A method of zeroing an electric proportional brake valve

Abstract

The application relates to a zero setting method of an electric proportional brake valve, wherein a state value is obtained according to three motor Hall sensor signals received by a controller, then the current state value and the last state value are compared by software to determine whether the motor is rotating forward or backward and the corresponding motor position is calculated, the feedback pressure is obtained according to a voltage signal output by a pressure sensor, so that the initial pressure and the full pressure are obtained, finally, the reference point and the mirror point are defined according to the obtained motor position, the initial pressure and the full pressure, so that the zero point is calculated. The application comprehensively processes the motor Hall sensor signals and the feedback hydraulic signals, and the controller is automatically zero set after being powered on, and is dynamically calibrated during the working process, so that the normal use of the electric proportional brake valve is ensured, the failure rate is reduced, and the service life is prolonged.

Description

Technical Field

[0001] This invention relates to the field of electro-proportional brake valve control, specifically to a method for zeroing an electro-proportional brake valve. Background Technology

[0002] The electro-proportional brake valve consists of a controller and a brake valve body. The motor, a brushless DC motor with a Hall sensor, is installed inside the valve body. The controller receives signals from the motor's Hall sensor and hydraulic pressure feedback from a pressure sensor. After processing, it outputs a motor control signal to control the direction and position of the brushless DC motor in the brake valve. The motor drives a lead screw through a reducer, converting the motor's circular motion into the lead screw's linear motion. The lead screw pushes a piston, compressing the hydraulic oil and generating hydraulic pressure. The hydraulic pressure is fed back to the controller via a pressure sensor. The software runs within the controller, with a control cycle of (5±0.5) ms.

[0003] The schematic diagram of the electro-proportional brake valve is as follows: Figure 1 As shown, the movement of the lead screw in the direction of decreasing hydraulic pressure is defined as retraction, and movement in the direction of increasing hydraulic pressure is defined as forward movement. The maximum retraction position of the lead screw is defined as the zero point, and the maximum forward movement position is defined as the maximum point. The lead screw can only move between the zero point and the maximum point. If the lead screw retracts beyond the zero point or forwards beyond the maximum point, it will cause the lead screw to jam, the motor to stall, and in severe cases, damage to the motor or even breakage of the valve body. During the operation of the controller, the position of the zero point must be determined. The distance from the zero point to the maximum point is a fixed value, thus determining the position of the maximum point and controlling the stroke of the lead screw between the zero point and the maximum point. Therefore, the determination of the zero point is crucial for the controller, and the process of determining the zero point is defined as zeroing.

[0004] The controller receives signals from the motor's Hall effect sensor to determine the number of motor revolutions. The number of revolutions is directly proportional to the reduction ratio of the reducer and the lead screw lead. By controlling the number and direction of motor revolutions, the lead screw stroke can be controlled. The number of motor revolutions is defined as the motor position, with positive and negative signs representing forward and reverse rotation, respectively. Therefore, the zero point position corresponds to the motor position. A typical electro-proportional brake valve structure diagram is shown below. Figure 2 As shown, it includes an oil outlet nozzle 1, an oil reservoir 2, a piston 3, a pressure regulating spring 4, a spring seat 5, a pin sleeve 6, a positioning pin 7, a return spring I 8, a valve core 9, a return spring II 10, an oil outlet C, a piston inner cavity E, a valve needle conical surface channel F, and a piston oil inlet channel G.

[0005] The traditional method of manually calibrating the zero point involves recording the zero-point position in a data power-loss protection chip during manual zeroing, and continuously saving the current position to the chip during motor operation. Upon the next power-on, the chip is read to record the motor's position from the previous power-loss and its position at zero point. This method has three drawbacks:

[0006] 1. There is a discrepancy between the motor position recorded before the power failure and the actual position of the motor after power-on;

[0007] 2. The motor position obtained from the Hall sensor signal may deviate from the actual position due to signal loss or interference;

[0008] 3. The deviations from the first two points accumulate, and the deviations become larger and larger, requiring recalibration after a period of time. Summary of the Invention

[0009] To address the above problems, this invention provides a method for zeroing an electro-proportional brake valve that automatically zeros the controller after power-on and dynamically calibrates it during operation.

[0010] The technical solution adopted by the present invention to solve the above-mentioned technical problems is: a method for zeroing an electro-proportional brake valve, comprising the following steps,

[0011] S1, Motor position calculation

[0012] The controller receives signals from three motor Hall sensors. For each rotation of the motor, each signal changes twice, from 0 to 1 or from 1 to 0. The three signals change a total of 6 times, decomposing one rotation into 6 states. Each state corresponds to 30 degrees, and each state corresponds to a unique state value formed by the combination of the three signals. As the motor rotates, the 6 states cycle continuously. The software compares the current state value with the previous state value to determine whether the motor is rotating forward or backward and calculates the corresponding motor position.

[0013] S2, Feedback Pressure Calculation

[0014] The pressure sensor converts the hydraulic pressure into an output voltage signal, which is processed by the hardware circuit and sent to the software. The software then calculates the actual hydraulic pressure, i.e., the feedback pressure P, based on the pressure sensor parameters and the amplification ratio of the hardware circuit. f ,

[0015] The voltage after hardware circuit processing is denoted as C. The relationship between the hydraulic pressure and the output voltage signal of the pressure sensor is fixed and denoted as the function F(x). The amplification ratio of the hardware circuit is fixed and denoted as the function G(x). The feedback pressure Pf is calculated according to equation (1).

[0016] P f =F -1 (G -1 (C)) (1)

[0017] S3, Zeroing Algorithm

[0018] The zero point is calculated by defining a reference point and a mirror point based on the motor position obtained in step S1 and the initial pressure and full pressure obtained in equation (1) in step S2. Let the motor position be defined as the reference point, denoted as R, when the pressure is n% of the full pressure (where 3≤n≤10); let the motor position be defined as the mirror point when the pressure is (2*n)% of the full pressure. The difference between the reference point and the mirror point is denoted as L. When the lead screw retracts L from the reference point, it is defined as the zero point Z. The specific steps include the following:

[0019] S301, power on, L initialized to the empirical value L0;

[0020] S302, when the initial pressure is less than 1% of the full pressure, set the current position as the initial zero point Z0 and the initial reference point as R0 = Z0 + L0;

[0021] S303, when the initial pressure is greater than 1% of the full pressure, control the lead screw to move to the reference point, record the position R0 of the initial reference point, and the initial zero point Z0 = R0 - L0;

[0022] S304, when the electro-proportional valve is working, it determines whether it has passed through a reference point or a mirror point. When it passes through a reference point, it updates the reference point position R according to equation (2). When it passes through a mirror point, it updates L and Z according to equations (3) and (4), where R last L last R is the reference point position of the previous control cycle. now L now The reference point position for the current control cycle, and the range of a and b (0~1).

[0023] R = a * R last +(1-a)*R now (2)

[0024] L = b * L last +(1-b)*L now (3)

[0025] Z = RL (4)

[0026] Preferably, in step S1, the controller triggers software processing at the rising and falling edges of each Hall sensor signal. The software compares the current state value with the previous state value to determine whether the motor is rotating forward or backward by 30 degrees. When powered on, the motor position is set to 0. If the motor rotates forward by 30 degrees, the motor position is incremented by 1; if it rotates backward by 30 degrees, the motor position is decremented by 1. The resolution of the motor position is 30 degrees.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] This invention integrates the signals from the motor Hall sensor and the feedback hydraulic signal. After the controller is powered on, it automatically zeroes and dynamically calibrates during operation, thereby ensuring the normal use of the electro-proportional brake valve, reducing the failure rate, and extending its service life. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the electro-proportional brake valve of the present invention;

[0030] Figure 2 This is a structural diagram of the electro-proportional brake valve of the present invention;

[0031] Figure 3 This is a signal diagram of the motor Hall sensor of the present invention;

[0032] Figure 4 This is the feedback pressure diagram in this invention;

[0033] Figure 5 This is a diagram showing the relationship between the zero point, reference point, and mirror point in this invention;

[0034] Figure 6 This is a flowchart of the zeroing algorithm in this invention. Detailed Implementation

[0035] The following will combine Figure 1-6 The present invention will be described in detail below. The illustrative embodiments and descriptions herein are used to explain the invention, but are not intended to limit the invention.

[0036] A method for zeroing an electro-proportional brake valve includes the following steps:

[0037] S1, Motor position calculation

[0038] The controller receives signals from three motor Hall effect sensors. For each revolution of the motor, each signal transitions twice, from 0 to 1 or from 1 to 0. The three signals transition a total of six times, decomposing one revolution into six states. Each state corresponds to 30 degrees, and each state corresponds to a unique state value formed by the combination of the three signals. As the motor rotates, these six states cycle continuously. The software compares the current state value with the previous state value to determine whether the motor is rotating forward or backward and calculates the corresponding motor position. The motor Hall effect sensor signal diagram is shown below. Figure 3 As shown, a change in the status value from left to right represents forward rotation, and a change from right to left represents reverse rotation of the motor.

[0039] The controller triggers software processing on the rising and falling edges of each Hall sensor signal. The software compares the current state value with the previous state value to determine whether the motor is rotating forward or backward by 30 degrees. When powered on, the motor position is set to 0. If it rotates forward by 30 degrees, the motor position is incremented by 1; if it rotates backward by 30 degrees, the motor position is decremented by 1. The resolution of the motor position is 30 degrees.

[0040] S2, Feedback Pressure Calculation

[0041] The pressure sensor converts the hydraulic pressure into an output voltage signal, which is processed by the hardware circuit and sent to the software. The software then calculates the actual hydraulic pressure, i.e., the feedback pressure P, based on the pressure sensor parameters and the amplification ratio of the hardware circuit. f Feedback pressure such as Figure 4 As shown,

[0042] The voltage after hardware circuit processing is denoted as C. The relationship between the hydraulic pressure and the output voltage signal of the pressure sensor is fixed and denoted as the function F(x). The amplification ratio of the hardware circuit is fixed and denoted as the function G(x). The feedback pressure Pf is calculated according to equation (1).

[0043] P f =F -1 (G -1 (C)) (1)

[0044] S3, Zeroing Algorithm

[0045] The zero point is calculated by defining a reference point and a mirror point based on the motor position obtained in step S1 and the initial pressure and full pressure obtained in equation (1) of step S2. When the pressure is n% of the full pressure (where 3≤n≤10), the corresponding motor position is defined as the reference point, denoted as R; when the pressure is (2*n)% of the full pressure, the corresponding motor position is defined as the mirror point. The position difference between the reference point and the mirror point is denoted as L. When the lead screw retracts L from the reference point, it is defined as the zero point Z. The relationship between the zero point, reference point, and mirror point is shown in the diagram below. Figure 5 As shown, the specific steps include the following, such as Figure 6 As shown,

[0046] S301, power on, L initialized to the empirical value L0;

[0047] S302, when the initial pressure is less than 1% of the full pressure, set the current position as the initial zero point Z0 and the initial reference point as R0 = Z0 + L0;

[0048] S303, when the initial pressure is greater than 1% of the full pressure, control the lead screw to move to the reference point, record the position R0 of the initial reference point, and the initial zero point Z0 = R0 - L0;

[0049] S304, when the electro-proportional valve is working, it determines whether it has passed through a reference point or a mirror point. When it passes through a reference point, it updates the reference point position R according to equation (2). When it passes through a mirror point, it updates L and Z according to equations (3) and (4), where R last L last R is the reference point position of the previous control cycle. now L nowThe reference point position for the current control cycle, and the range of a and b (0~1).

[0050] R = a * R last +(1-a)*R now (2)

[0051] L = b * L last +(1-b)*L now (3)

[0052] Z = RL (4)

[0053] This invention integrates the signals from the motor Hall sensor and the feedback hydraulic signal. After the controller is powered on, it automatically zeroes and dynamically calibrates during operation, thereby ensuring the normal use of the electro-proportional brake valve, reducing the failure rate, and extending its service life.

[0054] The technical solutions provided by the embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the embodiments of the present invention. The descriptions of the embodiments above are only for helping to understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the embodiments of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for zeroing an electro-proportional brake valve, characterized in that, Includes the following steps: S1, Motor position calculation The controller receives signals from three motor Hall sensors. For each rotation of the motor, each signal changes twice, from 0 to 1 or from 1 to 0. The three signals change a total of 6 times, decomposing one rotation into 6 states. Each state corresponds to 30 degrees, and each state corresponds to a unique state value formed by the combination of the three signals. As the motor rotates, the 6 states cycle continuously. The software compares the current state value with the previous state value to determine whether the motor is rotating forward or backward and calculates the corresponding motor position. S2, Feedback Pressure Calculation The pressure sensor converts the hydraulic pressure into an output voltage signal, which is processed by the hardware circuit and sent to the software. The software then calculates the actual hydraulic pressure, i.e., the feedback pressure P, based on the pressure sensor parameters and the amplification ratio of the hardware circuit. f , The voltage after hardware circuit processing is denoted as C. The relationship between the hydraulic pressure and the output voltage signal of the pressure sensor is fixed, denoted as the function F(x). The amplification ratio of the hardware circuit is fixed, denoted as the function G(x). The feedback pressure P... f Solve according to equation (1) P f =F -1 (G -1 (C)) (1) S3, Zeroing Algorithm The zero point is calculated by defining a reference point and a mirror point based on the motor position obtained in step S1 and the initial pressure and full pressure obtained in equation (1) in step S2. Let the motor position be defined as the reference point, denoted as R, when the pressure is n% of the full pressure (where 3≤n≤10); let the motor position be defined as the mirror point when the pressure is (2*n)% of the full pressure. The difference between the reference point and the mirror point is denoted as L. When the lead screw retracts L from the reference point, it is defined as the zero point Z. The specific steps include the following: S301, power on, L initialized to the empirical value L0; S302, when the initial pressure is less than 1% of the full pressure, set the current position as the initial zero point Z0 and the initial reference point as R0 = Z0 + L0; S303, when the initial pressure is greater than 1% of the full pressure, control the lead screw to move to the reference point, record the position R0 of the initial reference point, and the initial zero point Z0 = R0 - L0; S304, when the electro-proportional valve is working, it determines whether it has passed through a reference point or a mirror point. When it passes through a reference point, it updates the reference point position R according to equation (2). When it passes through a mirror point, it updates L and Z according to equations (3) and (4), where R last L last R is the reference point position of the previous control cycle. now L now The reference point position for the current control cycle, and the range of a and b (0~1). R=a*R last +(1-a)*R now (2) L=b*L last +(1-b)*L now (3) Z = RL (4).

2. The zeroing method for the electro-proportional brake valve according to claim 1, characterized in that: In step S1, the controller triggers software processing at the rising and falling edges of each Hall sensor signal. The software compares the current state value with the previous state value to determine whether the motor is rotating forward or backward by 30 degrees. When powered on, the motor position is set to 0. If it rotates forward by 30 degrees, the motor position is incremented by 1; if it rotates backward by 30 degrees, the motor position is decremented by 1. The resolution of the motor position is 30 degrees.

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