder is pneumatic equipment. In this cylinderis used for sliding LIFT movement . The cylinder and piston Rod is engaged in single solid unit. It moves across up and down. Air is supplied to cylinder in A+ and Aposition. Movement of slide is depending upon the pressure of air. 3

SOLENOID VALVE Solenoid valve is device, which is used to control the movement of slide. This is achieved by controlling a coil, when this coil energizes the flow of the air from compressor through the valve is allowed just by lifting the stopper with coil’s magnetic field. We are using 230v ac solenoid valve, it needs a AC voltage of 230v is needed to energize valve’s coil. The solenoid valve is connected to microcontroller output . The valve is connected to air cylinder. MAGNETIC REED SENSOR UNIT; The magnetic sensors are used for limiting the position of the elevator cabin. Three sensors are mounted on a plastic plate as shown in figure.

MAGNETIC SENSOR

The plastic plate with the sensor is mounted on the left side of the elevator cabin unit .The height of the plastic plate can be adjusted with the help of bolt and nuts in order to set the minimum gap between the magnet and magnetic sensor

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MAGNETIC PLATE

MAGNETIC SENSOR 1

MAGNETIC SENSOR 2

MAGNETIC SENSOR 3

PLASTIC PLATE

HEIGHT ADJUSTABLE BOLT NUT

NOVOPAN PLYWOOD

WORKING PRINCIPLE MICROCONTROLLER controls the solenoid coil to actuate the cylinder cabin up and down. To start the operation, the job is placed inside the cabin and the ON switch is pressed in the switch board. This switch sends the 24v dc signal to the input of the controller . Controller gives the output signal as per the program. controller drive the solenoid coil through the 24V relay. Here we use 5/3 way solenoid operated directional control valve . This valve is used to stop the piston rod of double acting cylinder at required position between the A+ and A—position. When the cabin crosses the required floor, the magnetic sensor sends the signal to the input of the controller. Controller switch off the supply to the solenoid coil at the required floor. The required floor is selected by pressing the push button in the switch board. The pressure required to operate this system is 5 to 6 bar.

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CIRCUIT DETAILS 1. Micro controller system 2. Interface Circuit for stepper motor 3. Power supply (230V A.C. to 12 V and 5V DC) 4. Key Board Circuit MICRO CONTROLLER SYSTEM: This system monitors the engine condition by using PIC 16F870 (28 pin IC Package) micro controller. The pin details of micro controller are shown in figure.

The circuit diagram for this micro controller board is shown below,

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MOTHER BOARD CIRCUIT DETAILS

in no 2&5.The pin no 1 is RESET switch..The INPUTS are connected to port B .The OUTPUTS are connected to PORT C.6 MHZ crystal is connected to pin no 9,10. Keypad interface; Here seven soft micro switches are soldered in the main board and their connections are shown below.

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PORT B (KEYPAD)INPUT & OUTPUT CIRCUIT

c) 5 to 12V interface circuit: Here we have to drive the 12V DC stepper motor. The 5V signal from the PIC 16F 870 micro controller is fed into the input of interface circuit. TIP 120 Darlington transistor is used here for high speed switching purpose and the Diode IN 4007 is for the safety of TIP 120 transistor during the collapsing of magnetic field from the stepper motor coil. This interface circuit is shown in fig.

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5V TO 12V INTERFACE CIRCUIT

POWER SUPPLY 5V DC AND 12V DC; A 12 –0 v step down transformer is used to step down 230V AC to 12V AC .This 12V AC supply is converted to 12V DC using four rectifier diodes. The voltage from the rectifier section is regulated to 12V DC using 7812 IC . From 12V DC the 7805 IC is used for regulating 5V DC for the power supply of microcontroller. the power supply circuit is shown in fig.

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INTRODUCTION: All the electronic components starting from diode to Intel IC’s only work with a DC supply ranging from +5V to +12V. We are utilizing for the same, the cheapest and commonly available energy source of 230V-50Hz and stepping down, rectifying, filtering and regulating the voltage. STEP DOWN TRANSFORMER: When AC is applied to the primary winding of the power transformer, it can either be stepped down or stepped up depending on the value of DC needed. In our circuit the transformer of 230V/15-0-15V is used to perform the step down operation where a 230V AC appears as 15V AC across the secondary winding. Apart from stepping down voltages, it gives isolation between the power source and power supply circuitries. RECTIFIER UNIT: 10

In the power supply unit, rectification is normally achieved using a solid state diode. Diode has the property that will let the electron flow easily in one direction at proper biasing condition. As AC is applied to the diode, electrons only flow when the anode and cathode is negative. Reversing the polarity of voltage will not permit electron flow. A commonly used circuit for supplying large amounts of DC power is the bridge rectifier. A bridge rectifier of four diodes (4 x IN4007) are used to achieve full wave rectification. Two diodes will conduct during the negative cycle and the other two will conduct during the positive half cycle, and only one diode conducts. At the same time one of the other two diodes conducts for the negative voltage that is applied from the bottom winding due to the forward bias for that diode. In this circuit due to positive half cycle D1 & D2 will conduct to give 0.8V pulsating DC. The DC output has a ripple frequency of 100Hz. Since each alteration produces a resulting output pulse, frequency = 2 x 50 Hz. The output obtained is not a pure DC and therefore filtration has to be done. The DC voltage appearing across the output terminals of the bridge rectifier will be somewhat less than 90% of the applied rms value. Normally one alteration of the input voltage will reverse the polarities. Opposite ends of the transformer will therefore always be 180 degree out of phase with each other. For a positive cycle, two diodes are connected to the positive voltage at the top winding. FILTERING CIRCUIT: Filter circuits which is usually capacitor acting as a surge arrester always follow the rectifier unit. This capacitor is also called as a decoupling capacitor or a bying capacitor, is used not only to ‘short’ the ripple with 11

frequency of 120Hz to ground but also to leave the frequency of the DC to appear at the output. A load resistor R1 is connected so that a reference to the ground is maintained. C1, R1 is for bying ripples. C2, R2 is used as a low filter, i.e. it es only low frequency signals and byes high frequency signals. The load resistor should be 1% to 2.5% of the load. 1000f/25V : for the reduction of ripples from the pulsating 10f/25V

: for maintaining the stability of the voltage at the load side.

0.1f

: for bying the high frequency disturbances

BLOCK DIAGRAM FOR POWER SUPPLY

STEP DOWN

TRANSFORMER

BRIDGE

POSITIVE

RECTIFIER

CHARGE CAPACITOR

5V

12V

REGULATOR

MOTHER

BOARD

VOLTAGE REGULATOR: 12

REGULATOR

DISPLAY

BOARD

RELAY

The voltage regulators play an important role in any power supply unit. The primary purpose of a regulator is to aid the rectifier and filter circuit in providing a constant DC voltage to the device. Power supplies without regulators have an inherent problem of changing DC voltage values due to variations in the load or due to fluctuations in the AC linear voltage. With a regulator connected to the DC output, the voltage can be maintained within a close tolerant region of the desired output. IC7812 and 7912 is used in this project for providing +12V and 12V DC supply.

5 TO 12 V DC DRIVE CARD

Here we have to drive the 12V DC load. The 5V signal from the PIC 16F870 micro-controller is fed into the input of interface circuit. SL100 transistor is used here for high speed switching purpose and IRF 540N

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MOSFET is connected to the motor to handle the larger current drawn by the motor.

MECHANICAL ASSEMBLY DRAWING

PNEUMATIC ELEVATOR

DOUBLE ACTING CYLINDER

M.S.STAND

BASE

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DESCRIPTION OF PNEUMATIC COMPONENTS 1. Double acting air cylinder with piston arrangement. 2. Spool valve (2 position 5 ports valve) 3. Pneumatic fittings a. Bulk head union b. Flexible hoses c. Air compressors DOUBLE ACTING AIR CYLINDER WITH PISTON ARRANGEMENT: It consists of a piston inside a cylindrical housing called a barrel. Attached to one end of the piston is a rod which the rod end has one port. This rod end port is used for entrance of air and extends outside one end of the cylinder. At another end is a port for exit of air. Double acting cylinder can be extended and retracted pneumatically. The smallest bore size of an double acting cylinder is 1 1/8 inch. The piston, which is made of ductile Iron, contains u-cup packing to seal against leakage between the piston and barrel. The ports are located in the end caps, which are secured to the barrel by bolts and nuts.

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DIRECTING CONTROL VALVES: A direction control valve is used to change the direction of air flow as and when required by the system for reversing the machine tool devices. A direction control valve may be classified, according to the construction of the internal moving parts, as 1. Rotary spool Type. 2. Sliding Spool Type. 3. Solenoid operated valves SOLENOID OPERATED VALVES: Solenoid valves are electromechanical devices like relays and contractors. A solenoid valve is used to obtain mechanical movement in machinery by utilizing fluid or air pressure. The fluid or air pressure is applied to the cylinder piston through a valve operated by a cylindrical electrical coil. The electrical coil along with its frame and plunger is known as the solenoid and the assembly of solenoid and mechanical valve is known as solenoid valve.

The solenoid valve is thus another important

electromechanical device used in control of machines. Solenoid valves are of two types, 1. Single solenoid spring return operating valve,(5/2) 2. Double solenoid operating valve. In fig 1 is shown a single solenoid spring return valve in its de-energized condition. The symbol for the solenoid and the return are also shown. The solenoid valve is shown connected to the cylinder to help readers understand 16

the solenoid valve action. In the de energized condition, the plunger and the valve spool position as shown in figure 1.

In this position of spool, port P is connected to port A and port B is connected to tank or exhaust (i.e. atmosphere) if air is used. Spring pressure (S) keeps the spool in this condition as long as the coil is de energized. Fluid pressure from port P through port A is applied to the left side of the cylinder piston. Thus the cylinder piston moves in the right direction. Now when the solenoid coil is energized, plunger is attracted and it pushes the spool against spring pressure. The new position of plunger and spool are shown in fig 2.

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In this position of spool, port A gets connected to tank and port P gets connected to port B. Thus pressure is applied to the cylinder piston from right and moves the piston rod to the left. At the same time fluid in the other side is drained out to the tank. When the solenoid coil is again de energized, the spring (S) will move the spool to its original position as shown in figure 1. Thus, normally when the solenoid coil is de energized the piston rod remains extended.

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PNEUMATIC FITTINGS: There are no nuts to tighten the tube to the fittings as in the conventional type of metallic fittings. The tube is connected to the fitting by a simple push ensuring leak proof connection and can be released by pressing the cap and does not require any special tooling like spanner to connect (or) disconnect the tube from the fitting. SPECIFICATION OF THE FITTING: Body Material

- Plastic

Collect/Thread Nipple

- Brass

Seal

- Nitrate Rubber

Fluid Used

- Air

Max. Operating Pressure

- 7 Bar

Tolerance on OD of the tubes

-  1 mm

Min. Wall thickness of tubes

- 1 mm.

FLEXIBLE HOSES: The Pneumatic hoses, which is used when pneumatic components such as actuators are subjected to movement. Hose is fabricated in layer of elastomer or synthetic rubber, which permits operation at high pressure. The standard outside diameter of tubing is 1/16 inch. If the hose is subjected to rubbing, it should be encased in a protective sleeve. 19

ADVANTAGES AND LIMITATIONS ADVANTAGES:  The Pneumatic arm is more efficient in the technical field  Quick response is achieved  Simple in constructions  Easy to maintain and repair  Cost of the unit is less when compared to other robotics  No fire hazard problem due to over loading  Comparatively the operation cost is less  The operation of arm is faster because the media to operate is air  Continuous operation is possible without stopping. LIMITATIONS:  High torque cannot be obtained.  Load Carrying capacity of this unit is not very high (3 – 5 kgs). While working, the compressed air produces noise, therefore a silencer may be used.

APPLICATIONS DISCHARGE OF WORKPIECE: The arm fed has wide application in low cost automation. It can be used in automated assembly lines to pick-up the finished product from workstation and place them in the bins. It can also be used to pick-up the raw material and place them on the conveyor belts and vice versa. JOB CLAMPING:

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This unit can also be used in clamping operations in certain areas of mass productions where clamping and unclamping have to be done at high speeds. The applications of this unit is limited to operations which involves moderate clamping forces. TRANSFER OF JOBS BETWEEN WORK STATION: The gripping method used in a low cost automation to move the work piece from one workstation to another. The combination of an angular rotary motion is the principle behind this method. The gripper holds the work rigidly. The to and fro motion is achieved by means of the actuating cylinder. TOOL CHANGING APPLICATION: When the pneumatic arms are made smaller in size they can be used in automatic tool changer in CNC turning and drilling machines, by attaching suitable tool holding device to the rotary cylinder.

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PNEUMATIC CIRCUIT DIAGRAM

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COST ESTIMATION

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DETAILS

COST Rs.

1. Double acting cylinder unit

1400

2. 5/3 double solenoid directional control valve

1200

3. M.S. tube stand

300

4. Microcontroller unit

2400

5. Novo ban Board

200

6. Magnetic sensor unit

400

TOTAL

5900/-

CONCLUSION

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We make this project entirely different from other projects. Since concepts involved in our project is entirely different that a single unit is used to various purposes, which is not developed by any of other team . By doing this project we gained the knowledge of pneumatic system and how automation can be effectively done with the help of pneumatic system. It is concluded that any automation system can be done with the help of controller& pneumatic system. We have successfully completed the project work on using pneumatic control at our Institute. By doing this project work, we understood the working principle and uses of various controls, switches, relays etc. It will be of no doubt that pneumatic system will be an integrated part of any automation process in any industry. Once again we express our sincere thanks to our staff .

BIBLIOGRAPHY 25

1. Low cost automation with pneumatics

-

FESTO

2. Electro pneumatics

-

3. Hydraulics & pneumatics for Power Production -

Harry L – Stewart

4. Basic pneumatics

- FESTO

FESTO

5. www.google.com 6. Workshop Technology

- Hajra Chowdry

7. Production Technology

-R.S. Khurmi

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