CN117909684A - A motor motion direction recognition method based on dual Hall sensors - Google Patents

Abstract

The invention discloses a motor movement direction identification method based on a dual Hall sensor, comprising the following steps: continuously reading square wave values of two Hall pulse signals inputted, arranging and combining the square wave values of the two Hall pulse signals at the same time in a certain order, and converting the combined square wave values into binary values; recording the converted binary values as Hallstate, and introducing an array HALLDX[a] corresponding to a kinds of binary values, the length of the array is a, and the a values contained in the array correspond to the binary values; substituting the binary values into the array as subscripts to obtain a value; subtracting a historical value from the value, and recording the difference between the two as temp_hall; judging whether the motor is forward or reverse according to the value of temp_hall, when the motor is running normally and the running direction remains unchanged, the values temp_hall obtained by the forward and reverse rotation of the motor are both preset as The invention has high precision, strong anti-interference ability, accuracy and adaptability.

Description

A method for identifying motor movement direction based on dual Hall sensors

Technical Field

The invention belongs to the field of automotive electronics, and in particular relates to a method for identifying the movement direction of a motor based on dual Hall sensors.

Background technique

With the widespread use of automotive sensors, Hall sensors are also gradually used in automobiles. The most common use of Hall sensors is to be used together with motors to form drive motors with Hall sensors. As a type of Hall motor, the dual Hall sensor motor has good stability and will not lose the signal when the motor speed is too fast. Therefore, it is also very common in automobiles. The most common ones are car windows and sunroofs, most of which are driven by dual Hall sensor motors. In the simulation stage, it is often necessary to process the Hall signal to obtain the motor speed and motion state.

At present, many traditional algorithms directly judge the direction of movement of the motor based on the different rotation directions of the motor and the different positions of the output dual Hall signals. The advantage of this method is that the algorithm has weak anti-interference ability. Once interference occurs, the output Hall waveform will be incomplete, which will lead to incorrect judgment.

Summary of the invention

The purpose of the present invention is to provide a method for identifying the movement direction of a motor based on a dual Hall sensor, which not only takes into account the characteristics of the motor, but also gives full play to the advantages of the dual Hall sensor, has high precision, strong anti-interference ability, accuracy and adaptability, and can also be expanded to other fields.

To solve the above technical problems, the technical solution of the present invention is: a method for identifying the movement direction of a motor based on a dual Hall sensor, comprising the following steps:

S100, continuously reading the square wave values of the two Hall pulse signals input, arranging and combining the square wave values of the two Hall pulse signals at the same time in a certain order, and converting the combined square wave values into binary values; wherein the binary values converted in one cycle are a kinds, and are arranged and circulated according to a certain rule, and a is a positive even number greater than or equal to 4;

S200, the converted binary value is recorded as Hallstate, and an array HALLDX[a] corresponding to a binary value is introduced, the length of the array is a, and the a values contained in the array correspond to the binary value; the binary value is substituted into the array as a subscript to obtain a value recorded as HALLDX[Hallstate];

S300, subtract the historical value HALLDX[Hallstatelast] from HALLDX[Hallstate], and record the difference between the two as temp_hall; wherein the historical value HALLDX[Hallstatelast] is the HALLDX[Hallstate] calculated in the previous cycle;

S400, judging whether the motor is rotating forward or reverse according to the value of temp_hall. When the motor is running normally and the direction of rotation remains unchanged, the values of temp_hall obtained when the motor is rotating forward and reverse are both preset to There are a total of a values, and the values are all different.

The following steps are also included:

S500, when the value of temp_hall is 0, the count value of the preset timer is judged. When the count value of the timer is less than the preset threshold, the count value is increased by 1, and the process jumps to S700; when the value of the timer is greater than the preset threshold, the motor is judged to be stopped, and the process jumps to S700;

S600, when the value of temp_hall is not a preset a value or 0 obtained by the forward and reverse rotation of the motor, the Hallerror value is judged, and when the Hallerror value is less than the preset error threshold, the Hallerror value is increased by 1, and the method is jumped to S700; when the Hallerror value is greater than the preset error threshold, an error signal is sent to end the method; wherein, Hallerror is a Hall error flag, and when it is judged that the motor is in an abnormal state, the variable is called, and its value is compared with the preset error threshold to determine whether the motor is in an abnormal state;

S700, assign the value of Hallstate to Hallstatelast, and jump to S100 to perform calculation of the next cycle.

The following steps are also included:

S800, calculate the motor speed according to the Hall pulse signal, the calculation method is:

Where n is the motor speed, t is the time interval, and s is the number of Hall pulses read within the time interval t.

The following steps are also included:

S900, calculate the commutation current during the operation of the motor, and the calculation method is:

Wherein, _ia is the armature current when there is no commutation between the brush and the commutator segment, _t0 is the time required for commutation, _Tk is the commutation time period, _er is the reactance potential of the commutation element, _ew is the induced potential of the commutation environment, the commutation element includes the first commutator segment and the second commutator segment, _r1 and _r2 are the contact resistances of the first commutator segment, the second commutator segment and the brush respectively.

The following steps are also included:

S1000, when the current of the motor is commutated, a high-frequency component is generated, which is called the current commutation pulsation frequency. The current pulsation frequency has the following relationship with the motor speed:

Among them, f is the current pulse frequency, k is the number of commutator segments, and n is the motor speed obtained by the Hall sensor;

The current ripple is conditioned by the circuit to obtain a square wave similar to the Hall pulse. The current ripple period T is obtained through the square wave, and the motor speed w calculated by the current ripple is calculated as follows:

The following steps are also included:

S1100: When the running direction of the motor changes, due to the inertia inside the motor and the inertia of the load, the motor needs a certain amount of time to complete the reverse rotation.

The following steps are also included:

S1200, collecting the speed data of the motor. The motor speed w obtained by current ripple calculation in S1000 and the motor speed n obtained by the Hall sensor, both of which have a maximum motor speed n _max determined during the actual collection process, and the abnormal data in the two are eliminated according to the maximum motor speed n _max ; wherein, the collection period of the motor speed data is consistent with the collection period of the Hall pulse signal.

The following steps are also included:

S1300, storing the collected motor speed data in groups of four, and calculating the average motor speed value of each group of data.

The following steps are also included:

S1400, setting an error threshold, making a difference between the motor speed calculated by the current ripple and the motor speed obtained by the Hall sensor in the same cycle, and taking the absolute value of the result, expressed as:

n _p =|nw|

Where n is the average motor speed value of a set of data obtained by the Hall sensor, w is the average motor speed value of the set of data corresponding to n obtained by current ripple calculation, and _np is the absolute value of the difference between the two;

The absolute value of the difference between the two groups is compared with the error threshold to determine the size of the error between the two.

A computer-readable storage medium stores a computer program, wherein the computer program, when executed by a processor, implements the steps of any of the methods described above.

Compared with the prior art, the present invention has the following beneficial effects:

The present invention has a strong anti-interference ability while ensuring high accuracy and a simple and stable algorithm structure. When the Hall signal fluctuates, it will not affect the accuracy of the algorithm itself, thereby improving the overall reliability and robustness of the system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a flow chart of an embodiment of the present invention;

FIG2 is a schematic diagram of the clockwise rotation of a motor and a corresponding square wave diagram of a dual-path Hall signal in an embodiment of the present invention;

3 is a schematic diagram of the counterclockwise rotation of the motor and a corresponding square wave diagram of the dual-path Hall signal in an embodiment of the present invention;

FIG4 is a diagram showing the square wave values of two Hall signals and the converted binary numbers at a specific moment in an embodiment of the present invention;

FIG5 is a calculation diagram of the difference temp_hall at different times in an embodiment of the present invention;

6 is a schematic diagram of the structure of the connection between the motor and the commutator segment according to an embodiment of the present invention;

FIG. 7 is a schematic diagram showing the principle of generating motor commutation current in an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

The technical solution of the embodiment of the present invention is: a method for identifying the movement direction of a motor based on a dual Hall sensor, comprising the following steps:

Step 100, as shown in FIG1, first continuously read the square wave values of the two input Hall pulse signals, and arrange the square wave values of the two Hall signals at the same time in a certain order, such as arranging the square wave value of the first Hall signal in front and the square wave value of the second Hall signal in the back, for example: 01 and convert the values into binary values in this order, the converted value is 1, recorded as value b.

Step 200, assign the value of value b to Hallstate. In this embodiment, an array length of 4 is taken as an example, and an array HALLDX[4] is introduced with a length of 4. When the motor movement direction remains unchanged, in one cycle, there are only 4 kinds of binary numbers obtained in step 100, and they are arranged and circulated according to a certain rule. Therefore, 4 appropriate numbers are set in the array as needed, and the binary number is brought into the array as a subscript to obtain a number, HALLDX[Hallstate].

Step 300, subtract the value HALLDX[Hallstatelast] obtained in the last method entry from the value HALLDX[Hallstate] obtained in step 300, and assign the obtained value to temp_hall.

Step 400, when the motor is running normally and the direction is unchanged, and the value selected in the array HALLDX[4] is appropriate, there are only two cases for the value temp_hall obtained by using this method to make the difference, that is, when the motor is rotating forward, the difference value obtained is p or q (corresponding to the two preset values obtained when the motor is rotating forward), and when the motor is rotating reversely, the difference value obtained is m or n (corresponding to the two preset values obtained when the motor is rotating reversely).

Step 500, when the difference is 0, it is necessary to continue to judge. When the difference is 0, the stop count is increased by 1. When the stop exceeds the threshold, it is judged that the motor has stopped. The method is to run once every 64us. The two Hall signal values collected within a period of time are the same. A threshold is set. When the number of stop times when the difference temp_hall is 0 does not exceed the threshold, stop is increased by 1 and the next step is performed; when stop is greater than the threshold, it is judged that the motor is in a stopped state and the next step is performed.

Step 600, when the obtained difference temp_hall is not equal to p, q, m, n or 0, it may be that a Hall square wave error occurs or the square wave fluctuates due to signal interference. When this happens, determine whether the Hallerror value is greater than the set threshold. When it is less than the threshold, Hallerror is increased by 1 and the next step is continued; when it exceeds the threshold, an error signal is sent and the method is exited.

Step 700, when the motor has no error, assign the value of Hallstate to Hallstatelast, and return to step 100 to perform the calculation again.

When the motor is operating normally, as shown in Figures 2 and 3, Figure 2 is a schematic diagram of the motor rotating clockwise, and the right side of Figure 2 is a schematic diagram of two cycles of dual Hall signal square waves; Figure 3 is a schematic diagram of the motor rotating counterclockwise and two cycles of Hall pulse signal square waves. Figures 2 and 3 respectively capture two different Hall signal square wave values at 8 moments in two cycles, from _t1 to _t8 , and _t1 ' to _t8 '.

According to the obtained value converted into a binary number, as shown in Figure 4, the obtained binary number is sorted according to a certain rule. When the motor rotates clockwise, the binary number a is: 0, 1, 3, 2, 0, 1, 3, 2; when the motor rotates counterclockwise, the binary number a' is: 2, 3, 1, 0, 2, 3, 1, 0. Sorting is performed in two orders respectively.

At this time, set the value of array HALLDX[4], each binary number corresponds to a value in the array, and the required temp_hall value is obtained after subtraction. For example, set the array to HALLDX[4] = [0,1,3,2]. When the motor rotates clockwise, this set of binary numbers a is put into the array, and the values obtained are 0, 1, 2, 3, 0, 1, 2, 3. The difference between two adjacent numbers is subtracted from the previous number by the latter number. The difference temp_hall obtained is: 1, 1, 1, -3, 1, 1, 1. The values obtained are only 1 and -3. Then, it will be cycled according to this rule. Similarly, when the motor rotates counterclockwise, it can be obtained that a' is put into array HALLDX[4], and a set of numbers can be obtained: 3, 2, 1, 0, 3, 2, 1, 0. Similarly, the difference temp_hall can be obtained as -1, -1, -1, 3, -1, -1, -1, and the values obtained are only -1 and 3.

Step 800, read the Hall pulse signal and calculate the motor speed. The calculation formula is as follows: Where n is the motor speed, s is the number of Hall pulses read in time t, and t is the time interval (in seconds). Multiply by 60 to convert the speed from the number of pulses per second to the speed per minute.

Step 900, calculate the commutation current during the operation of the motor according to the motor characteristics. When the motor rotor rotates, the brush contacts the commutator segments of the commutator, causing the circuit to change, thereby causing the current to flow, as shown in Figures 6 and 7. The commutation current can be used as an important parameter for reference of the motor operation status. The commutation current calculation formula is as follows: Wherein, _ia is the armature current when there is no commutation between the brush and the commutator segment; t is the time required for commutation; _Tk is the commutation time period; _ew is the induced potential outside the commutation; _r1 and _r2 are the contact resistances of the first commutator segment, the second commutator segment and the brush respectively.

Step 1000: The motor current commutation generates a high-frequency component called the current commutation pulsation frequency. The current pulsation frequency and the motor speed are in the following relationship: Where f is the current pulse frequency, k is the number of commutator segments, and n is the number of motor revolutions. The current ripple can be conditioned by the circuit to obtain a square wave similar to the Hall pulse. The current ripple period T can be obtained from the square wave, and the motor speed w can be calculated using the following formula:

Step 1100, when the direction of the motor changes, due to the inertia inside the motor and the inertia of the load, the motor needs a certain amount of time to complete the reverse rotation. During this process, the output torque and speed of the motor will change. Specifically: when the direction of the motor changes, the motor rotor needs to stop and restart rotation. During this transition period of the direction, the speed of the motor will decrease and gradually recover as the rotor re-accelerates.

Step 1200, for this purpose, the motor speed data is collected, and the motor speed w is calculated by current ripple and the motor speed n is obtained by the Hall sensor. The maximum motor speed of both is determined during the actual collection process, and the abnormal data of the two calculated motor speed data needs to be eliminated.

Step 1300: The motor speed data collection is consistent with the Hall pulse signal collection cycle, and a round of data sampling is completed every 64us. The method completes data processing by setting the motor speed threshold n _max . When data greater than the threshold appears, it is discarded. At the same time, the motor speed values calculated are stored in an array in groups of four, and the average motor speed of the array is calculated. The average motor speed obtained by current ripple is also obtained in the same way.

Step 1400: In the actual process, there is a certain deviation between the motor speed collected based on the Hall signal and the motor speed collected based on the current ripple. It is necessary to define the error between the two and set a threshold n_dv. Taking a corresponding array as an example, the difference between the average motor speeds obtained by the two methods is calculated and the absolute value of the result is taken to obtain the difference between the absolute values of the two _np = |nw|.

Therefore, when the average speed of the motor at the current moment is less than the average speed at the previous moment, and the motor speed difference is less than the threshold, it can be determined that the direction of the motor movement has changed, and when the difference temp_hall is equal to 1 or -3, it can be determined that the motor is rotating clockwise; when the difference temp_hall is equal to -1 or 3, it can be determined that the motor is rotating counterclockwise. When the motor stops, the values of the two Hall signals are both 0. When the number of times the temp_hall signal is 0 exceeds the threshold, and the difference in the average motor speed is 0, it is determined that the motor is stopped.

It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A method for identifying the direction of motor movement based on dual Hall sensors, characterized in that it comprises the following steps: S100, continuously reading the square wave values of the two Hall pulse signals input, arranging and combining the square wave values of the two Hall pulse signals at the same time in a certain order, and converting the combined square wave values into binary values; wherein the binary values converted in one cycle are a kinds, and are arranged and circulated according to a certain rule, and a is a positive even number greater than or equal to 4; S200, the converted binary value is recorded as Hallstate, and an array HALLDX[a] corresponding to a binary value is introduced, the length of the array is a, and the a values contained in the array correspond to the binary value; the binary value is substituted into the array as a subscript to obtain a value recorded as HALLDX[Hallstate]; S300, subtract the historical value HALLDX[Hallstatelast] from HALLDX[Hallstate], and record the difference between the two as temp_hall; wherein the historical value HALLDX[Hallstatelast] is the HALLDX[Hallstate] calculated in the previous cycle; S400, judging whether the motor is rotating forward or reverse according to the value of temp_hall. When the motor is running normally and the direction of rotation remains unchanged, the values of temp_hall obtained when the motor is rotating forward and reverse are both preset to There are a total of a values, and the values are all different. 2. The method for identifying the direction of motor movement based on dual Hall sensors according to claim 1, further comprising the following steps: S500, when the value of temp_hall is 0, the count value of the preset timer is judged. When the count value of the timer is less than the preset threshold, the count value is increased by 1, and the process jumps to S700; when the value of the timer is greater than the preset threshold, the motor is judged to be stopped, and the process jumps to S700; S600, when the value of temp_hall is not a preset a value or 0 obtained by the forward and reverse rotation of the motor, the Hallerror value is judged, and when the Hallerror value is less than the preset error threshold, the Hallerror value is increased by 1, and the method is jumped to S700; when the Hallerror value is greater than the preset error threshold, an error signal is sent to end the method; wherein, Hallerror is a Hall error flag, and when it is judged that the motor is in an abnormal state, the variable is called, and its value is compared with the preset error threshold to determine whether the motor is in an abnormal state; S700, assign the value of Hallstate to Hallstatelast, and jump to S100 to perform calculation of the next cycle. 3. The method for identifying the motor movement direction based on dual Hall sensors according to claim 1, further comprising the following steps: S800, calculate the motor speed according to the Hall pulse signal, the calculation method is: Where n is the motor speed, t is the time interval, and s is the number of Hall pulses read within the time interval t. 4. The method for identifying the motor movement direction based on dual Hall sensors according to claim 1, further comprising the following steps: S900, calculate the commutation current during the operation of the motor, and the calculation method is: Wherein, _ia is the armature current when there is no commutation between the brush and the commutator segment, _t0 is the time required for commutation, _Tk is the commutation time period, _er is the reactance potential of the commutation element, _ew is the induced potential of the commutation environment, the commutation element includes the first commutator segment and the second commutator segment, _r1 and _r2 are the contact resistances of the first commutator segment, the second commutator segment and the brush respectively. 5. The method for identifying the motor movement direction based on dual Hall sensors according to claim 4, characterized in that it also includes the following steps: S1000, when the current of the motor is commutated, a high-frequency component is generated, which is called the current commutation pulsation frequency. The current pulsation frequency has the following relationship with the motor speed: Among them, f is the current pulse frequency, k is the number of commutator segments, and n is the motor speed obtained by the Hall sensor; The current ripple is conditioned by the circuit to obtain a square wave similar to the Hall pulse. The current ripple period T is obtained through the square wave, and the motor speed w calculated by the current ripple is calculated as follows: 6. The method for identifying the motor movement direction based on dual Hall sensors according to claim 5, characterized in that it also includes the following steps: S1100: When the running direction of the motor changes, due to the inertia inside the motor and the inertia of the load, the motor needs a certain amount of time to complete the reverse rotation. 7. The method for identifying the motor movement direction based on dual Hall sensors according to claim 5, characterized in that it also includes the following steps: S1200, collecting the speed data of the motor. The motor speed w obtained by current ripple calculation in S1000 and the motor speed n obtained by the Hall sensor, both of which have a maximum motor speed n _max determined during the actual collection process, and the abnormal data in the two are eliminated according to the maximum motor speed n _max ; wherein, the collection period of the motor speed data is consistent with the collection period of the Hall pulse signal. 8. The method for identifying the motor movement direction based on dual Hall sensors according to claim 7, further comprising the following steps: S1300, storing the collected motor speed data in groups of four, and calculating the average motor speed value of each group of data. 9. The method for identifying the motor movement direction based on dual Hall sensors according to claim 8, characterized in that it also includes the following steps: S1400, setting an error threshold, making a difference between the motor speed calculated by the current ripple and the motor speed obtained by the Hall sensor in the same cycle, and taking the absolute value of the result, expressed as: n ₀ = |nw| Where n is the average motor speed value of a set of data obtained by the Hall sensor, w is the average motor speed value of the set of data corresponding to n obtained by current ripple calculation, and _np is the absolute value of the difference between the two; The absolute value of the difference between the two groups is compared with the error threshold to determine the size of the error between the two. 10. A computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 9 are implemented.