CN116518836A - Permanent magnet synchronous linear motor displacement measurement method, device, computer and medium - Google Patents
Permanent magnet synchronous linear motor displacement measurement method, device, computer and medium Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/02—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width or thickness
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
- G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
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Abstract
The invention provides a displacement measurement method, a device, a computer and a medium of a permanent magnet synchronous linear motor, wherein the method comprises the steps of obtaining the magnetic field intensity generated by a stator of the permanent magnet synchronous linear motor and detected by a plurality of magnetic sensors as a first magnetic field intensity in the displacement process of a rotor of the permanent magnet synchronous linear motor, obtaining the displacement distance of the rotor of the permanent magnet synchronous linear motor, measured by a displacement sensor, as a first displacement distance, and establishing a mapping relation between the magnetic field intensity and the displacement distance; acquiring a second magnetic field intensity of a stator of the permanent magnet synchronous linear motor; and calculating a second displacement distance of the rotor of the permanent magnet synchronous linear motor based on the second magnetic field intensity and the mapping relation. And the mapping relation between the magnetic field intensity and the displacement distance is established by taking the acquired magnetic field intensity and the displacement distance of the rotor as references, a mathematical analysis model of the magnetic field intensity distribution is not required to be established, displacement calculation errors caused by inaccurate magnetic field models are avoided, and the displacement calculation speed and accuracy are improved.
Description
Technical Field
The invention relates to the technical field of permanent magnet synchronous linear motor displacement measurement, in particular to a permanent magnet synchronous linear motor displacement measurement method, a device, a computer and a medium.
Background
The permanent magnet synchronous linear motor can realize linear motion driving without a transmission structure, has the advantages of high motion precision, high response speed, simple structure and the like, and is widely applied to various electromechanical systems. In order to realize high-precision position output control of the system, precise position measurement is indispensable.
At present, a position measurement mode of a commercial permanent magnet synchronous linear motor usually adopts a photoelectric encoder, so that micron-level measurement resolution is easy to achieve, however, the cost is high, and the measurement light is extremely easy to be influenced by ambient light, mechanical vibration and the like, so that the measurement light has strict requirements on working environment and installation conditions. In addition, displacement measurement based on magnetic sensors is proposed, which is less susceptible to environmental disturbances such as dust, oil stains, etc., with higher reliability and low cost.
The displacement measurement based on the magnetic sensor mostly utilizes the magnetic sensor to detect the magnetic field intensity of the magnetic field generated by the stator magnetic steel at the current position of the rotor, and then solves the position through the established magnetic field intensity distribution model (magnetic field model). For the magnetic field generated by the permanent magnets which are periodically arranged in the linear motor, a common magnetic field model is a harmonic model, namely, the intensity of the magnetic field is generally considered to be in a fourier series function relation with a finite order of position. Since describing the relationship between magnetic field strength and position using a finite order harmonic function under the assumption that the magnetic field strength distribution has periodicity will produce a higher order error residual whose magnitude decreases slowly as the model order increases, the existence of the error residual makes the magnetic field model inaccurate, resulting in loss of position resolution accuracy, while using an excessively high model order will increase the amount of calculation and reduce the position measurement bandwidth.
In summary, due to strong nonlinearity of the magnetic field intensity distribution and deviation between the actual permanent magnet processing, installation conditions and design values, it is not practical to seek a strictly accurate actual magnetic field mathematical analysis model, but the existing fitting approximation of various mathematical analysis functions to the actual magnetic field intensity distribution inevitably generates approximation errors, even if the order is improved, the improvement of the precision is still limited and great computing resource consumption is brought.
Disclosure of Invention
Based on the foregoing, it is necessary to provide a method, a device, a computer and a medium for measuring the displacement of a permanent magnet synchronous linear motor.
A displacement measurement method of a permanent magnet synchronous linear motor comprises the following steps:
in the displacement process of a rotor of a permanent magnet synchronous linear motor, acquiring a sequence of magnetic field intensity, which is generated by a stator of the permanent magnet synchronous linear motor within a preset time length and detected by a plurality of magnetic sensors, as a first magnetic field intensity, and acquiring a displacement distance, which is measured by a displacement sensor, of the rotor of the permanent magnet synchronous linear motor as a first displacement distance, wherein each magnetic sensor is arranged on the rotor of the permanent magnet synchronous linear motor;
determining the corresponding relation between the first magnetic field intensity and the first displacement distance based on the time sequence, and establishing a mapping relation between the magnetic field intensity and the displacement distance;
Acquiring a second magnetic field intensity of a stator of the permanent magnet synchronous linear motor;
and calculating a second displacement distance of the rotor of the permanent magnet synchronous linear motor based on the second magnetic field intensity and the mapping relation.
In one embodiment, the step of determining the correspondence between each of the first magnetic field strengths and each of the first displacement distances based on the time series, and establishing the mapping relationship between the magnetic field strengths and the displacement distances includes:
determining a corresponding relation between each first magnetic field intensity and each first displacement distance based on a time sequence;
and establishing a magnetic field intensity distribution continuous interpolation function related to the displacement distance through interpolation of the first magnetic field intensity to the first displacement distance and piecewise linear difference of the first magnetic field intensity to the first position distance, so as to obtain a mapping relation between the magnetic field intensity and the displacement distance.
In one embodiment, the step of interpolating each of the first displacement distances by each of the first magnetic field strengths includes:
establishing a displacement arithmetic sequence { x (k) } = {0, h,2h, }, wherein h is a displacement step size;
by applying a first magnetic field strength { B m (t n ) For the first displacement distance { x (t) n ) Interpolation to obtain the mth magnetic sensor signal B of the mover at displacement x (k) m (k)，B m (k) The method comprises the following steps:
wherein t is n ,t n+1 Satisfy x (k) ε [ x (t) n ),x(t n+1 )]；
The step of piecewise linearly differencing the distance from each of the first locations by each of the first magnetic field strengths includes:
by combining the mth magnetic sensor signal { B } m (k) Performing piecewise linear interpolation on the first position distance { x (k) }, and establishing a magnetic field intensity distribution continuous interpolation function:
the magnetic field intensity distribution continuous function established based on the signals of the magnetic sensors is as follows:
B(x)＝[B 1 (x),B 2 (x),...,B M (x)] T 。
in one embodiment, the step of calculating the second displacement distance of the mover of the permanent magnet synchronous linear motor based on the second magnetic field strength and the mapping relationship includes:
based on the second magnetic field strength and the mapping relation, a nonlinear equation set of the magnetic field strength at the moment to be detected is established;
and solving the nonlinear equation set by using a least square solution to obtain a second displacement distance of the rotor of the permanent magnet synchronous linear motor.
In one embodiment, the step of calculating the second displacement distance of the mover of the permanent magnet synchronous linear motor based on the second magnetic field strength and the mapping relationship includes:
Step 1, based on a pre-obtained magnetic field intensity distribution function B (x), a nonlinear equation system of magnetic field intensity at a moment t to be measured is established:
Y＝B(x)+e
wherein Y= [ Y ] 1 ,y 2 ,...,y M ] T As the signal of the magnetic sensor, e= [ e ] 1 ,e 2 ,...,e M ] T Is signal noise;
step 2, to minimize the functionTaking the t-1 moment displacement calculation result x as a target (t-1) As an iteration initial value +.>Time 0 displacement x (t-1) =0, the displacement x at time t is calculated according to the following iterative formula (t) Least squares solution of (2):
wherein, p is the iteration number, J (·) is the jacobian matrix of B (·), and the following is obtained:
wherein the derivative of the piecewise linear interpolation function B (x) at the interpolation point x (k) is defined as:
step 3, obtaining an error preset value epsilon and a maximum iteration number p max If (if)And p < p max Returning to the step 2 to continue iteration, otherwise ending the iteration to obtain a second displacement distance +.>
In one embodiment, each magnetic sensor is arranged on a rotor of the permanent magnet synchronous linear motor in an array.
A permanent magnet synchronous linear motor displacement measurement device, comprising:
the magnetic field and displacement acquisition module is used for acquiring a sequence of magnetic field intensity generated by a stator of the permanent magnet synchronous linear motor in a preset time length and detected by the magnetic sensor as a first magnetic field intensity in a displacement process of a rotor of the permanent magnet synchronous linear motor, and acquiring a displacement distance of the rotor of the permanent magnet synchronous linear motor, measured by the displacement sensor, as a first displacement distance, wherein the magnetic sensor is arranged on the rotor of the permanent magnet synchronous linear motor;
The mapping relation establishing module is used for determining the corresponding relation between the first magnetic field intensity and the first displacement distance based on the time sequence and establishing the mapping relation between the magnetic field intensity and the displacement distance;
the magnetic field real-time acquisition module is used for acquiring the second magnetic field intensity of the stator of the permanent magnet synchronous linear motor;
and the displacement real-time obtaining module is used for calculating and obtaining the second displacement distance of the rotor of the permanent magnet synchronous linear motor based on the second magnetic field intensity and the mapping relation.
A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor when executing the computer program performs the steps of:
in the displacement process of a rotor of a permanent magnet synchronous linear motor, acquiring a magnetic field intensity sequence, which is detected by a plurality of magnetic sensors, of a stator of the permanent magnet synchronous linear motor within a preset time length as a first magnetic field intensity, and acquiring a displacement distance, which is measured by a displacement sensor and is used for measuring the rotor of the permanent magnet synchronous linear motor, as a first displacement distance, wherein each magnetic sensor is arranged on the rotor of the permanent magnet synchronous linear motor;
Determining the corresponding relation between the first magnetic field intensity and the first displacement distance based on the time sequence, and establishing a mapping relation between the magnetic field intensity and the displacement distance;
acquiring a second magnetic field intensity of a stator of the permanent magnet synchronous linear motor;
and calculating a second displacement distance of the rotor of the permanent magnet synchronous linear motor based on the second magnetic field intensity and the mapping relation.
A computer readable storage medium having stored thereon a computer program which when executed by a processor performs the steps of:
in the displacement process of a rotor of a permanent magnet synchronous linear motor, acquiring a sequence of magnetic field intensity, which is generated by a stator of the permanent magnet synchronous linear motor within a preset time length and detected by a plurality of magnetic sensors, as a first magnetic field intensity, and acquiring a displacement distance, which is measured by a displacement sensor, of the rotor of the permanent magnet synchronous linear motor as a first displacement distance, wherein each magnetic sensor is arranged on the rotor of the permanent magnet synchronous linear motor;
determining the corresponding relation between the first magnetic field intensity and the first displacement distance based on the time sequence, and establishing a mapping relation between the magnetic field intensity and the displacement distance;
Acquiring a second magnetic field intensity of a stator of the permanent magnet synchronous linear motor;
and calculating a second displacement distance of the rotor of the permanent magnet synchronous linear motor based on the second magnetic field intensity and the mapping relation.
A computer program which, when executed by a processor, performs the steps of:
in the displacement process of a rotor of a permanent magnet synchronous linear motor, acquiring a magnetic field intensity sequence, which is detected by a plurality of magnetic sensors, of a stator of the permanent magnet synchronous linear motor within a preset time length as a first magnetic field intensity, and acquiring a displacement distance, which is measured by a displacement sensor and is used for measuring the rotor of the permanent magnet synchronous linear motor, as a first displacement distance, wherein each magnetic sensor is arranged on the rotor of the permanent magnet synchronous linear motor;
determining the corresponding relation between the first magnetic field intensity and the first displacement distance based on the time sequence, and establishing a mapping relation between the magnetic field intensity and the displacement distance;
acquiring a second magnetic field intensity of a stator of the permanent magnet synchronous linear motor;
and calculating a second displacement distance of the rotor of the permanent magnet synchronous linear motor based on the second magnetic field intensity and the mapping relation.
According to the method, the device, the computer and the medium for measuring the displacement of the permanent magnet synchronous linear motor, the mapping relation between the magnetic field intensity and the displacement distance is established by taking the acquired magnetic field intensity and the displacement distance of the rotor as references, a mathematical analysis model of magnetic field intensity distribution is not required to be established, displacement calculation errors caused by inaccuracy of the magnetic field model are avoided, the displacement calculation speed and the displacement calculation precision are improved, and the measuring precision is higher.
Drawings
FIG. 1 is a flow chart of a method for measuring displacement of a permanent magnet synchronous linear motor according to an embodiment;
FIG. 2 is a block diagram of a permanent magnet synchronous linear motor displacement measurement device according to one embodiment;
FIG. 3 is an internal block diagram of a computer device in one embodiment;
FIG. 4 is a schematic diagram of an embodiment of a displacement measurement system for a permanent magnet synchronous linear motor in one embodiment;
fig. 5 (a) is data collected by a displacement sensor, and fig. 5 (b) is data collected by a magnetic sensor;
FIG. 6 (a) shows the magnetic field strength versus displacement interpolation, and FIG. 6 (b) shows the magnetic field strength piecewise linear interpolation;
FIG. 7 (a) shows the displacement measurement results using the displacement measured by the displacement sensor as a reference value, and using the magnetic field intensity distribution fundamental wave model, the magnetic field intensity distribution fifth order harmonic model, and the method employed in the embodiment of the present invention, respectively;
FIG. 7 (b) shows measurement errors for three methods;
FIG. 8 shows the root mean square error comparison of the magnetic field intensity distribution fundamental wave model, the magnetic field intensity distribution fifth order harmonic model and the displacement measurement result of the method of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application.
Example 1
In this embodiment, as shown in fig. 1, a method for measuring displacement of a permanent magnet synchronous linear motor is provided, which includes:
step 110, in the process of displacement of the mover of the permanent magnet synchronous linear motor, acquiring a sequence of magnetic field intensity generated by the stator of the permanent magnet synchronous linear motor within a preset time length and detected by a plurality of magnetic sensors as a first magnetic field intensity, and acquiring a displacement distance of the mover of the permanent magnet synchronous linear motor, measured by a displacement sensor, as a first displacement distance, wherein each magnetic sensor is arranged on the mover of the permanent magnet synchronous linear motor, and the displacement sensor is arranged on the mover of the permanent magnet synchronous linear motor.
In this embodiment, M magnetic sensors are installed on a mover of a permanent magnet synchronous linear motor, where M is greater than 1, the magnetic sensors are used to detect magnetic field intensities generated by a stator, and the magnetic field intensities of the stator are detected by the plurality of magnetic sensors, so as to acquire a plurality of first magnetic field intensities. Specifically, each magnetic sensor continuously detects the magnetic field intensity of the stator for a preset time length, so as to obtain a plurality of magnetic field intensities in the preset time length, and the magnetic field intensities are collected in sequence for the preset time length, so that the first magnetic field intensity of the magnetic sensors is obtained. And a displacement sensor is arranged on the rotor of the permanent magnet synchronous linear motor, the displacement sensor is used for measuring the displacement distance of the rotor, and the displacement sensor can be a grating ruler.
In one embodiment, each magnetic sensor is disposed in an array on a mover of the permanent magnet synchronous linear motor. In this embodiment, the magnetic sensors are arranged in an array on the mover, so that the magnetic sensors at different positions can collect the magnetic field intensity that varies with the movement of the mover, and thus the magnetic field intensity of the stator at each time and each position can be accurately obtained.
In one embodiment, the magnetic sensors are equidistantly arranged on the mover of the permanent magnet synchronous linear motor along the moving direction of the mover. In this embodiment, each magnetic sensor along the moving direction of the mover can collect the magnetic field intensity that changes along with the movement of the mover, so that the accuracy of collecting the magnetic field intensity is effectively improved.
In the embodiment, the exciting coil of the mover is electrified or the mover is driven to move from one end of the guide rail to the other end by using external force, and the magnetic field intensity of the stator and the displacement distance of the mover are simultaneously obtained during the movement of the mover. In this embodiment, the magnetic sensor and the displacement sensor detect the magnetic field strength of the stator and measure the displacement distance of the mover, respectively, based on the same time axis, so that the first magnetic field strength and the first displacement distance can correspond in time sequence, that is, at each moment, there is the first magnetic field strength corresponding to the first displacement distance.
In this embodiment, as shown in fig. 4, the magnetic sensor is a hall sensor, the displacement sensor is a grating ruler bed angel, the hall sensor is used for detecting the intensity of the magnetic field, and the grating ruler sensor is used for measuring the displacement of the rotor. The magnetic field intensity signal detected by the Hall sensor is subjected to low-pass filtering through a low-pass filter on a signal processing board, converted into digital quantity through an analog-to-digital converter and then received by a Field Programmable Gate Array (FPGA); the displacement change pulse signal generated by the grating ruler displacement sensor is received by the FPGA after passing through a pulse counter on a signal processing board. And outputting a displacement measurement result to an upper computer after calculation in the FPGA.
Step 120, determining the corresponding relation between the first magnetic field intensity and the first displacement distance based on the time sequence, and establishing a mapping relation between the magnetic field intensity and the displacement distance.
In this embodiment, since the first magnetic field strength and the first displacement distance are acquired based on the same time axis, the correspondence relationship between the first magnetic field strength and the first displacement distance in time series can be determined.
And 130, obtaining the second magnetic field intensity of the stator of the permanent magnet synchronous linear motor.
It should be noted that the second magnetic field strength may be acquired in real time during the displacement process of the mover, or may be input from an input device of the computer device as input data, or may be read from a memory of the computer device. In this embodiment, after a mapping relationship between the magnetic field strength of the stator of the permanent magnet synchronous linear motor and the displacement distance of the mover is established, the magnetic field strength of the stator of the permanent magnet synchronous linear motor is collected in real time, and the obtained real-time magnetic field strength is the second magnetic field strength, which is the magnetic field strength of the stator at one moment in the displacement process of the mover, that is, the second magnetic field strength is the magnetic field strength of a moment, and is not the magnetic field strength of a sequence.
And 140, calculating a second displacement distance of the rotor of the permanent magnet synchronous linear motor based on the second magnetic field intensity and the mapping relation.
In this embodiment, based on the second magnetic field strength acquired in real time, the real-time displacement distance of the mover, that is, the second displacement distance, is calculated by using the mapping relationship between the magnetic field strength of the stator of the permanent magnet synchronous linear motor and the displacement distance of the mover. In some embodiments, the second magnetic field strength is a magnetic field strength of the stator at a moment in the displacement process of the mover, and thus, the second displacement distance calculated according to the second magnetic field strength is a displacement distance of the mover at the moment.
In other embodiments, the corresponding displacement distance of the mover, that is, the second displacement distance, may also be calculated according to the second magnetic field strength obtained by the input device or the second magnetic field strength read from the memory by using the mapping relationship between the magnetic field strength of the stator of the permanent magnet synchronous linear motor and the displacement distance of the mover.
In the embodiment, the mapping relation between the magnetic field intensity and the displacement distance is established by taking the acquired magnetic field intensity and the displacement distance of the rotor as references, a mathematical analysis model of magnetic field intensity distribution is not required to be established, displacement calculation errors caused by inaccuracy of the magnetic field model are avoided, the displacement calculation speed and accuracy are improved, and higher measurement accuracy is achieved.
In one embodiment, the step of determining the correspondence between each of the first magnetic field strengths and each of the first displacement distances based on the time series, and establishing the mapping relationship between the magnetic field strengths and the displacement distances includes: determining a corresponding relation between each first magnetic field intensity and each first displacement distance based on a time sequence; and establishing a magnetic field intensity distribution continuous interpolation function related to the displacement distance through interpolation of the first magnetic field intensity to the first displacement distance and piecewise linear difference of the first magnetic field intensity to the first position distance, so as to obtain a mapping relation between the magnetic field intensity and the displacement distance.
In one embodiment, the step of interpolating each of the first displacement distances by each of the first magnetic field strengths includes:
step one, continuously sampling at a preset rate through a magnetic sensor in the moving process of the sub-element, wherein the sampling time sequence is recorded as { t } n Recording movementIn the process, the magnetic field intensity signals of all the magnetic sensors and the displacement distance signals detected by the displacement sensors are recorded as { B }, and the signals of the mth magnetic sensor m (t n ) M=1, 2,..m, where M is the number of magnetic sensors, the signal of the displacement sensor is noted { x (t n )}，{x(t n ) And is an incremental sequence.
In one embodiment m=3, { x (t n ) The partial data of } is shown in FIG. 5 (a) { B m (t n ) The partial data of } is shown in fig. 5 (b).
Step two, a displacement arithmetic sequence { x (k) } = {0, h,2h, & gt } is established, wherein h is a displacement step length, and the first magnetic field intensity { B m (t n ) For the first displacement distance { x (t) n ) Interpolation to obtain the mth magnetic sensor signal B of the mover at displacement x (k) m (k)，B m (k) The method comprises the following steps:
wherein t is n ,t n+1 Satisfy x (k) ε [ x (t) n ),x(t n+1 )]；
M=3, b in one embodiment m (k) Part of the data of (a) is shown in fig. 6 (a).
Step three, the step of piecewise linearity difference of the distance between the first positions by the first magnetic field intensity includes:
by combining the mth magnetic sensor signal { B } m (k) Performing piecewise linear interpolation on the first position distance { x (k) }, and establishing a magnetic field intensity distribution continuous interpolation function:
the magnetic field intensity distribution continuous function established based on the signals of the magnetic sensors is as follows:
B(x)＝[B 1 (x),B 2 (x),...,B M (x)] T 。
in one embodiment, the partial data of m=3 and b (x) is shown in fig. 6 (b).
In one embodiment, the step of calculating the second displacement distance of the mover of the permanent magnet synchronous linear motor based on the second magnetic field strength and the mapping relation includes: based on the second magnetic field strength and the mapping relation, a nonlinear equation set of the magnetic field strength at the moment to be detected is established; and solving the nonlinear equation set by using a least square solution to obtain a second displacement distance of the rotor of the permanent magnet synchronous linear motor.
In one embodiment, the step of calculating the second displacement distance of the mover of the permanent magnet synchronous linear motor based on the second magnetic field strength and the mapping relation includes:
step 1, based on a pre-obtained magnetic field intensity distribution function B (x), a nonlinear equation system of magnetic field intensity at a moment t to be measured is established:
Y＝B(x)+e
wherein Y= [ Y ] 1 ,y 2 ,...,y M ] T As the signal of the magnetic sensor, e= [ e ] 1 ,e 2 ,...,e M ] T Is signal noise;
step 2, to minimize the functionTaking the t-1 moment displacement calculation result x as a target (t-1) As an iteration initial value +.>Time 0 displacement x (t-1) =0, the displacement x at time t is calculated according to the following iterative formula (t) Least squares solution of (2):
wherein, p is the iteration number, J (·) is the jacobian matrix of B (·), and the following is obtained:
wherein the derivative of the piecewise linear interpolation function B (x) at the interpolation point x (k) is defined as:
step 3, obtaining an error preset value epsilon and a maximum iteration number p max If (if)And p < p max Returning to the step 2 to continue iteration, otherwise ending the iteration to obtain a second displacement distance +.>
It should be understood that, although the steps in the flowchart of fig. 1 are shown in sequence as indicated by the arrows, the steps are not necessarily performed in sequence as indicated by the arrows. The steps are not strictly limited to the order of execution unless explicitly recited herein, and the steps may be executed in other orders. Moreover, at least some of the steps in fig. 1 may include multiple sub-steps or stages that are not necessarily performed at the same time, but may be performed at different times, nor do the order in which the sub-steps or stages are performed necessarily performed in sequence, but may be performed alternately or alternately with at least a portion of other steps or sub-steps of other steps.
Example two
In this embodiment, a method for measuring displacement of a permanent magnet synchronous linear motor is provided. In this embodiment, the permanent magnet synchronous linear motor displacement measurement method adopts the permanent magnet synchronous linear motor displacement measurement system as shown in fig. 4.
As shown in fig. 4, M hall sensors are used to detect the intensity of the magnetic field, and a grating ruler sensor is used to measure the displacement of the mover. The magnetic field intensity signal detected by the Hall sensor is subjected to low-pass filtering through a low-pass filter on a signal processing board, converted into digital quantity through an analog-to-digital converter and then received by a Field Programmable Gate Array (FPGA); the displacement change pulse signal generated by the grating ruler displacement sensor is received by the FPGA after passing through a pulse counter on a signal processing board. After the algorithm program of the invention is operated in the FPGA, the displacement measurement result is output to the upper computer.
And a, arranging sensors on a permanent magnet synchronous linear motor, arranging M (M & gt 1) magnetic sensors on a rotor of the permanent magnet synchronous linear motor to form an array for detecting the intensity of a magnetic field generated by stator magnetic steel, and simultaneously arranging a precise displacement sensor such as a grating ruler on the rotor for measuring the displacement of the rotor.
And b, collecting signal changes of all magnetic sensors and signal changes of the precise displacement sensor in the motor movement process as magnetic field reference data, establishing a mapping between magnetic field intensity and displacement through magnetic field intensity displacement interpolation and magnetic field intensity piecewise linear interpolation, and storing the mapping relationship into a memory.
And c, substituting the real-time signal of the magnetic sensor into the mapping relation between the magnetic field intensity and the displacement to obtain a nonlinear equation set about the displacement, and calculating the displacement to be measured in real time by using a least square method.
In one embodiment, step a comprises:
step a1: magnetic field intensity and displacement data acquisition: energizing exciting coil of mover or using external force to drive mover to move from original point of one end of guide rail to another end, setting magnetic sensor to continuously sample at given speed in the period, and recording the sampling time sequence as { t } n Recording all magnetic sensor signals and displacement sensor signals in the motion process, wherein the signal of the mth magnetic sensor is recorded as { B } m (t n ) M=1, 2,..m, where M is the number of magnetic sensors and the displacement sensor signal is noted { x (t n ) And is an incremental sequence.
In one embodiment m=3, { x (t n ) The partial data of } is shown in FIG. 5 (a) { B m (t n ) Partial data of } is as shown in FIG. 5 (b)Shown.
Step a2: magnetic field strength to shift interpolation: setting a displacement step h, establishing a displacement arithmetic sequence { x (k) } = {0, h,2h, &.}, and acquiring magnetic field intensity data { B } m (t n ) The displacement data { x (t) n ) Interpolation to obtain the mth magnetic sensor signal B at the position of the displacement x (k) m (k) The method comprises the following steps:
Wherein t is n ,t n+1 Satisfy x (k) ε [ x (t) n ),x(t n+ 1)]This is true.
M=3, b in one embodiment m (k) Part of the data of (a) is shown in fig. 6 (a).
Step a3: magnetic field strength piecewise linear interpolation: by combining magnetic field strength data { B m (k) Piecewise linear interpolation of displacement data { x (k) } to establish a continuous interpolation function of the magnetic field strength distribution:
the magnetic field intensity distribution continuous function established by all magnetic sensor signals is recorded as:
B(x)＝[B 1 (x),B 2 (x),...,B M (x)] T
in one embodiment, the partial data of m=3 and b (x) is shown in fig. 6 (b).
In one embodiment, step c comprises:
step 1: utilizing a magnetic field intensity distribution function B (x) obtained by preprocessing magnetic field data to establish a magnetic field intensity signal nonlinear equation set at the moment t to be detected:
Y＝B(x)+e
as an iteration initial value +.>In particular, the 0 moment displacement is x (t-1) =0, the displacement x at time t is calculated according to the following iterative formula (t) Least squares solution of (2):
wherein p is the number of iterations and J (& gt) is the jacobian matrix of B (& gt), i.e., there are
Wherein the derivative of the piecewise linear interpolation function B (x) at the interpolation point x (k) is defined as
Step 3: given an error preset value epsilon and a maximum number of iterations p max If (if)And p < p max Returning to the step 2 to continue iteration, otherwise ending the iteration to obtain a displacement solving result approximate to a true value ++>
In this embodiment, the displacement of the mover of the linear motor is measured by using the measuring system shown in fig. 4, and the displacement measurement result of the method of the present invention and the measurement result of the method respectively using the existing magnetic field intensity fundamental wave model and the magnetic field intensity fifth order harmonic model are shown in fig. 7 (a), and in fig. 7 (a), the displacement true value as a reference is measured by the grating scale sensor in fig. 4. The displacement measurement errors of the magnetic field intensity fundamental wave model, the magnetic field intensity fifth-order harmonic model and the method are shown in fig. 7 (b), and compared with the magnetic field intensity fundamental wave model and the magnetic field intensity fifth-order harmonic model method, the displacement measurement nonlinear error of the method based on the magnetic field non-model principle is smaller in the method of the invention as shown in fig. 7 (b). The root mean square error of the displacement measurement of the three methods is 5.06 μm, which is far lower than 203.7 μm and 127.5 μm of the other two prior methods, as shown in FIG. 8.
Example III
In this embodiment, as shown in fig. 2, there is provided a displacement measuring device for a permanent magnet synchronous linear motor, including:
the magnetic field and displacement acquisition module 210 is configured to acquire, during displacement of a mover of the permanent magnet synchronous linear motor, a sequence of magnetic field intensities generated by a stator of the permanent magnet synchronous linear motor within a preset time period and detected by a magnetic sensor as a first magnetic field intensity, and acquire a displacement distance of the mover of the permanent magnet synchronous linear motor, measured by a displacement sensor, as a first displacement distance, where the magnetic sensor is disposed on the mover of the permanent magnet synchronous linear motor;
the mapping relationship establishing module 220 is configured to determine, based on a time sequence, a correspondence relationship between each of the first magnetic field strengths and each of the first displacement distances, and establish a mapping relationship between the magnetic field strengths and the displacement distances;
the magnetic field real-time acquisition module 230 is configured to acquire a second magnetic field strength of the stator of the permanent magnet synchronous linear motor;
and the displacement real-time obtaining module 240 is configured to calculate, based on the second magnetic field strength and the mapping relationship, a second displacement distance of the mover of the permanent magnet synchronous linear motor.
In one embodiment, the mapping relation establishing module is configured to determine, based on a time sequence, a correspondence relation between each of the first magnetic field strengths and each of the first displacement distances; and establishing a magnetic field intensity distribution continuous interpolation function related to the displacement distance through interpolation of the first magnetic field intensity to the first displacement distance and piecewise linear difference of the first magnetic field intensity to the first position distance, so as to obtain a mapping relation between the magnetic field intensity and the displacement distance.
In one embodiment, the mapping relationship establishment module is further configured to:
establishing a displacement arithmetic sequence { x (k) } = {0, h,2h, }, wherein h is a displacement step size;
by applying a first magnetic field strength { B m (t n ) For the first displacement distance { x (t) n ) Interpolation to obtain the mth magnetic sensor signal B of the mover at displacement x (k) m (k)，B m (k) The method comprises the following steps:
wherein t is n ,t n+1 Satisfy x (k) ε [ x (t) n ),x(t n+1 )]；
The step of piecewise linearly differencing the distance from each of the first locations by each of the first magnetic field strengths includes:
by combining the mth magnetic sensor signal { B } m (k) Performing piecewise linear interpolation on the first position distance { x (k) }, and establishing a magnetic field intensity distribution continuous interpolation function:
the magnetic field intensity distribution continuous function established based on the signals of the magnetic sensors is as follows:
B(x)＝[B 1 (x),B 2 (x),...,B M (x)] T 。
in one embodiment, the displacement real-time obtaining module is configured to establish a nonlinear equation set of magnetic field strength at a time to be measured based on the second magnetic field strength and the mapping relationship; and solving the nonlinear equation set by using a least square solution to obtain a second displacement distance of the rotor of the permanent magnet synchronous linear motor.
In one embodiment, the displacement real-time acquisition module is further configured to
Based on a pre-obtained magnetic field intensity distribution function B (x), a nonlinear equation system of magnetic field intensity at the moment t to be measured is established:
Y＝B(x)+e
wherein Y= [ Y ] 1 ,y 2 ,...,y M ] T As the signal of the magnetic sensor, e= [ e ] 1 ,e 2 ,...,e M ] T Is signal noise;
to minimize the functionTaking the t-1 moment displacement calculation result x as a target (t-1) As an iteration initial valueTime 0 displacement x (t-1) =0, the displacement x at time t is calculated according to the following iterative formula (t) Least squares solution of (2):
wherein, p is the iteration number, J (·) is the jacobian matrix of B (·), and the following is obtained:
/>
wherein the derivative of the piecewise linear interpolation function B (x) at the interpolation point x (k) is defined as:
obtaining error preset value epsilon and maximum iteration number p max If (if)And p < p max Returning to the step 2 to continue iteration, otherwise ending the iteration to obtain a second displacement distance +.>
In one embodiment, each magnetic sensor is disposed in an array on a mover of the permanent magnet synchronous linear motor.
For specific limitations of the permanent magnet synchronous linear motor displacement measurement device, reference may be made to the above limitations of the permanent magnet synchronous linear motor displacement measurement method, and no further description is given here. All or part of each unit in the permanent magnet synchronous linear motor displacement measuring device can be realized by software, hardware and a combination thereof. The units can be embedded in hardware or independent of a processor in the computer equipment, and can also be stored in a memory in the computer equipment in a software mode, so that the processor can call and execute the operations corresponding to the units.
Example IV
In this embodiment, a computer device is provided. The internal structure thereof can be shown in fig. 3. The computer device includes a processor, a memory, a network interface, a display screen, and an input device connected by a system bus. Wherein the processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The nonvolatile storage medium stores an operating system and a computer program, and stores a mapping relation between the magnetic field intensity of a stator of the permanent magnet synchronous linear motor and the displacement distance of the mover. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The network interface of the computer device is used to communicate with other computer devices in which application software is deployed. The computer program when executed by a processor is used for realizing a permanent magnet synchronous linear motor displacement measurement method. The display screen of the computer equipment can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer equipment can be a touch layer covered on the display screen, can also be keys, a track ball or a touch pad arranged on the shell of the computer equipment, and can also be an external keyboard, a touch pad or a mouse and the like.
It will be appreciated by those skilled in the art that the structure shown in fig. 3 is merely a block diagram of some of the structures associated with the present application and is not limiting of the computer device to which the present application may be applied, and that a particular computer device may include more or fewer components than shown, or may combine certain components, or have a different arrangement of components.
In one embodiment, a computer device is provided comprising a memory storing a computer program and a processor that when executing the computer program performs the steps of:
in the displacement process of a rotor of a permanent magnet synchronous linear motor, acquiring a sequence of magnetic field intensity, which is detected by a plurality of magnetic sensors, of a stator of the permanent magnet synchronous linear motor within a preset time length as a first magnetic field intensity, and acquiring a displacement distance, which is measured by a displacement sensor and is used for measuring the rotor of the permanent magnet synchronous linear motor, as a first displacement distance, wherein each magnetic sensor is arranged on the rotor of the permanent magnet synchronous linear motor, and the displacement sensor is arranged on the rotor of the permanent magnet synchronous linear motor;
determining the corresponding relation between the first magnetic field intensity and the first displacement distance based on the time sequence, and establishing a mapping relation between the magnetic field intensity and the displacement distance;
Acquiring a second magnetic field intensity of a stator of the permanent magnet synchronous linear motor;
and calculating a second displacement distance of the rotor of the permanent magnet synchronous linear motor based on the second magnetic field intensity and the mapping relation.
In one embodiment, the processor when executing the computer program further performs the steps of:
determining a corresponding relation between each first magnetic field intensity and each first displacement distance based on a time sequence;
and establishing a magnetic field intensity distribution continuous interpolation function related to the displacement distance through interpolation of the first magnetic field intensity to the first displacement distance and piecewise linear difference of the first magnetic field intensity to the first position distance, so as to obtain a mapping relation between the magnetic field intensity and the displacement distance.
In one embodiment, the processor when executing the computer program further performs the steps of:
establishing a displacement arithmetic sequence { x (k) } = {0, h,2h, }, wherein h is a displacement step size;
by applying a first magnetic field strength { B m (t n ) For the first displacement distance { x (t) n ) Interpolation to obtain the mth magnetic sensor signal B of the mover at displacement x (k) m (k)，B m (k) The method comprises the following steps:
wherein t is n ,t n+1 Satisfy x (k) ε [ x (t) n ),x(t n+1 )]；
The step of piecewise linearly differencing the distance from each of the first locations by each of the first magnetic field strengths includes:
By combining the mth magnetic sensor signal { B } m (k) Performing piecewise linear interpolation on the first position distance { x (k) }, and establishing a magnetic field intensity distribution continuous interpolation function:
the magnetic field intensity distribution continuous function established based on the signals of the magnetic sensors is as follows:
B(x)＝[B 1 (x),B 2 (x),...,B M (x)] T 。
in one embodiment, the processor when executing the computer program further performs the steps of:
based on the second magnetic field strength and the mapping relation, a nonlinear equation set of the magnetic field strength at the moment to be detected is established;
and solving the nonlinear equation set by using a least square solution to obtain a second displacement distance of the rotor of the permanent magnet synchronous linear motor.
In one embodiment, the processor when executing the computer program further performs the steps of:
step 1, based on a pre-obtained magnetic field intensity distribution function B (x), a nonlinear equation system of magnetic field intensity at a moment t to be measured is established:
Y＝B(x)+e
wherein Y= [ Y ] 1 ,y 2 ,...,y M ] T As the signal of the magnetic sensor, e= [ e ] 1 ,e 2 ,...,e M ] T Is signal noise;
step 2, to minimize the functionTaking the t-1 moment displacement calculation result x as a target (t-1) As an iteration initial value +.>Time 0 displacement x (t-1) =0, the displacement x at time t is calculated according to the following iterative formula (t) Least squares solution of (2):
wherein, p is the iteration number, J (·) is the jacobian matrix of B (·), and the following is obtained:
Wherein the derivative of the piecewise linear interpolation function B (x) at the interpolation point x (k) is defined as:
step 3, obtaining an error preset value epsilon and a maximum iteration number p max If (if)And p < p max Returning to the step 2 to continue iteration, otherwise ending the iteration to obtain a second displacement distance +.>
In one embodiment, each magnetic sensor is disposed in an array on a mover of the permanent magnet synchronous linear motor.
Example five
In this embodiment, there is provided a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, performs the steps of:
in the displacement process of a rotor of a permanent magnet synchronous linear motor, acquiring a sequence of magnetic field intensity, which is detected by a plurality of magnetic sensors, of a stator of the permanent magnet synchronous linear motor within a preset time length as a first magnetic field intensity, and acquiring a displacement distance, which is measured by a displacement sensor and is used for measuring the rotor of the permanent magnet synchronous linear motor, as a first displacement distance, wherein each magnetic sensor is arranged on the rotor of the permanent magnet synchronous linear motor, and the displacement sensor is arranged on the rotor of the permanent magnet synchronous linear motor;
determining the corresponding relation between the first magnetic field intensity and the first displacement distance based on the time sequence, and establishing a mapping relation between the magnetic field intensity and the displacement distance;
Acquiring a second magnetic field intensity of a stator of the permanent magnet synchronous linear motor;
and calculating a second displacement distance of the rotor of the permanent magnet synchronous linear motor based on the second magnetic field intensity and the mapping relation.
In one embodiment, the computer program when executed by the processor further performs the steps of:
determining a corresponding relation between each first magnetic field intensity and each first displacement distance based on a time sequence;
and establishing a magnetic field intensity distribution continuous interpolation function related to the displacement distance through interpolation of the first magnetic field intensity to the first displacement distance and piecewise linear difference of the first magnetic field intensity to the first position distance, so as to obtain a mapping relation between the magnetic field intensity and the displacement distance.
In one embodiment, the computer program when executed by the processor further performs the steps of:
establishing a displacement arithmetic sequence { x (k) } = {0, h,2h, }, wherein h is a displacement step size;
by applying a first magnetic field strength { B m (t n ) For the first displacement distance { x (t) n ) Interpolation to obtain the mth magnetic sensor signal B of the mover at displacement x (k) m (k)，B m (k) The method comprises the following steps:
wherein t is n ,t n+1 Satisfy x (k) ε [ x (t) n ),x(t n+ 1)]；
The step of piecewise linearly differencing the distance from each of the first locations by each of the first magnetic field strengths includes:
By combining the mth magnetic sensor signal { B } m (k) Performing piecewise linear interpolation on the first position distance { x (k) }, and establishing a magnetic field intensity distribution continuous interpolation function:
the magnetic field intensity distribution continuous function established based on the signals of the magnetic sensors is as follows:
B(x)＝[B 1 (x),B 2 (x),...,B M (x)] T 。
in one embodiment, the computer program when executed by the processor further performs the steps of:
based on the second magnetic field strength and the mapping relation, a nonlinear equation set of the magnetic field strength at the moment to be detected is established;
and solving the nonlinear equation set by using a least square solution to obtain a second displacement distance of the rotor of the permanent magnet synchronous linear motor.
In one embodiment, the computer program when executed by the processor further performs the steps of:
step 1, based on a pre-obtained magnetic field intensity distribution function B (x), a nonlinear equation system of magnetic field intensity at a moment t to be measured is established:
Y＝B(x)+e
wherein Y= [ Y ] 1 ,y 2 ,...,y M ] T As the signal of the magnetic sensor, e= [ e ] 1 ,e 2 ,...,e M ] T Is signal noise;
step 2, to minimize the functionTaking the t-1 moment displacement calculation result x as a target (t-1) As an iteration initial value +.>Time 0 displacement x (t-1) =0, the displacement x at time t is calculated according to the following iterative formula (t) Least squares solution of (2):
Wherein, p is the iteration number, J (·) is the jacobian matrix of B (·), and the following is obtained:
wherein the derivative of the piecewise linear interpolation function B (x) at the interpolation point x (k) is defined as:
step 3, obtaining an error preset value epsilon and a maximum iteration number p max If (if)And p < p max Returning to the step 2 to continue iteration, otherwise ending the iteration to obtain a second displacement distance +.>
In one embodiment, each magnetic sensor is disposed in an array on a mover of the permanent magnet synchronous linear motor.
Example six
In this embodiment, a computer program is provided which, when executed by a processor, performs the steps of:
in the displacement process of a rotor of a permanent magnet synchronous linear motor, acquiring a sequence of magnetic field intensity, which is detected by a plurality of magnetic sensors, of a stator of the permanent magnet synchronous linear motor within a preset time length as a first magnetic field intensity, and acquiring a displacement distance, which is measured by a displacement sensor and is used for measuring the rotor of the permanent magnet synchronous linear motor, as a first displacement distance, wherein each magnetic sensor is arranged on the rotor of the permanent magnet synchronous linear motor, and the displacement sensor is arranged on the rotor of the permanent magnet synchronous linear motor;
determining the corresponding relation between the first magnetic field intensity and the first displacement distance based on the time sequence, and establishing a mapping relation between the magnetic field intensity and the displacement distance;
Acquiring a second magnetic field intensity of a stator of the permanent magnet synchronous linear motor;
and calculating a second displacement distance of the rotor of the permanent magnet synchronous linear motor based on the second magnetic field intensity and the mapping relation.
In one embodiment, the computer program when executed by the processor further performs the steps of:
determining a corresponding relation between each first magnetic field intensity and each first displacement distance based on a time sequence;
and establishing a magnetic field intensity distribution continuous interpolation function related to the displacement distance through interpolation of the first magnetic field intensity to the first displacement distance and piecewise linear difference of the first magnetic field intensity to the first position distance, so as to obtain a mapping relation between the magnetic field intensity and the displacement distance.
In one embodiment, the computer program when executed by the processor further performs the steps of:
establishing a displacement arithmetic sequence { x (k) } = {0, h,2h, }, wherein h is a displacement step size;
by applying a first magnetic field strength { B m (t n ) For the first displacement distance { x (t) n ) Interpolation to obtain the mth magnetic sensor signal B of the mover at displacement x (k) m (k)，B m (k) The method comprises the following steps:
wherein tn, tn+1 satisfy such that x (k) ∈ [ x (t) n ),x(t n+1 )]；
The step of piecewise linearly differencing the distance from each of the first locations by each of the first magnetic field strengths includes:
By combining the mth magnetic sensor signal { B } m (k) Performing piecewise linear interpolation on the first position distance { x (k) }, and establishing a magnetic field intensity distribution continuous interpolation function:
the magnetic field intensity distribution continuous function established based on the signals of the magnetic sensors is as follows:
B(x)＝[B 1 (x),B 2 (x),...,B M (x)] T 。
in one embodiment, the computer program when executed by the processor further performs the steps of:
based on the second magnetic field strength and the mapping relation, a nonlinear equation set of the magnetic field strength at the moment to be detected is established;
and solving the nonlinear equation set by using a least square solution to obtain a second displacement distance of the rotor of the permanent magnet synchronous linear motor.
In one embodiment, the computer program when executed by the processor further performs the steps of:
step 1, based on a pre-obtained magnetic field intensity distribution function B (x), a nonlinear equation system of magnetic field intensity at a moment t to be measured is established:
Y＝B(x)+e
wherein Y= [ Y ] 1 ,y 2 ,...,y M ] T As the signal of the magnetic sensor, e= [ e ] 1 ,e 2 ,...,e M ] T Is signal noise;
step 2, to minimize the functionTaking the t-1 moment displacement calculation result x as a target (t-1) As an iteration initial value +.>Time 0 displacement x (t-1) =0, the displacement x at time t is calculated according to the following iterative formula (t) Least squares solution of (2):
Wherein, p is the iteration number, J (·) is the jacobian matrix of B (·), and the following is obtained:
wherein the derivative of the piecewise linear interpolation function B (x) at the interpolation point x (k) is defined as:
step 3, obtaining an error preset value epsilon and a maximum iteration number p max If (if)And p < p max Returning to the step 2 to continue iteration, otherwise ending the iteration to obtain a second displacement distance +.>
In one embodiment, each magnetic sensor is disposed in an array on a mover of the permanent magnet synchronous linear motor.
Those skilled in the art will appreciate that implementing all or part of the above described methods may be accomplished by way of a computer program stored on a non-transitory computer readable storage medium, which when executed, may comprise the steps of the embodiments of the methods described above. Any reference to memory, storage, database, or other medium used in the various embodiments provided herein may include non-volatile and/or volatile memory. The nonvolatile memory can include Read Only Memory (ROM), programmable ROM (PROM), electrically Programmable ROM (EPROM), electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms such as Static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double Data Rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous Link DRAM (SLDRAM), memory bus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), among others.
The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples merely represent a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the invention. It should be noted that it would be apparent to those skilled in the art that various modifications and improvements could be made without departing from the spirit of the present application, which would be within the scope of the present application. Accordingly, the scope of protection of the present application is to be determined by the claims appended hereto.
Claims (10)
1. The displacement measurement method of the permanent magnet synchronous linear motor is characterized by comprising the following steps of:
in the displacement process of a rotor of a permanent magnet synchronous linear motor, acquiring a sequence of magnetic field intensity, which is generated by a stator of the permanent magnet synchronous linear motor within a preset time length and detected by a plurality of magnetic sensors, as a first magnetic field intensity, and acquiring a displacement distance, which is measured by a displacement sensor, of the rotor of the permanent magnet synchronous linear motor as a first displacement distance, wherein each magnetic sensor is arranged on the rotor of the permanent magnet synchronous linear motor;
Determining the corresponding relation between the first magnetic field intensity and the first displacement distance based on the time sequence, and establishing a mapping relation between the magnetic field intensity and the displacement distance;
acquiring a second magnetic field intensity of a stator of the permanent magnet synchronous linear motor;
and calculating a second displacement distance of the rotor of the permanent magnet synchronous linear motor based on the second magnetic field intensity and the mapping relation.
2. The method of claim 1, wherein the step of determining the correspondence between each of the first magnetic field strengths and each of the first displacement distances based on the time series, and establishing the mapping between the magnetic field strengths and the displacement distances comprises:
determining a corresponding relation between each first magnetic field intensity and each first displacement distance based on a time sequence;
and establishing a magnetic field intensity distribution continuous interpolation function related to the displacement distance through interpolation of the first magnetic field intensity to the first displacement distance and piecewise linear difference of the first magnetic field intensity to the first position distance, so as to obtain a mapping relation between the magnetic field intensity and the displacement distance.
3. The method of claim 2, wherein the step of interpolating each of the first displacement distances by each of the first magnetic field strengths comprises:
Establishing a displacement arithmetic sequence { x (k) } = {0, h,2h, }, wherein h is a displacement step size;
by applying a first magnetic field strength { B m (t n ) For the first displacement distance { x (t) n ) Interpolation to obtain the mth magnetic sensor signal B of the mover at displacement x (k) m (k)，B m (k) The method comprises the following steps:
wherein t is n ,t n+1 Satisfy x (k) ε [ x (t) n ),x(t n+1 )]；
The step of piecewise linearly differencing the distance from each of the first locations by each of the first magnetic field strengths includes:
by combining the mth magnetic sensor signal { B } m (k) Performing piecewise linear interpolation on the first position distance { x (k) }, and establishing a magnetic field intensity distribution continuous interpolation function:
the magnetic field intensity distribution continuous function established based on the signals of the magnetic sensors is as follows:
B(x)＝[B 1 (x),B 2 (x),...,B M (x)] T 。
4. the method according to claim 1, wherein the step of calculating a second displacement distance of the mover of the permanent magnet synchronous linear motor based on the second magnetic field strength and the map comprises:
based on the second magnetic field strength and the mapping relation, a nonlinear equation set of the magnetic field strength at the moment to be detected is established;
and solving the nonlinear equation set by using a least square solution to obtain a second displacement distance of the rotor of the permanent magnet synchronous linear motor.
5. The method of claim 4, wherein the step of calculating a second displacement distance of the mover of the permanent magnet synchronous linear motor based on the second magnetic field strength and the mapping relation comprises:
step 1, based on a pre-obtained magnetic field intensity distribution function B (x), a nonlinear equation system of magnetic field intensity at a moment t to be measured is established:
Y＝B(x)+e
wherein Y= [ Y ] 1 ,y 2 ,...,y M ] T As the signal of the magnetic sensor, e= [ e ] 1 ,e 2 ,...,e M ] T Is signal noise;
step 2, to minimize the functionTaking the t-1 moment displacement calculation result x as a target (t-1) As an iteration initial valueTime 0 displacement is x (t-1) =0, the displacement x at time t is calculated according to the following iterative formula (t) Least squares solution of (2):
wherein, p is the iteration number, J (·) is the jacobian matrix of B (·), and the following is obtained:
wherein the derivative of the piecewise linear interpolation function B (x) at the interpolation point x (k) is defined as:
step 3, obtaining an error preset value epsilon and a maximum iteration number p max If (if)And p < p max Returning to the step 2 to continue iteration, otherwise ending the iteration to obtain a second displacement distance +.>
6. The method of any one of claims 1-5, wherein each of the magnetic sensors is disposed in an array on a mover of the permanent magnet synchronous linear motor.
7. A permanent magnet synchronous linear motor displacement measuring device, characterized by comprising:
the magnetic field and displacement acquisition module is used for acquiring a sequence of magnetic field intensity generated by a stator of the permanent magnet synchronous linear motor in a preset time length and detected by the magnetic sensor as a first magnetic field intensity in a displacement process of a rotor of the permanent magnet synchronous linear motor, and acquiring a displacement distance of the rotor of the permanent magnet synchronous linear motor, measured by the displacement sensor, as a first displacement distance, wherein the magnetic sensor is arranged on the rotor of the permanent magnet synchronous linear motor;
the mapping relation establishing module is used for determining the corresponding relation between the first magnetic field intensity and the first displacement distance based on the time sequence and establishing the mapping relation between the magnetic field intensity and the displacement distance;
the magnetic field real-time acquisition module is used for acquiring the second magnetic field intensity of the stator of the permanent magnet synchronous linear motor;
and the displacement real-time obtaining module is used for calculating and obtaining the second displacement distance of the rotor of the permanent magnet synchronous linear motor based on the second magnetic field intensity and the mapping relation.
8. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor implements the steps of the method of any of claims 1 to 6 when the computer program is executed.
9. A computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when being executed by a processor, implements the steps of the method of any of claims 1 to 6.
10. A computer program, characterized in that the computer program, when being executed by a processor, implements the steps of the method of any of claims 1 to 6.
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