Detecting system and detecting method for unbalanced loading of transportation vehicles

[0025] The invention uses 16-bit F90F340 series single-chip microcomputer as the core, and uses a high-precision digital output displacement sensor as the detection element. The system calculates and displays the corresponding partial load according to the collected multi-path displacement information.

[0026] An unbalanced load detection system for transportation vehicles, such as figure 1 As shown, it includes MCU1 (MB90F340 series single-chip microcomputer), keyboard 2, display 3, communication unit 4, multiple displacement sensor 5, signal conditioning circuit 6, digital interface circuit 7, photoelectric isolation circuit 8, alarm unit 9, ROM/RAM 10 and clock circuit 11. The system has a standard RS485 communication interface, which cooperates with the upper computer to upload eccentric load information for subsequent work such as statistics and analysis.

[0027] MCU1 and its peripheral components, as well as the corresponding detection, judgment, and control programs solidified in the system; constitute a group of information control units; MCU regularly reads multiple displacement signals, and displays the results on the display 3 in real time through calculation, Through photoelectric isolation measures, the signal alarm output for overload and partial load adopts full Chinese display, which is convenient for the operator.

[0028] The keyboard 2 and the display 3 constitute a group of human-computer interaction interfaces.

[0029] The alarm unit 9 is arranged in the cab to facilitate the driver's understanding of vehicle unbalanced load information.

[0030] MCU1 is a 16-bit single-chip microcomputer with FLASH structure. Therefore, the program memory ROM does not need to be expanded. In order to realize digital calibration and calibration functions, various calibration parameters need to be stored. This system uses ferroelectric memory with power-off protection function. Memory RAM, in order to store the calibration parameters after calibration, and store the eccentric load information.

[0031] The system can automatically store the off-load information of the vehicle, and combined with the clock circuit 11 in the system, store the year, month, day, hour, minute, and second of the off-load information for later analysis of the off-load data. The memory adopts non-volatile memory, and the data storage is reliable. In the case of power failure, the data can still be stored for 10 years.

[0032] Such as figure 2 As mentioned, the four linear displacement sensors 5 of the present invention are respectively located on the left and right sides above the front axle at the bottom of the carriage and on the left and right sides above the rear axle to detect their displacement relative to the axle for judging the eccentric load state. The multiple displacement sensor 5 is connected to MCU1 through the signal conditioning circuit 6 and the digital interface circuit 7. After the displacement sensor signal passes through the signal conditioning circuit 6, it passes through the I 2 S digital interface circuit 7 is connected to MCU1. High-precision displacement sensor (can detect a displacement of 0.005mm), adopts digital linear displacement method, and the output signal is a differential Gray code, so the displacement sensor uses I 2 S digital interface form to communicate with MCU. The system reads the front, back, left, and right displacement sensor information in a time-sharing manner. Inside the host, it is necessary to convert the Gray code to a sequence number before calculation. The output of the sensor is of differential nature. Therefore, its connection with the MCU requires a conversion interface. In this system, the MAX488 communication interface is used as the I 2 The conversion chip of the S interface, that is, connect the displacement sensor and MCU through MAX488 to realize the I 2 S communication hardware connection. Since each sensor inputs and outputs differential signals, there are four wires, and the MCU does not have so many interfaces. Therefore, the four sensors are time-shared to the MCU through the analog switch for sampling. The MCU uses P85 and P86 ports to connect to the differential circuit , And control multiple analog switches through the P80 and P81 ports to select one of the four sensors in a time-sharing manner, and read the values ​​of the front, back, left and right displacement sensors. The principle of the sensor and MCU interface circuit is as follows image 3 Shown.

[0033] MCU reads multiple displacement signals regularly, and displays the results on the display 3 in real time through calculation. Through photoelectric isolation measures, the signal alarm output for overload and partial load adopts full Chinese display, which is convenient for the operator.

[0034] The judgment of eccentric load is made by comparing the detection result with the threshold value. The invention can be applied to different types of unbalanced load detection of automobile cargo transportation. If the unbalanced load detection is carried out according to the sinking amount of the bottom of the carriage, only the displacement sensor needs to be calibrated to be installed on the automobile used for unbalanced load detection. If the weight standard needs to be used for judgment, it is necessary to calibrate the relationship between the load weight and the sinking amount of the carriage, and the calibration result is stored in the system. According to the vehicle type or eccentric load discrimination method, choose to adopt displacement discrimination or weight discrimination, and input the corresponding discrimination threshold according to the corresponding discrimination method.

[0035] according to figure 2 , Fix the four displacement sensors and install them. When the vehicle is in good condition and no cargo is loaded, press the calibration key on the control box panel to complete the calibration of the displacement sensor.

[0036] There is a certain relationship between the sinking amount of the car compartment and the weight of the cargo. The sinking displacement and weight are calibrated in the laboratory, because there is a certain relationship between weight and displacement: W=k×s, W represents weight, s represents displacement, and k is The variable coefficients have different values ​​of k at different stages. They are determined in advance through experiments and stored in the system memory. When the system is working, when different displacements are detected, the system automatically uses the corresponding coefficients to calculate the weight. There are two ways to judge the partial load, which can be converted as needed.

[0037] 1. Direct calculation using displacement

[0038] 1) Through human-computer interaction, input the judged threshold Ks. Once the threshold is input, the system will automatically store the value, and it is not necessary to input the value for every operation;

[0039] 2) In the process of loading goods, the system automatically detects the sinking of the carriage through four sensors, corresponding to the displacements S1, S2, S3, S4;

[0040] 3) Calculate the difference between the left and right displacements: St=S1+S3-S2-S4;

[0041] 4) Eccentric load judgment

[0042] If: St

[0043] If: St>Ks, report left partial load;

[0044] Otherwise: it is considered that the cargo loading is balanced.

[0045] 2. Using weight to judge

[0046] 1) Through human-computer interaction, input the judged threshold Kw. Once the threshold is input, the system will automatically store the value, and it is not necessary to input the value for each operation;

[0047] 2) In the process of loading cargo, the system automatically detects the sinking amount of the carriage through four sensors, and automatically calculates the weight distribution in the four directions of front, rear, left and right according to W=k×s: corresponding to W1, W2, and W3, W4;

[0048] 3) Calculate the difference between the left and right weights: Wt=W1+W3-W2-W4;

[0049] 4) Eccentric load judgment

[0050] If: Wt>Kw, report left partial load;

[0051] If: Wt

[0052] Otherwise: it is considered that the cargo loading is balanced.