Integrated magnetic field constant control device and method

Abstract

The invention relates to the technical field of magnetic field constant control, and discloses an integrated magnetic field constant control device and method, and the device comprises a coil excitation device which is used for generating an adjustable magnetic field; the three-dimensional magnetic field distribution monitoring device is used for collecting magnetic field distribution data in real time; the magnetic field constant control device is used for dynamically adjusting the output of the coil excitation device based on the magnetic field distribution data; the magnetic field constant control device is integrated through the coil excitation device, the three-dimensional magnetic field distribution monitoring device and the magnetic field constant control device to form a closed-loop control framework. According to the integrated magnetic field constant control device and method, all-directional real-time monitoring and efficient regulation and control of the magnetic field are achieved, the precision, efficiency and stability of precision polishing are remarkably improved, and the strict requirements of the modern high-end manufacturing industry for ultra-precision part machining are met.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic field constant control, and particularly to an integrated magnetic field constant control device and method. Background Art

[0002] In today's precision manufacturing field, magnetic field constant control technology is a key link in achieving high-precision machining, and is widely used in many industries such as precision grinding of optical lenses, microelectronic chip manufacturing, and high-end precision machining. Taking the manufacturing of optical lenses as an example, according to data from market research institutions, the production of billions of optical lenses globally each year relies on the assistance of magnetic field constant control technology, which has a decisive impact on key quality indicators such as the final surface shape accuracy and surface roughness of the lenses.

[0003] Currently, there are already various magnetic field constant control devices on the market. However, upon in-depth exploration of their structures and principles, it is not difficult to find that there are many aspects that urgently need improvement. Looking at the excitation device, traditional designs mostly adopt a general-purpose architecture. For example, common coil excitation devices mostly use ordinary copper wire wound, with a wire diameter generally around 0.8 mm, arranged in a simple circular spiral array, and the number of turns is roughly around 150. Such a conventional structure is unable to cope when faced with new high-performance composite magnetorheological polishing fluids. The new polishing fluid, in order to meet strict polishing requirements, through innovative formula optimization, enables the particle size of magnetorheological particles to be accurately controlled within 20 - 30 nm. Its anti-settling performance is excellent, and the settling rate is reduced by nearly 50% compared to traditional polishing fluids. The agglomeration phenomenon is also effectively suppressed, and the agglomeration index is maintained at around 0.2. In contrast, the magnetic field intensity generated by the general excitation device fluctuates greatly. During the working process, the difference between the peak and valley values of the magnetic field intensity can reach about 20%. It is difficult to stably drive the magnetorheological particles in the new polishing fluid, resulting in a decline in the polishing efficiency by about 35% compared to the adapted state, and the average surface roughness of the processed lenses increases by about 2 nm.

[0004] In terms of magnetic field monitoring, most existing devices rely on basic monitoring means. For example, many magnetic control devices on the market use Gauss meters, whose measurement principle is based on classical electromagnetic induction theory, and can only perform single-point measurement of the magnetic field intensity in a single direction. Taking a certain best-selling traditional magnetic control device as an example, the measurement range of the Gauss meter it is equipped with only covers a spherical area with a radius of about 3 mm centered on the measurement probe. For the entire working area of the magnetorheological polishing machine, the coverage of the monitored data obtained is less than 25%. This means that in actual operation, it is difficult for operators to grasp the true distribution state of the magnetic field in real time and comprehensively, and more than 75% of the magnetic field abnormal areas may be ignored. The resulting magnetic field fluctuations will cause the surface shape accuracy deviation of local areas of the lens during polishing to reach ±0.4 μm, seriously damaging the product quality.

[0005] Focusing on the magnetic field regulation link, most of the existing magnetic control devices lack intelligent and precise regulation capabilities. Many devices adopt a relatively simple proportional regulation mode and do not have an advanced algorithm system built-in. For example, in some traditional products, when the detected magnetic field strength deviates from the preset value by 8%, the current is adjusted manually or through a simple automatic program, and each adjustment takes about 12 seconds, and the current adjustment accuracy can only be controlled within ±4%. When processing workpieces with complex shapes, such as precision mechanical parts with complex curved surfaces, due to the inability to perform rapid and precise point-to-surface combined magnetic field regulation on different regions, the polishing thickness deviation of the key parts of the parts can reach 0.04 mm, far from meeting the strict requirements of modern manufacturing for high-precision and high-reliability processing. In summary, the existing magnetic field constant control devices expose many performance evaluations when facing the growing demand for precision manufacturing and urgently need innovative solutions. Summary of the Invention

[0006] Aiming at the deficiencies of the existing technology, the present invention proposes an integrated magnetic field constant control device and method to solve the above technical problems.

[0007] In the first aspect, an integrated magnetic field constant control device is provided, including:

[0008] A coil excitation device for generating a controllable magnetic field;

[0009] A three-dimensional magnetic field distribution monitoring device for real-time collecting magnetic field distribution data;

[0010] A magnetic field constant control device for dynamically adjusting the output of the coil excitation device based on the magnetic field distribution data;

[0011] The magnetic field constant control device forms a closed-loop control architecture through the integration of the coil excitation device, the three-dimensional magnetic field distribution monitoring device, and the magnetic field constant control device.

[0012] Further, the coil winding of the coil excitation device is made of rare earth alloy material.

[0013] Further, the three-dimensional magnetic field distribution monitoring device includes a plurality of three-dimensional magnetic field sensors, and the three-dimensional magnetic field sensors are arranged at the spatial nodes of the magnetic field.

[0014] Further, the three-dimensional magnetic field sensors are respectively connected with a signal conditioning module and a data acquisition module.

[0015] Further, the three-dimensional magnetic field sensors are a sensor array based on the Hall effect, and the output signals of the three-dimensional magnetic field sensors are transmitted to the magnetic field constant control device after being filtered and digitized.

[0016] Further, the magnetic field constant control device includes a microprocessor, a storage unit, and a communication interface. The storage unit stores a control algorithm and preset magnetic field parameters, and the microprocessor is used to perform real-time data analysis and generate control instructions.

[0017] Further, the control algorithm dynamically adjusts the input current parameters of the coil excitation device based on the deviation value between the magnetic field distribution data and the preset parameters.

[0018] In a second aspect, an integrated magnetic field constant control method is provided. Based on the magnetic field constant control device described in any one of the foregoing, it includes:

[0019] Using a coil excitation device to generate an initial magnetic field;

[0020] Using a three-dimensional magnetic field distribution monitoring device to obtain real-time magnetic field data, where the real-time magnetic field data includes magnetic field strength, direction, and gradient information;

[0021] Based on the comparison result between the real-time magnetic field data and the preset magnetic field parameters, adjusting the output of the coil excitation device to achieve dynamic stability of the magnetic field.

[0022] Further, the generation of the initial magnetic field includes:

[0023] According to the target magnetic field distribution requirements, select the material and layout method of the coil winding, and apply an appropriate driving current.

[0024] Further, the adjustment step realizes real-time correction of the magnetic field deviation through an iterative optimization control algorithm.

[0025] The invention adopting the above technical solution has the following advantages:

[0026] Through the integrated magnetic field constant control device and method, the invention realizes an integrated magnetic field constant control device for omnidirectional real-time monitoring and efficient regulation of the magnetic field, so as to significantly improve the precision, efficiency, and stability of precision polishing, and meet the stringent requirements of modern high-end manufacturing for the processing of ultra-precision parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific embodiments of the present invention, the drawings required for the specific embodiments will be briefly introduced below. In all the drawings, the components or parts are not necessarily drawn to scale.

[0028] Figure 1 It is a schematic diagram of a special alloy coil winding in the integrated magnetic field constant control device of the present invention;

[0029] Figure 2 It is a circuit diagram of a current driver in the integrated magnetic field constant control device of the present invention;

[0030] Figure 3 This is the circuit diagram of the signal conditioning circuit in the integrated magnetic field constant control device of the present invention;

[0031] Figure 4 This is the comparison chart of the surface patterns observed by the microscope in the integrated magnetic field constant control device of the present invention;

[0032] Figure 5 This is the comparison chart of the surface roughness of multiple lenses in the integrated magnetic field constant control device of the present invention;

[0033] Figure 6 This is the captured image by the camera in the integrated magnetic field constant control device of the present invention;

[0034] Figure 7 This is the partial diagram of the magnetic field basic data in the integrated magnetic field constant control device of the present invention;

[0035] Figure 8 This is the flow chart of the integrated magnetic field constant control method of the present invention. Detailed implementation manners

[0036] Next, embodiments of the technical solution of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, so they are only examples and cannot be used to limit the protection scope of the present invention.

[0037] As Figures 1 to 8 shown, the integrated magnetic field constant control device of the present invention includes:

[0038] A coil excitation device for generating a controllable magnetic field;

[0039] A three-dimensional magnetic field distribution monitoring device for real-time collecting magnetic field distribution data;

[0040] A magnetic field constant control device for dynamically adjusting the output of the coil excitation device based on the magnetic field distribution data;

[0041] The magnetic field constant control device forms a closed-loop control architecture through the integration of the coil excitation device, the three-dimensional magnetic field distribution monitoring device, and the magnetic field constant control device.

[0042] In this embodiment, the coil winding of the coil excitation device is made of rare earth alloy material.

[0043] In this embodiment, the three-dimensional magnetic field distribution monitoring device includes a plurality of three-dimensional magnetic field sensors, and the three-dimensional magnetic field sensors are arranged at the spatial nodes of the magnetic field.

[0044] In this embodiment, the three-dimensional magnetic field sensors are respectively electrically connected to a signal conditioning module and a data acquisition module.

[0045] In this embodiment, the three-dimensional magnetic field sensor is a sensor array based on the Hall effect. The output signal of the three-dimensional magnetic field sensor is transmitted to the magnetic field constant control device after filtering and digital processing.

[0046] In this embodiment, the magnetic field constant control device includes a microprocessor, a storage unit, and a communication interface. The storage unit stores control algorithms and preset magnetic field parameters, and the microprocessor is used to perform real-time data analysis and generate control instructions.

[0047] In this embodiment, the control algorithm dynamically adjusts the input current parameters of the coil excitation device based on the deviation value between the magnetic field distribution data and the preset parameters.

[0048] Specifically, for the coil excitation device:

[0049] Material selection: A high-permeability alloy material containing rare earth neodymium element is selected. Compared with ordinary copper materials, the magnetic permeability of this alloy can be increased by 40%-60%, which can effectively enhance the magnetic field strength and stability, and still maintain good electromagnetic performance in high-temperature environments, ensuring long-term stable operation.

[0050] Structural design: An asymmetric array layout is adopted. According to the research on the magnetic properties of high-performance composite magnetorheological polishing fluid, the polishing fluid in different regions has different requirements for the magnetic field strength. Through calculation and simulation, the coil turns and wire diameter distribution are determined. The wire diameter ranges from 0.6 to 0.8 mm, and the number of turns is dynamically adjusted in the range of 120-180 turns according to the required magnetic field strength, accurately matching the magnetization requirements of each part of the polishing fluid, and controlling the uniformity deviation of the generated magnetic field strength within ±5%.

[0051] Drive system: A high-precision current driver, model XYD-300A, is adopted, which has the functions of continuously adjustable output current frequency in the range of 0-10 kHz and accurate adjustment of amplitude in the range of 0-10 A, and the current stability is better than ±0.5%. The current driver is connected to the coil winding through a double-layer shielded cable, and the shielding effectiveness reaches 80 dB, preventing external electromagnetic interference from affecting the current transmission accuracy and providing stable and accurate current drive for the coil.

[0052] Three-dimensional magnetic field distribution monitoring device:

[0053] Sensor layout: Integrate multiple three-dimensional magnetic field sensors based on the Hall effect, model HMC5883L, and a total of 10 sensor points are arranged in the key areas of the magnetorheological polishing machine, including near the inlet and outlet of the polishing fluid, the key parts of workpiece processing, and the angles where magnetic field fluctuations are likely to occur.

[0054] Signal Conditioning and Acquisition: The original magnetic field data collected by the sensor is a weak electrical signal, which is transmitted to the signal conditioning circuit through a signal line with low noise and high shielding performance. The signal conditioning circuit consists of a high-precision operational amplifier and a filter, which perform preprocessing operations such as amplifying the signal (amplification factor is 100 - 500 times) and filtering (using a 5th-order Butterworth low-pass filter to effectively filter out high-frequency interference noise), providing the signal-to-noise ratio and stability of the signal. The conditioned signal is sent to a data acquisition card, model NI-PCle-6363, which has high-speed and multi-channel data acquisition capabilities, with a sampling rate of up to 800 kHz per second. It can quickly convert the analog signal into a digital signal, and then transmit the magnetic field data to the magnetic field constant control device in real time through a high-speed data transmission line (transmission rate up to 200 Mbps per second).

[0055] Magnetic Field Constant Control Device:

[0056] Core Processor: A 32-bit ARM Cortex-M4 microprocessor is used, such as the STM32F407 model, with a main frequency of up to 168 MHz, responsible for running the built-in PID algorithm and the control logic of the entire device.

[0057] According to the requirements of magnetic field constant control for accuracy, the magnetic field intensity is controlled within the range of ±0.5% of the set value, and the required fast response speed, that is, it is required to make a response adjustment within 50 milliseconds when there is a step interference fluctuation in the magnetic field. Based on this, the value ranges of the proportional coefficient, integral time constant, and differential time constant are initially set.

[0058] For the proportional coefficient, starting from the empirical value of 0.8 and combining the previous test data, if it is found that the correction of the magnetic field intensity deviation is too slow, the proportional coefficient is gradually increased, with each adjustment amplitude controlled within 10%; if there is an overshoot phenomenon, that is, the actual magnetic field intensity oscillates for a long time and is difficult to stabilize after exceeding the target value, the proportional coefficient is appropriately reduced, also with each adjustment amplitude controlled within 10%, and the change curve of the magnetic field intensity is monitored in real time until an ideal response effect is achieved, so that the magnetic field intensity can quickly approach and stabilize at the target value.

[0059] In terms of adjusting the integral time constant, when there is a steady-state error in the system (when there is a fixed deviation of 0.3 Gauss between the stable value of the magnetic field intensity and the target value after long-term operation), gradually reduce the integral time constant to prompt the integral term to accumulate error signals faster to eliminate the steady-state error. Set the adjustment step to 2 seconds, and closely monitor the magnetic field fluctuation during the process to avoid oscillation caused by too strong integral action. For determining the differential time constant, for working conditions where the magnetic field changes rapidly, such as when the equipment starts or a strong external magnetic interference intervenes instantaneously, if the magnetic field intensity change rate is greater than 0.1 Gauss / millisecond, to suppress the overshoot risk brought by this rapid change, appropriately increase the differential time constant to enhance the system's "prediction" ability for the change trend. Set the initial adjustment amount to 0.05, and then fine-tune according to the actual magnetic field stabilization effect to ensure that the system can achieve magnetic field constant control under different working conditions. Through repeated testing and optimization, finally determine the PID algorithm parameters applicable to this magnetic field constant control device.

[0060] Storage and communication: Internally integrated with 1MB of Flash memory for storing information such as preset magnetic field parameters and algorithm parameters, and 192KB of SRAM for temporarily storing real-time data.

[0061] At the same time, an additional SD card is equipped for backing up data and storing long-term operation logs.

[0062] Control interface: Use the CAN bus interface to communicate with the current driver of the coil excitation device, and set the communication rate to 500Kbps to ensure accurate and timely transmission of instructions; use the Ethernet interface to connect to the data acquisition card of the three-dimensional magnetic field distribution monitoring device, with a transmission rate of 100Mbps, for receiving a large amount of magnetic field data and timely feedback of control instructions to achieve closed-loop and precise control of the entire magnetic field environment.

[0063] In some other embodiments, an integrated magnetic field constant control method is provided, based on the magnetic field constant control device of any one of the foregoing, including:

[0064] Step S01: Generate an initial magnetic field using a coil excitation device;

[0065] Step S02: Use a three-dimensional magnetic field distribution monitoring device to obtain real-time magnetic field data, where the real-time magnetic field data includes magnetic field intensity, direction, and gradient information;

[0066] Step S03: Based on the comparison result between the real-time magnetic field data and the preset magnetic field parameters, adjust the output of the coil excitation device to achieve dynamic magnetic field stability.

[0067] In this embodiment, the generation of the initial magnetic field includes:

[0068] According to the target magnetic field distribution requirements, select the material and layout method of the coil winding, and apply an appropriate drive current.

[0069] In this embodiment, the adjustment step realizes real-time correction of the magnetic field deviation through an iterative optimization control algorithm.

[0070] Working principle:

[0071] As the source of magnetic field generation, after the coil excitation device is started, special coil materials are selected based on the magnetic characteristic parameters obtained from in-depth analysis of high-performance composite magnetorheological polishing fluid (for example, through professional testing, the magnetorheological effect is most significant in the magnetic field strength range of 0.5 - 2T for this polishing fluid, and the magnetic permeability changes in the range of 2 - 5 relative magnetic permeability units).

[0072] For example, a high-permeability alloy containing 3% rare earth neodymium element is used. Compared with ordinary copper coils, its magnetic permeability can be increased by about 50%, which can efficiently converge the magnetic field. The coil windings are arranged in an asymmetric array layout, with the wire diameter controlled at 0.65 mm, and the number of turns distributed in the range of 120 - 180 turns according to the required magnetic field strength, so that different regions can generate magnetic field strengths that adapt to the needs of each part of the polishing fluid. When a current with a specific frequency (after repeated debugging, it is determined that when the frequency is 5KHz, the polishing fluid can reach the best response state) and amplitude (the current amplitude is dynamically adjusted within the range of 0 - 8A according to the polishing process) is applied, according to Ampere's circuital law, a high-intensity magnetic field with a distribution uniformity deviation controlled within ±5% is generated around the coil. This magnetic field precisely interacts with the magnetorheological particles in the polishing fluid, prompting the particles to quickly and orderly arrange into a chain-like structure, thereby changing the rheological properties of the polishing fluid and providing strong support for the polishing operation.

[0073] The three-dimensional magnetic field distribution monitoring device runs synchronously in real-time. It is equipped with multiple three-dimensional magnetic field sensors based on the Hall effect, distributed at key points within the magnetorheological polishing machine, with a total of 8 sensor points covering the working area. According to the principle of electromagnetic induction, the sensors capture the three-dimensional space information of the magnetic field with extremely high sensitivity (able to detect magnetic field changes at the microtesla level), including magnetic field strength, direction, and gradient changes.

[0074] The original magnetic field data collected by the sensors are weak electrical signals, which are transmitted to the signal conditioning circuit through signal lines with low noise and high shielding performance (the wire length is designed according to the internal layout of the device, with an average length of 1.2 meters).

[0075] The signal conditioning circuit performs preprocessing operations such as amplifying the signal (the amplification factor is 100 - 500 times) and filtering (using a 5th-order Butterworth low-pass filter to effectively filter out high-frequency interference noise), and then sends the processed signal to the data acquisition card. The data acquisition card has a sampling rate of up to 800kHz per second, quickly converts the analog signal into a digital signal, and then transmits the magnetic field data to the magnetic field constant control device in real-time through a high-speed data transmission line (the transmission rate reaches 200Mbps per second to ensure data immediacy).

[0076] The magnetic field constant control device incorporates a calibrated PID algorithm and operates on a 32-bit ARM Cortex-M4 microprocessor. This microprocessor is responsible for coordinating the control logic of the entire device. When it receives magnetic field data from the monitoring device, the PID algorithm quickly analyzes the data. Once it determines that the magnetic field intensity in a certain area deviates from the preset optimal value (for example, setting the magnetic field intensity deviation threshold to ±2%), it immediately issues an instruction to the current driver of the coil excitation device through the control interface. The current driver can regulate the magnitude (with a current regulation accuracy of up to ±0.3%) and direction of the current flowing through the coil, thereby adjusting the magnitude and distribution of the magnetic field in the corresponding area to ensure that the magnetic field in the entire working area is stabilized at an ideal state.

[0077] This self-developed integrated magnetic field constant control device:

[0078] I. Improvement in processing accuracy and quality:

[0079] Experimental preparation:

[0080] Select two groups of optical lens blanks of the same specification, with 10 pieces in each group, and label them as the experimental group and the control group respectively.

[0081] The experimental group uses the self-developed integrated magnetic field constant control device of the present invention for polishing, and the control group uses a traditional general excitation device with a conventional magnetorheological polishing fluid for operation.

[0082] Conduct performance tests on the high-performance composite magnetorheological polishing fluid to measure key parameters such as its magnetic permeability and magnetization intensity change curve. According to the parameters, set the parameters of the customized coil excitation device of the self-developed device, including the number of turns (150 turns in the key area), wire diameter (0.65 mm), and asymmetric array layout of the special alloy coil. At the same time, equip the traditional device with a conventional copper coil, and set the number of turns (150 turns), wire diameter (0.8 mm), and equidistant spiral array layout according to the general standard.

[0083] Experimental process:

[0084] Install the two groups of lenses on the corresponding magnetorheological polishing machines respectively, ensuring that the installation positions and fixing methods are the same. Start the polishing program. The experimental group passes a current with a specific frequency (5 kHz) and amplitude (dynamically adjusted between 0 - 8 A according to the initial state of the lens) to make the customized coil excitation device generate a magnetic field suitable for the polishing fluid; the control group passes conventional current parameters (frequency 3 kHz, amplitude 0 - 6 A) to drive the traditional excitation device to work.

[0085] During the polishing process, use a fluxgate magnetometer to select 5 evenly distributed measurement points in the lens processing area, measure the magnetic field intensity every 5 minutes, and record the magnetic field intensity uniformity data. At the same time, observe the arrangement state of the magnetorheological particles in the polishing fluid in real time through a microscope.

[0086] Experimental results:

[0087] After multiple measurements and taking the average value, the deviation of the magnetic field intensity uniformity in the experimental group was stably controlled within ±2%, while the deviation in the control group reached ±15%. Microscopic observation showed that the magnetorheological particles in the polishing fluid of the experimental group formed regular and stable chain-like structures, while the particle arrangement in the control group was relatively disordered. Finally, the surface roughness of the polished lenses was measured. The surface roughness of the lenses in the experimental group was significantly reduced from an average Ra of 0.8 micrometers to below Ra 0.2 micrometers, while the control group could only reach about Ra 0.6 micrometers. The surface shape accuracy of the lenses in the experimental group was significantly better than that of the control group, ensuring excellent optical performance.

[0088] Real-time monitoring and regulation experiment

[0089] Experimental preparation:

[0090] Prepare a batch of precision mechanical part blanks, a total of 20, randomly divided into two groups, with 10 in each group, which are used for the experiment of the self-developed device and the comparison experiment of the traditional device respectively. In the three-dimensional magnetic field distribution monitoring device of the self-developed device, install 8 high-precision three-dimensional magnetic field sensors (model HMC5883L) based on the Hall effect, which are distributed in the key areas of the magnetorheological polishing machine, and set the sampling rate of the data acquisition card (model NI-PCIe-6363) to 800 kHz per second. The magnetic field constant control device is built-in with a high-performance 32-bit ARM Cortex-M4 microprocessor (model STM32F407), runs a finely tuned PID algorithm, and sets the magnetic field intensity deviation threshold to ±2%. The traditional device uses a single-point gaussmeter and a simple proportional adjustment mode, and manually monitors the magnetic field intensity and adjusts the current.

[0091] Experimental process:

[0092] Start the polishing processes of the two groups of experiments simultaneously. When the polishing reaches half of the time, near the working areas of the two polishing machines, use small electromagnets to artificially create magnetic field fluctuations and interference to simulate abnormal situations that may occur in actual production. Observe the monitoring and regulation responses of the two groups of devices to magnetic field changes.

[0093] For the self-developed device, through a high-speed data transmission line (with a transmission rate of up to 200 Mbps per second), the monitoring device transmits real-time magnetic field data to the magnetic field constant control device. The microprocessor quickly analyzes the data. Once it determines that the magnetic field intensity deviates from the preset optimal value, it immediately sends precise instructions to the current driver (model XYD-300A) of the customized coil excitation device through the CAN bus interface. The current driver accurately regulates the magnitude (current regulation accuracy can reach ±0.3%) and direction of the current flowing through the coil within 0.5 seconds to restore the magnetic field stability. For the traditional device, the Gaussian meter reading is observed manually. When it is found that the magnetic field intensity deviates from the set value by 10%, the current is adjusted manually, and each adjustment takes about 10 - 15 seconds, and the adjustment accuracy can only be controlled within ±5%.

[0094] Table 1

[0095]

[0096] Table 2

[0097]

[0098] Experimental results:

[0099] After the precision mechanical parts are polished, the dimensional accuracy is detected, and a coordinate measuring machine is used to measure the dimensions of the key parts. The dimensional accuracy of the key parts of the parts processed by the self-developed device is controlled within ±0.02 mm, while the dimensional deviation of the parts processed by the traditional device is relatively large, and the dimensional accuracy of the key parts of some parts exceeds ±0.05 mm, indicating that the self-developed device can ensure that the magnetic field in the entire processing area is always stable in the ideal state, effectively avoiding the dimensional deviation of the parts caused by magnetic field fluctuations, and the processing quality far exceeds the existing technical level.

[0100] II. Improvement of processing efficiency

[0101] High-efficiency magnetic field excitation experiment

[0102] Two groups of semiconductor chip substrates with the same material and size, 8 pieces in each group, are selected for experiments on the self-developed device and the traditional device respectively. For the customized coil excitation device of the self-developed device, a high-permeability alloy material containing rare earth elements (containing 3% rare earth neodymium element) is used to make the coil, the wire diameter is 0.65 mm, and the number of turns is set according to the simulation optimization results, and a current with a specific frequency (5 kHz) and amplitude (dynamically adjusted from 0 - 8 A) is passed through. The traditional device uses a common copper coil, the wire diameter is 0.8 mm, the number of turns is 150, and a conventional current parameter (frequency 3 kHz, amplitude 0 - 6 A) is passed through.

[0103] Experimental process:

[0104] Start two groups of polishing experiments simultaneously, use a high-speed camera to capture the state changes of the polishing fluid in the initial stage, and record the time from the start of polishing to the time when the magnetorheological particles in the polishing fluid form an effective chain structure to participate in polishing.

[0105] Experimental results:

[0106] After taking the average value through multiple experiments, in the experiments with the self-developed device, the average time for the polishing fluid to reach the optimal working state is 30 seconds, while the traditional device requires about 45 seconds. Compared with the traditional device, the self-developed device can shorten the time for the polishing fluid to reach the optimal working state by 30%, thereby greatly improving the overall polishing efficiency.

[0107] Intelligent regulation to reduce downtime experiment

[0108] Experimental preparation:

[0109] Simulate a long-term continuous polishing production scenario, prepare two groups of the same polishing equipment, one group is installed with the self-developed integrated magnetic field constant control device, and the other group is equipped with a traditional magnetic field control device. In the self-developed device, the magnetic field constant control device has a built-in PID algorithm. Relying on the high-speed operation and processing ability of a 32-bit ARM Cortex-M4 microprocessor (model STM32F407), combined with the real-time feedback of the three-dimensional magnetic field distribution monitoring device, the response time requirement for the magnetic field strength to deviate from the preset optimal value (±2%) is set to complete the current adjustment within 0.5 seconds. The traditional device relies on manual experience or a simple proportional adjustment mode, and manually monitors the change of the magnetic field strength. When it is found that the magnetic field strength deviates from the set value by 10%, the current is adjusted, and each adjustment takes about 10 - 15 seconds.

[0110] Experimental process:

[0111] Let the two groups of equipment run continuously for 8 hours. During the operation, every 1 hour, place small magnets near the working area of the polishing machine or change the power supply, etc. to artificially create 5 magnetic field abnormal situations to simulate the interference factors in production, and record the downtime adjustment time of each group of devices caused by magnetic field anomalies.

[0112] Experimental results:

[0113] During the 8-hour operation of the self-developed device, the total downtime adjustment time caused by magnetic field anomalies accumulates to about 10 minutes, and the average adjustment time for each time is 0.5 seconds. While the total downtime adjustment time of the traditional device is as long as about 120 minutes, and the average adjustment time for each time is 10 - 15 seconds. This shows that the self-developed device greatly reduces the downtime adjustment time caused by magnetic field instability, thus ensuring the continuous and efficient progress of the processing process and effectively improving the comprehensive utilization rate of the equipment.

[0114] In summary, the self-developed integrated magnetic field constant control device has comprehensively optimized the precision polishing process, surpassing the existing technology in multiple dimensions such as processing accuracy and efficiency, providing solid support for the advancement of China's precision manufacturing industry to a higher level.

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the present invention, and they should all be covered within the scope of the claims and the description of the present invention.

Claims

1. An integrated magnetic field constant control device, characterized in that: include: A coil excitation device for generating an adjustable magnetic field; A three-dimensional magnetic field distribution monitoring device for collecting magnetic field distribution data in real time; A magnetic field constant control device, used for dynamically adjusting the output of the coil excitation device based on the magnetic field distribution data; The magnetic field constant control device integrates the coil excitation device, the three-dimensional magnetic field distribution monitoring device and the magnetic field constant control device to form a closed-loop control architecture.

2. The integrated magnetic field constant control device according to claim 1, characterized in that: The coil winding of the coil excitation device is made of rare earth alloy.

3. The integrated magnetic field constant control device according to claim 1, characterized in that: The three-dimensional magnetic field distribution monitoring device includes a plurality of three-dimensional magnetic field sensors, and the three-dimensional magnetic field sensors are arranged at the spatial nodes of the magnetic field.

4. The integrated magnetic field constant control device according to claim 3, characterized in that: The three-dimensional magnetic field sensor is respectively connected to a signal conditioning module and a data acquisition module.

5. The integrated magnetic field constant control device according to claim 3, characterized in that: The three-dimensional magnetic field sensor is a sensor array based on the Hall effect, and the output signal of the three-dimensional magnetic field sensor is transmitted to the magnetic field constant control device after filtering and digital processing.

6. The integrated magnetic field constant control device according to claim 1, characterized in that: The magnetic field constant control device includes a microprocessor, a storage unit and a communication interface. The storage unit stores a control algorithm and preset magnetic field parameters. The microprocessor is used to perform real-time data analysis and generate control instructions.

7. The integrated magnetic field constant control device according to claim 6, characterized in that: The control algorithm dynamically adjusts the input current parameters of the coil excitation device based on the deviation value between the magnetic field distribution data and the preset parameters.

8. An integrated magnetic field constant control method, characterized in that: The magnetic field constant control device according to any one of claims 1 to 7, comprising: An initial magnetic field is generated by using a coil excitation device; A three-dimensional magnetic field distribution monitoring device is used to obtain real-time magnetic field data, wherein the real-time magnetic field data includes magnetic field intensity, direction and gradient information; Based on the comparison result between the real-time magnetic field data and the preset magnetic field parameters, the output of the coil excitation device is adjusted to achieve dynamic stabilization of the magnetic field.

9. The integrated magnetic field constant control method according to claim 8, characterized in that: The generation of the initial magnetic field comprises: According to the target magnetic field distribution requirements, the material and layout of the coil winding are selected, and an adaptive driving current is applied.

10. The integrated magnetic field constant control method according to claim 8, characterized in that: The adjustment step realizes real-time correction of the magnetic field deviation through an iterative optimization control algorithm.

Images