Chapter 1: Introduction
1.1 Problem Summary:-
For our project we get training from'Austin Engineering Company'. Austin Engineering Company is manufacturing a different products ball bearings, cylindrical roller bearings, roller bearings, etc. After getting training we decide to make innovative device based on the servo motor in bearing machine. So we are choosing a machine slide control using servo motor.
Machine slide control using hydraulic system is many disadvantages slower motion of shaft, complex construction, leakage of oil problem, noise problem, vibration problem and it is very costly. Many other disadvantages of hydraulic system so machine slide is not proper working.
To solve this entire problem we try the machine slide control using servo motor. In this project we can use a servo motor because of the Cost, Smooth rotation at low speeds, Low cost drive, No power used at standstill, solved the problem of noise and vibration.
The aim of our project is that make it's less size, easily operate and smooth rotation of slide without any loss by using servo system. And the converting controlling system mechanical to electrical system in the machine slide controller.
1.3.1 Introduction of Industry:-
At present the'Austin Engineering Company' has become a wide and popular unit in market.
The 'Austin Engineering Company' was established in 1973.Company has established second unit as PATLA on 15th Feb. 1987.
Austin company is Products Manufacturer, Supplier and Exporter is different products ball bearings, roller bearing, cylindrical roller bearings, needle roller bearings, etc.
In 1986 company has started bearing in different countries such as USA, UK, Italy, UAE, Srilanka, Newzeland, Germany, Pakistan and Bangladesh etc.
1.3.2 Introduction of Project:-
In machine slide control using hydraulic system but in this system required many fault and problem like vibration, oil leakage, noise, loss power, component does not properly work, etc.
Now a day servo motor is more commonly used as a hydraulic system. Because of servo motor is a main advantage capacity to hold its position and it is helpful in position control in slide.
Servo motors are used in the a servo drive system and it is a accurate or highly dynamic. The feedback to the motor is through a resolver is used in analogue sensor of rotation or encoder is used to digital sensor of rotation. A servo motor is controlled by a servo encoder, possibly with a shaft controller.
Servo motor does not get over heated during operation resulting into low loss of power resulting into efficient operation.
Machine slide controller using servo motor is a fully automated slide control that also avoids any fault and is capable of without the need of any human interaction.
Machine slide controller by hydraulic system is using many number of equipment like a hydraulic pump, oil filter, 3 phase induction motor, relief valve, non return valve, solenoid valve, oil tank, oil level indicator, etc.
But now a day servo motor is using in the machine slide controller instead of conventional hydraulic system and it is less equipment use compare to the hydraulic system. In machine slide controller using servo system is use a servo motor, servo drive, single phase induction motor and gear box.
' Non skilled person can also operate.
' Smooth rotation at low speeds.
' Low cost drive.
' High efficiency.
' It is economical.
' Compact in size and portable.
' No any fuel cost.
' No vibration
' Noise free.
' Freedom from long & complicated component.
' For a industry
' Conveyor belt in machine
' Solar Tracking system
' Metal Cutting & Metal Forming machine
' Printing press/printer
' For CNC machine etc.
1.4 Literature Review:-
1.4.1 Literature Paper-1:-
'Position Control of an Ac Servo Motor Using Sliding Mode Controller with Disturbance Estimator'
Jung Woo Cheon, Seung Bok Choi, Hyun Jing Song And Jon Ho Ham
Department of Mechanical Engineering ,Inga University, Incheon South Korea
In this work, a new control methodology to achieve accurate position control of an AC servo motor subject to external disturbance is proposed. Unlike conventional sliding mode controller which requires a prior knowledge of the upper bound of external disturbance, the proposed technique called sliding mode controller with disturbance bound. The SMCDE is featured by an integrated average value of the imposed disturbance over a certain sampling period. By doing this undesirable chattering phenomenon in the estimation process can be effectively alleviated. The benefits of the proposed control methodology is empirically demonstrated on AC servo motor and control responses are evaluated through a comparative work between the proposed and conventional control schemes.
1.4.2 Literature Paper-2:-
'Control and Automation of Cylindrical Grinder
Using PLC, Drives and HMI'
Neha Kaushal, Rahul Sharma
International Journal of Engineering and Innovative Technology (IJEIT) Volume 3, Issue 9, March 2014
The focus of this paper work is in the automatic working of the entire machine or plant. Here in industrial automation, we can use PLC, Drives and HMI. With the help of devices we automate the entire machine. The present work, the entire working of the cylindrical grinder is controlled. During manual operation of cylindrical grinder working on the machines face difficulty in synchronizing the speed between grinding wheel and the job head. Both are continuously rotating at some speed. There is also a problem in the movement of slide, which brings the grinding wheel near to the work piece for appropriate cutting of the extra material from the work piece .So in order to overcome all these difficulties, we can use PM554. It gives command to various Servo drives, VFD Drives and switches. For proper starting of the machine, the proper interlocking should be done in PLC programming, satisfying various conditions.
Design Analysis, Design Methodology & Implementation Strategy
2.1 Block Diagram:-
Fig-2.1:- Block Diagram
The Fig.-1 shows the block diagram of the 'Fully Machine Slide Control with Servo Motor Instead of Conventional Hydraulic System'.
In this system comparator is compares the input signals with the control signal fed from feedback device. Depending on comparison a signal sliding mode controller adjust the speed of the servo motor.
Servo motor speed is detected by the sensors and delivered it to feedback device for smooth controlling operation to get desired results.
This power is given to the micro controller which is controlled the whole device and operate automatically. There is used sensor ,it can be sense or detect the object and protect against damaged.
The servo motors are used for moving the shaft or slide of machine. Modern servomotors use rotary encoders, either absolute or incremental. Absolute encoders can determine their position at power on, easily work and compact size. Incremental encoders are simpler, cheaper and work at faster speeds, incremental systems.
Sr. No. Hydraulic system Servo system
1 3 Phase induction motor Servo motor
2 Hydraulic Pump Servo drive
3 Oil Filter Feedback
4 Hydraulic Oil Sensor
5 Relief Valve Encoder
6 Non return Valve 1 Phase induction motor
7 Solenoid valve Gear Box
8 Hydraulic pipe
9 Oil tank
10 Oil level indicator
11 Pressure gauge
2.2.1 Hydraulic System:-
A hydraulic system is a drive or transmission system and it uses pressurized hydraulic fluid to the power hydraulic machinery. The term hydraulic system is a transfer of energy from flow and pressure, not from the kinetic energy of the flow.
Hydraulic system is the base of Pascal's law. As the pressure in the system is the same, the force that the fluid gives to the surroundings is there force equal to pressure '' area. So it is depend on the pressure of fluid and area of hydraulic unit.
Hydraulic system is a large number of equipment used. And its equipment size is very large. So this is not suitable for the slide machine control.
Fig 1.2:- Hydraulic Pump
Hydraulic pumps are used in hydraulic system systems. It can be hydrostatic or hydrodynamic pump. A hydraulic pump is a mechanical source of power that converts mechanical power into hydraulic energy. Hydraulic pump is generates flow with enough power to overcome pressure induced by the load at the pump outlet.
Hydraulic pump working principle, it is create a vacuum at the pump inlet, which forces liquid from the tank into the inlet line to the pump and by mechanical method delivers this liquid to the pump outlet and forces into the hydraulic system.
Hydrostatic pumps are positive displacement pumps while hydrodynamic pumps can be fixed displacement pumps, so the displacement cannot be adjusted or variable displacement pumps, it is a more complicated and difficult construction that allows the displacement to adjust.
2) Oil Filter:-
Hydraulic oil is passes through various components of the system then dirt, dust and metal particles may be to the oil and contaminate it.
Pumps, motors, shaft and valve have number of moving components. Due to motion of the moving part with to the stationary part there is a lot of wear and tear. In this process metal particles and other solid particle are released and get mixed with the hydraulic oil.
Many components have difficult dimension and tolerances. Oil filter are provided individually for all component hydraulic system to avoid failure and maintenance problem. Fig:-Oil Filter
3) Hydraulic oil:-
For maximum efficiency and hydraulic component life, that is a high quality, wide temperature range, stable hydraulic oil utilized which incorporates the viscosity limits.
The hydraulic oil is the blood of the hydraulic system, because of without hydraulic oil does not start hydraulic system. So it is very important to the hydraulic system. Useful oil is commonly used in the transfer of power hydraulic fluid act as a sealant, coolant and lubricant within machinery and component.
The electric fill pump is used to add hydraulic oil to the system. Hydraulic oil must be added used the hydraulic fill pump, so it is properly filtered from the return filters before entering the hydraulic tank.
4) Hydraulic Pipe:-
Fig: Hydraulic Pipe
Copper pipes, steel pipes, stainless steel pipes, and rubber pipe are used in piping for hydraulic system. Copper pipes are not used in common system because its pipe accelerates oxidation of petroleum based hydraulic fluids. Stainless steel pipes are more suitable for the hydraulic equipment.
5) Non-return valve:-
Non return valve is another name is a check valve, clack valve, non-return valve or one way valve. It is a valve that normally allows oil as a liquid or gas to flow in only one direction. Non return valve are two-port valves, so they have two openings in the body, one for oil to enter and the other for oil to out.
Fig:Non return valve
6) Oil level indicator:-
The oil level indicators are used for monitoring oil levels and temperature in various types of component. Typical using is hydraulic system in reservoirs and lubricating, cutting and cooling fluid tanks. Oil Level Indicators are suitable for service in mineral oils based hydraulic fluids. Fluid Level Indicators can be supplied with oil tank. Fig: Oil Level Indicator
Oil level indicate phase, temperature, vacuum, noise, vibration, mechanical shock, oil tank and shape and size of component. Also it is useful to indicate of the monitoring, control of continuous and discrete levels, physical size and mounting of the component of hydraulic system.
7) Oil Tank:-
The level of hydraulic oil in the hydraulic tank is very important in hydraulic system. If the oil level drops too very low, the suction strainers to the pumps can be exposed to air. Exposing a suction strainer to air will allow the air to enter the pump where tank will cause damage. When air mixes with oil in the suction line it forms bubbles. These bubbles are drawn into the pump and very tightly compressed by the pump's piston. As the compressed air bubbles leave, they expand very rapidly, like tiny explosions. These tiny explosions deteriorate the brass surface of the piston shoes very quickly and destroy the pump. Fig:-Oil Tank
This will maximum result in the additional failure of other major components. In many cases the complete hydraulic system and its components must be flushed to remove all contamination before the system returning to operation.
8) Relief Valve:-
Relief valve is always fixed with displacement hydraulic pumps. Pressure-compensated pump also may use a relief valve for some applications.
Relief valve working as a protecting the pump and the system from excess pressure. And no time should be the relief valve be used to pass excess pressure fluid to tank.
When hydraulic pump flow goes to tank, it generates heat. The relief valve in a good designed hydraulic circuit never relieves oil to tank unless there is a circuit or control damage. Fig: Relief valve
Relief valve work as a fuse or in the electric circuit. An electric circuit never damage a fuse unless it overload. When an electric circuit overloads, it is in until reset. Usually the person responsible for resetting the fuse looks for the reason it damage and fixes the problem before restarting the machine.
9) Pressure Gauge:-
A pressure gauge is a mechanical instrument designed for the measure the internal pressure and vacuum of a instrument or system. Pressure Gauges are offered in a variety of styles, sizes, and it is depend on the materials to meet the demands of standard and special applications.
Pressure gauges are constructed with a bourdon tube sensing element. When the sensing element is observed to pressure, it flexes and the resulting motion is transmitted as a measurement through a mechanical movement to the pointer. Fig:-Pressure Gauge
10) Solenoid Valve:-
Solenoid valve is a electro-mechanically operated valve. The valve is controlled by a electric current through a solenoid.
Solenoid valves are the frequently used control elements in hydraulic. Their tasks are to shut off, release, distribute and mix fluids. They are use in many application areas. Solenoids valve is main advantage of offer fast and safe switching, high reliability, long service life, good medium compatibility of the materials used, low control power and compact design. Fig: Solenoid valves
The plunger type actuator, which is used most frequently, pivoted armature actuators and rocker actuators are also used in hydraulic system.
11) 3 Phase induction motor:-
Fig:- 3 Phase induction motor
An electrical motor is such an electro-mechanical device and it is converts electrical energy into a mechanical energy. Three phase AC operation, most widely used motor is three phase induction motor .This type of motor does not require any starting device and it is a self starting induction motor.
Working principle of three phase induction motor it may observed that the rotor speed does not reach the synchronous speed produced by the stator. If the speeds equals, there would be no such relative speed, so no emf induced in the rotor, & no current would be flowing, therefore no torque would be generated.
Consequently the rotor cannot reach the synchronous speed. The difference between the stator or synchronous speed and rotor speeds is called the slip. The rotation of the magnetic field in the three phase induction motor has the advantage that no electrical connections need to be made to the rotor.
2.2.2 Servo System:-
Now a day, electric drive systems using electric servo motors can be controlled in better way and it can be easily compete with rotating hydraulic drive systems. Without competition for forces hydraulic system is not work. For these hydraulic systems will remain of interest and if such a system is available, it is easy and less loss to use this system for the rotating drives of the systems, also.
Servo system comprises to the servo drive and a servo motor use that operates with a PLC or CNC to perform complex, specialized moves in one or more directions, or axes. These complex and specialized moves, which are needed in the industrial and its known as motion control.
Servo systems are used in many different fields for automation in the motor industry, the petrol industry, machine tool industry, the textile industry, in packaging systems, warehousing systems and so on.
1) Servo motor:
Servomotor is a rotary actuator or linear actuator ,so this is allows for control of angular and linear position, velocity or acceleration. It consists of a suitable motor coupled to a sensor for position feedback. It is also requires a relatively controller, often a dedicated module designed specifically for use with servomotors.
Servomotors are not use a specific class of motor. The term servomotor is often used to refer to a motor suitable for use in a closed loop control system. Fig:-servo motor
Servo motors are used in many applications like a robotics, CNC machine, automation, manufacturing, machine tool, etc.
' Mechanism of Servo Motor:-
Servomotor is a closed loop servo system, that it is uses a position feedback to control its motion and control of position. The input signal of servo system is a either analogy or digital, and controlling of the output shaft.
Servo motor is connect with the encoder to provide position and speed feedback. In the servo motor simplest case of the position is measured. The measured position of the slide or shaft is compared to the command position, the external input to the controller. If the output position differs from that required, an error signal is generated which then causes the motor to rotate in either direction, as needed to bring the output shaft to the appropriate position. As the positions approach, the error signal reduces to zero and the motor stops.
The very simplest servomotors use position only sensing to the potentiometer of the servo motor. Servo motor is rotates at full speed.
Servo motors is using a resistive potentiometers as their position encoder. These are only used at the very simplest and cheapest level, it is in close loop with the servo motors. They are causes from wear and electrical noise in the potentiometer track. Although it would be possible to electrically differentiate their position signal to obtain a speed signal, PID controllers that can make use of such a speed signal generally warrants a more precise encoder.
In present servomotors use encoders,either absolute or incremental. Encoders can determine their position at power on, but are more complicated and expensive.
In the servo system incremental encoders are simpler, cheaper and work at faster speeds. Incremental systems, like servo motors, often combine their inherent ability to measure intervals of rotation with a simple zero position sensor to set their position at start up. Fig: Encoder
Instead of servo motors sometimes a motor with separate, external linear encoder is used. These motor linear encoder systems avoid inaccuracies in the drive train between the motor and load, but their design is made more complicated as they are no longer a pre packaged factory made system.
3) Servo Drive:-
Servo drive is the special electronic amplifier used to power electric servo systems. The servo drive monitors the feedback signal from the servomechanism and continually adjusts for deviation from expected behaviour.
It is provide a fully digital control over position, velocity or torque for synchronous, asynchronous, and linear or torque servo motors. Servo drives a wide selection of power sizes that are flexible to work with a variety of machine designs.
Fig: Servo Drive
Servo drive is the high dynamic and reliable, easily for operation of demanding industrial encironment, optimize to the servo motor.
4) Feedback & Sensor:-
Servo system, sometimes shortened to servo, is an automatic device that uses error sensing negative feedback to correct the performance of system and is defined by its function. It usually includes a built in encoder. The servo system is sometimes called a heterostat because of it is controls a system's behaviour by means of heterostasis.
The term correctly applies only to the systems where the feedback or error-correction signals used control mechanical position, speed or other parameters. For example, the automotive power window control is not a servomechanism, so there is no automatic feedback that controls position the operator does this by observation.
Fundamentally a servo system can be perform no more accurately than the accuracy of the feedback device controlling system. In addition, errors in speed or position can be introduced into the system by the less than perfect mechanisms that transfer the motor power to the load.
Environmental factors like electrical-mechanical noise or temperature may also introduce positioning errors. Sometimes the errors are acceptable, more frequently, however, they are not. After all, servomotors can be expensive, and the expectation is that they will be the reliable and accurate of positioning devices.
Some time it comes to high performance servo applications, feedback devices fall into different categories. Each offers unique advantages and disadvantages, both electrical and mechanical, which is a make one better suited for a particular application than another.
5) Gear Box:-
Gear box is connected to the servo motor in servo system, which is used to enables to rotation of slide faster, more accurately and without damage. It is needed to translate the high speed of the motor in a controlled movement of the shaft or slide. For example to pick a product without a gearbox the speed and velocity of this slide or shaft will demand the behaviour of motor and it will literally overshoot the target. Fig. Gear Box
6) Single phase induction motor:-
fig:-Single phase induction motor
Electric motors that using the single phase power supply for their operation are called as Single Phase Motors. Single phase induction motor is classified into many different types, but the mostly used single phase motors can be considered as Single Phase Induction Motors.
In the three phase motor usually operating with three phase power supply in which the three phases, phase shift of 120 degrees between two phases , then it produces a rotating magnetic field. Due to this, the current is induced in the rotor and causes an interaction between stator and rotor resulting the rotor to rotate.
Then single phase motors which are running with only single phase power supply, there are many different ways to start these motors one way is by using the single phase motor starter. All these starting methods, mostly a second phase, called as an auxiliary phase or start phase is produced to create a rotating magnetic field in the stator. Auxiliary phase and start phase are produced to the create a rotating magnetic field in the single phase induction motor stator.
2.3 Fault In Hydraulic System:-
Sr. No. Hydraulic System Fault
1 3 Phase induction motor speed control of induction motors are difficult, poor starting torque
2 Hydraulic Pump Maintenance Costly, Because of high friction, first movement of opening or closing requires a large amount of force.
3 Oil Filter Higher Cost
4 Hydraulic Oil Very Costly
6 Relief Valve Very Noise
7 Non return Valve Long flow period, start up and maintenance require large space.
8 Solenoid valve Vibration
9 Hydraulic pipe Higher Recruitment
10 Oil tank Oil Leakage
11 Oil level indicator Difficult to obtain accurate flow reading
12 Pressure gauge Limited in pressure size ratio
In the hydraulic system use a many number of component. And this components are number of occur fault during operation. And main disadvantage of hydraulic system is a complex construction, oil leakage problem, high vibration, more maintenance cost. So the machine does not proper work and slide is not continues rotate.
Conclusion And Future Work
Controller for a servo mechanism systems can be seen in this paper and with the example of compact size of machine, the addition of a servo system is fully possible and fully beneficial in the industry. It is reduce a size of machine, less power loss, output is accurate, maintenance cost is less and easily operate.
In this project we can covert the mechanical system to electrical system as a hydraulic system to the servo system. And we can conclude that the servo motor are more suitable for the converting and use in the slide machine. Because of the servo motor has capacity to hold its position which is helpful in position control.
3.2 Future Work:-
In our project we can convert mechanical system to electrical system. So we are using a servo system instead of hydraulic system in slide machine controller.
In Future we can for future work, a high level controller will be designed to control the motion of the servo mechanism operating at various speeds and achieving different modes of operation, a human machine interface would be required to facilitate the control of the mechanism. The final control scheme will be programmed to embed control circuit for heavy load machine.
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