Theoretical Basis With the idea mentioned above, when controlling the conveyor motor’s speed and detecting the object, to control the flying object motor to move in the right direction a
INTRODUCTION
Problem statement
In Vietnam, the manufacturing industry is currently one of the leading industries in
In September 2022, as manufacturers transitioned to a new phase of recovery following the challenges of the COVID-19 pandemic, industrial manufacturing experienced significant growth, with rates increasing by 1.8% from August 2022 and 13% compared to the same period last year Overall, the Industrial Production Index (IIP) rose by 9.6% year-on-year, reflecting a strong rebound in the sector.
In traditional industrial factories, machinery was primarily operated manually, with some modern advancements introducing automated equipment like cutting and label printing machines to reduce labor in production Today, technological advancements have led to the rise of automation devices that enhance efficiency and minimize the workforce required Engineers have developed innovative solutions, such as Flying Cutter Machines, which significantly improve production convenience and efficiency While older cutter machines offer low error rates and neat cutting paths, they are often time-consuming In contrast, systems utilizing Flying Cutter technology maximize productivity by maintaining continuous operation without the need to stop or slow down during cutting processes.
Goals
The "Flying Cutter Machine" project focuses on designing and constructing a system that enhances productivity and control through web-based supervision via LAN By developing this model, we aim to optimize parameters for improved performance, contributing significantly to advancements in Vietnam's material industry.
Project limitation
This project focuses on achieving speed synchronization between two motion axes when a sensor detects a passing object, known as Synchronous Control in Flying Shear applications It is important to note that certain components, such as the cutting and printing parts, are not discussed in this project.
This project only uses common controlling methods which are widely used and are capable of implementing Complicated or high demanding methods will not be mentioned
Research methods
Based on models in practice by researching on the Internet, I constructed the
“Flying Cutter Machine” model with the enthusiastic and thoughtful guidance of Advisor Tran Vi Do Ph.D.
Outline
Chapter 2 provides an overview of existing technology and theoretical foundations related to the system Building on these theories and requirements, Chapter 3 addresses the system's tasks, selecting necessary hardware and calculating data pertinent to synchronization of the two velocity axes and leading distance In Chapter 4, the model will be developed and configured with HMI and Web Server using WinCC Unified Chapter 5 presents the operational results of the model, followed by an evaluation based on these outcomes Finally, Chapter 6 concludes with recommendations for future work.
LITERATURE REVIEW AND OVERVIEW PROCESS
Existing technology
The finishing phase in industrial factories is crucial for maximizing production efficiency By creating a product chain and breaking it down into smaller parts, factories can enhance their output Key processes such as cutting and logo printing significantly influence the final quality and appearance of products Historically, these tasks were performed by skilled workers, necessitating a high level of precision However, various factors could still impact product quality To address these challenges, the integration of technology has led to the development of automatic manufacturing machines, effectively replacing human labor in the production process.
Traditional cutting machine technology relies on a Product Feeder Conveyor that halts to perform tasks such as cutting and printing Once these tasks are completed, it resumes importing product chains, creating a continuous process that significantly reduces manual labor while producing nearly finished products However, a notable drawback of this system is its inability to optimize production time and machine performance effectively.
The Rotary Shear Application is an advanced cutting machine that efficiently processes products without any waiting time, thanks to its servo motor control It utilizes a sensor for product detection and an encoder for measuring distance, enabling precise cutting of product chains into smaller pieces The servo motor speed is synchronized with the feeder conveyor motor speed, ensuring an accurate cutting ratio for optimal performance.
Figure 2.1.1.a Operation of rotary knife
Figure 2.1.1.b Operation of Rotary knife
While Rotary Shear Applications enhance performance by optimizing time efficiency, their effectiveness is limited to the cutting phase, where the cutting component remains fixed, ultimately compromising the system's flexibility.
The Flying Shear is an essential industrial tool for cutting and printing products without halting production, ensuring maximum machine productivity It features a tool mounted on a carriage that moves parallel or at an angle to the product flow The flying shear drive synchronizes the carriage's speed with the line, allowing for precise execution of cuts After cutting, the carriage decelerates and resets for the next operation This technology is also applicable in various other industries, such as packing, mechanical punching, and bottle filling, all of which can benefit from flying shear application software.
System overview
The Flying Cutter Application operates on the principle of synchronizing the moving distances between two axes of motion To address the identified challenges, we will develop a comprehensive operating model.
The sensor is positioned at the motor's original point of the flying object When it detects the object, it activates the motor to move back and forth along the axis.
- The encoder is connected to conveyor motor will read the engine’s speed and convey to the CPU where parameters are calculated
- CPU will read and process parameters, and export appropriate data to control the flying object motor
Theoretical Basis
To effectively control the speed of the conveyor motor and detect objects, it is essential to address several key challenges in directing the flying object's motor to ensure it operates at the correct speed and trajectory.
- Conveyor motor keeps constant speed when performing synchronous process
- When reaching the target point, the flying object on the synchronous axis must be back to the starting point to continue the new journey, which ensures the system’s continuity
All equipment, including sensors, conveyor motors, flying object motors, and encoders, is interconnected with the CPU to facilitate communication, data transfer, and coordination, ensuring the system operates smoothly and efficiently.
This article explores the theoretical foundations of the three identified problems, providing a framework for developing effective solutions to both existing and emerging challenges during the operational process.
2.3.1 Theoretical basis related to the control method of conveyor motor and flying object motor
The engine is a vital component of industrial conveyor transmission systems, where the focus is on utilizing moving engines for conveyor operation and controlling the ball screw axis Conveyor applications typically require speed control from the main actuator motor, whether running at a constant or variable speed DC and AC motors are commonly employed to achieve this speed regulation, while stepper and servo motors offer precise control of the ball screw axis Among these, servo motors present significant advantages over stepper motors, particularly in terms of enhanced controllability.
7 much stricter tasks than Stepper motor The price of these two motors must be carefully considered as they are not reasonable
After selecting the appropriate motor for the conveyor system, the next crucial step is to identify effective control methods for that motor The choice of control method is essential and should be based on specific demands, control magnitude, technical requirements, and the motor's intended purpose, whether it connects to the conveyor, operates a ball screw axis actuator, or serves another function By evaluating these factors, we can determine the most suitable motor control method.
Definition A Stepper motor essentially is an induction motor that converts control signals into discrete electrical pulses in succession, forming angular and other rotor movements
The Stepper motor has the ability to fix the rotor in the required position
Servo Motor is a type of closed-loop motor controlled by a pulse Encoder
The servo motor's output signal is linked to a control circuit, allowing for precise motion control and accurate positioning As the servo motor rotates, it feeds back information about its speed and position to the control circuit, ensuring optimal performance and responsiveness.
Accuracy When the stepper motor has a slip problem, it will affect the motion result, leading to incorrect position due to step loss
Works on Encoder pulse feedback, conditional closed-loop control and higher accuracy
Reliability Stepper motor has high durability, no brush, and compact size Large torque, low maintenance, rarely breakdown
Some servo motors are specially designed to tolerate high-frequency control signals, responding to sudden acceleration requests from the central controller
Complexity Less complicated control compared to Servo Motor
Controlling servos is more complex than managing stepper motors, as servo drivers demand higher power and exhibit weaker torque Additionally, DC servos are less durable due to their brush components, which require regular maintenance.
Table 2.3.1 Compare between Stepper Motor and Servo Motor
Through the comparison, we can see that with severe requirements of high accuracy transmissing mission of the ball screw axis actuator motor, we will have priority over servo motor
2.3.1.1 Speed control methods of Induction motor
The speed equation of Induction motor is:
• n: The output speed of Induction motor
• 𝑛 1 : The speed of rotating magnetic field
Therefore, if we want to change the speed of the induction motor, they will change one of three factor elements: p, f, s a) Changing The Number of Magnetic Poles
The speed control method discussed is specifically applicable to squirrel cage induction motors, as opposed to slip ring induction motors, which have a fixed number of poles in their rotor In contrast, the rotor of a squirrel cage motor can be modified to accommodate various pole configurations There are two primary methods to alter the number of poles in an induction motor.
The first method involves utilizing multiple stator winding sets, each designed for different pole configurations During operation, users can connect any one of these winding sets based on their speed requirements, while the remaining sets remain disconnected.
Increasing the number of poles leads to a reduction in speed This technique allows for speed variation only in distinct steps and can be costly due to the requirement for multiple stator windings.
The consequent pole changing method allows for the generation of an additional set of poles by reversing the coils, resulting in two distinct speed options Additionally, altering the auxiliary resistance within the rotor circuit can further influence performance.
Although the method is simple, the speed is adjusted continuously, but it causes losses in the rheostat, leading to a decrease in motor efficiency
When the slip coefficient has little change, the speed will be proportional to the frequency On the other hand, from the equation:
We find that ỉ 𝑚𝑎𝑥 is directly proportional to 𝐸 1
𝑓 1 If people keep the value ỉ 𝑚𝑎𝑥 const it is necessary to adjust both 𝐸1 và 𝑓1 The motor must use a particular power source: the inverter, the air compressor used in industry today
Using an inverter makes it possible for us to control the motor according to different rules ( 𝑈
𝑓, vector control method, …) That has created motor speed control systems with many advanced features d) Changing the voltage
The formula for the critical slip coefficient of an Induction motor is:
The limiting slip of the motor, denoted as 𝑆 𝑡ℎ, remains independent of voltage levels When the source voltage 𝑈 is reduced and 𝑅 2 ′ is constant, the critical slip coefficient 𝑆 𝑡ℎ will decrease proportionally to 𝑈², rather than reaching its maximum value 𝑀 𝑚𝑎𝑥 This adjustment is applicable only while the machine operates under load; conversely, when the machine is running without load and the power source is reduced, its speed remains largely unchanged.
2.3.1.2 Control methods of Servo motor and Stepper motor
After specifying the correct motor, choosing a proper motor control method comes next Here are three of the most popular methods for controlling both step and servo motors a) Pulse control
Digital Pulse Control, often referred to as step and direction control, is a widely used technique for managing stepper and servo motors This method is particularly effective when the primary PLC or controller in a machine supports high-frequency outputs, typically 20 kilohertz (kHz) or higher.
For effective step and direction control, a minimum pulse output frequency of 20 kHz is essential, although many users may prefer frequencies of 100 kHz or higher, with some controllers supporting up to 2 or 3 MHz However, opting for these high-frequency outputs can increase system costs To mitigate expenses, consider using lower frequency outputs by incorporating a stepper drive or an integrated stepper motor with Microstep Emulation, which represents a significant advancement in step motor technology.
10 technology enables smooth, microstep operation even when motors use low frequency pulse outputs
The control scheme configuration involves connecting the PLC's pulse output to the motor drive's step input, while a second non-pulse output is linked to the direction input The pulse frequency dictates the conveyor's speed and travel length, with the direction input signal controlling forward or reverse movement To ensure smooth starting and stopping of the conveyor, the PLC must gradually adjust the pulse frequency, preventing jerky motions during acceleration and deceleration Additionally, the system can implement velocity control using an analog input for enhanced precision.
Operating system
2.3.1 Technology requirements of the system
To design the system, we have some technical requirements to be the goal and orientation for following steps, specifically:
• The system must supervise and the speed of the conveyor must be changeable
• Sensor plays a role as a responsive equipment that can detect the moving object
• The system must respond to the motor’s velocity via encoder, which will be the data used to synchronize the servo motor’s movement
• In order that the operator can easily manage, the system must have a Human- Machine-Interface (HMI)
• Supervise and control the position of the flying object between the ball screw axis and the material
All those mentioned above are the basis that we can depend on, the orientation for us to start designing the model, and help us consider finding suitable equipment
The system is divided into 2 main phases: When the system is electric powered in the On status, it is in operation status: a) On status
In this operational status, the operator inputs the induction motor's speed to control the conveyor and also specifies the distance to calibrate the movement Meanwhile, the servo system guides the flying object along the ball screw axis back to its original position.
The conveyor operates at the predetermined speed, and when the sensor detects an object's movement, the servo motor rotates clockwise to align with the object Upon reaching the target point, the servo motor swiftly returns to its original position, ready for the next item During this process, the operator cannot adjust the conveyor's speed.
We have established a solid theoretical foundation that enables us to design hardware effectively, select the right equipment, and conduct precise calculations to ensure optimal model performance that meets all prior specifications.
HARDWARE DESIGN
System Design Requirements
According to requirements in Chapter 2, combining with the flying Cutter Machine’s requirements in reality, we will figure out some following designing demands:
- Controlling the conveyor’s moving speed to keep the system running at high speed, about 200 RPM, the higher the speed is, the greater performance will be made
- Adjusting the moving distance of the flying object This flying object will move back to the starting point after the power outage
- Have remote controllability, supervisable parameters including: conveyor velocity, counting put-in products, moving distance
- Error messaging system for operators to adjust and manage
- Easy-to-manage, easy-to-use HMI UX, user-friendly designed language
- The combination between CPU and components must be effectively and constantly operating, ensuring flexibility.
System technology process
3.2.1 Organize functional blocks in the system
- Mission: This block receives signals, results received from Sensor, Servo motor, Motor, calculates, conveys programmed commands, plays a role as the system’s CPU
- Include: 3 phases Induction motor connected to Feeder Conveyor
- Mission: Induction motor receives signals from Main computer It is connected to feeder conveyor to move the object in with expected velocity
Figure 3.2.1 Function blocks in system
- Mission: Sensor detects passing object, giving signals to Main computer and activates servo motor to move flying object to target point and return
3.2.2 Technological process of the system
The system operates through three key stages: Off Stage, Running Stage, and Synchronized Stage Each stage is designed to perform distinct tasks, ensuring the system functions effectively, consistently, and smoothly.
In this state, both the conveyor motor and servo motor will be in freeze mode, while a flying object is positioned at the starting point Operators must enter the operation name, as well as the required speed and moving distance for the conveyor motor.
If the parameters are not imported or are exceeded the threshold, an error message will be displayed b) Running Stage
Upon importing the necessary parameters, the system awaits the Start command from the operator through the HMI screen or hardware Once the Start command is executed, the conveyor will operate at the predetermined speed to facilitate the placement of objects.
A sensor detects passing objects and sends a signal to activate the servo motor, enabling the flying object to move in parallel with the detected object.
Once it reaches the target point, the servo motor will reverse to get the flying object back to the starting point quickly and wait for the next object
During synchronous operation, the operator is unable to modify the Conveyor Motor's speed In the event of an unexpected stop command, the Conveyor Motor will halt instantly, while the servo motor will gradually rotate to return the flying object to its original position, triggering an alarm to alert the system.
Control method selection
In today's market, there are many familiar PLC brands such as Mitsubishi, Omron, Delta, Siemens But PLC Siemens always has strong advantages compared to other brands as follows:
- PLC Siemens is strong in process control and control over communication
- Good flexibility, extensibility: Siemens analog modules are cheaper, simple to use
- There are specialized function blocks that support communication control
- Although Siemens PLC is available in both horizontal and vertical program structures, all PLC programs are still sequentially executed from top to bottom
- Besides, Siemens’ subroutine can support Local variables in order to be used more widely in programming
Siemens PLC stands out as the preferred choice for automation solutions, particularly within its S7 series, which includes the S7-200, S7-300, S7-1200, and S7-1500 models The S7-1200 model, in particular, excels in design, security, and advanced technology, making it a top contender in the market.
- Innovative design: compact, module board helps expand the controller easily without changing its physical dimensions
Siemens PLCs, particularly the S7-1200 series and TIA Portal, offer robust confidentiality features that safeguard against unauthorized modifications and ensure secure handling of sensitive data These systems include access protection mechanisms that prevent unauthorized access to algorithms and process protection modules, thereby enhancing operational availability and security.
- Well-equipped: The S7-series supports a variety of communication protocols,
Analog, HSC, PWM/PTO, Profinet…
3.3.2.1 Control method of Induction motor
To control the speed of a 3-phase induction motor, three primary methods are employed: adjusting the number of magnetic poles, altering the frequency, and modifying the voltage This approach is grounded in the theoretical principles discussed in Chapter 2.
Changing the frequency Changing the voltage
- Motor speed change can only be changed per step
- Rotor, stator windings need to be rewired
(especially depending on the type of 3-phase induction motor used)
- Using an Inverter gives you an edge because you can control the motor according to different ways
- Most of his 3-phase Induction motors on the market are suitable for inverters
- The most popular and modern method
- This method works only when the machine is no load, but when the machine is no-loaded and the power source is reduced, the speed is almost constant
Table 3.3.2.1.a Compare 3 control methods in Induction motor
Using an inverter to control the speed of an asynchronous three-phase motor offers significant advantages over other methods Therefore, we have chosen this approach for managing the motor's velocity in our model.
An inverter is a motor controller that regulates an electric motor by adjusting the frequency and voltage of its power supply It effectively manages the motor's ramp-up during start-up and ramp-down during shutdown, ensuring smooth operation.
The inverter has five main functions: Protect the motor, reduce mechanical wear, energy-saving, increase productivity, and meet technical needs
Inverter technology offers effective motor protection by allowing for precise speed adjustments, ensuring that the motor's starting current remains within safe limits Unlike the star-delta starting method, which can result in a starting current of up to 1.5 times the motor's rated current, inverters typically limit the starting current to only 4-6 times the rated current, enhancing operational efficiency and safeguarding the motor from potential damage.
- It has an electronic system of overcurrent protection, high voltage and low voltage protection.
→ Providing a safe system for operation
The inverter helps start the motor from low speed, making the start smoother and quieter
→ In case of large load motors, they cannot start up directly
18 or unintentionally which helps avoid damaging the mechanical part, the bearing, minimizes mechanical wear and increases the engine's life
Energy consumption - With an advantage of speed adjusting, the inverter can save a quite amount of energy for loads that do not usually run at capacity
→ Save about 20-30% electricity compared to systems using other starting methods
Using Direct-On-Line (DOL) starting results in a significantly high starting current compared to the rated current, leading to a rapid increase in energy consumption In contrast, an inverter facilitates a smooth and quiet motor start, preventing voltage drops that could affect other equipment in the system Additionally, it reduces the starting current below the rated level, contributing to electricity savings during the startup process.
- The inverter automatically turns off or slows down when reaching the desired pressure, then Inverter saves a lot of energy
Using an inverter significantly enhances motor performance by increasing its speed Typically, a motor operates at a frequency of 54-60Hz, with a standard speed of 1500rpm at 50Hz without an inverter However, when an inverter is utilized, the motor can reach speeds of 1800rpm at 60Hz, thereby boosting the system's output and accelerating ventilation fans.
Cost reduction - Based on the inverter topology using diodes and capacitors, the power factor cos𝜑 is at its suitable value of 0.96
- Reactive power of the motor is very low, negligible This results in reducing the current during operation, the cost of installing capacitors and the loss on the line.
Table 3.3.2.1.b Advantages of using Inverter for Induction motor
The conveyor system will be integrated with a 3-phase induction motor, utilizing an inverter for motor control A critical aspect of this setup is the real-time monitoring of engine revolutions during operation, which is essential for effective control and supervision of the motor's performance.
To effectively manage the revolutions and speed of a motor, it is essential to have a countable measurement system Utilizing a 3-phase induction motor linked to a conveyor, paired with a controlling inverter, I prioritize the use of an encoder for revolution counting This compact model makes the encoder an ideal, cost-effective solution, and it is widely recognized as the most popular method in contemporary applications.
An encoder is a crucial device that transforms data into different formats, specifically in position sensing where it detects and converts mechanical motion into an analog or digital output signal It primarily measures position, while also allowing for the derivation of velocity, acceleration, and direction in both linear and rotary movements.
The Encoder is a crucial component of the 3-phase Induction motor system, as it relays speed data to the PLC server Integrated with the motor, the Encoder records various parameters that influence the motor's performance, enabling it to work in conjunction with PLC programming software to effectively monitor and control motor speed as needed.
There are two main types of rotary pulse Encoder: Incremental Encoder and Absolute Encoder
An Absolute Encoder has a unique code for each shaft position which represents the absolute position of the encoder
An Incremental Encoder generates an output signal each time the shaft rotates at a certain angle
Absolute Encoder only need power when a reading is taken
It needs to be powered on throughout the operation of the device
An Absolute Encoder typically costs twice as much as an incremental encoder
These are less complex than their absolute counterparts, thus typically less expensive
It doesn’t lose the position information when the power is lost
Each time the power is lost, the reading must be reinitialized or the system shows an error
Table 3.3.2.2 Compare between Absolute Encoder and Incremental Encoder
Incremental Encoders, while more affordable than Absolute Encoders, have the drawback of losing their position settings during power outages, necessitating a reset However, their simplicity in signal handling makes them ideal for integrating with induction motors to monitor and provide feedback on motor speed Given that power outages in large systems are infrequent, opting for Incremental Encoders proves to be a cost-effective solution.
As what we mentioned in Chapter 2, we have 3 main methods to be able to control servo motor:
- Velocity control with analog input
I have chosen the Pulse Control method for supervising and controlling the Servo motor due to its cost-effectiveness, excellent controllability, and straightforward wiring to the PLC This method requires that the PLC supports PWM pulse generation at a minimum frequency of 20kHz, which is compatible with most PLCs in the S7-1200 line, making it a viable option for our needs.
Hardware
This block include: PLC play a role as CPU, HMI
• PLC Siemens S7-1215C DC/DC/DC
- Article number: 6ES7215-1AG40-0XB0
- Input current: 500mA CPU only; 1500mA CPU with all expansion modules
- Number of digital I/O: 14 DI, 10 DO, 6 HSC (high speed counter), 4 PTO (pulse train output) 100kHz
- Number of analog I/O: 2 AI with input voltage ranges 0-10VDC, 2 AO with output current ranges 0-20mA
• Besides, this software also supports designing, programming HMI communication via the PLCSIM software I can write programmes via the Tia Portal V17 programming software of Siemens
To supply power for CPU PLC S7-1200, an inverter to convert AC to DC is needed:
This block includes: Inverter, a 3-phase Induction motor, an encoder, a conveyor
- Rated input voltage/frequency: 3 phase 200-240V 50Hz/60Hz
• 3 Phase Induction motor 5IK90GU-SW
Figure 3.4.2.b 3 Phase Induction motor 5IK90GU -SW
- Rated torque (lb-in): 6(200VAC, 50Hz), 5(60Hz)
- Rated speed (RPM): 1300 (200VAC, 50Hz), 1600 [60 Hz]
- Output type: NPN open collector
- Pin assignment: Vcc (red), 0V (black), phase A (green), phase B (white), shield
Figure 3.4.2.c Rotary encoder LPD3806-400BM-G5-24C
- Diameter of the drive roll: 3,5cm
This block contains several components such as: Servo motor and Servo driver, ball screw axis and Sensor
+ Supply voltage: 3 phase or 1 phase 200-230VAC
+ Permissible voltage fluctuation: 3 phase or 1 phase 170-253VAC
+ Permissible voltage fluctuation: 3 phase or 1 phase 170-253VAC
Servo motors and drivers are typically sold together, simplifying the selection process for buyers and reducing potential risks An example of this is the MR-J3-20A servo driver, which is paired with the HF-KP23 servo motor.
Figure 3.4.3.b Servo motor HF -KP23
- Pins: Vcc (brown), 0V (blue), signal (black)
Design of the Flying Cutter Machine
After choosing all devices, the next part is constructing a hardware model for easily visualizing the whole system and designing suitable working principles
The system is presented as follows:
- Induction motor speed is controlled by the inverter will receive the signal from the PLC to feed the material at a maximum speed of 200 rpm
The sensor, positioned parallel to the starting point, detects objects and sends a signal to the PLC to initiate the servo motor This triggers a synchronizing process with a 1-second acceleration, ensuring maximum accuracy in synchronization.
- Synchronous range: is the distance between Starting position to End of synchronous position This distance is flexible and can be adjusted by the operator
- When the flying object reaches the end of synchronous position, the servo motor will reverse to bring the flying object back to the starting point
During synchronous operation, the operator is unable to adjust the speed of the conveyor motor Any changes to the parameters must be postponed until the synchronous process is completed, at which point the change command can be executed.
Flying Cutter machine is designed and built based on the principle of speed synchronous running between Servo motor connected to ball screw axis and Induction
To optimize the performance of the conveyor system powered by a 28 motor, it is essential to process parameters tailored to the specific characteristics of the chosen hardware This includes monitoring the speed of the induction motor via the encoder, assessing servo motor parameters, and ensuring synchronous operation.
3.5.2.1 Read the speed of the Induction motor through the Encoder
An encoder is installed at the drive roll of a conveyor to monitor its speed Once the encoder is connected and configured to read high-speed counters (HSC) from the programmable logic controller (PLC), it provides feedback signals in the form of INT data type The next step involves using the reference time in the subsequent calculations.
The number of pulses is read in reference time is 1s, this parameter helps the system to monitor the engine speed continuously
3.5.2.2 The parameter of Servo motor
Siemens' Tia Portal programming software enables effective control of servo motors through configuration and motion control programming Key parameters for configuration include pulses per motor revolution and acceleration/deceleration settings In this case, the ramp-up and ramp-down times are set to 1 second, allowing the servo motor to achieve 100 kHz, or an acceleration of 100,000 pulses/s² It is crucial to maintain appropriate ramp settings; excessive values may hinder the synchronous range The pulses per motor revolution are configured at 1,000 pulses.
To ensure precise synchronous operation between two motors, careful calculations based on the selected equipment are essential In this setup, an induction motor drives a conveyor roll with a diameter of 3.5 cm, allowing the motor to move the material approximately 11 cm per rotation, which equates to 400 pulses These pulses are then transmitted to the PLC via an encoder for feedback Additionally, the upper synchronous drive features a servo motor linked to a ball screw axis, with a screw pitch of 0.5 cm, facilitating accurate movement and control.
1000 pulses output of PLC to Servo motor driver, which will turn 1 round and lead flying cutter move 0.5cm
Table 3.5.2.3 Calculation of synchronous parameter
The ratio of induction motor pulses with encoder feedback to control the servo motor is 1:55, which is essential for synchronizing speed control The parameters associated with the ball screw axis can be determined by multiplying or dividing within the synchronous range or at the endpoint of the flying object.
2000 corresponding to 1cm in the model
The system operates by feeding material through an induction motor connected to a conveyor A sensor detects the material and sends a signal to the PLC to activate the servo motor During the synchronization phase, the servo motor requires time to accelerate to the desired velocity, as illustrated in the synchronizing velocity graph below (Figure 3.5.2.4.a).
The graph illustrates the relationship between distance and time for the Servo motor to achieve the same velocity as the Induction motor, which can be quantified using the following equation.
30 setting the acceleration parameter in Figure 3.5.2.2.b and the calculated velocity, the distance and time can be easily calculated
𝑣 0 : Initial velocity(cm/s) a: Acceleration/ Deceleration(cm/s 2 ) s: Distance(cm)
Servo motors can synchronize their velocity with induction motors, requiring a specific time and distance for optimal performance To ensure accurate operation, flying objects must reach a designated ready point, which is essential for the system to function effectively.
The time it takes for a servo motor to achieve synchronous velocity can be calculated using the formula \( s_m = vt \), where \( s_m \) represents the distance of the material on the conveyor from its original point Additionally, the distance the servo motor needs to cover to reach synchronous velocity is denoted as \( s_s \) The leading distance, which indicates the difference between the material's position and the servo motor's position, is given by \( s_l = s_m - s_s \).
Figure 3.5.2.4.b Physical variables of the system
Next, when the system is calculated and designed, the model “Flying Cutting Machine” will be built in practice.
Hardware
Next, I will present about how to wire the system’s equipment:
Figure 3.6.1.a Wiring between PLC and Servo driver
Figure 3.6.1.b Wiring between PLC and Inverter
Figure 3.6.1.c Wiring between PLC and Encoder, Sensor
Those images above are presenting how to wire the system’s equipment, we can rely on them to easily arrange and construct the hardware model
SOFTWARE DESIGN
Flow chart
Figure 4.2 Flow chart of system
Operating principle: When the system is electric powered, the first thing that the operator needs to do is import the velocity, the operator’s name as well as the moving
35 distance If accessible parameters are imported correctly, Conveyor motor will operate via the START command, the Servo motor will move to the Start position as well
The Sensor detects passing objects, triggering the Servo motor to initiate a synchronized process Once the object is within a specified distance, the cycle concludes, and the Servo motor returns to its starting position This operation continues until a STOP command is received, at which point the system halts.
In a synchronous process, the velocity cannot be altered until the cycle is complete If the operator inputs incorrect velocity or distance parameters, the system will halt its operation Additionally, any STOP command issued during the process will result in an immediate system stop.
HMI configuration
Based on the managing parameters and technical requirements outlined in Chapter 2, we have compiled a comprehensive list of essential managing parameters for HMI.
- The velocity of the Conveyor, we will change the speed based on the analog output pulse of the PLC controlling inverter
- Continuously counting Encoder pulse (Encoder connected to Conveyor)
- Controlling buttons such as Start/Stop
- Reset button to delete data of the moving system
- Home button to set up home Servo motor
- The board displays the operator’s name
- Pages that display historical errors of the system, data of the moving, Trend charts of the velocity of Conveyor and Servo motor
- Display parameters of Servo motor’s velocity, Servo position
From those must-be-managed parameters, must-have buttons on the HMI screen above, we will design the HMI interface which divided into 4 main pages:
The Overview interface presents the system's parameters, allowing users to click the (…) box to reveal essential values that need adjustment Key windows displayed include the control panel under POWER, the operator's name in the OPERATOR box, moving distance in the PROCESS section, and motor speed in the PARAMETER box Additionally, the "HOME" button is available to set the home position.
36 servo motor If operator want to reset all product informations then press “RESET” button
Products information will be stored in this tab, include product number, distance and name The product informations will be cleared by press “CLEAR” button
Trend tab display 2 main line parameters, there are Induction motor velocity and Servo motor velocity
Historical alarm will be stored History alarm tab The historical alarm will be clear after press “CLEAR” button
Wincc Unified Configuration
Wincc unified configuration is software that allows users to configure the web server to launch SCADA programs on it
SIMATIC Runtime Manager là phần mềm giúp chúng ta quản lý Wincc Unified projects
Figure 4.4.1.b Product Information screen Figure 4.4.1.a Overview screen
After programming the Flying Cutter Machine system using Tia Portal and WinCC Unified Configuration software, I will proceed to operate the system to analyze the results.
RESULTS AND EVALUATION
Result
- Stop stage: Stop light will display on the Control block, flying object is placed parallel with the Sensor
Figure 5.1.1.a Stop state in Control block
Figure 5.1.1.b Stop state in Executed Block
During the run stage, once the operator inputs all necessary parameters and issues the START command, the start light will activate The servo motor then guides the flying object to the designated start position, utilizing the parameters calculated by the PLC through the active command.
Figure 5.1.1.c Start state in Control block
Figure 5.1.1.d Start state in Executed block
- Moving Synchronous stage: When the Sensor detects the passing object, it will active Servo motor to move the flying object with the material
At first, Operator have to Login with an account, the system will be authorized with operator’s class
Upon logging into the account, users will be directed to the overview tab, where they can adjust various parameters To import the appropriate settings into the system, operators simply need to click on the (…) box.
Figure 5.1.2.b Stop state in HMI
After importing the suitable parameters, the system can change to Running status after START command After changing the motor speed, the operator has to press the
“ACTIVE” button to lead the flying object to start point Changing tab by select tab name in the top right corner of screen
Figure 5.1.2.c Start state in HMI
In trend interface, 2 parameters will display is velocity of Induction motor and servo motor
The product information screen will show some informations as piece number, distance and the operator’s name
The historical alarm will be stored in history tab and the status of the alarm, the operator easily manages and handles the error by see this tab
When we access to the IP of project, we can see this interface:
Figure 5.1.3.a Interface of Web Server
User management allows us to view details about created accounts and change their passwords However, it is essential to log in with an account that has been configured in TIA Portal under the security settings to access these features.
We can see information about the accounts that have been created, we can also change the password of the account here
• Wincc unified RT: We must be logged in to operate the system
• Wincc unified help: Make it easy for newbies to understand how to use Wincc Unified
Once logged into the system, we will see the following operating screens:
All screens of Web server were configurated same with HMI screens, so we can easily manage and operate both HMI or Web Server with the same configuration.
Evaluation
Compared to technical requirements mentioned in Chapter 2, as well as results from the operation, I have some records as follow:
- The system is sustainably operated, the conveyor's velocity can be up to 200
RPM, but the recommended velocity is about 50-100 RPM
Key factors that can be monitored and managed include the current speed of the conveyor, the movement path of the servo motor, and the position of objects as they traverse the conveyor system.
- Manageable, user-friendly HMI screen and Web Server
- The system’s errors notification will be sent and the system will be stopped to ensure safety
- Synchronization is well-running but there is still error about 1-2%
- The hardware still does not have optimal connection, especially the Executed block Therefore, the system still has error
- Sometimes the system has an Induction motor overheated error
CONCLUSION AND RECOMMENDATIONS
Conclusion
The system is efficiently designed and operates smoothly, with all equipment seamlessly integrated and coordinated, even though they are sourced from different manufacturers Based on the emulated results presented in Chapter 5, several suggested requirements for the system have been identified.
- The synchronous is well running, so that it can be applied in machines which helps increase the productivity of Vietnam’s industry
- HMI is designed to help the operator manage and control the parameters on the screen
- Successfully created Web Server uses LAN internet so that the operator can easily control everywhere in the factory
- The system is authorized to control
In contrast, the project is failed in design:
- Mechanical structures haven’t connected exactly and stability, so the errors exist in the operating process
- There is no grounding system for the model yet to avoid leakage current from devices
- Product informations haven't exported to Excels file.
Recommendations
- System should add 2 limit switches at 2 end points of the ball screw axis
- The system can insert many flying objects that helps the process more quickly
- Create your own server so you can monitor and control the system from anywhere
Synchronous control is an adaptable algorithm ideal for various systems, including cutting, sealing, and painting Each system possesses unique characteristics, necessitating careful examination and tailored programming to meet specific requirements effectively.
Trong 9 tháng đầu năm, giá trị tăng thêm của toàn ngành công nghiệp ước tính tăng 9,63% so với cùng kỳ năm trước.
[2] Eric Rice “3 ways to control motors for precision movement in positioning conveyors” Packaging Digest https://www.packagingdigest.com/conveyors/3-ways-control-motors-precision- movement-positioning-conveyors
[3] Siemens, AG “SIMATIC S7-1500T FlyingSawAdvanced LFlyingSaw for SIMATIC”
[4] Nidec “A Guide to Motion Control Technology Systems & Programming”