Modeling Of A Gantry Crane Using On-Off Motor Implementation.

MODELING OF A GANTRY CRANE USING ON-OFF MOTOR IMPLEMENTATION

SITI RADHIAH BINTI JUMALI

This report is submitted in partial fulfillment of the requirement for the award of Bachelor of Electronic Engineering (Industrial Electronics) With Honours

Faculty of Electronic and Computer Engineering Universiti Teknikal Malaysia Melaka

UNIVERSTI TEKNIKAL MALAYSIA MELAKA

FAKULTI KEJURUTERAAN ELEKTRONIK DAN KEJURUTERAAN KOMPUTER

BORANG PENGESAHAN STATUS LAPORAN

PROJEK SARJANA MUDA II

Tajuk Projek : MODELING OF A GANTRY CRANE USING ON-OFF MOTOR IMPLEMENTATION

Sesi

Pengajian : 2/2008/2009

Saya SITI RADHIAH BINTI JUMALI

mengaku membenarkan Laporan Projek Sarjana Muda ini disimpan di Perpustakaan dengan syarat-syarat kegunaan seperti berikut:

1. Laporan adalah hakmilik Universiti Teknikal Malaysia Melaka.

2. Perpustakaan dibenarkan membuat salinan untuk tujuan pengajian sahaja.

3. Perpustakaan dibenarkan membuat salinan laporan ini sebagai bahan pertukaran antara institusi pengajian tinggi.

4. Sila tandakan ( √ ) :

SULIT*

(Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia seperti yang termaktub di dalam AKTA RAHSIA RASMI 1972)

TERHAD* (Mengandungi maklumat terhad yang telah ditentukan oleh organisasi/badan di mana penyelidikan dijalankan)

TIDAK TERHAD

Disahkan oleh:

__________________________ ___________________________________

“I hereby declared that this report entitle Modeling of a Gantry Crane Using On-Off Motor Implementation is a result of my own work except for the works that have been

cited clearly in the references.”

Signature : ……….

Student Name : SITI RADHIAH BINTI JUMALI

“I hereby declared that I have read this report in my opinion this report is sufficient in terms of the scope and quality for the award the Bachelor of Electronic Engineering

(Industrial Electronics) With Honours.”

Signature : ……….

Supervisor’s Name : PN AZDIANA BINTI MD. YUSOP

Special dedicated to my beloved parents, family, teacher and fellow friends, who had strongly encourage and supported me in my entire journey of learning.

ACKNOWLEDGEMENT

First of all, I would like to thank my supervisor, Pn. Azdiana Binti Md. Yusop for all the information, knowledge and guidance throughout this project and also her patience and dedication. Secondly, I would like to thank all the people that have been involved directly and indirectly throughout the progression of this project. I also would like to thank to all my friends for their help and also information. Last but not least, to my father, thank you so much for his support and understanding

ABSTRACT

Crane payloads frequently swing with large amplitude motion that degrades safety and throughput. Open-loop methods have addressed this problem, and has proven effective on crane but just for reducing the sway during and after move. Closed-loop methods have also been used, but generally require the speed of the driving motors to be precisely controlled. This paper develops a feedback control method for controlling motors to cancel the measured payload oscillations by intelligently timing the ensuing on and off motor commands. To generate the on-off motor command the measurement using payload oscillation cancellation and vector input shaper calculation need to be used. The on-off motor command is design to control the trolley movement without vibration and reduce the swing angle of the payload.

ABSTRAK

Beban kren yang selalunya berayun dengan amplitud pergerakan yang besar akan mengurangkan tahap keselamatan dan nilai keluaran. Kaedah gelung terbuka telah menyelesaikan masalah ini dan telah dibuktikan berkesan tetapi hanya untuk mengurangkan hayunan pada beban semasa dan selepas pergerakan. Kaedah gelung tertutup juga telah digunakan untuk menyelesaikan masalah ini, tetapi secara keseluruhannya memerlukan ketepatan dalam mengawal kelajuan motor tersebut. Di dalam projek ini, kaedah suapan balik digunakan untuk mengawal motor untuk menghapuskan talaan beban oleh kadar masa yang tepat untuk menentukan arahan “on” dan “off” motor. Arahan “on-off motor” dihasilkan berpandukan kiraan ukuran sudut ayunan beban dan vektor bentuk masukan. Arahan “on-off motor” direka adalah untuk mengawal pergerakan troli tanpa gegaran dan mengurangkan sudut hayunan beban.

TABLE OF CONTENTS

CHAPTER ITEM PAGE

PROJECT TITLE i

DECLARATION FORM OF REPORT STATUS ii

DECLARATION iii

SUPERVISOR’S DECLARATION iv

DEDICATION v

ACKNOWLEDGEMENT vi

ABSTRACT vii

ABSTRAK viii

TABLE OF CONTENT xi

LIST OF TABLES xiii

LIST OF FIGURES xiv

I INTRODUCTION

1.1 Project Introduction 1

1.2 Project Objectives 2

1.3 Problem Statement 3

1.4 Scope Project 3

1.5 Methodology 4

1.6 Thesis Outlines 6

II LITERATURE REVIEW 7

2.1 Control System

2.1.1 On-off Motor Control 9

2.1.2 Feedback Control 10

2.1.3 PID Control 11

2.2 Non-Linear Control

2.2.1 Properties of Non-Linear System 12

III MODELLING A GANTRY CRANE

3.1 Introduction 13

3.2 Equation of Motion for Trolley 14 3.3 Concept of Sensorless Anti-

Swing Control 16

3.4 Vector Based Input Shaper Calculation 18 3.5 Payload Oscillation Cancellation 20

IV HARDWARE IMPLEMENTATION

4.1 Introduction 25

4.2 Hardware Requirement

4.2.1 Gantry Crane 26

4.2.2 DAQCard-700 27

4.2.3 BNC-2110 28

4.3 Electrical Components

4.3.1 Stepper Motor 29

V RESULTS AND ANALYSIS

5.1 Simulation

5.1.1 MATLAB and Simulink 32

5.1.2 Stateflow 33

5.1.3 Simulation Results 33

5.2 Analysis

5.2.1 Simulation Analysis 37

5.2.2 Swing Angle Analysis 38

5.3 Interfacing of the Block Design

5.3.1 x-PC Target 39

VI CONCLUSION AND FUTURE WORK

6.1 Conclusion 42

6.2 Future Work 43

REFERENCE 44

LIST OF TABLE

NO. TITLE PAGE

4.1 Specification of the Gantry Crane 26

4.2 The Digital Logic Levels 28

LIST OF FIGURES

NO. TITLE PAGE

1.1 The Gantry Crane 1

1.2 Block Diagram of Methodology 5

2.1 Input Shaping a Step Input 9

2.2 Feedback Block 10

2.3 A Block Diagram of PID Controller 11

3.1 Model of Gentry Crane 14

3.2 Sensorless Anti-swing Control 16

3.3 Impulse Sequence 18

3.4 Vector Diagram 18

3.5 Summing the 3 vector and get zero vibration 19

3.6 Vector represent for turning the motor on 20

3.7 Vector Diagram for Calculate time to turn motor off 21

3.8 Angle used to calculate command initiation time 22

4.1 Drawing Sketch of the Crane 26

4.2 The Trolley 27

4.3 The Connection of BNC with the Personal Computer 28

4.4 The Stepper Motor 29

5.1 The Function Block Parameter 33

5.2 The Stateflow Chart 34

5.3 The Discrete PID controller Parameter on Block Parameter 35

5.4 Position of the Trolley at Position Output 35

5.5 Swig Angle at Radian Output 36

5.6 Nonlinear Model Parameter 36

5.7 Settling Time for Position Graph 38

5.8 The xPC Target Entering 40

LIST OF APPENDICES

NO. TITLE PAGE

APPENDIX A HARDWARE 46

APPENDIX B A FEEDBACK CONTROL SYSTEM FOR

SUPPRESSING CRANE OSCILLATIONS

WITH ON-OFF MOTOR 47

CHAPTER I

INTRODUCTION

1.1 Project Introduction

A gantry crane is a type of overhead crane. With a gantry crane, the supports holding the crane up are fixed in location. They cannot move, and therefore the crane cannot move. For this reason, everything that the crane is going to lift must be brought to the crane. The supports form a large rectangular frame upon which the crane can move forward and back, and left and right. Anything that can be reached by the gantry crane is referred to as being in its operating area.

Gantry cranes are very common in factories, where they are used to move things along the factory floor as the product is slowly assembled. For instance, if one is building a large metal piece of equipment, the metal parts may arrive on a truck. The truck will park within the operating area of the gantry crane, and the gantry crane can then be used to unload the parts. The gantry crane may also be used to move the parts around, typically along the assembly line as the components are assembled.

From the privious project, the gantry crane is controlled by the PIC programming, that is programmed by the time and speed of the motor. In this situation the swing angle of the object can not be controlled.

The fundamental motions of a gantry crane consist of traversing, load hosting and load lowering [1]. When the crane is starting to move or the crane is stopping, it induces undesirable swinging of the suspended load. This swinging can caused damage to the payload or other objects in the workplace. Traditionally, an experienced crane operator is required to keep the oscillations under control. But, the operator should be expertise to control the crane. It is because that the payload is free to swing in a pendulum like motion.

There are many types of the approach that can be used to implement in gantry crane. Some of the approaches are open-loop and close-loop. The open-loop approach is the input shaping where input shaping is a feedforward control technique for improving the settling time and the positioning accuracy, while minimizing residual vibration, of computer-controlled machines. Moreover the close-loop approach needs the feedback controller to do the correction on the system.

1.2 Project Objectives

The objective of this project is to design the gantry crane system with feedback control method that will drive the system from initial position into a target position without vibration and reducing swing angle using on-off motor commands.

1.3 Problem Statement

Now in our industrial factory, there are so many accidents that involve the workers. One of the accidents is when the workers want to transport the heavy object in a workspace using the forklift. The forklift needs someone to drive it and control in their entire angle such back, front and around it. To reduce the accident in this situation, this gantry crane project are come out to solve the problem, but there are some problem with cranes is that the payload can swing freely. These oscillations pose safety hazards and can damage the payload and other objects in the workplace. Crane travel and transverse motion especially when starting or stopping, induce undesirable swinging on the suspended load. This swinging could cause the suspension rope to leave its groove which could lead to overwrapping and possibly serious accident. So there are some commands (on-off motor) that can control the oscillations and make it safe.

1.4 Scopes of Project

Firstly, do some researches about a gantry crane system with a feedback control system for suppressing crane oscillations with on-off motors. After that, feasibility study and read up related technical knowledge such as:

a) non-linear feedback b) on-off control

Then find the correct calculation to control the system of the motor. In this part, the calculation must be correct so that the control block can functioned correctly.

For the simulation part:

a) Derive the function to control the on-off motor.

b) Simulate by using the stateflow chart to control the motor by the angle of the swing.

c) Implement the block function by using the close-loop system.

d) Develop the mathematical modeling to control the on-off function by using MATLAB.

1.5 Methodology

In order to meet the objective of the project, the design of the system is consist of several stages. In the subsequent sections, each subsystem will be discussed in terms of criteria, calculations and selection of the project specifications. The following methods will be followed closely:

a) The initial stage of the project is basely solely on research about the basic concept of gantry crane whereby data and information are obtained through various medium, such as internet, books, journal, proceeding paper, broachers and more.

b) After the research about gantry crane had been done, research about on-off commands will be done. The research is about how to generate on-off commands and apply it to the gantry crane system.

c) Then the appropriate design circuit was find to implement the circuit. d) After finding the appropriate circuit, the implementation of the

mathematical function on the MATLAB is done in order to ensure that the motor are implement in the good situation for the on-off motor command.

Figure 1.2 Block Diagram of Methodology

Research for relevant information

Study and do research about the on/off motor

Finding and design circuit

Simulation using SIMULINK/MATLAB (implementation of On-Off

motor)

Program coding and testing: • Transmitter PIC • Receiver PIC

RESULT

Experimental testing

Project realization and verification

NOT OK

NOT OK OK

1.6 Thesis Outlines

This thesis is represented by seven chapters to describe the methodology of the project and the outline of the feedback control system for suppressing the crane oscillations with on-off motor implementation on the gantry crane.

Chapter I discuss the overview of the project in introduction, objectives, problem statement, scope of the project and methodology.

Chapter II explanation about the research and information regarding the facts from journal, books and other references. The literature reviews also are included in this chapter.

Chapter III describes the process of the project where the calculation and the research of the gantry crane are included.

Chapter IV elaborate about the devices that play the important role in this project and illustrates about the gantry crane model. This chapter also includes the hardware and software development and their methodology.

Chapter V explain about hardware implementation. This chapter consists of the information about the gantry crane model specification including the equipments, circuit and gantry specifications.

Chapter VI discuss the project finding base on the interfacing between the software and the hardware and the results of the project.

Chapter VII consist the conclusion of the project and the future recommendation to improve the project.

CHAPTER II

LITERATURE REVIEW

This chapter discuss the reference that had been used in term to get more information about gantry crane including the controller, requirement needed, and the characteristics of the gantry crane. This information is to ensure this project will achieve its objectives.

Cranes are frequently used to transport heavy objects in a cluttered workspace. One inherent problem with cranes is that the payload can swing freely. These oscillations pose safety hazards and can damage the payload or other objects in the workplace. Traditionally, an experienced crane operator is required to keep the oscillations under control. More recently, various control approaches have been applied to augment the operator’s skill. These approaches fall into open and closed-loop categories [1].

Open-loop approach is optimal control, which calculates a motion trajectory off line based on the mathematical model of the system but if the model is inaccurate, the performance will undergo. This is also the case with input shaping, but to a lesser degree [1].

To increase the ability of the controller the feedback control are need to be added. This feedback control is in the close-loop system that needs to control the velocity of the trolley and the swing angle of the cable to reduce the payload oscillation [1]. Most of automatic gantry crane controls proposed by researchers use two controllers for controlling both trolley position and swing of the crane payload. It is position controller and swing controller [2].

In other method of the feedback control is from conventional PID (proportional-integral-derivative) to intelligent the approaches [2]. Omar [3] proposed PD controls for both trolley position and swing suppression. Even PID controller is commonly used; they are not always used in the best way because the controller is often poorly tuned. It is quite common that derivative action is not used. The reason is that it is difficult to tuned three parameter by trial and error. A block diagram of PID controller in a closed-loop system.

From Park and Chang in “Vibration control of a telescopic handler using time delay control and commandless input shaping technique” another method to reduce the effect of disturbance on a vibration system is ‘commendless’ input shaping for a telescopic handler. They introduce a pulse that induces vibration equal in magnitude but opposite in phase of the vibration caused by unloading. They show the method’s potential by using it to reduce vibration by about 75%. However, issues of properly timing the pulse and ease of calibration appear to be challenging [4].

By Neil Singer [6] an input shaping is easier to derive and implement than time-optimal control schemes and does not require the feedback mechanisms of closed-loop and adaptive controllers. Rather than attempt to obtain exactly zero residual vibration (which is impossible on real machines), the version of Input Shaping described here yields non-zero, but low levels of sway. Input Shaping is implemented in real time by convolving the command signal with an impulse sequence (an input shaper). This process is illustrated in figure 2.1 with a step input and an input shaper containing three positive impulses. Note that the shaped input that results from the convolution has a rise time which is longer than the unshaped input by an amount equal to the duration of the input shaper. Similarly, the deceleration time of a shaped command is longer than the unshaped command.

1.3 Problem Statement

Now in our industrial factory, there are so many accidents that involve the workers. One of the accidents is when the workers want to transport the heavy object in a workspace using the forklift. The forklift needs someone to drive it and control in their entire angle such back, front and around it. To reduce the accident in this situation, this gantry crane project are come out to solve the problem, but there are some problem with cranes is that the payload can swing freely. These oscillations pose safety hazards and can damage the payload and other objects in the workplace. Crane travel and transverse motion especially when starting or stopping, induce undesirable swinging on the suspended load. This swinging could cause the suspension rope to leave its groove which could lead to overwrapping and possibly serious accident. So there are some commands (on-off motor) that can control the oscillations and make it safe.

1.4 Scopes of Project

Firstly, do some researches about a gantry crane system with a feedback control system for suppressing crane oscillations with on-off motors. After that, feasibility study and read up related technical knowledge such as:

a) non-linear feedback b) on-off control

Then find the correct calculation to control the system of the motor. In this part, the calculation must be correct so that the control block can functioned correctly.

For the simulation part:

a) Derive the function to control the on-off motor.

b) Simulate by using the stateflow chart to control the motor by the angle of the swing.

c) Implement the block function by using the close-loop system.

d) Develop the mathematical modeling to control the on-off function by using MATLAB.

In order to meet the objective of the project, the design of the system is consist of several stages. In the subsequent sections, each subsystem will be discussed in terms of criteria, calculations and selection of the project specifications. The following methods will be followed closely:

a) The initial stage of the project is basely solely on research about the basic concept of gantry crane whereby data and information are obtained through various medium, such as internet, books, journal, proceeding paper, broachers and more.

b) After the research about gantry crane had been done, research about on-off commands will be done. The research is about how to generate on-off commands and apply it to the gantry crane system.

c) Then the appropriate design circuit was find to implement the circuit. d) After finding the appropriate circuit, the implementation of the

mathematical function on the MATLAB is done in order to ensure that the motor are implement in the good situation for the on-off motor command.

Figure 1.2 Block Diagram of Methodology Research for relevant

information

Study and do research about the on/off motor

Finding and design circuit

Simulation using SIMULINK/MATLAB (implementation of On-Off

motor)

Program coding and testing: • Transmitter PIC • Receiver PIC

RESULT

Experimental testing

Project realization and verification

NOT OK

NOT OK OK

This thesis is represented by seven chapters to describe the methodology of the project and the outline of the feedback control system for suppressing the crane oscillations with on-off motor implementation on the gantry crane.

Chapter I discuss the overview of the project in introduction, objectives, problem statement, scope of the project and methodology.

Chapter II explanation about the research and information regarding the facts from journal, books and other references. The literature reviews also are included in this chapter.

Chapter III describes the process of the project where the calculation and the research of the gantry crane are included.

Chapter IV elaborate about the devices that play the important role in this project and illustrates about the gantry crane model. This chapter also includes the hardware and software development and their methodology.

Chapter V explain about hardware implementation. This chapter consists of the information about the gantry crane model specification including the equipments, circuit and gantry specifications.

Chapter VI discuss the project finding base on the interfacing between the software and the hardware and the results of the project.

Chapter VII consist the conclusion of the project and the future recommendation to improve the project.

CHAPTER II

LITERATURE REVIEW

This chapter discuss the reference that had been used in term to get more information about gantry crane including the controller, requirement needed, and the characteristics of the gantry crane. This information is to ensure this project will achieve its objectives.

Cranes are frequently used to transport heavy objects in a cluttered workspace. One inherent problem with cranes is that the payload can swing freely. These oscillations pose safety hazards and can damage the payload or other objects in the workplace. Traditionally, an experienced crane operator is required to keep the oscillations under control. More recently, various control approaches have been applied to augment the operator’s skill. These approaches fall into open and closed-loop categories [1].

Open-loop approach is optimal control, which calculates a motion trajectory off line based on the mathematical model of the system but if the model is inaccurate, the performance will undergo. This is also the case with input shaping, but to a lesser degree [1].

added. This feedback control is in the close-loop system that needs to control the velocity of the trolley and the swing angle of the cable to reduce the payload oscillation [1]. Most of automatic gantry crane controls proposed by researchers use two controllers for controlling both trolley position and swing of the crane payload. It is position controller and swing controller [2].

In other method of the feedback control is from conventional PID (proportional-integral-derivative) to intelligent the approaches [2]. Omar [3] proposed PD controls for both trolley position and swing suppression. Even PID controller is commonly used; they are not always used in the best way because the controller is often poorly tuned. It is quite common that derivative action is not used. The reason is that it is difficult to tuned three parameter by trial and error. A block diagram of PID controller in a closed-loop system.

From Park and Chang in “Vibration control of a telescopic handler using time delay control and commandless input shaping technique” another method to reduce the effect of disturbance on a vibration system is ‘commendless’ input shaping for a telescopic handler. They introduce a pulse that induces vibration equal in magnitude but opposite in phase of the vibration caused by unloading. They show the method’s potential by using it to reduce vibration by about 75%. However, issues of properly timing the pulse and ease of calibration appear to be challenging [4].

By Neil Singer [6] an input shaping is easier to derive and implement than time-optimal control schemes and does not require the feedback mechanisms of closed-loop and adaptive controllers. Rather than attempt to obtain exactly zero residual vibration (which is impossible on real machines), the version of Input Shaping described here yields non-zero, but low levels of sway. Input Shaping is implemented in real time by convolving the command signal with an impulse sequence (an input shaper). This process is illustrated in figure 2.1 with a step input and an input shaper containing three positive impulses. Note that the shaped input that results from the convolution has a rise time which is longer than the unshaped input by an amount equal to the duration of the input shaper. Similarly, the deceleration time of a shaped command is longer than the unshaped command.