A method for detecting the position of a linear motor based on a spatial Hall element

Abstract

The present invention discloses a method for detecting the position of a linear motor based on a spatial Hall element, belonging to the technical field of linear motors. High-precision position detection is achieved through the collaborative work of a reference Hall element and multiple compensation Hall elements. The compensation Hall elements are distributed on both the positive and negative sides of the axis of the reference element in a non-equidistant gradient manner, forming a differential signal pair to eliminate common-mode interference, and dynamically adjusting the sensitivity coefficient in combination with the axial spacing An and the radial distance Ln. The anomaly detection mechanism monitors the deviation amount in real time, switches to the redundant element group when the threshold is exceeded, and generates a fault diagnosis signal. Through the multi-dimensional signal fusion and dynamic compensation strategy, this method significantly improves the detection accuracy, anti-interference ability, and system reliability under complex working conditions.

Description

Technical Field

[0001] This application relates to the technical field of linear motors, and particularly to a method for detecting the position of a linear motor based on a spatial Hall element. Background Art

[0002] A linear motor converts electrical energy into linear motion based on the law of electromagnetic induction. In a linear motor, the interaction between a magnetic field and a conductor generates a force in the linear direction, thereby driving a load to perform linear motion. This eliminates the need to convert mechanical energy and improves the efficiency and accuracy of energy conversion. Linear motors are widely used in fields that require high precision, high speed, and high reliability, such as robots, automation equipment, high-speed transportation systems, and medical devices. The development of linear motor technology has promoted the progress of industrial automation and precision manufacturing technology. Currently, the position detection of linear motors is mainly achieved using encoders, magnetic gratings, or optical gratings. Although the theoretical accuracy of linear motors is very high, in practical applications, it may be limited by the resolution of the encoder and the non-uniformity of the magnetic field. Summary of the Invention

[0003] In view of the above technical problems, the present invention provides a method for detecting the position of a linear motor based on a spatial Hall element. The method includes the following steps:

[0004] Step S1: Simultaneously obtain the first magnetic signals of a reference Hall element and n compensation Hall elements. The compensation Hall elements are fixedly installed at preset positions on the linear motor. The preset positions are spaced from the reference Hall element along the axis of the linear motor by A n ， and the distance from the axis along the radial direction is L n . A n is the distance from the n th compensation Hall element along the axis of the linear motor to the plane where the reference Hall element is located. L n is the distance from the n th compensation Hall element to the axis of the linear motor. n is the number of compensation Hall elements. The axis of the linear motor is the center line of the magnetic axis.

[0005] Step S2: The first magnetic signals are the original magnetic signals of each Hall element. For the first magnetic signals of the reference Hall element and multiple different compensation Hall elements, based on the first magnetic signals, obtain the first position of the linear motor calculated by multiple different Hall elements W n .

[0006] Step S3: Process the first magnetic signal obtained by the reference Hall element to obtain the first position of the linear motor W 0 , through n the first positions of the linear motor calculated by W n different Hall elements, and compensate the first position of the linear motor W 0 through the position compensation algorithm to obtain the second position of the linear motor W’ , and the second position is the final position of the linear motor in the current state.

[0007] Further, the distance between the reference Hall element and the axis of the linear motor is L 0 . According to the set n Hall elements, compensate the first position of the linear motor W 0 . The position compensation algorithm is:

[0008] , where represents the position of the linear motor after compensation, represents the distance from the i-th Hall element to the axis of the linear motor, represents the distance from the j-th Hall element to the axis of the linear motor, represents the initial position parameter corresponding to the i-th Hall element;

[0009] Set different weights according to the magnitude of the distance Ln from the Hall element to the axis of the linear motor. The closer the Hall element is to the axis of the linear motor, the greater the weight of the proportion it occupies, so as to compensate and obtain the final position of the linear motor.

[0010] Further, the calculation process of the first position of the linear motor W n includes that the compensation Hall element and the reference Hall element form a differential signal pair, and the effective position signal is extracted by eliminating the common-mode magnetic field interference; the sensitivity coefficient of position calculation is dynamically adjusted according to the axial spacing An and the radial distance Ln of each compensation Hall element.

[0011] Further, the construction of the differential signal pair includes that at least two groups of compensation Hall elements are respectively located on the positive and negative axial sides of the reference Hall element; the radial distances from each compensation Hall element to the axis of the motor form a non-equidistant gradient distribution.

[0012] Further, the compensation Hall element and the reference Hall element form a differential signal pair to extract the effective position signal by eliminating the common-mode magnetic field interference; the sensitivity coefficient of position calculation is dynamically adjusted according to the axial spacing An and the radial distance Ln of each compensation Hall element.

[0013] Further, the position compensation algorithm includes step S101 of establishing a temperature drift compensation term related to the position signals of each Hall element based on the real-time measurement value of the temperature sensor.

[0014] Step S102 of dynamically adjusting the position weight distribution between the reference Hall element and the compensation Hall element according to the motor movement speed.

[0015] Step S103 of mapping the position deviation amounts of multiple compensation Hall elements to the axial position correction amount through spatial geometric relationships.

[0016] The position compensation algorithm includes constructing a spatial weight matrix composed of the parameters An and Ln; obtaining the reference position mapping table of each compensation Hall element through off-line calibration; and online updating the compensation coefficient by using the recursive least squares method.

[0017] It also includes an anomaly detection mechanism that continuously monitors the position deviation amounts between each compensation Hall element and the reference Hall element; when the abnormal deviation exceeding the set threshold continuously appears, it automatically switches to the redundant compensation Hall element group; the anomaly detection mechanism generates a diagnostic signal including the position identifier of the faulty element.

[0018] The beneficial effects of the present invention compared with the prior art are as follows: (1) By constructing a differential signal pair through the spatial layout of multiple Hall elements and combining the distance-weighted compensation algorithm and temperature drift correction, the present invention significantly improves the position detection accuracy; (2) By adopting dynamic sensitivity adjustment and redundant fault tolerance mechanism, the present invention enhances the anti-interference ability and system reliability, and effectively solves the position detection problem under the complex working conditions of the linear motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is an exemplary step flow chart of the position detection method of the present invention.

[0020] Figure 2 It is an exemplary step flow chart of the position compensation algorithm of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] Such as Figure 1The following is an exemplary step flowchart of the position detection method in this embodiment. The method includes the following steps:

[0023] Step S1, simultaneously obtain the first magnetic signals of the reference Hall element and n a compensation Hall element. The compensation Hall element is fixedly installed at a preset position on the linear motor. The preset position is spaced from the reference Hall element along the axis of the linear motor by A n ， The distance from the radial direction to the axis is L n at the position of A n is the n distance from the nth compensation Hall element along the axis of the linear motor to the plane where the reference Hall element is located, L n is the n distance from the nth compensation Hall element to the axis of the linear motor, n is the number of compensation Hall elements, and the axis of the linear motor is the center line of the magnetic axis.

[0024] Step S2, the first magnetic signal is the original magnetic signal of each Hall element. For the first magnetic signals of the reference Hall element and multiple different compensation Hall elements, according to the first magnetic signals, obtain the first position of the linear motor calculated by multiple different Hall elements W n .

[0025] Step S3, process the first magnetic signal obtained by the reference Hall element to obtain the first position W 0 of the linear motor. Through n the first positions of the linear motor calculated by different Hall elements W n , compensate the first position W 0 of the linear motor through the position compensation algorithm to obtain the second position W’ of the linear motor. The second position is the final position of the linear motor in the current state.

[0026] The distance between the reference Hall element and the axis of the linear motor is L 0 . According to the set n Hall elements, compensate the first position W 0 of the linear motor. The position compensation algorithm is:

[0027] , where represents the position of the linear motor after compensation, represents the distance from the ith Hall element to the axis of the linear motor, represents the distance from the jth Hall element to the axis of the linear motor, Represents the initial position parameter corresponding to the i-th Hall element; according to the distance from the Hall element to the axis of the linear motor L n The size of the Hall element is set with different weights. The closer the Hall element is to the axis of the linear motor, the greater the weight it has, thereby compensating for the final position of the linear motor.

[0028] In the above formula, Used to calculate the distance of the i-th Hall element The ratio of the total distance of all elements. If the i-th Hall element is very close to the axis, the ratio is small; if the i-th Hall element is far from the axis, the ratio is large. Its purpose is that the closer the distance, the greater the weight. The Hall element that is closer to the axis of the linear motor should provide a greater contribution of the initial position parameter (Wᵢ) to the final result (W') (that is, the higher the weight). Conversely, the farther the element is from the axis, the lower its weight should be. This is because it is generally believed that sensor signals close to the axis are stronger, more accurate, and less affected by interference. Due to the above characteristics, the compensation algorithm can bring the following beneficial effects. First, by giving greater weights to Hall elements closer to the motor axis, the algorithm prioritizes information from areas with stronger magnetic fields and more reliable signals, effectively suppressing noise, nonlinear errors, or the effects of installation deviations that may be introduced by distant sensors, thereby improving the calculation accuracy of the final position W'; secondly, by calculating The sum of is used as the denominator, which provides a relative normalization processing, enhances the robustness of the system and improves the anti-interference ability.

[0029] Linear motor first position W n The calculation process includes: the compensation Hall element and the reference Hall element form a differential signal pair, and the effective position signal is extracted by eliminating the common-mode magnetic field interference; the sensitivity coefficient of the position solution is dynamically adjusted according to the axial spacing An and radial distance Ln of each compensation Hall element.

[0030] The construction of the differential signal pair includes: at least two groups of compensation Hall elements are respectively located on the positive and negative sides of the axial direction of the reference Hall element; the radial distance from each compensation Hall element to the motor axis forms a non-equidistant gradient distribution.

[0031] The compensation Hall element and the reference Hall element form a differential signal pair, and the effective position signal is extracted by eliminating the common-mode magnetic field interference; the sensitivity coefficient of the position solution is dynamically adjusted according to the axial spacing An and radial distance Ln of each compensation Hall element.

[0032] likeFigure 2 As shown, the position compensation algorithm of this embodiment includes

[0033] Step S101: Based on the real-time measurement value of the temperature sensor, establish a temperature drift compensation term related to the position signals of each Hall element.

[0034] Step S102: Dynamically adjust the position weight distribution between the reference Hall element and the compensation Hall element according to the motor movement speed.

[0035] Step S103: Map the position deviation amounts of multiple compensation Hall elements to the axial position correction amount through spatial geometric relationships.

[0036] In the above steps, under the real-time monitoring of the temperature sensor, an association model between the output signal of the Hall element and the temperature is established. For example, high temperature may cause an increase in magnetoresistance or an offset of the Hall coefficient. By introducing polynomial fitting or neural network prediction, a temperature-related compensation coefficient is generated to correct the signal offset of each element in real time and suppress the influence of temperature drift on position calculation.

[0037] Adjust the weights of the reference and compensation elements according to the motor movement speed (such as low speed, high speed, rapid acceleration): Low-speed state: Rely on the high-sensitivity signals of the nearby compensation elements, and the weight distribution biases towards the elements with smaller Ln. High-speed state: Prioritize the stable signals of the distant elements to avoid the accumulation of dynamic errors, and at the same time combine the recursive least squares method to predict the position trend. Direction-switching transient: Temporarily increase the weight of the axially symmetric compensation elements to suppress the magnetic field distortion interference caused by commutation.

[0038] The position compensation algorithm includes constructing a spatial weight matrix composed of An and Ln parameters; obtaining the reference position mapping table of each compensation Hall element through offline calibration; and using the recursive least squares method to update the compensation coefficient online.

[0039] In this embodiment, map the position deviation amounts (ΔWn) of each compensation element to the axial correction amount through a spatial coordinate transformation model (such as a homogeneous transformation matrix). For example, utilize the geometric relationship between the radial distance Ln and the axial spacing An to construct a non-linear mapping function between the deviation amount and the axial displacement, and fuse multiple groups of correction amounts through Kalman filtering to output the smoothed final position W’.

[0040] The method of this embodiment also includes an anomaly detection mechanism, which continuously monitors the position deviation amounts between each compensation Hall element and the reference Hall element; when abnormal deviations exceeding the set threshold continuously occur, automatically switch to the redundant compensation Hall element group; the anomaly detection mechanism generates a diagnostic signal containing the position identifier of the faulty element.

[0041] The above content is only an example and illustration of the present invention. Those skilled in the art to which the present technology pertains may make various modifications or supplements to the described specific embodiments or use similar methods for substitution. As long as they do not deviate from the scope defined by the invention, they shall fall within the protection scope of the present invention.

Claims

1. A method for detecting the position of a linear motor based on a spatial Hall element, characterized in that: The method includes the following steps: Step S1, simultaneously obtain the first magnetic signals of a reference Hall element and n compensation Hall elements. The compensation Hall elements are fixedly installed at preset positions on the linear motor. The preset positions are spaced by A along the axis direction of the linear motor from the reference Hall element n , and the distance from the axis in the radial direction is L n The position, A n is the distance from the nth compensation Hall element along the axis of the linear motor to the plane where the reference Hall element is located, and L n is the distance from the nth compensation Hall element to the axis of the linear motor. n is the number of compensation Hall elements, and the axis of the linear motor is the magnetic axis center line; Step S2, the first magnetic signal is the original magnetic signal of each Hall element. For the first magnetic signals of the reference Hall element and multiple different compensation Hall elements, based on the first magnetic signal, the first position W of the linear motor calculated by multiple different Hall elements is obtained. n ; Step S3: Process the first magnetic signal obtained by the reference Hall element to obtain the first position W0 of the linear motor. The first position W of the linear motor is calculated by n different Hall elements. n , Compensate the first position W0 of the linear motor through a position compensation algorithm to obtain the second position W' of the linear motor. The second position is the final position of the linear motor in the current state. The distance between the reference Hall element and the axis of the linear motor is L0. According to the set n Hall elements, compensate the first position W0 of the linear motor. The position compensation algorithm is as follows: , where represents the position of the linear motor after compensation, represents the distance from the i-th Hall element to the axis of the linear motor, represents the distance from the j-th Hall element to the axis of the linear motor, represents the initial position parameter corresponding to the i-th Hall element; According to the distance L from the Hall element to the axis of the linear motor n different weights are set. The closer the Hall element is to the axis of the linear motor, the greater the weight of the proportion it occupies, so as to compensate and obtain the final position of the linear motor.

2. The linear motor position detection method based on a spatial Hall element according to claim 1, characterized in that: The first position W of the linear motor described above n The calculation process includes that the compensation Hall element and the reference Hall element form a differential signal pair, and the effective position signal is extracted by eliminating the common-mode magnetic field interference; the sensitivity coefficient of position calculation is dynamically adjusted according to the axial spacing An and the radial distance Ln of each compensation Hall element.

3. A method for detecting the position of a linear motor based on a spatial Hall element according to claim 2, characterized in that: The construction of the differential signal pair includes that at least two groups of compensation Hall elements are respectively located on the positive and negative axial sides of the reference Hall element; the radial distances from each compensation Hall element to the motor axis form a non-equidistant gradient distribution.

4. A linear motor position detection method based on a spatial Hall element according to claim 2, characterized in that: The compensation Hall element and the reference Hall element form a differential signal pair, and the effective position signal is extracted by eliminating the common-mode magnetic field interference; the sensitivity coefficient of position calculation is dynamically adjusted according to the axial spacing An and the radial distance Ln of each compensation Hall element.

5. A method for detecting the position of a linear motor based on a spatial Hall element according to claim 1, characterized in that: The position compensation algorithm includes Step S101, based on the real-time measurement value of the temperature sensor, establish a temperature drift compensation term related to the position signals of each Hall element; Step S102, dynamically adjust the position weight distribution between the reference Hall element and the compensation Hall element according to the motor movement speed; Step S103, map the position deviation amounts of multiple compensation Hall elements to the axial position correction amount through spatial geometric relations.

6. A method for detecting the position of a linear motor based on a spatial Hall element according to claim 1, characterized in that: The position compensation algorithm further includes constructing a spatial weight matrix composed of the parameters An and Ln; Obtain the reference position mapping table of each compensation Hall element through offline calibration; Adopt the recursive least squares method to update the compensation coefficient online.

7. A linear motor position detection method based on a spatial Hall element according to claim 1, characterized in that: It also includes an anomaly detection mechanism that continuously monitors the position deviation amounts between each compensation Hall element and the reference Hall element; when abnormal deviations exceeding the set threshold continuously appear, automatically switch to the redundant compensation Hall element group; the anomaly detection mechanism generates a diagnostic signal containing the position identifier of the faulty element.

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