Linear motor position detection method based on space Hall element

Abstract

The invention discloses a linear motor position detection method based on a space Hall element, belongs to the technical field of linear motors, and realizes high-precision position detection through cooperative work of a reference Hall element and a plurality of compensation Hall elements. The compensation Hall elements are distributed on the positive side and the negative side of the reference element in the axial direction in a non-equidistant gradient mode to form differential signal pairs to eliminate common-mode interference, and the sensitivity coefficient is dynamically adjusted by combining the axial distance An and the radial distance Ln. And the anomaly detection mechanism monitors the deviation value in real time, switches the redundant component group when the deviation value exceeds a threshold value and generates a fault diagnosis signal. According to the method, through a multi-dimensional signal fusion and dynamic compensation strategy, the detection precision, the anti-interference capability and the system reliability under complex working conditions are remarkably improved.

Description

Technical Field

[0001] The present application relates to the technical field of linear motors, and in particular to a linear motor position detection method based on a spatial Hall element. Background Art

[0002] Linear motors convert electrical energy into linear motion based on the law of electromagnetic induction. In linear motors, the interaction between the magnetic field and the conductor generates a force in the linear direction, thereby driving the load to move in a linear direction. 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 equipment. The development of linear motor technology has promoted the advancement of industrial automation and precision manufacturing technology. At present, the position detection of linear motors is mainly achieved using encoders and magnetic or optical gratings. Although the theoretical accuracy of linear motors is very high, in practical applications it may be limited by the encoder resolution and magnetic field inhomogeneity. Summary of the invention

[0003] In view of the above technical problems, the present invention provides a linear motor position detection method based on a spatial Hall element, the method comprising the following steps: Step S1, simultaneously obtain the reference Hall element and n The first magnetic signal of the compensation Hall element is fixedly mounted on a preset position of the linear motor, and the preset position is spaced by the reference Hall element along the axis direction of the linear motor. A n ， The distance from the axis along the radial direction is L n location, A n For the n The distance from the compensation Hall element to the plane where the reference Hall element is located along the axis of the linear motor. L n For the n The distance from the compensation Hall element to the linear motor axis, n To compensate for the number of Hall elements, the axis of the linear motor is the center line of the magnetic axis.

[0004] Step S2, the first magnetic signal is the original magnetic signal of each Hall element, and the first magnetic signals of the reference Hall element and the plurality of different compensation Hall elements are used to obtain the first position of the linear motor calculated by the plurality of different Hall elements according to the first magnetic signal. W n .

[0005] Step S3, processing the first magnetic signal obtained by the reference Hall element to obtain the first position of the linear motor W 0 ,pass n The first position of the linear motor calculated by different Hall elements W n , the first position of the linear motor is compensated by the position compensation algorithm W 0 Compensate and get the second position of the linear motor W’ , the second position is the final position of the linear motor in the current state.

[0006] Furthermore, the distance between the reference Hall element and the axis of the linear motor is L 0 , according to the setting n A Hall element is provided for the first position of the linear motor W 0 To compensate, the position compensation algorithm is: ,in represents the linear motor position 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; Different weights are set according to 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 its weight is, thereby compensating for the final position of the linear motor.

[0007] Furthermore, the first position of the linear motor 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.

[0008] Furthermore, the construction of the differential signal pair includes at least two groups of compensation Hall elements being respectively located on the positive and negative axial sides of the reference Hall element; and the radial distance from each compensation Hall element to the motor axis forms a non-equidistant gradient distribution.

[0009] Furthermore, the compensation Hall element and the reference Hall element form a differential signal pair, and an effective position signal is extracted by eliminating 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.

[0010] Furthermore, the position compensation algorithm includes, step S101, establishing a temperature drift compensation term related to the position signal of each Hall element based on the real-time measurement value of the temperature sensor.

[0011] Step S102 , dynamically adjusting the position weight distribution of the reference Hall element and the compensation Hall element according to the motor movement speed.

[0012] Step S103, mapping the position deviations of the plurality of compensated Hall elements to axial position corrections through spatial geometric relationships.

[0013] The position compensation algorithm includes: constructing a spatial weight matrix composed of An and Ln parameters; obtaining a reference position mapping table of each compensation Hall element through offline calibration; and updating the compensation coefficient online using the recursive least squares method.

[0014] It also includes an abnormality detection mechanism, which continuously monitors the position deviation between each compensation Hall element and the reference Hall element; when abnormal deviations exceeding the set threshold continue to occur, it automatically switches to a redundant compensation Hall element group; the abnormality detection mechanism generates a diagnostic signal containing a faulty element position identifier.

[0015] Compared with the prior art, the present invention has the following advantages: (1) The present invention constructs a differential signal pair by spatially arranging multiple Hall elements, and combines a distance weighted compensation algorithm and temperature drift correction to significantly improve the position detection accuracy; (2) The present invention adopts dynamic sensitivity adjustment and redundant fault tolerance mechanism to enhance the anti-interference ability and system reliability, and effectively solves the position detection problem of the linear motor under complex working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The present invention is a flowchart of an exemplary method for detecting a position.

[0017] Figure 2 The figure is a flowchart of an exemplary step of the position compensation algorithm of the present invention. DETAILED DESCRIPTION

[0018] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with 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 intended to limit the present invention.

[0019] like Figure 1 The figure is an exemplary step flow chart of the position detection method of this embodiment, and the method includes the following steps: Step S1, simultaneously obtain the reference Hall element and nThe first magnetic signal of the compensation Hall element is fixedly mounted on a preset position of the linear motor. The preset position is spaced by the reference Hall element along the axis of the linear motor. A n ， The distance from the axis along the radial direction is L n location, A n For the n The distance from the compensation Hall element to the plane where the reference Hall element is located along the axis of the linear motor. L n For the n The distance from the compensation Hall element to the linear motor axis, n To compensate for the number of Hall elements, the linear motor axis is the centerline of the magnetic axis.

[0020] Step S2, the first magnetic signal is the original magnetic signal of each Hall element, and the first magnetic signals of the reference Hall element and the plurality of different compensation Hall elements are used to obtain the first position of the linear motor calculated by the plurality of different Hall elements according to the first magnetic signal. W n .

[0021] Step S3, processing the first magnetic signal obtained by the reference Hall element to obtain the first position of the linear motor W 0 ,pass n The first position of the linear motor calculated by different Hall elements W n , the first position of the linear motor is compensated by the position compensation algorithm W 0 Compensate and get the second position of the linear motor W’ , the second position is the final position of the linear motor in the current state.

[0022] The distance between the reference Hall element and the linear motor axis is L 0 , according to the setting n A Hall element is used to determine the first position of the linear motor. W 0 To compensate, the position compensation algorithm is: ,in represents the linear motor position 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] like Figure 2 As shown, the position compensation algorithm of this embodiment includes: Step S101: establishing a temperature drift compensation term related to the position signal of each Hall element based on the real-time measurement value of the temperature sensor.

[0028] Step S102 , dynamically adjusting the position weight distribution of the reference Hall element and the compensation Hall element according to the motor movement speed.

[0029] Step S103, mapping the position deviations of the plurality of compensated Hall elements to axial position corrections through spatial geometric relationships.

[0030] In the above steps, under the real-time monitoring of the temperature sensor, a correlation model between the output signal of the Hall element and the temperature is established. For example, high temperature may lead to increased magnetic resistance or Hall coefficient offset. By introducing polynomial fitting or neural network prediction, a temperature-related compensation coefficient is generated to correct the signal offset of each component in real time and suppress the influence of temperature drift on position solution.

[0031] Adjust the weights of the reference and compensation elements according to the motor movement speed (such as low speed, high speed, and rapid acceleration): Low speed state: rely on the high-sensitivity signal of the close-range compensation element, and the weight distribution is biased towards the element with smaller Ln. High speed state: give priority to the stable signal of the long-range element to avoid dynamic error accumulation, and combine the recursive least squares method to predict the position trend. Direction switching transient: temporarily increase the weight of the axially symmetrical compensation element to suppress the magnetic field distortion interference caused by commutation.

[0032] The position compensation algorithm includes: constructing a spatial weight matrix composed of An and Ln parameters; obtaining a reference position mapping table of each compensation Hall element through offline calibration; and updating the compensation coefficient online using the recursive least squares method.

[0033] In this embodiment, the position deviation (ΔWn) of each compensation element is mapped to the axial correction value through a spatial coordinate transformation model (such as a homogeneous transformation matrix). For example, a nonlinear mapping function of the deviation and the axial displacement is constructed by using the geometric relationship between the radial distance Ln and the axial spacing An, and multiple groups of correction values ​​are fused through Kalman filtering to output the smoothed final position W'.

[0034] The method of this embodiment also includes an abnormality detection mechanism, which continuously monitors the position deviation of each compensating Hall element and the reference Hall element; when the abnormal deviation exceeding the set threshold value continues to occur, it automatically switches to the redundant compensating Hall element group; the abnormality detection mechanism generates a diagnostic signal containing the position identification of the faulty element.

[0035] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways. As long as they do not deviate from the scope defined by the invention, they shall all fall within the protection scope of the present invention.

Claims

1. A linear motor position detection method based on a spatial Hall element, characterized in that: The method comprises the following steps: Step S1, simultaneously obtain the reference Hall element and n The first magnetic signal of the compensation Hall element is fixedly mounted on a preset position of the linear motor, and the preset position is spaced by the reference Hall element along the axis direction of the linear motor. A n ， The distance from the axis along the radial direction is L n location, A n For the n The distance from the compensation Hall element to the plane where the reference Hall element is located along the axis of the linear motor. L n For the n The distance from the compensation Hall element to the linear motor axis, n To compensate for the number of Hall elements, the linear motor axis is the centerline of the magnetic axis; Step S2, the first magnetic signal is the original magnetic signal of each Hall element, and the first magnetic signals of the reference Hall element and the plurality of different compensation Hall elements are used to obtain the first position of the linear motor calculated by the plurality of different Hall elements according to the first magnetic signal. W n ; Step S3, processing the first magnetic signal obtained by the reference Hall element to obtain the first position of the linear motor W 0 ,pass n The first position of the linear motor calculated by different Hall elements W n , the first position of the linear motor is compensated by the position compensation algorithm W 0 Compensate and get the second position of the linear motor W’ , the second position is the final position of the linear motor in the current state.

2. A linear motor position detection method based on spatial Hall element according to claim 1, characterized in that: The distance between the reference Hall element and the linear motor axis is L 0 , according to the setting n A Hall element is provided for the first position of the linear motor W 0 To compensate, the position compensation algorithm is: ,in 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 linear motor axis 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.

3. A linear motor position detection method based on spatial Hall element according to claim 1, characterized in that: The calculation process of the first position Wn of the linear motor 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.

4. A linear motor position detection method based on spatial Hall element according to claim 3, characterized in that: 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.

5. The linear motor position detection method based on spatial Hall element according to claim 3 is characterized in that: The compensation Hall element and the reference Hall element form a differential signal pair, and extract the effective position signal 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.

6. A linear motor position detection method based on spatial Hall element according to claim 1, characterized in that: The position compensation algorithm includes, Step S101, establishing a temperature drift compensation term related to each Hall element position signal based on the real-time measurement value of the temperature sensor; Step S102, dynamically adjusting the position weight distribution of the reference Hall element and the compensation Hall element according to the motor movement speed; Step S103, mapping the position deviations of the plurality of compensated Hall elements to axial position corrections through spatial geometric relationships.

7. A linear motor position detection method based on spatial Hall element according to claim 1, characterized in that: The position compensation algorithm also includes constructing a spatial weight matrix consisting of An and Ln parameters; Obtaining a reference position mapping table of each compensation Hall element through offline calibration; The recursive least squares method is used to update the compensation coefficients online.

8. The linear motor position detection method based on spatial Hall element according to claim 1, characterized in that: It also includes an abnormality detection mechanism, which continuously monitors the position deviation between each compensation Hall element and the reference Hall element; when abnormal deviations exceeding the set threshold continue to occur, it automatically switches to a redundant compensation Hall element group; the abnormality detection mechanism generates a diagnostic signal containing a faulty element position identifier.

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