A precise powder throwing device based on hall principle

Abstract

The application discloses a precise powder feeding device based on a Hall principle, which comprises an upper computer communication unit, a main control processing unit, a Hall signal detection unit, a multi-channel motor driving unit, a powder feeding screw actuator and a power supply unit, wherein the main control processing unit adopts an STM32 single-chip microcomputer as a core controller and integrates a solidified half-circle metering closed-loop correction program, the Hall signal detection unit comprises a switching type Hall sensor and a rotating shaft magnetic steel, the Hall sensor outputs a pulse signal which is connected to an input capture channel of a main control timer, and a half-circle trigger signal of a motor rotating shaft is used as a minimum metering reference, and the upper computer communication unit integrates an isolation CAN communication circuit.The precise powder feeding device based on the Hall principle realizes zero-error correction of powder quantitative feeding, greatly improves metering resolution and is high in automation degree, and can be widely applied to powder metallurgy, chemical industry, building materials and food powder batching scenes.

Description

Technical Field

[0001] This invention relates to the field of automated powder quantitative feeding equipment, and in particular to a precision powder feeding device based on the Hall effect principle. Background Technology

[0002] In industrial powder batching production, screw-type powder feeders are commonly used to complete quantitative powder feeding. Existing powder feeding equipment mainly relies on a fixed motor speed and fixed running time to achieve quantitative feeding, or uses a full-cycle Hall pulse counting method to measure the screw rotation stroke. With the continuous development of technology, people's requirements for precise powder feeding devices are also getting higher and higher.

[0003] Existing powder feeding devices have certain drawbacks in use, such as poor metering accuracy: the smallest metering unit of traditional full-circle Hall counting is a complete circle, which cannot capture small strokes at the half-circle level, and there is a fixed metering error in a single feeding; the feeding method that relies on time control is affected by motor voltage fluctuations and load changes, and the actual output deviation from the set feeding amount can reach more than 5%, which cannot meet the requirements of high-precision batching process.

[0004] Weak anti-interference ability: Uneven density of powder materials, slight screw jamming, power grid voltage fluctuations, and motor start-up and shutdown impacts can all cause the actual rotation stroke of the motor to deviate from the theoretical value. The equipment has no real-time closed-loop correction mechanism, and the error continues to accumulate.

[0005] Insufficient reliability of hardware circuits: Traditional control boards lack strong and weak current isolation, and the large current of the motor drive interferes with the Hall sampling signal, resulting in frequent signal false triggering and counting jumps in dusty environments; the communication interface lacks isolation, and packet loss is easy to occur during communication between the host computer and field equipment.

[0006] Poor versatility: The single counting logic cannot adapt to powders of various particle sizes and flowability. It lacks multi-channel synchronous powder feeding and remote parameter sending functions. Multi-station production lines require multiple independent controllers, resulting in high costs.

[0007] Existing technologies lack an integrated precision powder feeding hardware and control scheme that can achieve high-precision sampling at the half-circle level, real-time closed-loop travel correction, and strong and weak current isolation and anti-interference. To address this, we propose a precision powder feeding device based on the Hall effect principle. Summary of the Invention

[0008] Technical problem solved: In view of the shortcomings of the existing technology, the present invention provides a precise powder dispensing device based on the Hall principle. Through half-circle Hall pulse fine counting closed-loop control and isolated hardware circuit design, it realizes zero-error quantitative powder dispensing and improves the stability and versatility of the equipment.

[0009] Technical Solution: To achieve the above objectives, the technical solution adopted by this invention is as follows: a precise powder feeding device based on the Hall effect principle, comprising a host computer communication unit, a main control processing unit, a Hall signal detection unit, a multi-channel motor drive unit, a powder feeding screw actuator, and a power supply unit. The main control processing unit uses an STM32 microcontroller as the core controller and integrates a fixed half-turn metering closed-loop calibration program. The Hall signal detection unit includes a switch-type Hall sensor and a rotating shaft magnet. The Hall sensor outputs a pulse signal that is connected to the main control timer input capture channel, using the half-turn trigger signal of the motor shaft as the minimum metering reference. The host computer communication unit integrates an isolated CAN communication circuit and an isolated RS485 communication circuit. The communication circuit receives the target feeding quantity parameter from the host computer. The main control processing unit uses a substitution calculation algorithm to convert the feeding quantity into the target total number of half-turns of the motor. The multi-channel motor drive unit includes multiple optocoupler isolated drive circuits, which output stepper motor drive signals to control the rotation of the powder feeding screw actuator. The main control processing unit compares the actual cumulative half-turns of the Hall effect sensor with the target half-turns in real time and dynamically fine-tunes the motor output to correct the rotation stroke. The power supply unit includes a 24V input step-down module and an isolated power chip, which outputs multiple isolated voltages of +12V, +5V0, and +3V3 to provide tiered power supply for the host computer communication unit, the main control processing unit, the Hall effect sensor detection unit, and the multi-channel motor drive unit.

[0010] As a preferred technical solution of this application, the main control processing unit is equipped with a minimum system circuit, including an 8MHz external crystal oscillator, a 32.768kHz low-speed crystal oscillator, a reset circuit, a BOOT start-up circuit, an LC filter power supply circuit, and equipped with 100nF, 2.2μF, and 15pF multi-level filter capacitors.

[0011] As a preferred technical solution of this application, the Hall signal detection unit is provided with multiple Hall acquisition channels. Each Hall sampling circuit is equipped with a 100R current-limiting resistor, a TVS electrostatic protection diode, and a 100nF filter capacitor. The signal is connected to the STM32 timer IO port after being isolated by a PC817 optocoupler.

[0012] As a preferred technical solution of this application, the CAN communication unit of the host computer adopts a CA-IS3050G isolated transceiver, the RS485 communication adopts a CA-IS3731HN isolated chip, and the communication bus end is configured with a 120Ω terminating matching resistor, a 39R current limiting resistor, and an SM712 surge protection device.

[0013] As a preferred technical solution of this application, the multi-channel motor drive unit includes a four-phase stepper motor isolation drive circuit. Each phase drive is composed of a strong and weak current isolation circuit consisting of an MMBT3904 / MMBT3906 transistor, an RC3P06 field-effect transistor, a B5819WS Schottky diode, and a PC817 optocoupler. The drive power supply is an isolated +24VM power supply.

[0014] As a preferred technical solution of this application, the power supply unit uses an LM5164DDAR step-down chip to convert 24V input to 12V, and is equipped with B1203S and B1205S isolated power supply modules to output 3.3V and 5V respectively. The power circuit is configured with 47μF and 220μF large-capacity energy storage capacitors and a 68uH power inductor.

[0015] As a preferred technical solution of this application, it also includes a relay output unit, in which two APAN3124 relays are driven by optocoupler isolation for external fans, alarm indicator lights and auxiliary actuators. The relay circuit is configured with a freewheeling diode and a 100nF filter capacitor.

[0016] As a preferred technical solution of this application, the closed-loop correction program logic of the main control processing unit is as follows: the host computer issues the feeding amount → calculates the target half-turn total number → the motor starts feeding powder → the Hall continuously collects half-turn pulses and accumulates the actual stroke → calculates the difference between the target and the actual value in real time → dynamically adjusts the motor PWM output speed. When the actual accumulated half-turn number is equal to the target value, the main control cuts off the motor drive and stops feeding powder.

[0017] Beneficial effects: Compared with the prior art, the present invention provides a precision powder feeding device based on the Hall principle, which has the following beneficial effects: The precision powder feeding device based on the Hall principle has significantly improved the metering accuracy: It abandons the whole circle counting and uses half circle as the smallest metering unit, which doubles the detection resolution, eliminates the inherent error of whole circle counting from the hardware source, and achieves zero feeding error with real-time closed-loop stroke correction.

[0018] Strong anti-interference capability under strong working conditions: The entire circuit is optically isolated for both strong and weak currents. Communication, Hall sampling, and motor drive are all equipped with isolation chips, filter capacitors, and TVS / Schottky protection. The isolated graded power supply eliminates power circuit interference and can adapt to industrial environments with dust, unstable voltage, and mechanical vibration.

[0019] Adaptive error compensation: During operation, the system captures stroke deviations caused by voltage fluctuations, powder blockage, and load changes in real time, and dynamically corrects the motor output speed and running time, preventing error accumulation.

[0020] Highly versatile and expandable: Supports CAN / RS485 dual-bus communication with host computer, multiple Hall effect sensors and multiple stepper motor drive channels, allowing a single controller to drive multiple workstations for synchronous powder feeding; supports address networking, adaptable to batch deployment in automated production lines.

[0021] High hardware integration: The integrated PCB circuit integrates the main control, power supply, communication, Hall effect sensor acquisition, motor drive, and relay output, eliminating the need for additional peripherals, simplifying assembly, and facilitating maintenance. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the MCU main control of a precision powder feeding device based on the Hall effect principle according to the present invention.

[0023] Figure 2 This is a schematic diagram of the main control chip in a precision powder feeding device based on the Hall effect principle according to the present invention.

[0024] Figure 3 This is a schematic diagram of isolated communication in a precision powder feeding device based on the Hall effect principle according to the present invention.

[0025] Figure 4 This is a schematic diagram of the multi-channel Hall signal acquisition and isolation in a precision powder feeding device based on the Hall principle according to the present invention.

[0026] Figure 5 This is a schematic diagram of the isolation and amplification of a single-channel Hall signal acquisition in a precision powder feeding device based on the Hall principle according to the present invention.

[0027] Figure 6 This is a schematic diagram of the isolated drive of a four-phase stepper motor in a precision powder feeding device based on the Hall effect principle according to the present invention.

[0028] Figure 7 This is a schematic diagram of the relay power drive in a precision powder feeding device based on the Hall effect principle according to the present invention.

[0029] Figure 8 This is a schematic diagram of the relay power output in a precision powder feeding device based on the Hall effect principle according to the present invention.

[0030] Figure 9 This is a schematic diagram of the peripheral devices, data acquisition, and address configuration in a precision powder dispensing device based on the Hall effect principle according to the present invention.

[0031] Figure 10 This is a schematic diagram of the power supply for the whole machine isolated in a precision powder feeding device based on the Hall effect principle according to the present invention. Detailed Implementation

[0032] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0033] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0034] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0035] like Figure 1-10As shown, a precision powder feeding device based on the Hall effect principle includes a host computer communication unit, a main control processing unit, a Hall signal detection unit, a multi-channel motor drive unit, a powder feeding screw actuator, and a power supply unit. The main control processing unit uses an STM32 microcontroller as the core controller and integrates a fixed half-turn metering closed-loop calibration program. The Hall signal detection unit includes a switch-type Hall sensor and a rotating shaft magnet. The Hall sensor outputs a pulse signal, which is connected to the main control timer input capture channel. The half-turn trigger signal of the motor shaft is used as the minimum metering reference. The host computer communication unit integrates an isolated CAN communication circuit and an isolated RS485 communication circuit for receiving data from the host computer. The target feeding quantity parameter issued by the machine is converted into the target total number of half-turns of the motor by the substitution algorithm in the main control processing unit. The multi-channel motor drive unit includes multiple optocoupler isolated drive circuits, which output stepper motor drive signals to control the rotation of the powder feeding screw actuator. The main control processing unit compares the actual cumulative number of half-turns of the Hall effect sensor with the target number of half-turns in real time, and dynamically fine-tunes the motor output to correct the rotation stroke. The power supply unit includes a 24V input step-down module and an isolated power chip, which outputs multiple isolated voltages of +12V, +5V0, and +3V3 to provide tiered power supply for the host computer communication unit, the main control processing unit, the Hall effect sensor signal detection unit, and the multi-channel motor drive unit.

[0036] The main control processing unit is equipped with a minimum system circuit, including an 8MHz external crystal oscillator, a 32.768kHz low-speed crystal oscillator, a reset circuit, a BOOT startup circuit, an LC filter power supply circuit, and is equipped with 100nF, 2.2μF, and 15pF multi-level filter capacitors.

[0037] The Hall signal detection unit is equipped with multiple Hall acquisition channels. Each Hall sampling circuit is equipped with a 100R current-limiting resistor, a TVS electrostatic protection diode, and a 100nF filter capacitor. The signal is connected to the STM32 timer IO port after being optocoupled by a PC817.

[0038] The host computer communication unit uses a CA-IS3050G isolated transceiver for CAN communication and a CA-IS3731HN isolated chip for RS485 communication. The communication bus is equipped with a 120Ω terminating resistor, a 39R current-limiting resistor, and an SM712 surge protection device.

[0039] The multi-channel motor drive unit includes a four-phase stepper motor isolated drive circuit. Each phase drive consists of a strong and weak current isolation circuit composed of MMBT3904 / MMBT3906 transistors, RC3P06 MOSFETs, B5819WS Schottky diodes, and PC817 optocouplers. The drive power supply is an isolated +24VM power supply.

[0040] The power supply unit uses an LM5164DDAR step-down chip to convert the 24V input to 12V, and is equipped with B1203S and B1205S isolated power supply modules to output 3.3V and 5V respectively. The power circuit is equipped with 47μF and 220μF large-capacity energy storage capacitors and a 68uH power inductor.

[0041] It also includes a relay output unit, with two APAN3124 relays driven by optocoupler isolation for connecting external fans, alarm indicator lights, and auxiliary actuators. The relay circuit is equipped with a freewheeling diode and a 100nF filter capacitor.

[0042] The closed-loop correction program logic of the main control processing unit is as follows: The host computer issues the feeding amount → the target half-turn total number is calculated → the motor starts feeding powder → the Hall effect continuously collects half-turn pulses and accumulates the actual stroke → the difference between the target and the actual value is calculated in real time → the motor PWM output speed is dynamically adjusted. When the actual accumulated half-turn number is equal to the target value, the main control cuts off the motor drive and stops feeding powder.

[0043] MCU main control module: The core is STM32F405RGT6, with an 8MHz high-speed crystal oscillator and an external 32.768kHz low-speed crystal oscillator on PC14 / PC15; PA / PB / PC / PD / PH pins are assigned multiple Hall counting channels (WM1_CNT~WM6_CNT, LLJ_HALL), four-phase stepper motor drive (STEPM_A / B / C / D), CAN / RS485 communication transceiver pins, and relay control output; equipped with NRST reset and BOOT start circuits, +3V3 power input with L2 / L3 10uH inductors + multi-stage 100nF capacitors for LC filtering, and independent filtering of analog power supply VDDA to reduce sampling noise.

[0044] Isolated Communication Module: Dual communication bus compatible design. The CAN bus uses a CA-IS3050G isolation chip, with 39R current-limiting resistors and 120R terminating resistors connected in parallel at both ends of CANH / CANL. The GND5 isolation ground is separated from the main control digital ground GND3. The RS485 uses a CA-IS3731HN isolated transceiver, configured with an RS485_DIR direction control pin. The bus port uses an SM712 bidirectional TVS to suppress surges and prevent electrostatic discharge damage to the chip in the industrial bus.

[0045] Hall effect signal acquisition module: The hardware circuits of the multiple Hall effect acquisition channels are completely identical. The Hall sensor output signal is connected via the XH-5AW terminal, with a series 100R current-limiting resistor R79 / R32, etc., and a parallel 100nF filter capacitor to suppress high-frequency glitches. Electrical isolation between the 24VM power side and the 3V3 main control side is achieved via a PC817 optocoupler. The signal at the rear end of the optocoupler is connected to the STM32 timer input capture channel, and the program is configured to capture the half-turn level toggle signal via dual-edge interrupt. Each circuit is equipped with an SMF6.5CA electrostatic protection diode to prevent electrostatic damage to the IO port in dusty and vibrating environments. Every half-turn of the shaft, the magnet passes the Hall sensor once, generating one pulse for the level toggle, and the main control counts one half-turn of travel.

[0046] Stepper motor drive module: Four-phase stepper motors STEPM_A~STEPM_D are independently isolated drives, with each phase having the same drive circuit structure. The main control 3V3 control signal is isolated by a PC817 optocoupler and then drives an MMBT3904NPN transistor. The transistor controls the RC3P06N channel MOSFET to turn on / off, and the MOSFET outputs 24VM power to drive the stepper motor windings. A B5819WS Schottky diode is connected in parallel across the windings to absorb the reverse electromotive force and prevent high voltage from damaging the power devices. The circuit is equipped with a 27K pull-up resistor and a 100R current-limiting resistor to stabilize the drive level.

[0047] Relay auxiliary output module: Two APAN3124 electromagnetic relays, corresponding to RLY1 and RLY2 respectively, are used for external cooling fans and audible and visual alarm devices. The main control IO output drives MMBT3904 switching transistors via PC817 optocoupler isolation, and the transistors control the power supply to the relay coils; a B5819WS freewheeling diode is connected in parallel with the coils to eliminate reverse voltage when power is off; a 0R resistor pad is reserved for fan interlock function, which can be soldered as needed to achieve fan linkage.

[0048] ADC Acquisition and Configuration Module: The voltage acquisition circuit consists of a dual-channel LM358DR operational amplifier. A 300mΩ sampling resistor acquires the bus voltage, which is then amplified by the operational amplifier and sent to the main control ADC_VOL pin. The program reads the supply voltage in real time for voltage fluctuation compensation calculation. Two-position DIP switches, ADDR_0 and ADDR_1, are connected to the main control I / O, allowing for device address differentiation when multiple devices are networked on a bus. R12 and R13 current limit drives LED1 and LED2 power / operation status indicators for easy on-site troubleshooting.

[0049] Isolated Power Supply Module: The entire power supply features a hierarchical isolation design. An external DC24V input is converted to a stable +12V via an LM5164DDAR synchronous step-down chip. A 68uH power inductor and 2.2uF / 100nF matching capacitors form a BUCK step-down circuit. The +12V output is connected to two isolated power supplies: B1203S (3.3V / 0.3A output, powering the main control, Hall effect, and signal circuits) and B1205S (5V / 0.4A output, powering the communication chip and optocoupler). A 24VM high-power power supply directly supplies the motor and relay loads. The power circuit is equipped with 47uF and 220uF large-capacity energy storage capacitors to suppress motor start-stop current surges. All power grounds (GNDM), signal grounds (GND3), and communication isolation grounds (GND5) are routed in separate zones, with single-point common grounds to reduce interference.

[0050] Complete working process of the whole machine Standby monitoring phase: The main control unit completes hardware self-test upon power-up, initializes timer input capture, CAN / 485 communication, and motor drive PWM peripherals; it listens in real time for feeding quantitative commands issued by the host computer through the communication interface and reads the target feeding weight parameters.

[0051] Parameter conversion stage: The main control unit has a built-in screw feeding calibration algorithm. Based on the screw lead, powder bulk density, and discharge volume per half revolution of the motor, the feeding weight is converted into the target total count threshold for half revolution of the motor and stored in memory as a closed-loop calibration benchmark.

[0052] Powder feeding stage: The main control outputs a PWM drive signal to the stepper motor isolation drive circuit, and the stepper motor drives the powder feeding screw to rotate at a constant speed. The powder inside the screw is conveyed along the spiral groove to complete the feeding.

[0053] Hall effect real-time sampling and correction stage: The motor shaft rotates synchronously, and the permanent magnet fixed on the shaft passes the Hall sensor every half revolution. The Hall output level flips pulse, which is sent to the main control timer capture channel after being isolated and filtered by an optocoupler. Every time the main control captures a pulse, the actual half revolution count is incremented by 1. The current actual cumulative value is compared with the target threshold in real time to calculate the travel difference.

[0054] If the actual motor speed slows down due to voltage drop, powder agglomeration and jamming, or increased load, and the cumulative Hall pulse amount is less than the theoretical value within the same time period, the main controller will automatically increase the PWM duty cycle to increase the motor speed. If the load decreases or the speed is too fast, the PWM output will be reduced to dynamically compensate for the stroke error.

[0055] Feeding Stop Phase: When the Hall effect sensor accumulates the actual number of half-turns, which equals the pre-calculated target total number of half-turns, the main controller immediately cuts off the stepper motor drive output, the screw stops rotating, and the precise quantitative powder feeding is completed; at the same time, the feeding completion signal and the actual half-turn count data are fed back to the host computer, so that the host computer can record the production data.

[0056] Abnormal protection phase: The ADC collects the bus voltage in real time. When the voltage is lower than the threshold, the motor speed is reduced to prevent step loss. If there is no pulse signal from the Hall sensor for a long time, the screw is determined to be stalled. The main controller cuts off the drive and triggers the relay alarm output to prompt the on-site operator to clean the powder blockage.

[0057] Complete isolation between strong and weak currents: The 24V power circuit of the motor, the relay circuit and the 3.3V main control signal circuit are all isolated by PC817 optocouplers, and the communication bus uses a dedicated isolated transceiver chip to block the conduction of electromagnetic interference in the power circuit.

[0058] Multi-level filtering protection: All signal ports are equipped with 100R current-limiting resistors + 100nF filter capacitors, and large-capacity electrolytic capacitors are connected in parallel at the power input. The analog power supply adds an LC filter circuit to suppress power supply noise. TVS and Schottky diodes are added to the bus and IO ports to achieve electrostatic discharge and surge protection.

[0059] Partitioned ground plane design: The PCB is divided into digital signal ground GND3, power load ground GNDM, and communication isolation ground GND5, with only a single-point ferrite bead connection to avoid ground loop interference with Hall pulse sampling signals and prevent count jumps and false triggers.

[0060] Working Principle: The core of this invention is the Hall half-turn pulse closed-loop correction control principle. The entire system forms a complete closed-loop control link: "upper computer parameter sending → feeding amount - half-turn conversion → motor-driven powder feeding → Hall half-turn high-precision pulse acquisition → real-time stroke difference comparison → motor-driven dynamic correction". Innovative metrological benchmark: Abandoning the traditional full-revolution counting, the Hall trigger signal of half-revolution of the rotating shaft is used as the smallest metrological unit, doubling the metrological resolution and eliminating the inherent metrological error of ±1 revolution caused by full-revolution counting; Real-time closed-loop feedback: Hall sensors continuously collect the physical rotation position of the shaft and provide real-time feedback on the actual rotation stroke. The main controller continuously compares the target stroke with the actual stroke. Dynamic error compensation: In response to interference factors such as voltage fluctuations, uneven powder density, slight mechanical jamming, and changes in motor load in industrial settings, it relies on Hall sampling to capture minute travel deviations, and finely adjusts the motor drive output parameters in real time to correct the rotational travel, ensuring that the final actual output is completely consistent with the set feed amount, thus achieving zero feed error. Hardware isolation guarantee: The full-channel isolation circuit ensures that Hall pulse sampling is not affected by the high current of the motor, ensuring accurate pulse counting without loss, and providing a reliable hardware signal foundation for closed-loop calibration.

[0061] This invention discloses a precision powder feeding device based on the Hall effect principle, belonging to the field of automated powder feeding control technology. This device relies on Hall effect sensing technology combined with a microcontroller-based precise counting program to complete powder feeding calibration with half a revolution as the smallest unit. It can automatically calculate the number of motor revolutions based on the feeding instructions issued by the host computer, achieving high-precision, zero-error quantitative feeding of powder materials. This completely solves the feeding deviation problems caused by unstable speed, voltage fluctuations, and mechanical wear in traditional powder feeding equipment.

[0062] I. Overall Composition of the Device This device mainly consists of a host computer communication unit, a main control processing unit, a Hall signal detection unit, a motor drive unit, a powder feeding actuator, and an embedded control program, forming a complete closed-loop precision powder feeding system. The device uses a Hall sensor as the core for position feedback and half-turn metering logic as the minimum feeding accuracy benchmark. By acquiring the motor shaft rotation position signal in real time, it achieves precise closed-loop correction of the powder feeding cycle count.

[0063] II. Core Working Principle In standby mode, the main control unit monitors the feeding command signals sent by the host computer in real time. When the host computer sends a working command specifying the feeding amount, the main control chip receives the command data and accurately converts the feeding amount parameters from the host computer into the target number of motor rotations using an internally fixed algorithm, thus determining the standard number of rotation steps and the half-rotation metering threshold required for this powder feeding.

[0064] After the device starts feeding powder, the main control unit outputs a drive signal to control the motor to run, which in turn drives the powder feeding screw actuator to rotate synchronously, thus conveying and feeding powder materials. At the same time, Hall sensors installed at the corresponding positions on the motor shaft or the powder feeding shaft sense the trigger signal of the magnet on the shaft in real time, converting the physical position of the mechanical rotation into a high-frequency pulse electrical signal, which is continuously fed back to the main control unit.

[0065] This invention's control program employs precise measurement logic with half a revolution as the smallest calculation unit, differing from the traditional full-revolution counting mode: each time the main control unit detects a Hall half-revolution trigger signal, it completes a precise measurement record, performing real-time accumulation, comparison, and correction of the motor's actual rotation stroke. The program continuously compares the "target set number of revolutions" with the "actual Hall sampled cumulative number of revolutions" in real time, dynamically monitoring rotational errors.

[0066] During the powder feeding process, if interference factors such as voltage fluctuations, changes in motor load, uneven powder density, or slight mechanical jamming cause deviations in motor speed or stroke, the Hall effect feedback of half-turn count data can capture minute stroke errors in real time. The main control unit dynamically corrects the motor drive output based on the real-time feedback data, corrects the rotation stroke, and ensures that the actual number of rotations strictly matches the target number of rotations calculated by the host computer, ultimately achieving a high-precision control effect with zero feeding error.

[0067] III. Detailed Work Logic of Each Unit 1. Host computer communication and parameter parsing unit The host computer issues quantitative feeding data instructions based on production needs. The main control board receives the data through the communication interface and completes the accurate conversion between the feeding amount and the number of motor rotations through the internal algorithm, generating the target half-rotation metering total for this feeding, providing benchmark parameters for accurate feeding.

[0068] 2. Hall signal detection unit Utilizing the Hall effect electromagnetic induction principle, as the shaft rotates with the motor, the magnet periodically passes through the Hall sensor, which outputs a corresponding pulse signal. This device abandons the traditional full-revolution counting method, using half a revolution as the smallest measurement unit. It can capture minute rotational strokes at the half-revolution level, significantly improving measurement resolution and eliminating the inherent accuracy error caused by traditional full-revolution counting at the hardware level.

[0069] 3. Closed-loop control logic of the main control program The main control program acquires Hall effect half-turn pulse signals in real time, continuously accumulates the actual number of rotations, and compares the difference with the preset target number of rotations in real time. It dynamically monitors the powder feeding stroke throughout the entire process. Once a deviation between the actual stroke and the target stroke is detected, it immediately fine-tunes the motor drive output parameters to correct the rotation speed and stroke, ensuring that the actual rotation amount of each powder feeding perfectly matches the set value, achieving a control effect with zero error.

[0070] 4. Motor drive and powder feeding execution unit The drive circuit receives a level drive signal, which drives the powder feeding motor to operate stably and causes the powder feeding mechanism to feed powder evenly. Under the closed-loop correction of the main control, the motor's running stroke is controlled throughout and is not affected by external operating conditions, ensuring accurate, uniform, and stable powder feeding.

[0071] IV. Overall Work Loop and Beneficial Effects This invention employs a complete closed-loop control logic: "parameter distribution from host computer → rotation conversion → motor-driven powder feeding → high-precision Hall effect half-rotation sampling → real-time error comparison → stroke correction." Leveraging the high-resolution detection capability of Hall effect sensors and a refined half-rotation counting program, it completely solves the defects of traditional powder feeding equipment, such as low accuracy, susceptibility to operating conditions, and fixed feeding errors. This device can achieve zero-error precise output for quantitative powder feeding, boasting high metering accuracy, strong operational stability, adaptability to various complex powder feeding conditions, a high degree of automation, and extremely strong practicality and versatility.

[0072] It should be noted that, in this document, relational terms such as first and second (number one, number two), etc., are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0073] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A precision powder throwing device based on the Hall principle, comprising a host computer communication unit, a main control processing unit, a Hall signal detection unit, a multi-channel motor drive unit, a powder throwing screw rod actuator, and a power supply unit, characterized in that: The main control processing unit uses an STM32 microcontroller as the core controller and integrates a fixed half-turn metering closed-loop calibration program. The Hall signal detection unit includes a switch-type Hall sensor and a rotating shaft magnet. The Hall sensor outputs a pulse signal that is connected to the main control timer input capture channel, using the motor shaft half-turn trigger signal as the minimum metering reference. The host computer communication unit integrates isolated CAN communication circuits and isolated RS485 communication circuits to receive the target feeding quantity parameters sent by the host computer. The main control processing unit uses a substitution calculation algorithm to convert the feeding quantity into electrical... The multi-channel motor drive unit includes multiple optocoupler-isolated drive circuits, which output stepper motor drive signals to control the rotation of the powder feeding screw actuator. The main control processing unit compares the actual cumulative half-turn count with the target half-turn count in real time and dynamically fine-tunes the motor output to correct the rotation stroke. The power supply unit includes a 24V input step-down module and an isolated power chip, which outputs +12V, +5V0, and +3V3 multi-channel isolated voltages to provide tiered power supply for the host computer communication unit, the main control processing unit, the Hall signal detection unit, and the multi-channel motor drive unit.

2. The precision powder dispensing device based on the Hall principle according to claim 1, characterized in that: The main control processing unit is equipped with a minimum system circuit, including an 8MHz external crystal oscillator, a 32.768kHz low-speed crystal oscillator, a reset circuit, a BOOT startup circuit, an LC filter power supply circuit, and is equipped with 100nF, 2.2μF, and 15pF multi-level filter capacitors.

3. The precision powder dispensing device based on the Hall principle according to claim 1, characterized in that: The Hall signal detection unit is equipped with multiple Hall acquisition channels. Each Hall sampling circuit is configured with a 100R current-limiting resistor, a TVS electrostatic protection diode, and a 100nF filter capacitor. The signal is connected to the STM32 timer IO port after being isolated by a PC817 optocoupler.

4. The precision powder dispensing device based on the Hall principle according to claim 1, characterized in that: The host computer communication unit uses a CA-IS3050G isolated transceiver for CAN communication and a CA-IS3731HN isolated chip for RS485 communication. The communication bus is equipped with a 120Ω terminating resistor, a 39R current-limiting resistor, and an SM712 surge protection device.

5. The precision powder dispensing device based on the Hall principle according to claim 1, characterized in that: The multi-channel motor drive unit includes a four-phase stepper motor isolated drive circuit. Each phase drive consists of a strong and weak current isolation circuit composed of MMBT3904 / MMBT3906 transistors, RC3P06 MOSFETs, B5819WS Schottky diodes, and PC817 optocouplers. The drive power supply is an isolated +24VM power supply.

6. The precision powder dispensing device based on the Hall principle according to claim 1, characterized in that: The power supply unit uses an LM5164DDAR step-down chip to convert 24V input to 12V, and is equipped with B1203S and B1205S isolated power modules to output 3.3V and 5V respectively. The power circuit is configured with 47μF and 220μF large-capacity energy storage capacitors and a 68uH power inductor.

7. The precise powder dispensing device based on the Hall effect principle according to claim 1, characterized in that: It also includes a relay output unit, with two APAN3124 relays driven by optocoupler isolation for connecting external fans, alarm indicator lights, and auxiliary actuators. The relay circuit is equipped with a freewheeling diode and a 100nF filter capacitor.

8. The precise powder dispensing device based on the Hall effect principle according to claim 1, characterized in that: The closed-loop correction program logic of the main control processing unit is as follows: the host computer issues the feeding amount → calculates the target half-turn total number → the motor starts feeding powder → the Hall effect continuously collects half-turn pulses and accumulates the actual stroke → calculates the difference between the target and the actual value in real time → dynamically adjusts the motor PWM output speed. When the actual accumulated half-turn number is equal to the target value, the main control cuts off the motor drive and stops feeding powder.

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