阅读说明：本技术 一种利用霍尔传感器精确测量电机动子位移的方法及系统 (method and system for accurately measuring displacement of motor rotor by using Hall sensor ) 是由 张敬良 于 2019-11-11 设计创作，主要内容包括：本发明公开了一种利用霍尔传感器精确测量电机动子位移的方法及系统,该方法包括如下步骤：步骤S1,于电机动子上固定N个霍尔传感器形成的阵列；步骤S2,获取所述N个霍尔传感器的输出,判断当前时刻霍尔传感器阵列所工作在的与磁极对的相对区域,确定该区域工作在线性区的传感器输出,从而计算出霍尔传感器阵列与定子的位移,通过本发明,可实现利用最少的霍尔传感器实现低成本高精度的电机动子位移测量目的。(the invention discloses a method and a system for accurately measuring the displacement of a motor rotor by using a Hall sensor, wherein the method comprises the following steps: step S1, fixing an array formed by N Hall sensors on a motor rotor; and step S2, obtaining the outputs of the N Hall sensors, judging the relative area of the Hall sensor array working at the current moment and the magnetic pole pair, and determining the sensor output of the area working in the linear area, thereby calculating the displacement of the Hall sensor array and the stator.)

1. a method for accurately measuring the displacement of a motor rotor by using a Hall sensor comprises the following steps:

step S1, fixing an array formed by N Hall sensors on a motor rotor;

and step S2, acquiring the outputs of the N Hall sensors, judging the relative area of the Hall sensor array working at the current moment and the magnetic pole pair, and determining the sensor output of the area working in the linear area, thereby calculating the displacement of the Hall sensor array and the stator.

2. The method for accurately measuring the displacement of the rotor of the motor by using the Hall sensor as claimed in claim 1, wherein: in the step S1, in step S,and tau is the magnetic pole pitch of the motor,The distance between adjacent sensors is (N-1)/NxT, which is the length of the linear region of the Hall sensor output on the X-axis.

3. the method for accurately measuring the displacement of the rotor of the motor by using the Hall sensor as claimed in claim 2, wherein: the length of the hall sensor array is limited to within twice the pole pitch of the motor.

4. The method for accurately measuring the displacement of the rotor of the motor by using the Hall sensor as claimed in claim 2, wherein: if the nth Hall sensor is away from the first Hall sensorThen, the nth hall sensor is placed at the following position:

τ。

5. The method for accurately measuring the displacement of the motor mover by using the hall sensor as claimed in claim 1, wherein the step S2 further comprises:

step S200, performing region segmentation on the output of the Hall sensor array, determining the Hall sensor working in a linear region in the region where the Hall sensor array is located at the current moment and the corresponding region, and determining the relative position of the Hall array and the current magnetic pole pair;

Step S201, resolving a displacement of the motor rotor according to a relative position of the hall sensor array in the current magnetic pole pair and a number of magnetic pole pairs crossed by the hall sensor array.

6. the method for accurately measuring the displacement of the motor rotor by using the Hall sensor as claimed in claim 5, wherein: the basic principle of the region division is that in each region, only one hall sensor operates in the linear region.

7. the method for accurately measuring the displacement of the motor rotor by using the Hall sensor as claimed in claim 6, wherein: in step S200, the relative positions of the hall sensor array and the magnetic pole pair are:

pos=Zone_No×Cross_Value×2+sel_h

wherein Zone No is the area number where the hall sensor array is currently located,the intersection point values of the linear regions of every two Hall sensors,The Hall sensor working in a linear region is positioned in the current region.

8. The method for accurately measuring the displacement of the rotor of the motor by using the hall sensor as claimed in claim 7, wherein: in step S201, the displacement of the motor mover is calculated as follows:

pos_abs=pos+Track_No×Cross_Value×12

wherein Track No is the magnetic pole pair number crossed by the Hall sensor array.

9. the method for accurately measuring the displacement of the rotor of the motor by using the hall sensor as claimed in claim 8, wherein: the number of the crossed magnetic pole pairs Track _ No of the Hall sensor array is a relative value, the initial value of the Hall sensor array is 0, one is reduced when one magnetic pole pair is crossed in the reverse direction, and one is increased when one magnetic pole pair is crossed in the forward direction.

10. A system for accurately measuring the displacement of a motor rotor by using a Hall sensor comprises:

the Hall sensor arrangement unit is used for determining the number N and the positions of the arranged Hall sensors so as to fix an array formed by the N Hall sensors on the motor rotor;

and the displacement calculation unit is used for acquiring the outputs of the N Hall sensors, judging that the Hall sensor array works in a relative area with the magnetic pole pair at the current moment, and determining the sensor output of the area working in a linear area, so that the displacement of the Hall sensor array and the stator is calculated.

Technical Field

the invention belongs to the field of servo drive control, and particularly relates to a method and a system for accurately measuring the displacement of a motor rotor by using a Hall sensor.

background

the basis of industrial robots, various numerical control equipment and automatic production lines lies in the real-time motion control of various servo/linear motors, and the accurate measurement of the current displacement between a motor stator and a rotor is the basis for realizing the accurate control of the torque, the speed and the position of the motor, so that the measurement of the motor stator and the rotor is very important in the motion control of the motor.

In servo motors and linear motors, the current position measurement method generally obtains the relative position of a rotor and a stator by two modes of an optical encoder (an optical ruler and an optical reading head) or a magnetic encoder (a magnetic ruler and a magnetic reading head). However, both of the above-mentioned methods use the discretized photoetching degree or magnetic scale as an extra ruler, and have the following disadvantages:

1. the initial relative position of the rotor and the stator cannot be measured, in order to measure the initial relative position of the rotor and the stator, an additional sensor is required to be added, or additional scales and a reading head are added to be converted into an absolute value encoder and magnetic declination setting is carried out;

2. On the linear motor, along with the increase of the stroke, the optical scale or the magnetic scale is also correspondingly increased, so that the cost is increased;

3. The measurement precision directly depends on the scale, and the cost is obviously increased along with the improvement of the precision;

4. It is difficult to mount on a subminiature servo motor or a linear motor due to the mounting requirements of the ruler and the reading head.

disclosure of Invention

In order to overcome the defects in the prior art, the invention aims to provide a method and a system for accurately measuring the displacement of a motor rotor by using a hall sensor, so as to realize the purpose of measuring the displacement of the motor rotor with low cost and high precision by using the least hall sensor.

in order to achieve the above and other objects, the present invention provides a method for accurately measuring the displacement of a motor mover by using a hall sensor, comprising the steps of:

Step S1, fixing an array formed by N Hall sensors on a motor rotor;

And step S2, acquiring the outputs of the N Hall sensors, judging the relative area of the Hall sensor array working at the current moment and the magnetic pole pair, and determining the sensor output of the area working in the linear area, thereby calculating the displacement of the Hall sensor array and the stator.

preferably, in step S1,And tau is the magnetic pole pitch of the motor,linear region of output for Hall sensor is in X-axisAnd the distance between adjacent sensors is (N-1)/Nxτ.

Preferably, the length of the hall sensor array is limited to within twice the pole pitch of the motor.

preferably, if the nth Hall sensor is at a distance from the first Hall sensorthen, the nth hall sensor is placed at the following position:

τ。

Preferably, the step S2 further includes:

step S200, performing region segmentation on the output of the Hall sensor array, determining the Hall sensor working in a linear region in the region where the Hall sensor array is located at the current moment and the corresponding region, and determining the relative position of the Hall array and the current magnetic pole pair;

Step S201, resolving a displacement of the motor rotor according to a relative position of the hall sensor array in the current magnetic pole pair and a number of magnetic pole pairs crossed by the hall sensor array.

Preferably, the basic principle of the region division is that in each region there is only one hall sensor operating in the linear region.

preferably, in step S200, the relative positions of the hall sensor array and the magnetic pole pair are:

pos=Zone_No×Cross_Value×2+sel_h。

wherein Zone No is the area number where the hall sensor array is currently located,the intersection point values of the linear regions of every two Hall sensors,The position of the Hall sensor working in the linear region in the current regionand (4) placing.

Preferably, in step S201, the displacement of the motor mover is calculated as follows:

pos_abs=pos+Track_No×Cross_Value×12

Wherein Track No is the magnetic pole pair number crossed by the Hall sensor array.

Preferably, the number of the magnetic pole pairs crossed by the Hall sensor array Track _ No is a relative value, the initial value of the relative value is 0, one is reduced when one magnetic pole pair is crossed in the reverse direction, and one is increased when one magnetic pole pair is crossed in the forward direction.

In order to achieve the above object, the present invention further provides a system for accurately measuring the displacement of a motor mover by using a hall sensor, comprising:

the Hall sensor arrangement unit is used for determining the number N and the positions of the arranged Hall sensors so as to fix an array formed by the N Hall sensors on the motor rotor;

And the displacement calculation unit is used for acquiring the outputs of the N Hall sensors, judging that the Hall sensor array works in a relative area with the magnetic pole pair at the current moment, and determining the sensor output of the area working in a linear area, so that the displacement of the Hall sensor array and the stator is calculated.

Compared with the prior art, the method and the system for accurately measuring the displacement of the motor rotor by using the Hall sensors realize the purpose of measuring the displacement of the motor rotor by fixing the array consisting of the Hall sensors on the motor rotor and by using the Hall sensors, the sensitivity of the Hall sensors can be fully utilized to ensure the resolution of the position.

drawings

FIG. 1 is a schematic diagram showing the relative positions of a Hall sensor and a magnetic pole;

FIG. 2 shows a schematic output diagram of a Hall sensor at different X positions;

FIG. 3 is a schematic diagram showing the arrangement of magnetic poles and the output of each Hall sensor in the Hall array;

FIG. 4 is a flow chart illustrating steps of a method for accurately measuring the displacement of a motor rotor by using a Hall sensor according to the present invention;

FIG. 5 is a waveform diagram of the Hall outputs of the three Hall sensor arrays in the embodiment of the present invention, wherein the Hall outputs cross a magnetic pole pair in a reverse direction at a constant speed and then return to a starting point in a forward direction;

FIG. 6 is a schematic diagram of signals output by the three Hall sensors and analyzed by the position when the three Hall sensor arrays cross over two magnetic pole pairs at a constant speed in a reverse direction and then return to a starting point in a forward direction in the embodiment of the present invention;

FIG. 7 is a system architecture diagram of a system for accurately measuring motor mover displacement using Hall sensors according to the present invention;

Wherein, in fig. 1, 1-hall sensor 1; 2-hall sensor 2; 3-hall sensor 3; 4-magnetic pole.

Detailed Description

other advantages and capabilities of the present invention will be readily apparent to those skilled in the art from the present disclosure by describing the embodiments of the present invention with specific embodiments thereof in conjunction with the accompanying drawings. The invention is capable of other and different embodiments and its several details are capable of modification in various other respects, all without departing from the spirit and scope of the present invention.

The principle of the invention using hall sensors is explained first below:

fig. 1 shows a schematic diagram of the relative positions of a hall sensor and a magnetic pole, wherein the hall sensor is placed in the middle of the magnetic pole on the Y-axis, the distance between the hall sensor and the magnetic pole on the Z-axis is kept unchanged, and the hall sensor moves along the X-axis. It can be seen from the output signal of the typical hall sensor shown in fig. 2 that, in the interval directly below the adjacent magnetic pole, the output signal of the hall sensor and the displacement signal have a linear characteristic, and the smaller the distance between the hall sensor and the magnetic pole on the Z-axis, the larger the slope of the hall output signal, i.e., the more sensitive the hall output signal is to the displacement, the higher the position resolution accuracy is under a certain signal noise, but the faster the hall output signal enters a nonlinear or saturated region, and the smaller the linear region is.

fig. 3 shows the arrangement of magnetic poles in the linear motor and the output schematic diagram of each hall sensor in the hall array, in the present invention, the rotating motor can be regarded as a radial split, plane development. When a hall sensor 1 (fixed on the mover) is placed above the rotor and moved along the X-axis, the required position resolution accuracy is achieved by reducing the distance in the Z-axis direction as described above, and the output signal is shown as a solid line curve No. 1 below fig. 3 (without loss of generality, the nonlinear region is represented by a saturation region). In order to linearly resolve the displacement between the rotor and the stator in the whole stroke, the required number of the Hall sensors isWhere τ is the pole pitch,is the length of the linear region of the hall sensor output on the X-axis. In fig. 3, a hall array of N =3 (the distance between adjacent hall sensors is 2 τ/3) is shown, and the output of the corresponding individual hall sensor as the sensor array moves along the X-axis.

For any value of N (N > = 2), the distance between adjacent sensors is: (N-1)/Nxτ. If N is large, the length of the Hall array can exceed 2 tau, and the length of the Hall array can be limited within 2 tau through the following processing as long as the size of the Hall sensor allows. The distance between the nth Hall sensor and the first Hall sensor is based on the first Hall position,

(1)

if it is notthe nth hall sensor can be placed in the following positions:

(2)

The nth Hall output lags behind 2 pi in time sequence, so that the position analysis is not influenced, and the initial relative position of the rotor and the magnetic pole can be better reflected.

fig. 4 is a flowchart illustrating steps of a method for accurately measuring the displacement of a motor mover by using a hall sensor according to the present invention. As shown in fig. 4, the method for accurately measuring the displacement of the motor rotor by using the hall sensor of the present invention comprises the following steps:

step S1, fixing an array formed by N Hall sensors on the motor rotor, whereinand tau is the magnetic pole pitch of the motor,The distance between adjacent sensors is the length of the linear region of the hall sensor output on the X-axis: (N-1)/NxT, and the length of the Hall sensor array is limited to be within 2T.

In the present invention, as mentioned above, if N is relatively large, the length of the hall sensor array will exceed 2 τ, so as long as the hall sensor size allows, the length of the hall sensor array can be limited to 2 τ by the following process. The position of the first Hall sensor is taken as a reference, and the distance between the nth Hall sensor and the first Hall sensor is as follows:

if it is notThe nth hall sensor can be placed in the following positions:

although the output of the nth Hall sensor lags behind 2 pi in time sequence, the output of the nth Hall sensor does not influence the position analysis and can better reflect the initial relative position of the rotor and the magnetic pole.

And step S2, acquiring the outputs of the N Hall sensors, judging that the Hall sensor array works in a relative area with the magnetic pole pair at the current moment, and determining the sensor output of the area working in a linear area, thereby calculating the displacement of the Hall sensor array and the stator.

specifically, step S2 further includes:

and S200, performing region segmentation on the output of the Hall sensor array, determining the Hall sensor working in a linear region in the region where the Hall sensor array is located at the current moment and the corresponding region, and determining the relative position of the Hall array and the current magnetic pole pair. In the present invention, the basic principle of region division is that there is only one hall sensor operating in the linear region in each region.

in the specific embodiment of the present invention, without loss of generality, three hall sensor arrays are taken as an example, and fig. 5 shows output signals of the hall sensors in the process that the hall array moves in a constant speed in a reverse direction, crosses a pair of magnetic poles, and then moves back to an initial point in a constant speed in a positive direction in fig. 3. The saturation area is replaced by a nonlinear area, the intersection point value of the linear areas of every two Hall sensors is normalized to +/-0.5, and the positive direction is defined as Hall sensor 1 (namely Hall in the figure)₁) Output leading Hall sensor 2 (Hall in figure)₂) The Hall sensor 2 outputs a leading Hall sensor 3 (i.e. Hall in the figure)₃) Otherwise, the direction is the reverse direction.

The basic principle of region division is that each region has only one hall sensor working in a linear region, generally, if there are N hall sensors, the hall sensor is divided into 2N regions, taking three hall sensors as an example, as shown in fig. 5, when the hall sensor array moves in the opposite direction, the hall sensor array sequentially passes through regions Z5, Z4, … and Z0; the forward motion passes through zones Z0, Z1, …, and Z5 in sequence.

The respective regions are defined as follows:

Z5:

Z4:

Z3:

Z2:

Z1:

Z0:

whereinIs composed ofand (4) outputting by a Hall sensor. In practical application, in order to overcome noise interference, the following judgment criteria are adopted for region segmentation:

Z5: h₂＞h₃＞h₁；

Z4: h₂＞h₁＞h₃；

Z3: h₁＞h₂＞h₃；

Z2: h₁＞h₃＞h₂；

Z1: h₃＞h₁＞h₂；

Z0: h₃＞h₂＞h₁；

The relative positions of the Hall sensor array and the magnetic pole pair are determined by the areaAnd the position of the Hall sensor working in the linear region in the current regionAnd (6) determining. The specific analysis method is as follows:

Thus, the relative position (pos) of the hall sensor array and the current pole pair resolves to:

pos=Zone_No×Cross_Value×2+sel_h 。

wherein Zone No is the area number where the hall sensor array is currently located,the crossing point value of the linear regions of two hall sensors is 0.5 as shown in fig. 5 in the specific embodiment of the invention.

Step S201, resolving a displacement of the motor rotor according to a relative position of the hall sensor array in the current magnetic pole pair and a number of magnetic pole pairs crossed by the hall sensor array.

during the whole movement, the displacement (pos _ abs) of the mover (hall array) can be represented by the number of magnetic pole pairs (Track _ No) crossed by the hall array and the position (pos) of the hall array in the current magnetic pole pair as:

pos_abs=pos+Track_No×Cross_Value×12

Wherein Track _ No is a relative value with a starting value of 0, decreases by one when crossing a pole pair in the reverse direction (Zone _ No changes from 0 to 5), and increases by one when crossing a pole pair in the forward direction (Zone _ No changes from 5 to 0), and the specific calculation process is as follows:

Where Zone _ No _ P is the area number of the last sampling point.

FIG. 6 shows the position resolution signals as the Hall array reverses direction across two pole pairs and then returns to the starting point. Unlike fig. 5, the hall signals in fig. 6 are superimposed with 20% noise, and although the Zone _ No is disturbed by the noise at the inversion point, this does not affect the position resolution, and the overall displacement (pos _ abs) of the mover (hall array) remains linear.

Fig. 7 is a system architecture diagram of a system for accurately measuring the displacement of a motor mover by using a hall sensor according to the present invention. As shown in fig. 7, the system for accurately measuring the displacement of the motor rotor by using the hall sensor according to the present invention includes:

A Hall sensor arrangement unit 701 for determining the number N and the positions of the Hall sensors arranged so as to fix an array formed by the N Hall sensors on the motor rotor, whereinAnd tau is the magnetic pole pitch of the motor,the length of a linear region output by the Hall sensor on the X axis is as follows: (N-1)/NxT, and the length of the Hall sensor array is limited to be within 2T.

in the invention, if N is larger, the length of the Hall sensor array exceeds 2 tau, so as long as the Hall sensor size allows, the length of the Hall sensor array is limited within 2 tau through the following processing. The position of the first Hall sensor is taken as a reference, and the distance between the nth Hall sensor and the first Hall sensor is as follows:

if it is notthe nth hall can be placed in the following positions:

Although the nth Hall output lags behind 2 pi in time sequence, the nth Hall output does not influence the position analysis and can better reflect the initial relative position of the rotor and the magnetic pole.

and the displacement calculation unit 702 is configured to obtain outputs of the N hall sensors, determine that the hall sensor array works in a region opposite to the magnetic pole pair at the current time, determine the sensor output of the region working in a linear region, and thereby calculate the displacement between the hall sensor array and the stator.

Specifically, the displacement calculation unit 702 further includes:

and the relative position calculating unit is used for carrying out region segmentation on the output of the Hall sensor array, determining the Hall sensor working in a linear region in the region where the Hall sensor array is located at the current moment and the corresponding region, and determining the relative position of the Hall array and the current magnetic pole pair. In the present invention, the basic principle of region division is that there is only one hall sensor operating in the linear region in each region.

The basic principle of region segmentation is that there is only one hall sensor operating in the linear region in each region. Taking fig. 5 as an example, when the hall sensor array moves in the opposite direction, the hall sensor array passes through the zones Z5, Z4, … and Z0 in sequence; the forward motion passes through zones Z0, Z1, …, and Z5 in sequence. The respective regions are defined as follows:

Z5:

Z4:

Z3:

Z2:

Z1:

Z0:

whereinIs composed ofAnd (4) outputting by a Hall sensor. In practical application, in order to overcome noise interference, the following judgment criteria are adopted for region segmentation:

Z5: h₂＞h₃＞h₁；

Z4: h₂＞h₁＞h₃；

Z3: h₁＞h₂＞h₃；

Z2: h₁＞h₃＞h₂；

Z1: h₃＞h₁＞h₂；

Z0: h₃＞h₂＞h₁；

the relative position of the Hall sensor array and the magnetic pole pair is determined by the current region position of the Hall sensor working in the linear region in the region and the corresponding regionAnd outputting the decision. The specific analysis method is as follows:

Thus, the relative position (pos) of the hall sensor array and the current pole pair resolves to:

pos=Zone_No×Cross_Value×2+sel_h 。

Wherein Zone No is the area number where the hall sensor array is currently located,The intersection values of the linear regions of every two Hall sensors are obtained.

And the displacement analyzing unit is used for analyzing the displacement of the motor rotor according to the relative position of the Hall sensor array in the current magnetic pole pair and the number of the magnetic pole pairs crossed by the Hall sensor array.

during the whole movement, the displacement (pos _ abs) of the mover (hall array) can be represented by the number of magnetic pole pairs (Track _ No) crossed by the hall array and the position (pos) of the hall array in the current magnetic pole pair as:

pos_abs=pos+Track_No×Cross_Value×12

Wherein Track No is a relative value with a starting value of 0, decreases by one when crossing a pole pair in the reverse direction (Zone No changes from 0 to 5), and increases by one when crossing a pole pair in the forward direction (Zone No changes from 5 to 0), which is specifically calculated as follows:

Where Zone _ No _ P is the area number of the last sampling point.

In summary, the method and system for accurately measuring the displacement of the motor rotor by using the hall sensors of the present invention fix the array formed by the hall sensors on the motor rotor, and realize the displacement measurement of the motor rotor by using the hall sensors, and can fully utilize the sensitivity of the hall sensors to ensure the resolution of the position.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Modifications and variations can be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the present invention. Therefore, the scope of the invention should be determined from the following claims.