Electric drive control system for corn precision high-speed seed metering

Abstract

The invention discloses a single driver control system of an air suction disc type corn precision seeder suitable for high-speed operation, which is characterized by comprising a main controller, an upper computer, a single controller, a Hall sensor, an orthogonal encoder, a direct current brush motor, a motor driver, a reduction gearbox and a seed guide pipe, when the seed-metering device works, the upper computer sends a target rotating speed and a seeding density parameter, counts and calculates the working speed through the Hall sensor, feeds back the rotating speed of the motor through the encoder, and dynamically adjusts and corrects the parameter through the logic self-adaptive PID, so that the rotating speed of the seed-metering device is matched with the working speed, and the precise synchronization of the seed-metering rotating speed and the working speed is realized.

Description

Technical Field

[0001] The invention belongs to the field of intelligent seeding technology, and particularly relates to a single driver and control system of an air suction disc type corn precision seeding machine suitable for high-speed operation. Background Art

[0002] Traditional seeding control methods usually rely on manual or old-fashioned mechanical seeding. Due to the lag in speed tracking and insufficient seeding accuracy of the current seeding drive system and control system under high-speed conditions, uneven and inaccurate conditions may occur during the seeding process, requiring manual intervention to process the seed position. In response to the above problems, there is already a traditional PID control seeding system, but the drive system and PID algorithm control are still not coordinated. Therefore, how to make the control system more efficient and accurate to achieve efficient seeding is a technical problem that needs to be solved urgently by technicians in this field. Summary of the invention

[0003] The purpose of the present invention is to provide an air-suction disc type high-speed corn precision seeding electric drive control system, which can achieve precise synchronization between the seeding device rotation speed and the seeder operating speed by optimizing the motor drive circuit design and the adaptive control algorithm, thereby improving the uniformity and reliability of high-speed seeding.

[0004] The technical solution of the present invention is as follows: An electric drive control system based on air-suction disc high-speed corn precision seeding, the control system at least comprises a main controller, a host computer, a single controller, a Hall sensor, an orthogonal encoder, a DC brushed motor, a motor driver, a reduction box and a seed guide tube; the main controller is connected to the host computer via a CAN bus communication, the single controller integrates an STM32F103C8T6 single-chip microcomputer, and is respectively connected to the Hall sensor, the orthogonal encoder, the motor driver and a current and voltage detection circuit; the Hall sensor is installed on the planter walking wheel shaft for real-time acquisition of the operating speed; the orthogonal encoder is installed on the motor output shaft to feed back the actual motor speed to the main controller.

[0005] Wherein, the DC brushed motor is mechanically connected to the air suction disc seed meter through a reduction box, and the seed guide tube is fixed below the seed meter outlet; The motor driver comprises a MOSFET current amplifier circuit, a TC4422 driver chip, a Schottky diode clamp circuit and a relay switch control circuit; wherein the MOSFET current amplifier circuit is used to amplify the drive signal to provide a bidirectional current for the motor, the circuit is connected to the TC4422 driver chip, the TC4422 driver chip is connected to the PWM output end of the main controller, and is used to improve the MOSFET gate drive capability, the Schottky diode (D4) clamp circuit in the amplifier circuit is connected in parallel with both ends of the motor to suppress the impact of the reverse electromotive force on the circuit, and the relay (RELAY1) switch control circuit is connected to the IO port of the main controller to realize the start and stop and emergency braking of the motor.

[0006] In particular, the DC brush motor uses a JGB37-520 high-speed, low-torque motor to adapt to the high-speed rotation requirements of the air suction disc seed metering device; the motor driver input voltage is 24V and the maximum output current is 10A.

[0007] In particular, the logic adaptive PID control algorithm is embedded in the main controller, and dynamically adjusts the proportional, integral and differential coefficients according to the speed deviation and deviation change rate between the Hall sensor and the encoder to achieve closed-loop speed tracking.

[0008] Compared with the prior art, the beneficial effects of the present invention are: the use of MOSFET full-bridge drive circuit and TC4422 chip to ensure the stable operation of the motor under high-frequency PWM modulation to meet the instantaneous torque requirements of high-speed seeding; based on the gain-adjustable logic adaptive PID algorithm, the control parameters are corrected in real time to overcome the adjustment lag problem of traditional PID under nonlinear conditions; Schottky diode clamping and relay redundant protection design can effectively suppress voltage surges during the start and stop of the motor and extend the system life; the main controller and the single-cell controller work together through the CAN bus to support multi-cell expansion, which is suitable for large-scale seeding machine group control scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 : Flow chart of the control system of the present invention;

[0010] Figure 2 : Schematic diagram of the motor drive circuit of the present invention; DETAILED DESCRIPTION

[0011] The technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0012] like Figure 1As shown in the flow chart, the purpose of the present invention is achieved through the following scheme: the designed logic adaptive PID controlled air suction type corn precision seeding electric drive system should be based on the air suction disc seeding device, at least including integrated DC brush motor drive, logic adaptive PID speed regulation algorithm and multi-module collaborative control to achieve high-speed precision seeding. The main control module is connected to the single-unit controller and the drive module through the TC4422 driver chip input pin, wherein the relay control interface is input to the optocoupler isolation chip TLP-4; the main control module is connected to the sensor and feedback module; the single-unit controller drive module is connected to the seeding actuator through the IRF3205 MOSFET full-bridge output terminal; the main control module is connected to the host computer. Among them, the main control module includes a main controller single-chip microcomputer and an information data transmission module; the mobile terminal is connected to the Android mobile terminal via wireless Bluetooth.

[0013] The seeding execution mechanism comprises an air disc seeding device and a seed guiding pipe; the seed guiding pipe is connected with the disc seeding device.

[0014] In this example, the main control microcontroller adopts the STM32F103C8T6 microcontroller (LQFP48 package), which has a built-in 72MHz Cortex-M3 core and integrates a 12-bit ADC, 4-channel UART and 8-channel PWM output.

[0015] The single-body controller and drive module includes a motor driver circuit, a protection circuit and a connection interface. The motor driver circuit is driven by a MOSFET full-bridge. Four IRF3205 MOSFETs (D5-D8) form an H-bridge. The protection circuit is connected in parallel to both ends of the motor through the SS34 (D4) of the Schottky diode. The relay controller is controlled by the PC13 pin.

[0016] The sensor and feedback module includes a Hall sensor and an orthogonal encoder; the Hall sensor is installed on the wheel axle of the seed drill, and the signal is input to the single-chip microcomputer PA0 (EXTI0 interrupt pin); the orthogonal encoder is installed on the motor output shaft, and the AB ends are respectively connected to the single-chip microcomputer PA6 and PA7.

[0017] like Figure 1 As shown, the logic adaptive PID control algorithm design package block control process and algorithm implementation; wherein the control process first performs logic adaptive processing on the input variables, and sets the target speed (set by the host computer) ( ) and actual speed (Encoder feedback) The difference is set as the speed deviation , the differential of the speed deviation is recorded as the deviation change rate ; Secondly, it is processed according to the logic adaptive control strategy; the center of gravity method is used to solve the logic and PID parameter update, and finally the PWM signal is output to TC4422 through (PA8) for calculation; the algorithm implementation includes timer interrupt and encoder orthogonal decoding mode; the timer interrupt is used to perform PID calculation and PWM update, and the encoder orthogonal encoding mode is used to read the speed value in real time.

[0018] In the example, the mobile terminal is an Android mobile terminal, such as a mobile phone, a tablet, etc.

[0019] In this example, Figure 2 As shown, the initialization phase is first carried out. The host computer sends the target speed (such as 600rpm) and sowing density parameters through the CAN bus; the single-chip computer initializes the PWM, encoder, and ADC peripherals, and loads the logic adaptive PID initial parameters. Then it enters the operation phase, the Hall sensor pulse is counted through the EXTI0 interrupt, the operating speed (unit km / h) is calculated, and then the motor speed is fed back through the encoder. The logic adaptive PID dynamically adjusts the PWM duty cycle to match the seed metering speed with the operating speed. When the seed guide tube photoelectric sensor detects that there are no seeds passing through for three consecutive times, it will trigger an alarm and stop the motor. In addition, long pressing the emergency stop button of the mobile interrupt can disconnect the relay RELAY1, the motor is powered off, and the CAN bus sends a fault code to the host computer to record the abnormal state.

[0020] Preferably, the motor driver uses IRF3205 (55V / 110A) type MOSFET, and the interface is D5-D8 gate connected to TC4422.

[0021] Preferably, the encoder uses an E6B2-CWZ6Z (1000PPR) quadrature encoder with two interfaces: A phase PA6 and B phase PA7.

[0022] Preferably, the power management uses a LM7805 (5V / 1A) voltage regulator chip with input and output interfaces IN-24V, OUT-5V.

[0023] Preferably, the communication module adopts HC-05 (Class 2) Bluetooth module with interfaces TX-PA9 and RX-PA10.

[0024] The present invention discloses an electric drive control system based on air suction high-speed corn precision seeding, which is used to solve the technical problems of rotation speed tracking lag and insufficient sowing uniformity of traditional seeding devices under high-speed operation. The electric drive control system at least includes: a main controller, a host computer, a single controller, a Hall sensor, an orthogonal encoder, a DC brush motor, a motor driver and a seed guide tube; the main controller is connected to the host computer through a CAN bus, and the single controller integrates an STM32F103C8T6 single-chip microcomputer, which is respectively connected to the Hall sensor, the orthogonal encoder and the motor driver; the DC brush motor is mechanically connected to the air suction disc seeding device through a reduction box, and the seed guide tube is fixed below the seeding device outlet; the motor driver is composed of a MOSFET full-bridge circuit, a TC4422 driver chip, a Schottky diode clamping circuit and a relay switch control circuit, and the motor speed is adjusted by a PWM signal; the main controller uses a gain-adjusted logic adaptive PID algorithm to dynamically correct the control parameters based on the operating speed collected by the Hall sensor and the motor speed fed back by the encoder, so as to achieve precise synchronization of the seeding speed and the operating speed. The present invention significantly improves the seeding accuracy and system reliability under high-speed conditions by cooperating with modular circuit design and adaptive control algorithm.

[0025] The above is a preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes (such as replacing MOSFET models, optimizing logic rule bases, etc.) according to the technical solution and its concept of the present invention within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention.

Claims

1. An electric drive control system for high-speed precision seeding of corn, characterized in that: The control system comprises at least a main controller (1), a host computer (2), a single controller (3), a Hall sensor (4), an orthogonal encoder (5), a DC brush motor (6), a motor driver (7), a reduction box (8), a seed guide tube (9), and an air suction disc seed metering device (10); the main controller (1) is connected to the host computer (2) via a CAN bus communication, the single controller (3) integrates an STM32F103C8T6 single chip microcomputer, and the pin IO interface of the single chip microcomputer is respectively connected to the Hall sensor (4), the orthogonal encoder (5), the motor driver (7) and the current and voltage detection circuit; the Hall sensor (4) is installed on the walking wheel shaft of the seeding machine; the orthogonal encoder (5) is installed on the motor output shaft. The DC brush motor (6) is mechanically connected to the air suction disc seed metering device (10) via a reduction box (8), and the seed guide tube (9) is fixed below the outlet of the seed metering device (10).

2. An electric drive control system for high-speed precision seeding of corn according to claim 1, wherein the motor driver (7) comprises a MOSFET current amplifier circuit (11), a TC4422 driver chip (12), a Schottky diode (13) clamping circuit and a relay (14) switch control circuit; wherein the MOSFET current amplifier circuit (11) is used to amplify the drive signal to provide a bidirectional current for the motor, the circuit is connected to the TC4422 driver chip (12), the TC4422 driver chip (12) is connected to the PWM output end of the main controller (1) to improve the MOSFET gate drive capability, the Schottky diode (13) clamping circuit in the amplifier circuit is connected in parallel with both ends of the motor to suppress the impact of the reverse electromotive force on the circuit, and the relay (14) switch control circuit is connected to the IO port of the main controller (1) to realize the start and stop and emergency braking of the motor.

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