An embedded high-speed balance wheel control method

Abstract

The application belongs to the application field of high-speed balance wheel on conveying line, and specifically discloses a kind of embedded high-speed balance wheel control method, and the balance wheel system is controlled, and the balance wheel system includes belt conveyor two, belt conveyor one and balance wheel in order from front to back, and the balance wheel is composed of multiple rows of rollers and servo motors, and a row of rollers is controlled by a servo motor to swing direction;The application uses embedded control circuit board to control the balance wheel, measures the shape of the package, tracks the position of the package, efficiently separates the package on the balance wheel and ensures the separation quality, and avoids the occurrence of abnormal phenomena such as package hanging after the package is separated by the balance wheel and enters the next equipment (belt conveyor or compartment, etc.).

Description

Technical Field

[0001] This invention relates to the application of high-speed balance wheels on conveyor lines, and in particular to an embedded high-speed balance wheel control method. Background Technology

[0002] With the rapid development of the e-commerce logistics industry, swing wheel sorting equipment is being used more and more widely in logistics sorting systems. Swing wheel sorting equipment is used for automated sorting in logistics. It mainly consists of a conveyor swing wheel, a synchronous steering controller, a transmission device, and a frame. During operation, it identifies materials based on instructions and information issued by the management system. The synchronous steering controller changes the running direction of the conveyor swing wheel, transferring the items to the diversion conveyor. It is widely applicable to the sorting of various boxes, bags, turnover boxes, bottles, books, parcels, electronic products, etc., in various logistics distribution centers.

[0003] However, existing swing wheel sorting equipment does not measure the shape of the package, nor does it accurately calculate the trajectory of the package in the swing wheel. This will result in the separation efficiency of the swing wheel and the trajectory of the package not being optimal at the same time. This can easily cause abnormal phenomena such as package snagging when the package enters the next device (belt conveyor or sorting box, etc.) after being separated by the swing wheel. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides an embedded high-speed balance wheel control method that enables the balance wheel to quickly and efficiently separate the package and ensures that the package has a good motion trajectory after being separated from the balance wheel.

[0005] To achieve the above objectives, the present invention is implemented according to the following technical solution:

[0006] An embedded high-speed balance wheel control method controls a balance wheel system, which, from front to back, includes a second belt conveyor, a first belt conveyor, and a balance wheel. The balance wheel consists of multiple rows of rollers and a servo motor, with each row of rollers controlled by a servo motor to oscillate in one direction. The embedded high-speed balance wheel control method includes the following steps:

[0007] S1. A measuring light curtain for measuring the shape of a package and obtaining its position is installed between the rear end of belt conveyor 2 and the front end of belt conveyor 1. Through-beam photoelectric sensors for measuring the shape of a package and obtaining its position are installed on both sides of the rear end of belt conveyor 1. Belt conveyor 2, belt conveyor 1, swing wheel, through-beam photoelectric sensors and measuring light curtain are respectively connected to an embedded control circuit board and controlled by the embedded control circuit board.

[0008] S2. After the balance wheel system is powered on, the embedded control circuit board performs a self-test to check whether the motor and photoelectric components are abnormal and to find the zero position of the balance wheel. If an abnormality is detected during the self-test, an alarm will be generated to prompt maintenance personnel to handle the abnormality. If the self-test is normal, proceed to step S3.

[0009] S3. Receives information on the left and right swing of the package from the embedded control circuit board, measures the shape and position of the package by measuring the light curtain and through-beam photoelectric detection, calculates the package's trajectory, and controls the rollers and servo motor of the swing wheel to achieve fast and efficient separation of the package and ensure that the package has a good motion trajectory after separation from the swing wheel, preventing the package from getting caught on the next device.

[0010] Furthermore, in step S2, the specific method for finding the zero position of the balance wheel is as follows: install a proximity switch on the leftmost or rightmost side of the balance wheel, one for each row of rollers. When the balance wheel is first powered on, let the balance wheel slowly swing toward the position of the proximity switch. When a row of rollers detects the proximity switch signal, that row of rollers stops swinging. When all rows of rollers detect the proximity switch, rotate the roller rows in the opposite direction by θ degrees, and the balance wheel will find the zero position.

[0011] Furthermore, in step S3, the specific process of detecting the shape and position of the package by measuring the light curtain and through-beam photoelectric detection is as follows:

[0012] Assume the speed of the belt conveyor is V. p After the package passes through the measuring light curtain, the total time t for the package to pass through the measuring light curtain is obtained. p Thus, the maximum length L of the package can be calculated. m =V p* t p The maximum width W of the package is obtained by counting the maximum number of light beams blocked by the measuring light curtain as the package passes through it. m Therefore, for any package, we treat it as a standard rectangle. At this time, we obtain the distances from the two sides of the package to the two sides of the balance wheel as y1 and y2, respectively, which gives us the positioning of the package.

[0013] Furthermore, in step S3, the specific steps for calculating the package's trajectory are as follows:

[0014] When the package leaves the balance wheel, the distance between the farthest end of the package and the entrance of the balance wheel is greater than a certain fixed value L0; assuming a package separates on one side of the balance wheel, the distance L that the farthest end of the package travels in the horizontal direction along the balance wheel is... X =L0+L m Vertical running distance L y =y0, assuming the roller's running speed is V0, and the angle between the roller and the horizontal running direction is θ, then the horizontal component of the velocity V 0X =V0*COSθ, the vertical component of velocity V 0y =V0*SINθ, then the horizontal running time t x =L X / V 0X , i.e. t x =(L0+L m) / (V0*COSθ), vertical running time t y =y0 / V 0y , i.e. t y =(y0+W m ) / (V0*SINθ), when t y ≥t x When t is greater than the time spent moving vertically, the package will leave the balance wheel at a position greater than L0, ensuring optimal package separation quality and efficiency. y ≤t x When the time spent moving vertically is less than the time spent moving horizontally, the package's position leaving the balance wheel will inevitably be less than L0, posing a risk to the quality of package separation. Therefore, after the package enters the balance wheel, it should first be allowed to move in the direction of travel for a period of time t1, and then rotated to the direction in which the package needs to leave. This ensures that the package leaves the balance wheel at the minimum distance L0, where t1 = t y -t x That is, t1 = (y0 + W) m ) / (V0*SINθ)-y0 / V 0y Thus, the motion curve wrapped around the balance wheel is obtained;

[0015] Assume the length of the belt conveyor between the light curtain and the balance wheel is L. f The belt conveyor runs at a speed of V. p The time t for the package to pass through the conveyor belt is then... f =L f / V p When the package leaves the measuring light curtain, the balance wheel obtains the shape, size, and position of the package, calculates the running time of the package in the horizontal direction and the running time in the vertical direction, and determines the running trajectory of the package.

[0016] Furthermore, in step S3, the specific steps for controlling the balance wheel's rollers and servo motor are as follows:

[0017] Assume the maximum rotational speed of the balance wheel is ω m The maximum angle is θ m The servo motor continuously controls the rollers to be positioned at ±θ. m Swinging within a range;

[0018] Assume the motor acceleration is A cc deceleration D ec Then the total angle of segment a is θ. a =(ω m *ω m ) / (2A cc The total angle of segment c is θ. c =(ω m *ωm ) / (2D ec Therefore, when 2θ m ≥θ a +θ c If segment b exists, then T exists; otherwise, segment b does not exist. b =(2θ) m -(θ a +θ c )) / ω m T a =ω m / A cc T c =ω m / D ec Total time T all =T a +T b +T c If segment b does not exist, then the total time is... Maximum speed at this time The above is from -θ m Go to +θ m and +θ m Go to -θ m The acceleration and deceleration curves of the servo motor;

[0019] The system tracks the position of the beginning and end of the package in real time. When the end of the previous package just leaves a certain row of rollers, the system controls the servo motor of that row of rollers according to the acceleration and deceleration curve to adjust the rotation direction of that row of rollers and move it to the direction where the next package needs to be separated.

[0020] Preferably, the main control chip of the embedded control circuit board is the STMicroelectronics STM32F407, a high-performance microcontroller based on the ARM7 architecture.

[0021] Preferably, the embedded control circuit board communicates with the servo motor of the roller using PWM pulses, and changing the duty cycle of the PWM pulses corresponds to changing the speed of the servo motor.

[0022] Compared with existing technologies, this invention uses an embedded control circuit board to control the balance wheel, measure the shape of the package, and track the position of the package, so that the package can be separated efficiently on the balance wheel and the separation quality can be guaranteed. This avoids abnormal phenomena such as packages getting caught in the next device (belt conveyor or grid, etc.) after the package is separated by the balance wheel. Attached Figure Description

[0023] Figure 1 This is a flowchart of the embedded high-speed balance wheel control method of the present invention.

[0024] Figure 2 This is a structural diagram of the balance wheel system.

[0025] Figure 3 This is a diagram showing the trajectory of the balance wheel.

[0026] Figure 4 This is a diagram showing the direction of the balance wheel's oscillation.

[0027] Figure 5 This is a graph showing the acceleration and deceleration curves of a servo motor. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0029] like Figure 1 As shown, this embodiment proposes an embedded high-speed balance wheel control method to control the balance wheel system. The balance wheel system includes, from front to back, a second belt conveyor 2, a first belt conveyor 4, and a balance wheel 6. The balance wheel 6 consists of multiple rows of rollers and servo motors, with each row of rollers controlled by a servo motor to oscillate in one direction. The embedded high-speed balance wheel control method includes the following steps:

[0030] S1, such as Figure 2 As shown, a measuring light curtain 3 is installed between the rear end of belt conveyor 2 and the front end of belt conveyor 4 to measure the shape of package 1 and obtain its position. Through-beam photoelectric sensors 5 are installed on both sides of the rear end of belt conveyor 4 to measure the shape of the package and obtain its position. Belt conveyor 2, belt conveyor 4, swing wheel 6, through-beam photoelectric sensors 5, and measuring light curtain 3 are connected to an embedded control circuit board, which controls them. In this embodiment, the main control chip of the embedded control circuit board is the STMicroelectronics STM32F407, a high-performance microcontroller based on the ARM7 architecture, with an operating frequency of up to 180MHz. The circuit board integrates multiple interfaces such as TCP, RS485, CAN, analog signals, and input / output IO. The circuit board communicates with the main controller via TCP, using LWIP (Lightweight TCP / IP protocol), which requires fewer resources (40KB of code ROM and tens of KB of RAM), making it very suitable for the TCP communication needs of embedded devices. Compared to a PLC, this significantly reduces production costs and shortens the delivery cycle.

[0031] S2. After the balance wheel system is powered on, the embedded control circuit board performs a self-test to check whether the motor and photoelectric components are abnormal and to find the zero position of the balance wheel. If an abnormality is detected during the self-test, an alarm will be generated to prompt maintenance personnel to handle the abnormality. If the self-test is normal, proceed to step S3.

[0032] In this embodiment, the horizontal direction at the center of the balance wheel is defined as the 0-degree direction, and the maximum angle of left and right swing is ±θ. When the balance wheel is first powered on, it needs to be initialized to find the zero position. Subsequent swings are based on this zero position. The method for finding the zero position is as follows: install a proximity switch on the far left (or far right) of the balance wheel, one for each row of rollers (or one for multiple rows of rollers as needed). When the balance wheel is first powered on, let the balance wheel slowly swing toward the position of the proximity switch. When a row of rollers detects the proximity switch signal, that row of rollers stops swinging. When all rows of rollers detect the proximity switch, rotate the roller rows in the opposite direction by θ degrees, and the balance wheel finds the zero position.

[0033] Of course, after the self-test is normal, the balance wheel needs to be checked to see if it is in local mode or remote mode. In local mode, the balance wheel can be started by the button on the control box panel, and the balance wheel can also be made to perform left and right swing tests, etc. This embodiment takes remote mode as an example.

[0034] S3: The embedded control circuit board receives the left and right swing information of the package from the main controller. It measures the shape and position of the package by measuring the light curtain and through-beam photoelectric detection, calculates the package's running trajectory, and controls the rollers and servo motor of the swing wheel to achieve fast and efficient separation of the package and ensure that the package has a good movement trajectory after separation from the swing wheel, so that the package will not get caught on the next device.

[0035] The specific process of detecting the shape and position of the package by measuring the light curtain and through-beam photoelectric detection is as follows:

[0036] like Figure 2 As shown, assume the speed of the belt conveyor is V. p After the package passes through the measuring light curtain, the total time t for the package to pass through the measuring light curtain is obtained. p Thus, the maximum length L of the package can be calculated. m =V p* t p The maximum width W of the package is obtained by counting the maximum number of light beams blocked by the measuring light curtain as the package passes through it. m Therefore, for any package, we treat it as a standard rectangle. At this time, we obtain the distances from the two sides of the package to the two sides of the balance wheel as y1 and y2, respectively, which gives us the positioning of the package.

[0037] like Figure 3 As shown, the specific steps for calculating the package's trajectory are as follows:

[0038] When the package leaves the balance wheel, the distance between the farthest end of the package and the entrance of the balance wheel is greater than a certain fixed value L0; assuming a package separates on one side of the balance wheel, the distance L that the farthest end of the package travels in the horizontal direction along the balance wheel is... X =L0+L m Vertical running distance L y=y0, assuming the roller's running speed is V0, and the angle between the roller and the horizontal running direction is θ, then the horizontal component of the velocity V 0X =V0*COSθ, the vertical component of velocity V 0y =V0*SINθ, then the horizontal running time t x =L X / V 0X , i.e. t x =(L0+L m ) / (V0*COSθ), vertical running time t y =y0 / V 0y , i.e. t y =(y0+W m ) / (V0*SINθ), when t y ≥t x When t is greater than the time spent moving vertically, the package will leave the balance wheel at a position greater than L0, ensuring optimal package separation quality and efficiency. y ≤t x When the time spent moving vertically is less than the time spent moving horizontally, the package's position leaving the balance wheel will inevitably be less than L0, posing a risk to the quality of package separation. Therefore, after the package enters the balance wheel, it should first be allowed to move in the direction of travel for a period of time t1, and then rotated to the direction in which the package needs to leave. This ensures that the package leaves the balance wheel at the minimum distance L0, where t1 = t y -t x That is, t1 = (y0 + W) m ) / (V0*SINθ)-y0 / V 0y Thus, the motion curve wrapped around the balance wheel is obtained;

[0039] Assume the length of the belt conveyor between the light curtain and the balance wheel is L. f The belt conveyor runs at a speed of V. p The time t for the package to pass through the conveyor belt is then... f =L f / V p When the package leaves the measuring light curtain, the balance wheel obtains the shape, size, and position of the package, calculates the running time of the package in the horizontal direction and the running time in the vertical direction, and determines the running trajectory of the package.

[0040] A balance wheel consists of rows of rollers. Typically, one or more rows of rollers are controlled by a servo motor to oscillate. An embedded control circuit board communicates with the servo motors of the rollers using PWM pulses. Changing the duty cycle of the PWM pulses correspondingly changes the speed of the servo motor, causing the rollers to accelerate uniformly and thus steadily increasing the speed of the balance wheel. This is achieved simply by changing the duty cycle of the PWM pulses corresponding to the speed. Assuming one servo motor controls one row of rollers, such as... Figure 4 As shown, the specific steps for controlling the balance wheel's rollers and servo motor are as follows:

[0041] Assume the maximum rotational speed of the balance wheel is ω m The maximum angle is θ m The servo motor continuously controls the rollers to be positioned at ±θ. m The oscillation occurs within a certain range; taking a maximum rotation angle as an example, when the roller array rotates from -θm to +θm, the motor needs to complete a process from acceleration to constant speed, then to deceleration, and finally to a stop. Figure 5 As shown, the curve represents the path from a to b and then to c.

[0042] Assume the motor acceleration is A cc deceleration D ec Then the total angle of segment a is θ. a =(ω m *ω m ) / (2A cc The total angle of segment c is θ. c =(ω m *ω m ) / (2D ec Therefore, when 2θ m ≥θ a +θ c If segment b exists, then T exists; otherwise, segment b does not exist. b =(2θ) m -(θ a +θ c )) / ω m T a =ω m / A cc T c =ω m / D ec Total time T all =T a +T b +T c If segment b does not exist, then the total time is... Maximum speed at this time The above is from -θ m Go to +θ m and +θ m Go to -θm The acceleration and deceleration curves of the servo motor;

[0043] The system tracks the position of the beginning and end of the package in real time. When the end of the previous package just leaves a certain row of rollers, the system controls the servo motor of that row of rollers according to the acceleration and deceleration curve to adjust the rotation direction of that row of rollers and move it to the direction where the next package needs to be separated.

[0044] After the above steps, we used an embedded control circuit board to control the balance wheel, measure the shape of the package, and track the position of the package, so that the package could be separated efficiently on the balance wheel and the separation quality could be guaranteed, achieving the expected results.

[0045] The technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made in accordance with the technical solutions of the present invention fall within the protection scope of the present invention.

Claims

1. An embedded high-speed balance wheel control method for controlling a balance wheel system, wherein the balance wheel system comprises, from front to back, a second belt conveyor, a first belt conveyor, and a balance wheel, the balance wheel consisting of multiple rows of rollers and a servo motor, and each row of rollers is controlled by a servo motor to control the oscillation direction; characterized in that: The embedded high-speed balance wheel control method includes the following steps: S1. A measuring light curtain for measuring the shape of a package and obtaining its position is installed between the rear end of belt conveyor 2 and the front end of belt conveyor 1. Through-beam photoelectric sensors for measuring the shape of a package and obtaining its position are installed on both sides of the rear end of belt conveyor 1. Belt conveyor 2, belt conveyor 1, swing wheel, through-beam photoelectric sensors and measuring light curtain are respectively connected to an embedded control circuit board and controlled by the embedded control circuit board. S2. After the balance wheel system is powered on, the embedded control circuit board performs a self-test to check for any abnormalities in the motor and photoelectric components, and locates the balance wheel zero position. The specific method for locating the balance wheel zero position is as follows: install a proximity switch on the far left or far right of the balance wheel, one for each row of rollers. When the balance wheel is first powered on, it slowly swings towards the proximity switch position. After all roller rows detect the proximity switch signal, rotate the roller rows in the opposite direction by θ degrees to complete the balance wheel zero position calibration. If the self-test is abnormal, an alarm will be triggered to prompt maintenance; if the self-test is normal, proceed to step S3. S3. The embedded control circuit board receives the left and right swing information of the package sent by the main controller. It measures the shape and position of the package by measuring the light curtain and through-beam photoelectric detection. Based on the horizontal and vertical velocity decomposition, it calculates the package's running trajectory: it sets that the distance between the end of the package and the entrance of the swing wheel is greater than a fixed value L0 when the package leaves the swing wheel, and calculates the horizontal running time tx and the vertical running time ty of the package; when ty≥tx, it directly controls the swing wheel to turn and complete the package separation; when ty≤tx, after the package enters the swing wheel, it runs along the running direction for a delay time t1=ty-tx, and then the swing wheel is turned to the package separation direction to ensure the minimum distance L0 when the package leaves the swing wheel; at the same time, it tracks the position of the head and tail of the package in real time. When the tail of the previous package just leaves a certain row of rollers, it immediately controls the servo motor of that row of rollers to switch to the separation direction required for the next package, realizing gapless high-speed sorting.

2. The embedded high-speed balance wheel control method according to claim 1, characterized in that, In step S3, the specific process of detecting the shape and position of the package by measuring the light curtain and through-beam photoelectric detection is as follows: Assume the speed of the belt conveyor is V. p After the package passes through the measuring light curtain, the total time t for the package to pass through the measuring light curtain is obtained. p Thus, the maximum length L of the package can be calculated. m =V p* t p The maximum number of light beams blocked by the measurement light curtain is counted to obtain the maximum width Wm of the package; the package is regarded as a standard rectangle, and the distances y1 and y2 from the two sides of the package to the two sides of the balance wheel are obtained to complete the package positioning.

3. The embedded high-speed balance wheel control method according to claim 1, characterized in that, In step S3, the servo motor adopts a three-segment acceleration / deceleration curve planning: Assuming the maximum rotational speed of the balance wheel is The maximum swing angle is θm, the motor acceleration is Acc, and the deceleration is Dec; calculate the angle of the acceleration phase. Deceleration angle ;when At that time, the oscillation process includes an acceleration phase, a constant speed phase, and a deceleration phase, and the total running time Tall = Ta + Tb + Tc; when At that time, there is no constant speed section; the swing is completed directly by accelerating or decelerating.

4. The embedded high-speed balance wheel control method according to claim 1, characterized in that: The main control chip of the embedded control circuit board is the STMicroelectronics STM32F407, a high-performance microcontroller based on the ARM7 architecture.

5. The embedded high-speed balance wheel control method according to claim 4, characterized in that: The embedded control circuit board communicates with the servo motor of the roller using PWM pulses, and changing the duty cycle of the PWM pulses changes the speed of the servo motor accordingly.

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