Intelligent control system and method of linear motor

Abstract

The invention relates to the technical field of linear motor control, and particularly discloses an intelligent control system and method for a linear motor, and the method comprises the following steps: receiving an energy recovery instruction and a high-precision positioning instruction, and obtaining real-time position data and real-time vibration data; determining whether to start a thrust ripple compensation mode or not according to the level of the positioning precision instruction; when the thrust fluctuation compensation mode is started, obtaining a current phase compensation amount A1 and a current amplitude compensation amount A2 based on a thrust fluctuation fingerprint database; obtaining a target recovery current phase and a target recovery current amplitude based on the current phase compensation amount A1 and the current amplitude compensation amount A2; and controlling a linear motor to execute an energy recovery process based on the target recovery current phase and the target recovery current amplitude. The electromagnetic thrust is stable during energy recovery, and it is ensured that CNC machining movement always keeps high stability and consistency.

Description

Technical Field

[0001] This invention relates to the field of linear motor control technology, specifically to an intelligent control system and method for a linear motor. Background Technology

[0002] Linear motors, as a high-end drive core that breaks through the traditional transmission architecture, are a key supporting technology for modern precision manufacturing and intelligent equipment. They directly convert electrical energy into linear motion through electromagnetic principles, eliminating mechanical friction and transmission errors at their source. Their core advantages lie in high precision, high response, high rigidity, and low loss, achieving nanometer-level positioning accuracy and millisecond-level dynamic response.

[0003] In high-speed, precision CNC machine tools for industrial automation, linear motor direct-drive systems face a core contradiction: the irreconcilable electromagnetic interference problem exists between energy recovery functionality and the requirement for nanometer-level positioning accuracy. To achieve braking energy recovery, the system must actively adjust the current parameters of the motor windings. However, this DC control process exacerbates the inherent end effect of the linear motor, causing distortion of its internal magnetic field and resulting in significant electromagnetic thrust fluctuations. For precision machining that demands nanometer-level stability, these fluctuations are directly transmitted to the relative position between the tool and the workpiece, causing unacceptable machining errors and leading to product scrap. Summary of the Invention

[0004] The purpose of this invention is to provide an intelligent control system and method for linear motors to solve the above-mentioned technical problems.

[0005] The objective of this invention can be achieved through the following technical solutions: A method for intelligent control of a linear motor includes the following steps: It receives energy recovery commands and high-precision positioning commands from the CNC system, and acquires real-time position data and real-time vibration data of the linear motor actuator; Whether to enable the thrust fluctuation compensation mode depends on the level of the positioning accuracy command. When the thrust fluctuation compensation mode is enabled, the real-time position data and real-time vibration data are input into a pre-generated thrust fluctuation fingerprint database for matching and querying. The thrust fluctuation fingerprint database records the current phase compensation amount and current amplitude compensation amount corresponding to maintaining electromagnetic thrust stability under different combinations of real-time position data and real-time vibration data. Based on the results of the matching query, obtain a set of corresponding current phase compensation A1 and current amplitude compensation A2; Based on the current phase compensation amount A1, the phase of the basic recovery current phase A1' calculated for executing the energy recovery command is corrected to generate the target recovery current phase; Based on the current amplitude compensation A2, the basic recovery current amplitude A2' calculated for executing the energy recovery command is corrected to generate the target recovery current amplitude; Based on the target recovery current phase and the target recovery current amplitude, the linear motor is controlled to perform the energy recovery process.

[0006] As a further aspect of the present invention: the process of pre-generating a thrust fluctuation fingerprint database includes: Install a load of a preset mass on the linear motor actuator to establish the reference load condition for the linear motor system. Under the aforementioned reference load conditions, a series of standard position points are selected within the entire stroke range of the linear motor; At each selected standard location point, at least two steady-state vibration environments with different dominant frequencies are simulated; During the duration of each of the aforementioned steady-state vibration environments, a set of probe current signals covering different phases and amplitude combinations are applied to the stator windings of the linear motor, and corresponding electromagnetic thrust response data are collected simultaneously. For all the probe current signals and electromagnetic thrust response data collected at standard position point i and steady-state vibration environment j, a set of current compensation parameters is calculated by the system identification method. The current compensation parameters include current phase compensation and current amplitude compensation. This set of current compensation parameters is associated with the reference load conditions, standard position point i and steady-state vibration environment j to obtain a data in the thrust fluctuation fingerprint database.

[0007] As a further aspect of the present invention: inputting real-time position data and real-time vibration data into a thrust fluctuation fingerprint database for matching and querying includes: Based on the real-time location data, the target point is selected from the thrust fluctuation fingerprint database as the standard location point that is closest to the target point. Extract the real-time vibration spectrum features of the real-time vibration data and compare them one by one with the spectrum features of various steady-state vibration environments corresponding to the target point to obtain multiple similarity levels; Select a set of current compensation parameters A3 corresponding to the highest similarity. The current phase compensation amount and the current amplitude compensation amount in the current compensation parameter A3 are the current phase compensation amount A1 and the current amplitude compensation amount A2.

[0008] As a further aspect of the present invention: the process of obtaining the phase and amplitude of the basic recycled current includes: The real-time motion speed of the linear motor and the spatial distribution waveform of the magnetic field of the stator permanent magnet of the linear motor are obtained. The real-time motion speed and the spatial derivative of the spatial distribution waveform are convolved to calculate the back electromotive force waveform. Extract the zero-crossing information of the back EMF waveform and use the electrical angle corresponding to the zero-crossing point as the initial value of the phase of the basic recovery current. Based on the real-time motion speed and the preset braking deceleration curve, the electromagnetic braking force that causes the actuator to decelerate according to the braking deceleration curve is calculated based on Newton's second law. The electromagnetic braking force is divided by the thrust constant of the linear motor to obtain the initial value of the basic recovery current amplitude.

[0009] As a further aspect of the present invention, the process of obtaining the phase and amplitude of the basic recycled current further includes: The difference between the real-time motion speed and the target speed is used as a speed error signal and input to the first PID controller. The initial value of the basic recovery current phase is used as a feedforward quantity and superimposed on the output of the first PID controller to generate the corrected basic recovery current phase, that is, the basic recovery current phase A1' is obtained. The speed error signal is input to the second PID controller, and the initial value of the basic recovery current amplitude is superimposed on the output of the second PID controller as a feedforward quantity to generate the corrected basic recovery current amplitude, that is, the basic recovery current amplitude A2' is obtained. The control parameters of the first PID controller and the second PID controller are predetermined based on the Ziegler-Nichols tuning method.

[0010] As a further aspect of the present invention: generating the target recovery current phase and the target recovery current amplitude includes: The basic recovery current phase A1' is subjected to reverse transformation to generate the transformed current phase. The transformed current phase is algebraically superimposed with the current phase compensation A1 to generate the target recovery current phase. The target recovery current amplitude is generated by multiplying the basic recovery current amplitude A2' with the current amplitude compensation A2.

[0011] As a further aspect of the present invention: the energy recovery process includes: Based on the preset window length and slide compensation, several time windows are set; Calculate the variance of the mover's position within the current time window; When the variance is less than a set threshold, the energy recovery stage begins, and the target recovery current amplitude is gradually increased while keeping the phase of the target recovery current constant. When the variance is greater than or equal to the set threshold, switch to the positioning priority stage and apply the target recovery current phase and target recovery current amplitude to the linear motor.

[0012] As a further aspect of the present invention: when the level of the positioning accuracy command is greater than a preset accuracy threshold, the thrust fluctuation compensation mode is activated; When the level of the positioning accuracy command is less than or equal to the preset accuracy threshold, the thrust fluctuation compensation mode is not enabled, and the linear motor is controlled to perform the energy recovery process based on the basic recovery current phase A1' and the basic recovery current amplitude A2'.

[0013] An intelligent control system for a linear motor includes: It receives energy recovery commands and high-precision positioning commands from the CNC system, and acquires real-time position data and real-time vibration data of the linear motor actuator; Whether to enable the thrust fluctuation compensation mode depends on the level of the positioning accuracy command. When the thrust fluctuation compensation mode is enabled, the real-time position data and real-time vibration data are input into a pre-generated thrust fluctuation fingerprint database for matching and querying. The thrust fluctuation fingerprint database records the current phase compensation amount and current amplitude compensation amount corresponding to maintaining electromagnetic thrust stability under different combinations of real-time position data and real-time vibration data. Based on the results of the matching query, obtain a set of corresponding current phase compensation A1 and current amplitude compensation A2; Based on the current phase compensation amount A1, the phase of the basic recovery current phase A1' calculated for executing the energy recovery command is corrected to generate the target recovery current phase; Based on the current amplitude compensation A2, the basic recovery current amplitude A2' calculated for executing the energy recovery command is corrected to generate the target recovery current amplitude; Based on the target recovery current phase and the target recovery current amplitude, the linear motor is controlled to perform the energy recovery process.

[0014] The beneficial effects of this invention compared to the prior art are as follows: This invention establishes a thrust fluctuation fingerprint database corresponding to operating condition characteristics and performs compensation and stage switching based on real-time operating conditions during the control process, achieving coordinated control of linear motors between energy recovery and high-precision positioning. This invention can actively suppress thrust fluctuations caused by electromagnetic field distortion during braking energy recovery, enabling the motor to maintain smooth motion and controllable position while executing energy recovery commands, thereby effectively avoiding positioning deviations caused by disturbances to the mover. The control strategy of this invention allows the motor to dynamically match optimal compensation parameters under different operating conditions, ensuring continuous and stable thrust output. Furthermore, by adjusting the control priority during the recovery process in stages, it achieves a smooth transition in the energy recovery process and adaptive optimization of positioning control. Therefore, this invention can maintain the stability and consistency of machining motion even under high-speed braking and energy recovery conditions, significantly improving the overall control performance and machining reliability of the linear motor drive system under complex operating conditions. Attached Figure Description

[0015] The invention will now be further described with reference to the accompanying drawings.

[0016] Figure 1 This is a flowchart illustrating an intelligent control method for a linear motor according to the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0018] Please see Figure 1 As shown, this invention is an intelligent control method for a linear motor, comprising the following steps: It receives energy recovery commands and high-precision positioning commands from the CNC system, and acquires real-time position data and real-time vibration data of the linear motor actuator; Whether to enable the thrust fluctuation compensation mode depends on the level of the positioning accuracy command. In a preferred embodiment of the present invention, when the level of the positioning accuracy command is greater than a preset accuracy threshold, the thrust fluctuation compensation mode is activated; When the level of the positioning accuracy command is less than or equal to the preset accuracy threshold, the thrust fluctuation compensation mode is not enabled, and the linear motor is controlled to perform the energy recovery process based on the basic recovery current phase A1' and the basic recovery current amplitude A2'.

[0019] When the thrust fluctuation compensation mode is enabled, the real-time position data and real-time vibration data are input into a pre-generated thrust fluctuation fingerprint database for matching and querying. The thrust fluctuation fingerprint database records the current phase compensation amount and current amplitude compensation amount corresponding to maintaining electromagnetic thrust stability under different combinations of real-time position data and real-time vibration data. In another preferred embodiment of the present invention, the process of pre-generating a thrust fluctuation fingerprint database includes: To establish representative benchmark data, a load of a certain mass is first applied to the linear motor mover to ensure that the force state of the motor under this load condition is consistent with the actual working environment, thereby forming a reference basis that matches the electromagnetic force and mechanical response.

[0020] Subsequently, several standard position points are selected within the entire stroke range of the mover. Each position point corresponds to a specific state of the spatial distribution of the motor's magnetic field, which can reflect the effects of end effects, magnetic field gradient changes, and stator winding spatial harmonics.

[0021] To simulate the various dynamic disturbances that a motor might experience during actual operation, a steady-state vibration environment is artificially applied at each location point. A steady-state vibration environment refers to an external disturbance state in which the vibration amplitude and frequency remain stable over a certain period. Its dominant frequency represents the frequency component with the most concentrated energy in that vibration environment, typically corresponding to the resonance characteristics of the mechanical structure or the frequency of the external disturbance source. By controlling the drive signal of the external vibration excitation device and changing the excitation frequency and direction of the vibration table or support structure, steady-state vibration environments with different dominant frequencies can be artificially constructed, thereby reproducing various typical operating conditions under controlled conditions.

[0022] To identify the thrust response pattern of the motor under different operating conditions, a set of probe current signals is applied to the stator winding during the duration of each vibration environment. The probe signals consist of a series of current waveforms with different phases and amplitudes. The design principle is to cover the space of the main current parameters that may affect the generation of electromagnetic thrust, so as to ensure that the subsequent identification process can fully reflect the nonlinear characteristics of the motor.

[0023] When a probe current is input to the motor, the sensor synchronously acquires the electromagnetic thrust response generated by the mover. By analyzing the dynamic relationship between current changes and thrust changes, the electromechanical coupling characteristics of the electromagnetic system under the current "position-vibration" combination can be revealed. The system identification method extracts the phase shift and amplitude change trends in this relationship to calculate the current phase compensation and current amplitude compensation required to maintain thrust stability. These parameters characterize the optimal current adjustment direction and amplitude required to counteract thrust fluctuations under specific operating conditions. The role of the system identification method in this invention is to identify the electromechanical coupling characteristics of the electromagnetic system under specific operating conditions by analyzing the correspondence between the input and output, given that the probe current is the input and the thrust response is the output. This identification process first performs a correlation analysis on the probe current signal and the thrust response signal in the time or frequency domain. By comparing the periodic characteristics of the two, the portion of the thrust fluctuation that is the same as the probe current is separated. In this process, the system identification method utilizes the phase correspondence between input and output to determine whether the peak thrust fluctuation leads or lags behind the probe current, thereby extracting the phase offset. Simultaneously, by observing the variation trend of thrust fluctuation amplitude under different probe current amplitude conditions, it obtains the regular characteristics of the influence of current amplitude variation on thrust fluctuation intensity. Phase offset represents the dynamic misalignment of the thrust response relative to the current excitation, while amplitude variation trend represents the system's sensitivity direction and degree to current disturbances under that operating condition. After obtaining these two characteristics, the system identification method, based on the principle of "counteracting output fluctuations through input adjustment," reverse-derives the current adjustment direction that most effectively reduces thrust fluctuations: the phase offset is mapped inversely to a current phase compensation amount to counteract the phase misalignment of thrust fluctuations; the amplitude variation trend is mapped inversely to a current amplitude compensation amount to suppress the amplitude variation of thrust fluctuations. Through this identification process based on the input-output relationship, a set of current compensation parameters most suitable for stabilizing thrust can be determined at each specific location and vibration state, and this parameter is recorded as an operating condition fingerprint in the thrust fluctuation fingerprint database.

[0024] Each set of compensation parameters, along with its corresponding load conditions, location point number, and vibration environment characteristics, constitutes a record in the thrust fluctuation fingerprint database. As the number of samples under different operating conditions increases, the fingerprint database gradually covers the entire operating space, enabling the rapid acquisition of the corresponding current compensation solution by matching real-time operating conditions during actual control, thus achieving feedforward prediction and accurate correction of complex electromagnetic interference.

[0025] Based on the results of the matching query, obtain a set of corresponding current phase compensation A1 and current amplitude compensation A2; In a preferred embodiment, inputting real-time location data and real-time vibration data into the thrust fluctuation fingerprint database for matching and querying includes: Based on the real-time location data, the target point is selected from the thrust fluctuation fingerprint database as the standard location point that is closest to the target point. Extract the real-time vibration spectrum features of the real-time vibration data and compare them one by one with the spectrum features of various steady-state vibration environments corresponding to the target point to obtain multiple similarity levels; Select a set of current compensation parameters A3 corresponding to the highest similarity. The current phase compensation amount and the current amplitude compensation amount in the current compensation parameter A3 are the current phase compensation amount A1 and the current amplitude compensation amount A2.

[0026] Understandably, the similarity assessment is based on matching analysis between real-time vibration data and the spectral characteristics of existing vibration environments in the fingerprint database. The real-time vibration signal, after undergoing a Fast Fourier Transform (FFT) to obtain its spectral distribution, reflects the distribution pattern of vibration energy across different frequency bands under the current operating conditions. Each steady-state vibration environment in the fingerprint database also corresponds to a set of spectral characteristics processed in the same way. The system normalizes the two sets of spectra on the same frequency coordinates to eliminate amplitude scale differences, and then calculates their cosine similarity, which reflects the degree of similarity.

[0027] Based on the current phase compensation amount A1, the phase of the basic recovery current phase A1' calculated for executing the energy recovery command is corrected to generate the target recovery current phase; Based on the current amplitude compensation A2, the basic recovery current amplitude A2' calculated for executing the energy recovery command is corrected to generate the target recovery current amplitude; In a preferred embodiment of the present invention, the process of obtaining the phase and amplitude of the base recycle current includes: The real-time motion speed of the linear motor and the spatial distribution waveform of the magnetic field of the stator permanent magnet of the linear motor are obtained. The real-time motion speed and the spatial derivative of the spatial distribution waveform are convolved to calculate the back electromotive force waveform. Extract the zero-crossing information of the back EMF waveform and use the electrical angle corresponding to the zero-crossing point as the initial value of the phase of the basic recovery current. Based on the real-time motion speed and the preset braking deceleration curve, the electromagnetic braking force that causes the actuator to decelerate according to the braking deceleration curve is calculated based on Newton's second law. The electromagnetic braking force is divided by the thrust constant of the linear motor to obtain the initial value of the basic recovery current amplitude.

[0028] The difference between the real-time motion speed and the target speed is used as a speed error signal and input to the first PID controller. The initial value of the basic recovery current phase is used as a feedforward quantity and superimposed on the output of the first PID controller to generate the corrected basic recovery current phase, that is, the basic recovery current phase A1' is obtained. The speed error signal is input to the second PID controller, and the initial value of the basic recovery current amplitude is superimposed on the output of the second PID controller as a feedforward quantity to generate the corrected basic recovery current amplitude, that is, the basic recovery current amplitude A2' is obtained. The control parameters of the first PID controller and the second PID controller are predetermined based on the Ziegler-Nichols tuning method.

[0029] It should be noted that in a linear motor, the motion velocity of the mover and the spatial distribution of the stator magnetic field jointly determine the waveform of the back electromotive force (EMF) generated in the coil. By convolving the real-time motion velocity with the spatial derivative of the magnetic field spatial distribution, the instantaneous relationship between the rate of change of the magnetic field and the mover velocity can be synthesized, thus obtaining the EMF change law reflecting the current electromagnetic coupling state of the motor. The role of convolution is to capture the non-uniformity of the magnetic field along the stroke direction, so that the calculated back EMF can truly reflect the dynamic coupling relationship between magnetic field distortion and mover motion, ensuring that the subsequent current phase calculation is consistent with the actual electrical angle.

[0030] The zero-crossing point of the back electromotive force waveform corresponds to the instantaneous reversal point of the direction of electromagnetic field energy conversion. Its electrical angle can accurately reflect the synchronous position of the mover in the magnetic field. Therefore, using it as the initial value of the phase of the basic recovery current can keep the braking current and the change of magnetic flux optimally aligned, thereby improving the effectiveness of energy recovery from the source.

[0031] Subsequently, the electromagnetic braking force is calculated based on the real-time motion speed and the preset braking deceleration curve. This is the key link that connects the mechanical motion requirements with the electromagnetic drive capability. By establishing a mapping between speed changes and thrust requirements through Newton's second law, and then using the thrust constant to convert the force requirements into an initial value of the current amplitude, the energy correspondence from mechanical constraints to electrical commands is realized.

[0032] To further eliminate deviations caused by system dynamic lag during braking, a two-stage PID controller with speed error as input is employed to dynamically correct the current phase and amplitude, respectively. The PID controller can compensate for sudden disturbances and non-ideal responses in real time without compromising the physical meaning of the feedforward calculation, ensuring that the phase A1' and amplitude A2' of the base regenerative current maintain both rapid responsiveness and steady-state accuracy to the target braking force. Its control parameters are pre-tuned using the Ziegler-Nichols method, maintaining stable regulation performance under different inertia conditions.

[0033] The core principle of the entire process is to establish a synchronization reference using the back electromotive force as an electrical reference, construct an amplitude target using the braking force requirement as a mechanical reference, and achieve coordination between the two through closed-loop feedback, so that the base recovery current can achieve a dynamic balance between energy recovery efficiency and mover stability, providing a precise and controllable base current signal for subsequent thrust fluctuation compensation.

[0034] Based on the target recovery current phase and the target recovery current amplitude, the linear motor is controlled to perform the energy recovery process.

[0035] The generation of the target recovery current phase and the target recovery current amplitude include: The basic recovery current phase A1' is subjected to reverse transformation to generate the transformed current phase. The transformed current phase is algebraically superimposed with the current phase compensation A1 to generate the target recovery current phase. The target recovery current amplitude is generated by multiplying the basic recovery current amplitude A2' with the current amplitude compensation A2.

[0036] In another preferred embodiment of the present invention, the energy recovery process includes: Based on the preset window length and slide compensation, several time windows are set; Calculate the variance of the mover's position within the current time window; When the variance is less than a set threshold, the energy recovery stage begins, and the target recovery current amplitude is gradually increased while keeping the phase of the target recovery current constant. When the variance is greater than or equal to the set threshold, switch to the positioning priority stage and apply the target recovery current phase and target recovery current amplitude to the linear motor.

[0037] Understandably, during the braking process of a linear motor, the mover gradually transitions from high-speed motion to rest, and its mechanical and electromagnetic states are constantly changing. The variance of the mover position reflects the amplitude and stability of position fluctuations. When the variance is large, it indicates that the system still has strong vibrations or disturbances. If the energy recovery current amplitude is increased too early, the change in electromagnetic thrust will be superimposed on the original dynamic fluctuations, further amplifying the position error and destroying stability. Therefore, in the stage of large variance, the control logic is switched to position priority to keep the system at a low energy recovery intensity to stabilize the mover position and suppress electromagnetic force disturbances. When the variance decreases below the set threshold, it means that the mover has entered a relatively stable controlled area, and the mechanical inertia and electromagnetic response have reached equilibrium. At this time, gradually increasing the target recovery current amplitude can improve energy recovery efficiency without causing new displacement oscillations. The principle of dividing the stages based on variance is to treat position stability as a dynamic process state quantity. By quantifying the degree of position fluctuation in real time, the energy recovery control has adaptive adjustment capabilities. The coordinated switching between the two stages allows the system to prioritize motion accuracy in the initial braking phase and then pursue maximum energy recovery after stabilization. This achieves a dynamic balance between stability and efficiency in the time dimension, enabling the linear motor to maintain high-precision positioning and complete efficient energy recovery throughout the braking process. This avoids the performance loss caused by coupling conflicts in traditional constant control strategies.

[0038] It is worth noting that the phase and amplitude of the target recovery current are not fixed values ​​within different time windows, but are dynamically updated as the mover state and electromagnetic conditions change in real time. Within each time window, the system recalculates the compensation amount based on the current motion speed, position variance, and fingerprint database matching results, and adjusts the phase alignment angle and amplitude of the target current to ensure that the current output is always consistent with the current magnetic field distribution and energy recovery requirements, thereby guaranteeing the continuity of the braking process and the stability of the control. The overall design concept of this invention is based on a renewed understanding of the coupling mechanism between linear motor energy recovery and high-precision positioning. Traditional methods often attempt to simultaneously meet braking force and position accuracy requirements within a unified controller framework. However, due to the strong interaction between electromagnetic thrust fluctuations and braking current, adjusting the parameters of any single loop will have a ripple effect, making it impossible to balance stability and efficiency. This invention breaks through this approach by decomposing the problem into two independent but ultimately collaborative control layers: one layer focuses on the energy recovery task, calculating the basic recovery current required to generate braking force; the other layer focuses on thrust fluctuation suppression, using a pre-established thrust fluctuation fingerprint library to achieve personalized compensation. During the execution phase, these two layers are integrated into a set of target current commands, enabling energy recovery and precision control to proceed simultaneously without interference, fundamentally eliminating the structural contradictions inherent in traditional control methods.

[0039] In terms of thrust fluctuation suppression, the solution introduces a feedforward compensation mechanism based on operating condition fingerprints. By collecting probe current and thrust response data under different locations and vibration environments, a fingerprint database containing current phase and amplitude compensation amounts is formed. During actual operation, the system performs matching queries based on real-time location and vibration data, directly calling the compensation parameters closest to the operating condition, achieving precise anti-disturbance control without the need for remodeling. This approach replaces complex nonlinear calculations with data experience, making the compensation process real-time and targeted. Since the compensation amount is only responsible for balancing electromagnetic thrust fluctuations and does not change the energy distribution logic of the recovered current, it can stably output thrust without compromising braking efficiency, thus avoiding positioning deviations caused by energy recovery at the source.

[0040] In the generation of the basic energy recovery current, the scheme extracts the electrical angle from the back EMF waveform, calculates the braking force requirement, and combines it with PID control to form a dynamic correction mechanism, ensuring that the phase and amplitude of the energy recovery current are always consistent with the motion of the mover. Convolution calculation reflects the coupling relationship between the spatial distribution of the magnetic field and the velocity change, ensuring that the current command is synchronized with the actual electromagnetic environment; while the introduced PID regulation compensates for system inertia and response delay, achieving a balance between rapid braking and stable convergence of the current. This part provides a stable and reliable foundation for energy recovery, providing high-precision electrical support for the superposition of compensation control.

[0041] In the dynamic management of the energy recovery phase, the solution proposes a phase switching mechanism based on position variance, using the position fluctuation of the mover within a time window as the state variable to determine the control focus. When the position fluctuation is large, priority is given to stabilizing the positioning and suppressing electromagnetic interference; when the fluctuation decreases, the recovery current amplitude is gradually increased to improve the energy recovery rate. This design enables the system to automatically adjust the control objective according to the evolution of operating conditions, achieving a smooth transition from precision-first to efficiency-first. Through this time-adaptive strategy, the system maintains a continuous, stable, and efficient operating state throughout the braking process, thus truly realizing the synergistic unity between energy recovery and high-precision positioning of the linear motor.

[0042] An intelligent control system for a linear motor includes: It receives energy recovery commands and high-precision positioning commands from the CNC system, and acquires real-time position data and real-time vibration data of the linear motor actuator; Whether to enable the thrust fluctuation compensation mode depends on the level of the positioning accuracy command. When the thrust fluctuation compensation mode is enabled, the real-time position data and real-time vibration data are input into a pre-generated thrust fluctuation fingerprint database for matching and querying. The thrust fluctuation fingerprint database records the current phase compensation amount and current amplitude compensation amount corresponding to maintaining electromagnetic thrust stability under different combinations of real-time position data and real-time vibration data. Based on the results of the matching query, obtain a set of corresponding current phase compensation A1 and current amplitude compensation A2; Based on the current phase compensation amount A1, the phase of the basic recovery current phase A1' calculated for executing the energy recovery command is corrected to generate the target recovery current phase; Based on the current amplitude compensation A2, the basic recovery current amplitude A2' calculated for executing the energy recovery command is corrected to generate the target recovery current amplitude; Based on the target recovery current phase and the target recovery current amplitude, the linear motor is controlled to perform the energy recovery process.

[0043] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. An intelligent control method for a linear motor, characterized in that, Includes the following steps: It receives energy recovery commands and high-precision positioning commands from the CNC system, and acquires real-time position data and real-time vibration data of the linear motor actuator; Whether to enable the thrust fluctuation compensation mode depends on the level of the positioning accuracy command. When the thrust fluctuation compensation mode is enabled, the real-time position data and real-time vibration data are input into a pre-generated thrust fluctuation fingerprint database for matching and querying. The thrust fluctuation fingerprint database records the current phase compensation amount and current amplitude compensation amount corresponding to maintaining electromagnetic thrust stability under different combinations of real-time position data and real-time vibration data. Based on the results of the matching query, obtain a set of corresponding current phase compensation A1 and current amplitude compensation A2; Based on the current phase compensation amount A1, the phase of the basic recovery current phase A1' calculated for executing the energy recovery command is corrected to generate the target recovery current phase; Based on the current amplitude compensation A2, the basic recovery current amplitude A2' calculated for executing the energy recovery command is corrected to generate the target recovery current amplitude; Based on the target recovery current phase and the target recovery current amplitude, the linear motor is controlled to perform the energy recovery process.

2. The intelligent control method for a linear motor according to claim 1, characterized in that, The process of pre-generating a thrust fluctuation fingerprint database includes: Install a load of a preset mass on the linear motor actuator to establish the reference load condition for the linear motor system. Under the aforementioned reference load conditions, a series of standard position points are selected within the entire stroke range of the linear motor; At each selected standard location point, at least two steady-state vibration environments with different dominant frequencies are simulated; During the duration of each of the aforementioned steady-state vibration environments, a set of probe current signals covering different phases and amplitude combinations are applied to the stator windings of the linear motor, and corresponding electromagnetic thrust response data are collected simultaneously. For all the probe current signals and electromagnetic thrust response data collected at standard position point i and steady-state vibration environment j, a set of current compensation parameters is calculated by the system identification method. The current compensation parameters include current phase compensation and current amplitude compensation. This set of current compensation parameters is associated with the reference load conditions, standard position point i and steady-state vibration environment j to obtain a data in the thrust fluctuation fingerprint database.

3. The intelligent control method for a linear motor according to claim 2, characterized in that, The real-time location data and real-time vibration data are input into the thrust fluctuation fingerprint database for matching and querying, including: Based on the real-time location data, the target point is selected from the thrust fluctuation fingerprint database as the standard location point that is closest to the target point. Extract the real-time vibration spectrum features of the real-time vibration data and compare them one by one with the spectrum features of various steady-state vibration environments corresponding to the target point to obtain multiple similarity levels; Select a set of current compensation parameters A3 corresponding to the maximum similarity. The current phase compensation amount and the current amplitude compensation amount in the current compensation parameter A3 are the current phase compensation amount A1 and the current amplitude compensation amount A2.

4. The intelligent control method for a linear motor according to claim 1, characterized in that, The process of obtaining the phase and amplitude of the base recycle current includes: The real-time motion speed of the linear motor and the spatial distribution waveform of the magnetic field of the stator permanent magnet of the linear motor are obtained. The real-time motion speed and the spatial derivative of the spatial distribution waveform are convolved to calculate the back electromotive force waveform. Extract the zero-crossing information of the back EMF waveform and use the electrical angle corresponding to the zero-crossing point as the initial value of the phase of the basic recovery current. Based on the real-time motion speed and the preset braking deceleration curve, the electromagnetic braking force that causes the actuator to decelerate according to the braking deceleration curve is calculated based on Newton's second law. The electromagnetic braking force is divided by the thrust constant of the linear motor to obtain the initial value of the basic recovery current amplitude.

5. The intelligent control method for a linear motor according to claim 4, characterized in that, The process of obtaining the phase and amplitude of the base recycle current also includes: The difference between the real-time motion speed and the target speed is used as a speed error signal and input to the first PID controller. The initial value of the basic recovery current phase is used as a feedforward quantity and superimposed on the output of the first PID controller to generate the corrected basic recovery current phase, that is, the basic recovery current phase A1' is obtained. The speed error signal is input to the second PID controller, and the initial value of the basic recovery current amplitude is superimposed on the output of the second PID controller as a feedforward quantity to generate the corrected basic recovery current amplitude, that is, the basic recovery current amplitude A2' is obtained. The control parameters of the first PID controller and the second PID controller are predetermined based on the Ziegler-Nichols tuning method.

6. The intelligent control method for a linear motor according to claim 1, characterized in that, The generation of the target recovery current phase and the target recovery current amplitude include: The basic recovery current phase A1' is subjected to reverse transformation to generate the transformed current phase. The transformed current phase is algebraically superimposed with the current phase compensation A1 to generate the target recovery current phase. The target recovery current amplitude is generated by multiplying the basic recovery current amplitude A2' with the current amplitude compensation A2.

7. The intelligent control method for a linear motor according to claim 1, characterized in that, The energy recovery process includes: Based on the preset window length and slide compensation, several time windows are set; Calculate the variance of the mover's position within the current time window; When the variance is less than a set threshold, the energy recovery stage begins, and the target recovery current amplitude is gradually increased while keeping the phase of the target recovery current constant. When the variance is greater than or equal to the set threshold, switch to the positioning priority stage and apply the target recovery current phase and target recovery current amplitude to the linear motor.

8. The intelligent control method for a linear motor according to claim 1, characterized in that, When the level of the positioning accuracy command is greater than the preset accuracy threshold, the thrust fluctuation compensation mode is activated. When the level of the positioning accuracy command is less than or equal to the preset accuracy threshold, the thrust fluctuation compensation mode is not enabled, and the linear motor is controlled to perform the energy recovery process based on the basic recovery current phase A1' and the basic recovery current amplitude A2'.

9. An intelligent control system for a linear motor, characterized in that, Includes the following steps: It receives energy recovery commands and high-precision positioning commands from the CNC system, and acquires real-time position data and real-time vibration data of the linear motor actuator; Whether to enable the thrust fluctuation compensation mode depends on the level of the positioning accuracy command. When the thrust fluctuation compensation mode is enabled, the real-time position data and real-time vibration data are input into a pre-generated thrust fluctuation fingerprint database for matching and querying. The thrust fluctuation fingerprint database records the current phase compensation amount and current amplitude compensation amount corresponding to maintaining electromagnetic thrust stability under different combinations of real-time position data and real-time vibration data. Based on the results of the matching query, obtain a set of corresponding current phase compensation A1 and current amplitude compensation A2; Based on the current phase compensation amount A1, the phase of the basic recovery current phase A1' calculated for executing the energy recovery command is corrected to generate the target recovery current phase; Based on the current amplitude compensation A2, the basic recovery current amplitude A2' calculated for executing the energy recovery command is corrected to generate the target recovery current amplitude; Based on the target recovery current phase and the target recovery current amplitude, the linear motor is controlled to perform the energy recovery process.

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