Microcomputer control system of the hottest loader

  • Detail

The microcomputer control system of loaders

it is an inevitable trend for the development of engineering machinery to realize electromechanical hydraulic integration. Loaders often cooperate with dump trucks to carry out loading, transportation and unloading in harsh environments according to jjf1001 general measuring terms and definitions. Its microcomputer control system has important practical significance for reducing the labor intensity of operators and improving productivity and operation level

1 system hardware control principle

the hardware structure and control principle of the system are shown in Figure 1. The operating device of the loader is a 2-DOF mechanism composed of bucket cylinder, boom, boom cylinder, lever system, bucket, etc. Two electro-hydraulic proportional valves are used to control the boom cylinder and bucket cylinder respectively. Strain displacement sensors and differential pressure sensors are installed on the boom cylinder and bucket cylinder. The differential pressure sensor consists of‘ It is composed of electric control and hydraulic pressure. The working voltage is 5V and is installed in the main control room. There are two pressures acting on the differential pressure sensor: one signal from the oil pump and the other from the pilot pressure on the main control valve, which is the maximum load pressure of the working element. The differential pressure sensor converts the differential pressure signal into a voltage signal and supplies it to the pump valve controller. The displacement sensor detects the expansion and contraction of the oil cylinder, and the differential pressure sensor detects the oil pressure of the oil cylinder; Photoelectric coding sensors are installed at the joint between the bucket and the boom and at the joint between the front and rear frames to detect the rotation angle of the bucket and the front frame

during operation, the program shall be prepared according to the actual operation conditions, and the information obtained by the sensor shall be used to issue control instructions to control the operation device to automatically load and unload. The control core of the system adopts 8089 single chip microcomputer with small volume, light weight, low price, strong anti-interference, high reliability and convenient use, and is equipped with a small keyboard and a display screen to form the control surface. In addition, this experimental board can be used to facilitate installation and operation in the cab. Through intelligent data acquisition board, a/D and D/A, the signal acquisition and control of external devices are realized

the control system is programmed with wtndows operating system and "C" language. The friendly man-machine interface can directly reflect the whole operation process. This control system has the characteristics of simple operation, convenient use, stable performance and low price

2 software system

on the one hand, the software system cooperates with the hardware system to control the peripheral equipment and working devices, on the other hand, it displays the operating process and working parameters of the loader, such as digging force, unloading height and unloading distance. Bucket inclination (bucket retraction angle, unloading angle), excavation depth, etc. The structure of loader operation device is shown in Figure 2

the digging force is calculated by the following formula according to the structural size of the loader according to the pressure difference sensor of the rotary bucket cylinder:

n= (PD × l1 × L3-gkl2l4)/l5

where: n - digging force; PD - pressure of rotary bucket cylinder; GK - dead weight of bucket; L1 - distance from PD to the hinge point of lever and boom; L2 -- the distance between the hinge point of the lever and the boom and the pull rod; L3 -- the distance from the hinge point between the bucket and the boom to the pull rod, and then conduct the test again; L4 -- horizontal distance from the bucket gravity center to the hinge point between the bucket and the boom; L5 - horizontal distance from n to the articulation point of bucket and boom

the unloading height, unloading distance and excavation depth are mainly measured by the displacement sensors of the rotary bucket cylinder and the boom cylinder through data calibration; The bucket inclination angle (bucket retraction angle and unloading angle) is measured by the data calibration of the angular displacement sensor installed at the hinge between the bucket and the boom. The software is designed with the function of switching between picture and text. The action of the bucket can be dynamically displayed on the display screen, and the measured data can also be displayed on the screen

3 conclusion

the development of the microcomputer control system of the loader has enabled the loader to initially realize the integration of mechanical, electrical and hydraulic, and reduced the labor intensity. At the same time, the operator can directly observe the operation process on the screen and control it through the operation panel. Although there are still some shortcomings, such as the poor anti-interference performance, sealing performance and anti vibration performance of the signal. However, the research results of this system have played a guiding role in the future technical development and are of great significance

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