The latest control system of the hottest undergrou

  • Detail

With the development of science and technology and the application of computer technology, the control technology of underground loaders has also undergone fundamental changes. From the original manual operation to semi-automatic direction, it greatly simplifies the operation of the underground loader, improves the driver's comfort and the production capacity of the underground loader

1 at the same time, electronic control technology of diesel engine

at present, there are two diesel engines for underground loaders in the world that use electronic control technology: Detroit company of the United States and caterpillar company of the United States. Now take the electronic control system (DDEC) of Detroit company as an example to illustrate its composition and working principle

DDEC is a fully integrated engine management and control system, which is composed of electronic control components (ECM), electronic pump nozzles (EUI) and various sensors

ecm is the "brain" of the system. It is actually a computer with great power. The signals received by the system from the operator, the engine and various sensors installed on the machine are transmitted to the ECM. The ECM receives these electronic input signals, and after analysis, it can know what the driver wants to do, what the machine is doing, and the temperature, speed, oil pressure, load factor, etc. of the current engine. Then the ECM compares these input information with the data in the memory (the limit values of diesel engine design, such as engine power, engine protection, exhaust emission limit; various limit values set by machine users, such as maximum vehicle speed, etc.) and outputs signals to control the injection time and quantity of fuel nozzle, or adjust the performance of engine and machine, etc. The information transmission process is shown in Figure 1

there are two indicator lights on the engine dashboard, one is yellow and the other is red. When the fault is small, the yellow light is on, indicating that the engine should be checked after shifting; When the fault is large, the red light is on, and the machine should be shut down immediately to avoid engine damage. DDEC can automatically monitor engine faults, including low coolant level, high coolant temperature, low oil pressure, high oil temperature, high fuel temperature, low fuel pressure, nozzle response time, high crankcase pressure, low battery voltage and engine overspeed

in order to obtain more relevant information from the ECM and determine the fault as soon as possible, the following three devices are usually used:

(1) the analog sensor is used before diagnosis and the digital sensor switch is used after diagnosis: the simple diagnostic switch is installed on the instrument panel. As long as the driver gently presses this button, the engine inspection light will flash digitally. This number corresponds to the small card to find out the fault, which will clearly indicate the problem

(2) electronic display: this electronic display replaces the typical mechanical instrument panel. The electronic display of Detroit Diesel engine can show any problems, as shown in Figure 2

Figure 2 electronic display

(3) portable diagnostic tool: as long as you insert the portable diagnostic tool into the DDEC system, you can quickly identify the location of the problem. This tool is affordable and easy to use. The same tool can be used to change the user's options, such as no-load speed, maximum walking speed of the machine, etc

2 semi-automatic and full-automatic control of power shift transmission for underground loaders

at present, fixed axle power shift transmission of Clark company or planetary power shift transmission of cat company are widely used in underground loaders. Due to the adoption of semi-automatic or automatic gear shifting, the service performance and operation performance of the underground loader are improved, and the driver only needs to pay attention to driving. The difference between semi-automatic shift and full-automatic shift is that the latter shifts automatically with the change of load and speed. Now take APC of c1ark company. 100 automatic control system as an example to illustrate its composition and working principle (Figure 3)

Figure 3 composition of automatic control system

1. Control box 2. Electronic gear selector 3. Transmission and direction control valve

4. Turbine sensor 5. Engine sensor 6. Throttle sensor 7. On

off and display 8. Transmission temperature and pressure sensor 9, engine

temperature and pressure sensor 10. clutch release switch

(1) control box. There is a central processor in the control box, which receives the data signals of the controller, torque converter, transmission and throttle in the cab, processes them according to these signals and the predetermined requirements of the machine, and then sends electronic signals to the transmission, so as to carry out the corresponding operation at the fastest speed. The process is shown in Figure 4

Figure 4 control process of automatic control system

2) electronic gear selector. It can preset each shift gear, so as to provide simple and stable shift operation, so that the handle type and console type controllers can be used with most transmissions, reduce the driver's concentration, and protect the transmission system. The selector is connected with a high-power microcomputer and display, and plays the role of reverse protection, reverse gear setting, speed reduction protection, neutral start protection, automatic locking of torque converter, semi-automatic shift and pre start gear setting

(3) speed and direction control valve. It is an actuator, controlled by the central processing unit and electronic gear selector, and its function is to shift gears according to the predetermined requirements

(4) turbine sensor. Used to detect torque converter oil temperature and turbine speed

(5) engine sensor. It is used to raise the movable table to detect various characteristics of the engine

(6) throttle sensor. It is a part of the pedal assembly, replacing the mechanical connection from the cab to the throttle, transforming the control of the throttle into an electrical signal and sending it to the central processing unit

(7) switches and displays on the control panel. It can diagnose hardware faults, check the function of the throttle sensor and the operation of the speed sensor. If the machine fails, all outputs will be turned off

(8) transmission temperature and pressure sensor. Check the transmission oil temperature and clutch pressure

(9) engine temperature and pressure sensor. Check the engine oil pressure and temperature

(10) clutch disengagement switch. The driver can use the brake pedal to shift the transmission to the neutral position, which can provide sufficient engine power for realizing other functions of the machine

3 overall control

the traditional control system of underground loader includes steering control lever (or steering wheel), reversing control lever, shift control lever, bucket lifting and lowering control lever, bucket retracting and tipping control lever, parking brake lever, accelerator pedal and brake pedal, that is, the so-called six rod two plate control. In order to reduce the labor intensity of drivers and reduce misoperation, in recent years, underground loaders have adopted single lever and double lever, and the traditional mechanical control is replaced by electric control

the single lever combines the three levers of steering, shifting and reversing into one lever (the so-called stic system). For example, catepillar's series of underground loaders adopt this form. As long as the joystick is moved left and right, the vehicle can be controlled to turn left or right. The forward and backward of the vehicle are controlled by the trigger switch on the abdomen of the control lever. The two buttons on the upper part of the joystick are used to shift gears. The upper left button is an upshift switch, which can be pressed once to raise a gear, and the lower right button is a downshift switch, which can be pressed once to lower a gear. Double control levers combine reversing and shifting into one lever, that is, reversing and shifting are completed by the same control lever, such as the electric control lever of C1 company

recently, German paus company introduced a new two lever control system, which has no steering wheel and foot pedal, and all controls are on two levers. Press the left joystick forward to control the boom lowering; Pull back to control the boom to rise; Pull to the right and load the bucket; Pull to the left and unload the bucket: the throttle control and braking are controlled by the button directly behind the left joystick. Push the right joystick forward, turn the vehicle right s, pull back, and turn the vehicle left; Pull to the right, and the vehicle will retreat; Pull to the left and the vehicle will move forward. The button directly behind the left joystick controls the vehicle speed

the control system does not need hydraulic pipelines, which increases the operating space of the cab and makes the driver's operation more comfortable. This kind of control system is more meaningful for minicomputers

4 remote control device and automatic loading system

in order to operate in dangerous mining areas, greatly improve safety and productivity, and improve operating conditions, various underground loader manufacturers have launched remote control underground loaders. Early radio remote control devices must be operated by people standing near the dangerous area. Recently, German paus company adopted the remote control device of Canadian nartilos company in the new tiger 300D underground loader

there are two cameras directly in front of the loader and one camera directly behind it. The camera transmits the image to the display screen of the remote control box through the transmission receiving device on the machine. When someone is standing on the road, the vehicle will slow down automatically and stop automatically if necessary. This device not only expands the driver's vision, but also allows a wider range of radio control, but also is safer

from the late 1980s to the early 1990s, Swedish T-rib rock company and lkab company have been conducting research on automatic loading and transportation systems. In this system, transportation and unloading are completely controlled by computer, and loading is still remotely controlled by operators. After several years of research and development, the first real uro 2500e underground loader equipped with automatic loading system has been used in Kiruna mine, Sweden, at the end of 1999

in order to realize automation of underground mining, we must overcome a series of difficulties. Underground mines are different from open-pit mines. The latter uses global positioning system (GPS) to guide vehicles, while the former cannot receive GPS signals. Therefore, t-rock company adopts a new navigation system, that is, two sets of navigation systems are installed on each underground loader. One system is inertial navigation equipment, which has a set of gyroscope, which is connected with the computer in the transmission system to measure the acceleration and deceleration of the machine and continuously monitor the running distance and speed. The laser scanner installed in the front and rear of the loader continuously depicts the section of the mine roadway on the horizontal and vertical planes, and can record and remember the shape of each point on the travel route, and then feed back to the central computer in the control room, so that the computer can accurately understand the real-time position of each underground loader, so as to avoid the collision between this machine and another machine

before automatic operation, a large amount of information must be input manually. For example, the underground loader should first rely on human control to identify the work cycle process, that is, the driver in the cab or use the TV remote control system to control the underground loader to move slowly along the set operation route, so that the underground loader can learn the basic operation cycle at one time, including walking and various loading and unloading operations, and then return to the original place of departure. In the room, TV remote control equipment is used to operate the underground loader, and the computer controls the transportation and unloading. A driver can monitor three underground loaders at the same time in the control room

Copyright © 2011 JIN SHI