Abstract
With the popularization and development of industrial automation, the demand for controllers increases year by year, the application of handling robot is also gradually popularized, mainly in the automotive, electronics, machining, food, medicine and other fields of the production line or goods loading and unloading and transferring, which can be a better way to conserve energy and improve the transportation equipment or product It can better save energy and improve the efficiency of transportation equipment or products to reduce the limitations and deficiencies of other handling methods and meet the requirements of modern economic development.
The mechanical structure of this manipulator mainly includes hydraulic steel controlled by two solenoid valves to realize the rising and falling movement of the manipulator and the action of clamping the workpiece, two electric motors with different speeds control the forward and reverse rotation of the motor through two coils respectively, so as to realize the movement movement of the trolley's fast-forwarding, slow-forwarding, fast-returning and slow-returning motion; its action switching relies on the travel switches (SQ1--- SQ9) which are set up in each different part. --SQ1-SQ9) generated in different parts of the action switch on and off signal transmission to the PLC controller, through the PLC internal program output different signals to drive the external coil to control the motor or solenoid valve to produce different actions, can realize the precise positioning of the manipulator; its action process includes: descending, clamping, rising, slow in, fast in, slow in, delay, descending, relaxation, rising, slow back, fast back, slow back; its operation mode Including: return to the original position, manual, single step, single cycle, continuous; to meet the production of a variety of operational requirements.
Keywords: handling robot, programmable logic controller (PLC), hydraulics, solenoid valves
ABSTRACT
With the popularity of industrial automation and development, the demand for year-on With the popularity of industrial automation and development, the demand for year-on year increase of controller, handling the application of robot gradually popularity, mainly in the automotive, electronic, mechanical processing, food, medicine and other areas of the the automotive industry. food, medicine and other areas of the production line or cargo transportation, we can be more good to save energy and improve the transport efficiency of equipment or products, to reduce restrictions on other modes of transportation and inadequate to meet the requirements of modern economic development.
The manipulator mechanical structure includes two solenoid valves controlled by hydraulic manipulator steel to achieve the increased decline in sports and workpiece clamping action. in sports and workpiece clamping action, the two different motor speed through the two motor coils positive control in order to achieve car of the fast- forward, slow forward, fast rewind. forward, slow forward, fast rewind, slow movement back movement; conversion by setting its action in various different parts of the trip switch (SQ1 ---) generated on-off signal (SQ9). SQ9) generated on-off signal transmission to the PLC controller, through the PLC internal different output signal, which drives the external coil to control the motor or solenoid valves have a different action, the robot can achieve precise positioning; their course of action include: decline in clamping increased, slow forward, fast forward, slow progress, the extension of , the drop in, relax, rise, slow back, rewind, slow back; its operation, including: Back in situ, manual, the robot can achieve precise positioning. including: Back in situ, manual, single-step, single cycle, continuous; to meet the production requirements of the various operations and maintenance .
Keywords: handling mechanical hands, Programmable Logic Controller (PLC), hydraulic, solenoid valve
Contents
Preface... .............................. .............................. .............................. .1
Chapter 1: Overview of Manipulators
1.1 A Brief Overview of the Application of Handling Manipulators ..................... .............................. ......2
1.2 Significance of the application of manipulators .................. .............................. ...............3
1.3 Overview of the development of manipulators ......... .............................. ........................3
Chapter 3 PLC Control System Design of Handling Manipulator< /p>
3.1 Structure of the handling robot and its action ........................ ..............................
3.2 Hardware design of the handling robot system ........................ ..............................
3.3 Control program design of the handling robot ........................ ..............................
1 Operation panel and action description ........................ .............................. ......
2 I/O allocation ..................... .............................. ........................
3 Ladder diagram design .............................. .............................. .........
1) General design of ladder diagram ............... .............................. ...............
2) Design of each part of ladder diagram ......... .............................. ..................
3) Drawing PLC control ladder diagram for handling robot ...... .............................. ......
Conclusion ..................... .............................. .............................. .........
Thanks .................. .............................. .............................. ............
References ............... .............................. .............................. ................... Attachment: Statement Table Ladder Diagram I/O Wiring Diagram
Introduction
Mechanical hand: mechanical hand, also known as automated hand, auto hand
Can be imitated by the human hand and arm of certain action functions, used in accordance with a fixed procedure for grasping, carrying objects or operating tools of the automatic operating devices. It can replace the heavy labor of people to achieve the mechanization and automation of production, can be operated in harmful environments to protect personal safety, and therefore widely used in machinery manufacturing, metallurgy, electronics, light industry and atomic energy and other sectors.
Manipulator mainly consists of three main parts: hand, motion mechanism and control system. The hand is used to grasp the workpiece (or tool) parts, according to the shape of the object to be grasped, size, weight, material and operational requirements and a variety of structural forms, such as clamping type, holding type and adsorption type. Motion mechanism, so that the hand to complete a variety of rotation (swing), mobile or compound movement to achieve the required action, change the position and posture of the object being grasped. The independent movements of the motion mechanism, such as lifting, telescoping, rotating, etc., are called the degrees of freedom of the manipulator. In order to grasp objects in any position and orientation in space, six degrees of freedom are required. Degrees of freedom are a key parameter in the design of a robot. The more degrees of freedom, the greater the flexibility of the robot, the more versatile, and the more complex its structure. General specialized manipulator has 2 to 3 degrees of freedom.
The types of manipulator, according to the drive can be divided into hydraulic, pneumatic, electric, mechanical manipulator; according to the scope of application can be divided into specialized manipulator and general-purpose manipulator two kinds; according to the trajectory control can be divided into point control and continuous trajectory control manipulator.
Manipulators are usually used as additional devices for machine tools or other machines, such as loading and unloading and transferring workpieces on automatic machine tools or automatic production lines, and replacing cutting tools in machining centers, etc., and generally do not have an independent control device. Some operating devices need to be directly manipulated by people, such as the atomic energy sector to manipulate dangerous goods master-slave operator is also often referred to as a manipulator. The application of robot in the forging industry can further develop the production capacity of forging equipment, improve the heat, tired and other labor conditions.
Manipulator first from the United States began to develop. 1958 United States United Controls developed the first manipulator.
Chapter I Overview of Manipulators
1.1 A Brief Overview of the Application of Handling Manipulators
In modern industry, the mechanization and automation of the production process has become a prominent theme. In the machinery industry, processing, assembly and other production is discontinuous. Special-purpose machine tools is an effective way to automate mass production, program-controlled machine tools, CNC machine tools, machining centers and other automated machinery is an important way to effectively solve the automation of multi-species small-lot production.
But in addition to cutting itself, there are a large number of loading and unloading, handling, assembly and other operations, to be further mechanized. According to information, the United States production of all industrial parts, 75% of small-lot production; metal processing production batch of three-quarters of the following 50 pieces, the parts are really processed on the machine tool time is only 5% of the parts production time. From here can be seen, loading and unloading, handling and other processes of mechanization of the urgency of the industrial robot is to achieve the automation of these processes and produced. Robots can be in the space to grasp the object, flexible and diverse actions, applicable to change the production of varieties of medium and small batch automated production, widely used in flexible automated lines.
Domestic and foreign machinery industry, the railroad sector in the machine handling mechanical hand is mainly used in the following areas:
1. Thermal processing applications
Thermal processing is a high-temperature, hazardous and heavy manual labor, since a long time on the request for the realization of automation. In order to improve work efficiency, and to ensure the personal safety of workers, especially for large, small, low-speed and manpower can not handle the work is more need to use robotic operation.
2. Cold machining applications
Cold machining robot is mainly used for diesel engine parts and shafts, disks and boxes and other parts of the single machining of loading and unloading and tool installation. Further in the program control, digital control and other machine tool applications, become an integral part of the equipment. Recently, more in the processing line, automatic line on the application, become a machine tool, equipment, up and down the process of connecting the important in section.
3. Disassembly and repair
Disassembly and repair is one of the railroad industrial system of heavy manual labor more departments, promoting the development of robots. At present, the domestic railroad factories, machine sections and other departments, has been used to dismantle the robot three-way valve, hook tongue, decomposition of brake cylinders, loading and unloading of axle boxes, assembly of wheel pairs, removal of asbestos, etc., to reduce labor intensity, improve the efficiency of dismantling and repair and installation. In recent years, also developed a bus painting general-purpose robotic hand, can be used to the interior of the bus for continuous painting to improve labor conditions, improve the quality and efficiency of the spray paint.
In recent years, with the computer technology, electronic technology and sensing technology in the robot more and more applications, industrial robot has become an important factor in industrial production to improve labor productivity.
1.2 The significance of the application of the manipulator
In the machinery industry, the significance of the application of the manipulator can be summarized as follows:
1. It can improve the degree of automation of the production process
The application of the manipulator is conducive to the improvement of the degree of automation of the material transfer, the loading and unloading of the workpieces, the replacement of cutting tools, and the assembling of the machine, etc., so that the labor productivity and the production costs can be reduced. Labor productivity, reduce production costs, accelerate the pace of mechanization and automation of industrial production.
2. can improve labor conditions, to avoid personal accidents in high temperature, high pressure, low temperature, low pressure, dust, noise, odor, radioactive or other toxic contamination, as well as narrow workspace and other occasions, the direct operation of human hands is dangerous or impossible. The application of robots can be partially or completely instead of people to safely complete the operation, greatly improving the labor conditions of workers. In some simple but repetitive operations, the robot instead of manpower to work, can be avoided due to fatigue or negligence caused by the operation of personal accidents.
3. It can reduce manpower and facilitate rhythmic production
Application of robot instead of manual work, which is a direct reduction of manpower on one side, and at the same time, due to the application of the robot can work continuously, which is another side of the reduction of manpower. Therefore, in automated machine tools and integrated processing automatic production lines, almost all of them are now equipped with manipulators to reduce manpower and more accurately control the beat of production to facilitate rhythmic production.
In summary, the effective application of manipulators is an inevitable trend in the development of the machinery industry.1.3.3 Overview of the development of manipulators and the trend of development
1.3 Overview of the development of manipulators
Specialized manipulators, after several decades of development, have now entered into the era marked by the general-purpose manipulators. Due to the application and development of general-purpose manipulators, which in turn promotes the development of intelligent robots. Intelligent robot involved in the knowledge content, not only including general mechanical, hydraulic, pneumatic and other basic knowledge, but also the application of some electronic technology, television technology, communication technology, computing technology, radio control, bionics and prosthetic technology, etc., so it is a comprehensive and strong new technology. At present, both domestic and foreign countries attach great importance to the development of this new technology, over the past few decades, the research and development of this technology has been relatively active, the design is constantly being modified, the variety is constantly increasing, and the field of application is also constantly expanding.
As early as the 1940s, with the development of the atomic energy industry, has appeared to simulate the first generation of articulated manipulators.
50 ~ 60 years that made the transfer and loading and unloading of workpieces of general-purpose robot and CNC teaching reproduction robot. This robot is also known as the second generation of robots. Such as Unimate (Unimate) robot belongs to this type.
60 ~ 70 years, and successively to the general-purpose robot for automobile body spot welding and stamping production line, that is, the second generation of the robot this new technology into the application stage.
80-90 years, assembly robot in its heyday, especially in Japan.
90's robots in the special purpose has a greater development, in addition to industrial applications, agriculture, forestry, mining, aerospace, marine, recreation, sports, medical care, service industry, military field has a greater application.
After the 90's, with the rapid development of computer technology, microelectronics technology, network technology, etc., robotic technology has also been rapid diversified development.
In short, the main experience of the current manipulator is divided into three generations:
The first generation of manipulators mainly rely on manual control, the control mode of open-loop, no identification capabilities; the direction of the improvement is mainly will be low-cost and improve the accuracy; the second generation of manipulators are equipped with electronic computer control system, with vision, tactile ability, and even the ability to listen and think. Research to install a variety of sensors, the received information feedback, so that the robot has a feeling function; the third generation of robots can independently complete the task in the work process. It keeps in touch with electronic computers and television equipment, and gradually develops into a flexible system FMS (Flexible Manufacturing System) and flexible manufacturing cell FMC (Flexible Manufacturing Cell) in an important part.
1.4 The development trend of the robot
Currently, the domestic industrial machinery is mainly used in machine tool processing, casting and forging, heat treatment, etc., the number, variety,
Performance can not meet the needs of industrial production development.
Therefore, the country is mainly to gradually expand the scope of application of the robot, focusing on the development of casting and forging, heat treatment of the robot, in order to reduce labor intensity, improve working conditions. In the application of specialized robots at the same time, the corresponding development of general-purpose robots, and the conditions of the development of instructional robots, computer-controlled robots and combined robots.
The movement components of the manipulator, such as telescoping, swinging, lifting, traverse, tilting and other institutions, as well as for different types of clamping mechanism, designed as a typical general-purpose institutions, so that according to different operational requirements, the selection of typical components, can be composed of a variety of different uses of the manipulator. Both to facilitate the design and manufacture, but also easy to change the work, expanding the scope of application. At the same time to improve accuracy, reduce impact, positioning accuracy, in order to better play the role of the manipulator. In addition, we should also vigorously study the servo type, memory reproduction type, as well as tactile, visual and other properties of the robot, and consider the computer linkage, and gradually become a basic unit of the entire machinery manufacturing system.
In the foreign machinery manufacturing industry, industrial manipulator application more, faster development. At present, mainly used for machine tools, die forging press loading and unloading, as well as spot welding, painting and other operations, it can be in accordance with the pre-established operating procedures to complete the required operations, but does not have any sensing feedback ability to cope with changes in the outside world. If some deviation occurs, it will cause damage to the parts and even the manipulator itself. For this reason, the development trend of foreign manipulators is to vigorously develop some intelligent manipulators, so that they have a certain degree of sensing ability to feedback changes in external conditions and make corresponding changes. Such as the position of the occurrence of a slight deviation, that can be corrected, and self-testing, focusing on the study of the visual function and haptic function.
Visual function that is installed in the robot with a TV camera and optical rangefinder (i.e., distance sensor) and satellite computers. When working, the TV camera turns the image of the object into a video signal and then transmits it to the computer so that it can analyze the type, size, color and orientation of the object and send out commands to control the manipulator to carry out the work.
Tactile function that is installed in the robot with tactile feedback control device. When working, the manipulator first stretches out its fingers to look for the workpiece, and then reaches forward to grab the workpiece through the pressure-sensitive components installed in the fingers to produce tactile effects.
The size of the hand's grip can be controlled by the pressure-sensitive components installed in the inner part of the fingers to automatically adjust the size of the grip. In short, with the development of sensing technology, the ability of the manipulator's assembly operations will be further improved. By 1995, about 50% of the world's automobiles are assembled by robots.
The development of today's robotic hand is more mainly the combination of robotic hand and flexible manufacturing system and flexible manufacturing unit, so as to fundamentally change the current state of mechanical manufacturing system of manual operation.
1.5 Overview of PLC and its application in the robot
1. Overview of the application and development of programmable controllers
Programmable controllers (programmable controller), now generally referred to as PLC (programmable logic controller), which is based on microprocessors, integrated with the programmable logic controller (PLC). Microprocessor-based, integrated computer technology, semiconductor integration technology, automatic control technology, digital technology, communication network technology developed a general industrial automatic control device. With its significant advantages in metallurgy, chemical industry, transportation, electric power and other fields to obtain a wide range of applications, has become one of the three pillars of modern industrial control.
Before the introduction of programmable controllers, the industrial control field is dominated by relay control. Traditional relay control has a simple structure, easy to grasp, inexpensive and other advantages, widely used in industrial production. But the control device is large, slow action, power consumption, less functional, especially because it relies on hardware wiring system, wiring complicated, when the production process or control object change, the original wiring engraved control panel (cabinet) must be changed or replaced, versatility and flexibility is poor
2.PLC applications
PLC application is very wide, and the application field is rapidly expanding. In the rapid expansion of PLC for today's PLC can almost be said that where the need for control systems exist on the need for PLC, especially in recent years, PLC's cost-effective and improving has been widely used in metallurgy, machinery, petroleum, chemical industry, light power, electric power and other industries.
Press PLC control type, its application can be broadly divided into the following aspects.
1). For logic control
This is the most basic and widely used aspect of PLC. PLC is used to replace relay control and sequence controller control. Examples include electrical control of machine tools, control of packaging machinery, automatic elevator control, etc.
2). For analog control
PLC can convert between analog and digital quantities and control analog quantities through analog I/O modules.
3). For digital control in machining
Modern PLC has strong data processing capabilities, it can be closely integrated with the digital control (NC) and computer control (CNC) in machining to realize digital control.
4). For industrial robot control
5). For multi-layer distributed control system
High-function PLC has strong communication connectivity, which can realize the communication between PLC and PLC, between PLC and remote I/O, and between PLC and host computer. Thus forming a multi-layer distributed control system or factory automation network.
3. Features of PLC
1). High reliability, strong anti-interference ability
PLC can work reliably in harsh environments such as electromagnetic interference, power supply voltage fluctuations, mechanical vibration, temperature changes, etc., PLC's average failure-free interval is high, Japan's Mitsubishi Corporation's F1 series of PLCs average failure-free interval of up to 300,000h, which is not comparable to the general microcomputer.
2). Control system is simple, versatile
Since the PLC is using software programming to achieve control functions, the same control object, when the control requirements change the function of the control system needs to be changed, do not have to change the PLC hardware equipment, only need to change the software program accordingly.
3
Since the sixties of last century, the robot was realized as a product, the development of its application is also developing, the use of robot handling objects, assembly, cutting, spray dyeing, etc., the application is very wide. Now it has been applied in various industries such as machinery manufacturing, metallurgy, chemical industry, electric power, mining, building materials, light industry, food, environmental protection and so on. For example: the most typical development is that producers will be a large number of applications of this product in the health industry (automatic biochemical analyzers), so as to achieve the urgent need for a short period of time, a large number of samples in the health inspection data requirements, but in the field of health manipulator due to the use of samples plus a single enzyme reagent chromogenic method, and the use of filter structure design, resulting in the price of reagents is expensive, which restricts the development of the product market. With the advancement of technology, the design of manipulator has broken the single reagent, heating and filter constraints. With the rapid development of society, the requirements of industrial site manipulator will be more and more high, and its technology is more and more mature.
Manipulator is a control object often encountered in the field of industrial automatic control. Manipulator can complete many tasks, such as moving objects, assembly, cutting, spray dyeing and so on, the application is very wide. Application of PLC control robot to achieve a variety of prescribed process actions, can simplify the control line, cost savings, improve labor productivity. Figure 1 is the robot handling items schematic diagram.
Figure 1 the robot to move the schematic
The task of the robot in the figure is to carry the goods on the conveyor belt A to the conveyor belt B. In order to make the robot move accurately, in the limit position of the robot installed limit switches SQ1, SQ2, SQ3, SQ4, SQ5, respectively, the robot for the grasping, left turn, right turn, rising, falling action limit, and send out the action of the Input signal of the action in place. The conveyor belt A is equipped with a photoelectric switch SP, which is used to detect whether the items on the conveyor belt A are in place or not. The start and stop of the robot is controlled by the start button SB1 and stop button SB2 in the figure.
The conveyor belts A and B are dragged by an electric motor. The up, down, left, right, gripping, relaxing and other actions of the manipulator are driven by hydraulic pressure and controlled by six solenoid valves respectively.
2 Manipulator action flow
Conveyor B is in continuous operation, so there is no need for PLC control.
Manipulator and conveyor belt C Sequential action requirements are:
1) Press the start button SB1, the robot system works. Firstly, the rising solenoid valve is energized, and the arm rises to the rising limit switch action;
2) the left turning solenoid valve is energized, and the arm turns left to the left turning limit switch action;
3) the descending solenoid valve is energized, and the arm descends to the descending limit switch action;
4) the start of the conveyor belt A running, by the photoelectric switch SP detects the conveyor belt A has any items delivered, if the items are detected, then the gripping solenoid valve will be activated. If the item is detected, the gripping solenoid valve will be energized, and the manipulator will grip the item, and the gripping limit switch will be activated;
5) the arm will rise again, and the rising limit switch will be activated again;
6) the right turn solenoid valve will be energized, and the arm will turn right, and the right turn limit switch will be activated;
7) the arm will fall again, and the descending limit switch will be activated again;
8) release the solenoid valve will be energized, and the manipulator will loosen the grip. Electromagnetic valve is energized, the robot release the hand claw, after a delay of 2 seconds, to complete a handling task, and then repeat the cycle of the above process.
9) When the stop button SB2 is pressed or the power is cut off, the manipulator stops at the current working step, and when it is restarted, the manipulator continues to work according to the action before stopping.
Based on the sequential action requirements for the robot, you can draw a timing diagram as shown in Figure 2. From the timing diagram can be made from the manipulator shown in Figure 3 action flow chart.
Figure 2 robotic Furna so as to make the sequence diagram
Figure 3 robotic action flow chart
3 PLC selection and its I/O point number allocation
3.1 PLC selection
Because of the robot system's input/output points, the requirements of the electrical control part of the small size, low cost, and the ability to use a computer to monitor and manage the PLC, so the selection of Japan's OMRONT PLC, the OMRONT PLC is the best choice for the robot system. And management, so the choice of Japan's OMRON (Rishi) company produced a multi-function small C20P host. The machine has 12 input points and 8 output points, and there are 136 auxiliary relays, 16 special function relays, 160 holding relays, 8 temporary storage relays, 48 timers/counters, and 64 16-bit data storage.
3.2 I/O point number assignment
Based on the flow chart of the robot action shown in Figure 3, the I/O point assignment of the electrical control system can be determined as shown in Table 1.
Table 1 Robot control I/O allocation
Based on the flowchart of Fig. 3 and the I/O allocation table of Table 1, a state transfer diagram can be prepared as shown in Fig. 4.
Fig. 4 Robot State Transfer Diagram
4 Programming and Program Run
4.1 Programming with Stepping Instruction
Based on the state transfer diagram in Fig. 4, a stepping ladder program is compiled as shown in Fig. 5.
In Fig. 5, the function of the "all outputs prohibited" part is to prohibit all outputs at the time of stopping, so that the robot stops at the current step; when restarted, it can continue to move from the pre-stopping step.
In the condition that the state is transferred from HR010 to HR000, the normally closed contact of the holding relay is added, and its function is as follows: when the manipulator is working in an intermediate step, if the PLC loses power or stops running, the manipulator stops in the intermediate step; after the PLC is restored to power or put into operation again, because the holding relay HR has the function of state power failure protection, therefore, when it restarts, one of them is disconnected, and the other one is disconnected, and the other one is disconnected. After the PLC is restored or put back into operation, because the holding relay HR has the function of state disconnection protection, so when restarting, one of them is disconnected, so that HR000 can not be set, and the manipulator can only continue to move from the subsequent work step of the holding relay that was set before stopping.
4.2 Program operation
Press the start button SB1, the input point 0000 is ON, the auxiliary relay 1000 as the interlock condition is ON, the interlock command IL is on, IL and ILC coil between the normal operation, "all outputs are prohibited" is lifted. If the normally closed contacts (Figure 1) are all ON, the holding relay HR000 is turned on, and output point 0503 energizes the ascending solenoid valve, and the arm rises. When the arm rises into place, the rising limit switch closes input point 0005, holds relay HR001 on, resets HR000, and output point 0501 energizes the left turn solenoid valve, and the arm turns left. ...... Whenever a subsequent step is in place and the limit conditions are met, the state will be transferred to the next step. When the state is transferred to HR008 is ON, output point 0506 energizes the relaxation solenoid valve, the manipulator relaxes, and at the same time timer TIM00 is timed. When 2 seconds have elapsed, the state is transferred to HR000, and the program starts cycling again from the first working step.
When stopping, press the stop button SB2, 0001 is disconnected, auxiliary relay 1000 is OFF, the interlock command is disconnected, all outputs are prohibited, but the state of each holding relay is protected by power failure, and the manipulator stops at the current working step. When the start button is pressed again, the interlock command is turned on, the output before stopping is restored, and the manipulator continues to move in the work step in which a holding relay was ON before stopping.
5 Conclusion
This paper describes the design and application of the C series P-type small multifunctional PLC produced by Japan's OMRON company in the manipulator step control. Explained the principle of action of the robot, design requirements, program design methods. The program introduced in this paper has been successfully applied in actual production.