Wood chip discharging spiral position monitoring system and monitoring method

Abstract

The invention discloses a wood chip unloading spiral position monitoring system and a monitoring method, which realize high-precision and low-cost displacement detection by combining gear pulse counting with dynamic calibration of a limit switch. Limiting switches are arranged at the starting point, the ending point and the middle point of the track, gear counting errors are corrected in real time through a controller, and the problems that a traditional encoder is poor in interference resistance and large in accumulative error are effectively solved. In addition, the system supports wireless communication expansion and is suitable for industrial scenes such as wood chip conveying.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of material conveying equipment, and relates to a wood chip unloading screw position monitoring system and a monitoring method. BACKGROUND

[0002] The existing unloading screw position detection system mainly relies on a rotary encoder or a laser ranging device, and has the following defects: 1) high cost: high-precision encoders are expensive and need to be calibrated and maintained regularly; 2) poor anti-interference ability: the encoder is easily affected by mechanical vibration, dust pollution and humidity, resulting in signal distortion or loss; 3) large cumulative error: in long-term operation, due to gear slipping, wear or temperature change, the position detection deviation gradually accumulates, affecting the positioning accuracy.

[0003] The existing gear counting system, such as a 6-tooth gear cooperating with two pulse sensors XS1 and XS2, although simple in structure, is prone to counting errors due to signal delay or jitter when switching between forward and reverse rotation, and lacks real-time calibration function, making it difficult to meet high reliability requirements. SUMMARY

[0004] The present application aims to provide a wood chip unloading screw position monitoring system and a monitoring method, which optimizes the cooperative work of gear counting and limit switch, realizes high-precision and low-cost displacement detection, and solves the problems of large cumulative error and poor anti-interference ability in the prior art; the system has the characteristics of dynamic calibration, redundant verification and strong expansibility.

[0005] The technical solution of the present application is as follows: The wood chip unloading screw position monitoring system comprises: A gear-rack transmission unit comprising a gear and a rack that mesh with each other, for converting the rotational motion of the unloading screw into linear displacement; A pulse sensor for detecting the number of gear rotations and generating a pulse signal; A limit switch group, a plurality of limit switches arranged along the track; A controller configured to calculate real-time displacement according to the pulse signal and correct the displacement calculation value when the limit switch is triggered to eliminate cumulative error; The gear-rack transmission unit meshes to drive the unloading screw walking mechanism to move; the pulse sensors XS1 and XS2 are installed on the side of the gear to detect the change in gear shape; the limit switch comprises at least a start limit switch and an end limit switch; the controller connects all sensors and limit switches through a cable, and the pulse signal line and the limit switch signal line are connected to the input port of the controller; the controller outputs control signals to the motor driver.

[0006] Further, the number of pulse sensors is two, and the pulse sensors are installed with a preset phase difference for detecting the rotation direction of the gear; the gear has 6 teeth, and the count is increased or decreased by 1 when the signals of 2 teeth are detected.

[0007] Further, the controller supports the count direction switching U / D-N signal, and "1" represents forward rotation counting, and "0" represents reverse rotation counting.

[0008] Further, the limit switch group includes three or more limit switches arranged at the starting point, the ending point and at least one intermediate calibration point of the walking track.

[0009] The wood chip unloading screw position monitoring method comprises the following steps: 1) detecting the rotation pulse of the gear driving the walking of the unloading screw through a pulse sensor; 2) calculating the real-time displacement of the unloading screw according to pulse accumulation; 3) starting a dynamic calibration process when the limit switch arranged on the walking track is triggered; 4) in the dynamic calibration process, the parameters of displacement calculation are corrected according to the known position information of the triggered limit switch to eliminate the cumulative error.

[0010] Further, the parameters of displacement calculation include: calculating a correction coefficient K, K = theoretical displacement value / current measured displacement value; and updating the conversion relationship between the pulse and the displacement by using K.

[0011] The innovation points of the present application and the beneficial effects generated thereby are as follows: (1) Dynamic segmented calibration mechanism: the system sets forced calibration points at the starting point, the ending point and the intermediate position, automatically compares the theoretical displacement and the actual pulse count value through the triggering of the limit switch, and corrects the counter error in real time. For example, the intermediate limit point is compared with the theoretical tooth number (such as 300 teeth) and the actual detected tooth number (such as 288 teeth), and the displacement amount corresponding to a single tooth is dynamically adjusted, so that the cumulative error is effectively suppressed.

[0012] (2) Redundancy fault-tolerant design and reliability improvement: the gear counting and limit switch double-checking strategy is adopted to form a redundant signal path, thereby enhancing the fault-tolerant capability and operation reliability of the system under complex working conditions.

[0013] (3) Anti-interference signal processing optimization: the pulse signal is denoised by combining hardware filtering (such as RC circuit) and software algorithm (such as digital filtering), so that the false triggering and counting deviation caused by electromagnetic interference or mechanical vibration are significantly reduced.

[0014] (4) Low-cost and highly scalable architecture: The general-purpose pulse sensor and standard controller are used as the core to replace the traditional high-precision encoder, which significantly reduces the cost while ensuring the accuracy. The system supports integrated wireless communication modules, which facilitates remote state monitoring and fault diagnosis, and has good functional scalability. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a schematic diagram of the system structure.

[0016] Figure 2 is a control logic flowchart.

[0017] Figure 3 is an error compensation algorithm flowchart.

[0018] Figure 4 is an extended function block diagram of Example 2.

[0019] In the figure: 1-gear; 2-rack; 3-unloading spiral walking mechanism; 4-pulse sensor XS1; 5-pulse sensor XS2; 6-limit switch S1; 7-limit switch S2; 8-limit switch S3; 9-controller; 10-wireless communication module; 11-database; 12-cloud server; 13-user interface. DETAILED DESCRIPTION

[0020] The two preferred embodiments of the present application will be described in detail below in conjunction with the accompanying drawings.

[0021] Example 1: Basic embodiment This embodiment provides a wood chip unloading spiral position monitoring system and a monitoring method.

[0022] Figure 1 The wood chip unloading spiral position monitoring system is shown.

[0023] Mechanical transmission part: The gear-rack transmission unit composed of gear 1 and rack 2 is used to convert the rotary motion of the gear into the linear displacement of the unloading spiral walking mechanism 3. The gear 1 parameters are: modulus 2, number of teeth 6, pitch circle diameter 12 mm, and circumference 37.7 mm. Therefore, the gear displaces 37.7 mm for each rotation.

[0024] The sensing part: includes two pulse sensors XS1 4 and XS2 5, which are installed on the side of the gear 1, detect the number of gear rotation teeth, and generate a phase difference pulse signal. The gear 1 is designed as 6 teeth, and the count increases or decreases 1 when 2 teeth are detected, thereby improving the resolution and anti-interference ability. The limit switch group includes start limit switch S1 6, end limit switch S2 7 and intermediate limit switch S3 8, which are arranged at an interval of about 1 meter along the track to provide an absolute position reference. In addition, the system can also be configured with left and right emergency limit switches to deal with abnormal situations.

[0025] The control core: the controller 9 connects all sensors and limit switches through a cable. It receives pulse signals and limit switch signals, and outputs control signals to the motor driver. The controller supports count direction switching U / D-N signal, "1" indicating forward count, and "0" indicating reverse count.

[0026] Figure 2 The method for monitoring the position of the wood chip unloading screw is shown, comprising the following steps: 1) Detect the rotation pulse of the gear driving the unloading screw to walk through the pulse sensor. After the system is started, the unloading screw walking mechanism 3 is reset to the starting point, triggering the start limit switch S1 6, and the controller 9 clears the internal counter. During walking, the pulse sensors XS1 4 and XS2 5 detect the change of gear tooth shape and generate pulse signals. The controller 9 determines the motion direction through the level of U / D-N signal ("1" for forward count, "0" for reverse count).

[0027] 2) Calculate the real-time displacement of the unloading screw according to the pulse accumulation. The controller 9 accumulates the pulse signal, and calculates the real-time displacement according to the gear circumference (37.7mm / turn) and the pulse count (1 count per 2 teeth). For example, the gear corresponds to 6 teeth per turn, generates 3 counts, and the displacement is 37.7mm.

[0028] 3) When the limit switch set on the walking track is triggered, the dynamic calibration process is started. When the walking mechanism triggers any limit switch (such as start S1, intermediate S3 or end S2), the controller 9 immediately interrupts the normal process and starts the dynamic calibration sub-process.

[0029] 4) In the dynamic calibration process, according to the known position information of the triggered limit switch, the parameters of displacement calculation are corrected to eliminate the accumulated error.

[0030] The specific calibration sub-process is shown in the following table: Figure 3 (1) The controller 9 reads the current actual count value (N_actual).

[0031] ​(2) Obtain the theoretical count value (N_theoretical) of this section. For example, the distance from the starting point to the middle limit switch S3 is 30 meters, and the theoretical tooth number is 300 teeth (based on gear parameters and pulse counting rules).

[0032] (3) Calculate the correction coefficient K: K = N_theoretical / N_actual.

[0033] (4) Update the conversion relationship between pulses and displacement using K: single tooth corresponding displacement S_new = S_old × K. For example, if the theoretical displacement of 30 meters corresponds to 300 teeth, and 288 teeth are actually detected, then K = 300 / 288 ≈ 1.0417, and the new single tooth displacement is corrected by multiplying the original value by K. Apply the new parameters, and use the corrected conversion relationship for subsequent displacement calculation until the next calibration.

[0034] (5) When reaching the end limit switch S2 7, the walking mechanism stops, and the controller 9 records the final position and updates the system.

[0035] Example 2: Extended implementation Wood chip unloading screw position monitoring system. Based on Example 1, this example further adds remote monitoring function, and the system architecture is shown in FIG. 2. Figure 4 In the local system, the controller 9 is connected with the wireless communication module 10 (such as Wi-Fi module).

[0036] The controller 9 sends real-time position, calibration records, device status and alarm information to the cloud server 11 through the wireless communication module 10.

[0037] The cloud server 11 stores the data in the database 12, and can display it to the user through the user interface 13 (such as PC or mobile phone App), realizing remote monitoring, historical data query and predictive maintenance.

Claims

1. A wood chip unloading auger position monitoring system, characterized in that, include: A gear-rack transmission unit, comprising meshing gears and a rack, is used to convert the rotational motion of the unloading auger into linear displacement; A pulse sensor is used to detect the number of teeth rotating in a gear and generate a pulse signal. Limit switch assembly, with multiple limit switches arranged along the track; The controller is configured to calculate the real-time displacement based on pulse signals and correct the calculated displacement value to eliminate accumulated errors when the limit switch is triggered; The gear-rack transmission unit meshes to drive the unloading screw travel mechanism to move; the pulse sensors XS1 and XS2 are installed on the side of the gear to detect changes in tooth profile; the limit switches include at least a start limit switch and an end limit switch; the controller connects all sensors and limit switches via cables, and the pulse signal line and limit switch signal line are connected to the controller input port. The controller outputs control signals to the motor driver.

2. The wood chip unloading auger position monitoring system according to claim 1, characterized in that: The pulse sensor is installed with a preset phase difference to detect the rotation direction of the gear. The gear has 6 teeth, and the count increases or decreases by 1 when a signal of 2 teeth is detected.

3. The wood chip unloading auger position monitoring system according to claim 1, characterized in that: The controller supports counting direction switching U / DN signals, where "1" indicates forward counting and "0" indicates reverse counting.

4. The wood chip unloading auger position monitoring system according to claim 1, characterized in that: The limit switch group includes three or more limit switches arranged at the starting point, ending point and at least one intermediate calibration point of the travel track.

5. A method for monitoring the position of a wood chip unloading auger, characterized in that... Includes the following steps: 1) The rotation pulses of the gears driving the unloading screw are detected by a pulse sensor; 2) Calculate the real-time displacement of the unloading screw based on pulse accumulation; 3) When the limit switch set on the travel track is triggered, the dynamic calibration process is started; 4) In the dynamic calibration process, the displacement calculation parameters are corrected based on the known position information of the triggered limit switch to eliminate cumulative errors.

6. The method for monitoring the position of the wood chip unloading auger according to claim 5, characterized in that: In step 4), the parameters for calculating the corrected displacement include: calculating the correction coefficient K, where K = theoretical displacement value / current measured displacement value; and using K to update the conversion relationship between pulse and displacement.

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