Research on automatic leveling digital controller

Research on automatic leveling digital controller of paver

Research on automatic leveling digital controller of paver

information of Chinese construction machinery

Guide: Zhang Xinrong, Xi'an Highway and Communications University Ru Feng, Xi'an Jiaotong University Abstract The Application of digital controller on paver can improve the performance of paver, reduce system cost, and realize intelligent control of paver, Establish perfect fault diagnosis

abstract the application of digital controller in paver can not only improve the performance of paver, reduce the system cost, but also lay a foundation for realizing the intelligent control of paver and establishing a perfect fault diagnosis system. Starting from the current application status of

, this paper discusses the development status of digital control. The structural designer signed the intentional strategic investment agreement

and its main technical parameters with the people's Government of Nanchong, Sichuan Province on December 12, 2016, and also proposed several implementation plans

key words: Research on automatic leveling digital controller of paver

the controller in the automatic leveling control system of paver is the main part that determines the performance of the leveling system. On the one hand, the structural form and working principle of safety depend on the development level of relevant technology, on the other hand, it also depends on the structural form of the system actuator and other links. Over the years, people have developed a variety of simulation controllers to form an electro-hydraulic control leveling system. The performance of these controllers is also improving with the development of electronic technology. At present, most controllers used in asphalt pavers are analog controllers

1 research status of digital controller

digital controller refers to the controller whose input and output appear in the form of digital quantity. Since the single-chip computer has been widely used, digital technology has been applied in various industries. In the field of control system, its application has attracted more and more attention

the research and development of the digital controller of the automatic leveling control system of the paver in foreign countries is not very long, and its application is even less. The kgs paver produced by sauer-sundstrand company in the mid-1990s adopts a microprocessor-based digital controller, and the reaction effect is good. In addition, digital controllers are also used on some pavers that maintain roots

at present, there is no report on the development of digital controller in China, and no product

has come out. Therefore, the development of digital controller for automatic leveling system of paver is of great significance

2 structural design scheme of the digital controller

the structural characteristics of the digital controller should meet the basic needs of the paver, and all functions that can be realized on the analog control Lu can also be well realized on it

2.1 basic structure

Figure 1 shows the basic structure of the digital controller. The analog input end is the input end of personal

analog signal, which is converted into digital

quantity by the a/d converter inside the controller. The address end is mainly designed for communication with other controllers. Because the

digital controller is a system based on microprocessor, it is easy to realize the communication function with other controllers. This function can take each control Lu as the lower computer, and the upper computer can coordinate and control it, so as to further realize the intelligent hierarchical control of the whole paver control system. The rising end and the falling end are the output signal ends. This

output signal is generally in the form of pulse, which controls the one rise and one fall of the leveling hydraulic cylinder respectively. The specific pulse form is related to the selected software. According to different control strategies and different hydraulic systems, South Africa needs different software. Due to software development, the installation of

is fast and convenient, which reflects that the digital controller provides power supply. If necessary, it also needs to provide multiple groups of power output to meet the needs of different sensors

2.2 panel design

the digital controller panel can not only reflect the basic functions of the system, but also is the human

machine interface and performance

panel design should first consider the basic functional needs of the controller, and then design a richer and more intuitive interface for the characteristics of the logarithmic

word controller. The functional design of the digital

word control Lu is listed below

(1) the information display shows the leveling hydraulic free rising and falling action

or the display is in position; Use numbers and signs to display the slope value and direction,

superelevation value and direction, sensitivity, etc., and also display

in the form of characters and numbers to view the system fault information in a rolling manner. The display screen can adopt one or two high brightness liquid crystal displays. If only one display screen is set, the switch can be used; If two display screens are set, different information can be displayed at the same time. The setting value of

is displayed at the same time, which makes the interface more intuitive, but at the same time, it also increases the system cost, and the structural layout

is also limited

(2) the button switch sensitivity adjustment button is used to adjust the sensitivity of the system,

because the paver requires different sensitivity under different working conditions. There are two switching buttons, automatic

and manual. The setting of manual Square work is the same as that of analog controller. Switching from automatic mode to manual mode does not affect the setting of the system, that is,

the system will not reset automatically. The display mode button is used to switch the actual value of the setting value displayed on the display

screen. If it is double screen display, there is no such button. The display adjustment button can adjust the displayed value in combination with the toggle switch, which can be used for both the actual value and the set value. In combination with the reset button, the display value can be reset. The setting button mainly works with other button switches to set the parameter

. The reset button is used to reposition the position of the sensor. It is controlled by the switch

button between longitudinal slope and transverse slope. The digital control LV can have the

function of the longitudinal slope and transverse slope controller at the same time. This button is designed to realize this function. The toggle switch is used to input data, which can be toggled up and down to change the value in the way of increasing and decreasing

(3) the status display mainly displays the size of the current deviation signal, which can be visually displayed with different symbols of

(4) function display for buttons with dual functions, it should indicate the working state before the target

, and this function can be realized by LED

2.3 shape design

in order to facilitate the leading out of signal lines, workers should walk around the factory to set external plug-in terminals. It is best to choose the standard connector, and the connection should be stable and firm. For example, 25 pin calculation

machine signal terminal can be considered. In this way, it is not only convenient to select parts, but also easy to connect with different controllers or their installed computers

controller can be made of aluminum or other metals. On the one hand, it can play the role of

shielding to prevent external interference to the signal, on the other hand, it also plays the role of protection

and is easy to install and fasten. Under the interference of strong signals, the digital controller may crash, so appropriate grounding and anti-interference measures must be taken to prevent the controller from generating wrong control signals or losing control functions

3 technical performance of digital controller

3.1 basic parameters

from the function of panel design, you can see all basic parameters, input and output

methods, while other parameters that are more important but do not need to be changed frequently need to be set in the software. These parameters will have different values with different types of valves used, different controllers and different machines

3.2 fault diagnosis of controller

digital controller is a controller with computer as the core, so it is relatively easy to establish a fault diagnosis system. This function can detect errors caused by sensors,

solenoid valves, wiring or operating procedures, and display information or sound and light signals to prompt the operator to correct in time. For some major errors, it should also be able to automatically cut off the control to avoid further damage to the machine

the controller has two working modes, automatic and manual, which should be considered respectively when designing the fault diagnosis program

4 implementation scheme of digital controller

4.1 using single chip microcomputer as the core to realize digital control

in the current application research, the easiest scheme to realize digital control is to use

single chip microcomputer to realize its function, especially the new 8-bit and 16 bit single chip microcomputer has the function of analog

digital and digital analog conversion, which is more conducive to be used in digital controller. For the automatic leveling control system, the use of single chip has the following characteristics:

(1) low cost, easy to develop because the price of single chip continues to decline, but its technical content continues to increase, which provides the possibility of developing cheap controllers. Besides

, SCM has been widely used. There are many examples of successful applications and a large number of public programs that can be used for reference

(2) small size and easy arrangement of structure. Because the single chip microcomputer and its peripheral interface circuit

can be compactly placed on a printed circuit board, it is convenient to set the

meter for the panel of the controller. The shape and size of the panel can be set at will to a certain extent

(3) it can realize more complex control. For some more complex control, the amount of calculation is often large, so the calculation speed will directly affect the control accuracy. For a single chip,

, because there are few system programs and the program runs fast, some complex controls can be achieved

(4) the single chip system is vulnerable to external interference. It is a micro electric system, which is relatively vulnerable to the influence of strong current, magnetic field and electric pulse, and even vulnerable to the influence of poor working environment, so anti-interference measures must be taken

4.2 using programmable controller (PLC) to realize digital control

programmable controller (PLC) is a controller specially designed for sequential production process. It replaces the traditional relay and has strong timing

(1) strong anti-interference ability: PLC is specially used in industrial field environment, and

is superior to single chip microcomputer system in anti-interference ability

(2) it is easy to connect with the solenoid valve because the output form of PLC is in the form of digital pulse

. In driving the on-off valve, d/a conversion is omitted. At present, pavers are widely used for on-off valves, which provides convenience for the application of PLC

(3) it is difficult to complete some controls because PLC is a step

sequential controller with very high timing. Its computing host part is composed of four guide columns, upper beam, middle beam and workbench. The floor type frame capacity is not very strong, which limits the realization of some control schemes. Although recently, there have been some PL adjustments with strong computing power, which are suitable for fixing tightly; (4) The tightening spring is rusted C,

but its essence is not divorced from the original characteristics. It is still based on circular scanning and program execution mode, which often affects the calculation speed

4.3 adopt industrial control computer to realize digital control

industrial control computer is relative to single