Flutter waveform generation algorithm for proportional valve controller

Abstract

The invention discloses a flutter waveform generation algorithm for a proportional valve controller. The flutter waveform generation algorithm comprises the following steps: S1, determining a basic function Y; s2, correcting and adjusting the basic function Y based on actual requirements to obtain a function Y1; s3, compressing the function Y1 to obtain a function Y2; s4, calculating a function waveform from a parameter 0 based on engineering application calculation, and translating the waveform to obtain a function Y3; and S5, combining the function Y3 with the output PWM wave to finally output a PWM waveform with flutter frequency, adjusting and correcting the basic waveform to obtain a target function, and finally combining the target function with the PWM waveform to obtain a flutter waveform for controlling the proportional valve. The flutter waveform generation algorithm for the proportional valve controller has the advantages that a valve element of a proportional valve is controlled to generate jitter with a certain frequency, mechanical friction force is in a dynamic friction force mode, and meanwhile, the hysteresis effect of a valve body can be overcome, so that the effect of starting accurate control is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of proportional valves, and in particular to a dither waveform generation algorithm for a proportional valve controller. Background Art

[0002] Hydraulic proportional valves are widely used in many fields, including industrial automation production, machine tool industry, agriculture, aerospace, medical equipment, automobile industry, etc. The development trend of hydraulic proportional valves is towards higher performance, smaller size and more integration. Proportional valves are divided into ordinary proportional valves and servo proportional valves. The servo proportional valve has an integrated controller and comes with valve core displacement feedback. In addition to easier control, the valve body opening size can also be collected. However, servo proportional valves are often large in size, difficult to repair after a failure, and not particularly adaptable.

[0003] To realize electrical control of the proportional valve, the proportional valve solenoid coil must be precisely controlled. The common method of controlling the solenoid coil is to directly use PWM to adjust the solenoid coil voltage. This adjustment method has poor control linearity due to the friction, mechanical stress and hysteresis effect of the valve body mechanical structure. The proportional valve cannot be precisely controlled to open at a small opening, resulting in the inability to operate the crane slowly. Summary of the invention

[0004] In view of the above problems, a dither waveform generation algorithm for a proportional valve controller is provided, aiming to solve the problems existing in the prior art.

[0005] The specific technical solutions are as follows:

[0006] A dither waveform generation algorithm for a proportional valve controller comprises the following steps:

[0007] S1. Determine the basis function Y;

[0008] S2. Based on actual needs, modify and adjust the basic function Y to obtain function Y1;

[0009] S3, compressing the function Y1 to obtain the function Y2;

[0010] S4, based on engineering application calculations, the function waveform needs to be calculated from parameter 0, and the waveform is translated to obtain function Y3;

[0011] S5. Combine the function Y3 with the output PWM wave to finally output a PWM waveform with a dither frequency.

[0012] The above-mentioned dither waveform generation algorithm for the proportional valve controller also has the characteristic that the basic function Y is a trigonometric function Y=sin(x).

[0013] The above-mentioned dither waveform generation algorithm for the proportional valve controller also has the following characteristics: the step S2 further includes:

[0014] S21, correct the basic function so that its frequency is corrected to B, and obtain function Y0;

[0015] S22. Based on actual conditions, determine the adjustment frequency C, and obtain the function Y1 based on the adjustment frequency C.

[0016] The above-mentioned dither waveform generation algorithm for the proportional valve controller also has the following feature: in step S21, the value of B is 1, the frequency of the basic function is corrected to 1, and the function Y0=sin(2πx) is obtained.

[0017] The above-mentioned dither waveform generation algorithm for the proportional valve controller also has the following characteristics: the adjustment frequency C is 65 Hz, and the function Y0 is adjusted to a function of 65 Hz, resulting in the function Y1 = sin(2πx×65).

[0018] The above-mentioned dither waveform generation algorithm for the proportional valve controller also has the characteristic of compressing the function Y1 between 0 and 1 to obtain the function Y2 = 0.5sin(2πx×65)+0.5.

[0019] The above-mentioned dither waveform generation algorithm for the proportional valve controller also has the following feature: according to the waveform of the function Y2, the waveform is shifted by π / 2 so that the waveform of the function Y2 starts from 0, and the function Y3=0.5sin(2πx×65-π / 2)+0.5 is obtained.

[0020] The dither waveform generation algorithm used in the above-mentioned proportional valve controller also has the following characteristics: the function Y3 is combined with the output PWM wave to output a PWM waveform with a dither frequency, that is, D1 = (0.5sin(2πx×65-π / 2)+0.5)*D2, where D1 is the output value of the PWM wave after adjustment, and D2 is the standard output PWM duty cycle value.

[0021] In summary, the beneficial effects of this scheme are:

[0022] In the dither waveform generation algorithm for the proportional valve controller provided by the present invention, the objective function is obtained by adjusting and modifying the basic waveform, and finally the objective function is combined with the PWM waveform to obtain the dither waveform for controlling the proportional valve. The dither waveform generation algorithm for the proportional valve controller provided by the present invention has the function of controlling the valve core of the proportional valve to produce a certain frequency of dithering, and the mechanical friction force is in the dynamic friction force mode, and can overcome the hysteresis effect of the valve body to achieve the effect of starting precise control. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the flow of the dither waveform generation algorithm used in the proportional valve controller of the present invention. DETAILED DESCRIPTION

[0024] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0026] The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited thereto.

[0027] Figure 1 FIG. 1 is a flow chart of a dither waveform generation algorithm for a proportional valve controller of the present invention, as shown in FIG. Figure 1 As shown, the dither waveform generation algorithm for the proportional valve controller provided in this embodiment includes the following steps:

[0028] S1. Determine the basis function Y;

[0029] S2. Based on actual needs, modify and adjust the basic function Y to obtain function Y1;

[0030] S3, compressing the function Y1 to obtain the function Y2;

[0031] S4, based on engineering application calculations, the function waveform needs to be calculated from parameter 0, and the waveform is translated to obtain function Y3;

[0032] S5. Combine the function Y3 with the output PWM wave to finally output a PWM waveform with a dither frequency.

[0033] In the above embodiment, the basis function Y is a trigonometric function Y=sin(x).

[0034] In the above embodiment, step S2 also includes:

[0035] S21, correct the basic function so that its frequency is corrected to B, and obtain function Y0;

[0036] S22. Based on actual conditions, determine the adjustment frequency C, and obtain the function Y1 based on the adjustment frequency C.

[0037] In the above embodiment, in step S21, the value of B is 1, the frequency of the basic function is corrected to 1, and the function Y0=sin(2πx) is obtained.

[0038] In the above embodiment, the frequency C is adjusted to 65 Hz, and the function Y0 is adjusted to a function of 65 Hz, thereby obtaining the function Y1 = sin(2πx×65).

[0039] It should be noted that, based on the actual project situation, the recommended dither frequency for the proportional valve spool is generally 65HZ. At this time, the sine function needs to be adjusted to a 65HZ basic function. When the recommended dither frequency for the proportional valve spool is other frequencies, corresponding adjustments can be made.

[0040] In the above embodiment, the function Y1 is compressed between 0 and 1, and the function Y2=0.5sin(2πx×65)+0.5 is obtained.

[0041] It should be noted that since the PWM output waveform has no negative value, the function needs to be compressed to control it between 0 and 1.

[0042] In the above embodiment, according to the waveform of function Y2, it can be known that the waveform is shifted by π / 2 so that the waveform of function Y2 starts from 0, and function Y3=0.5sin(2πx×65-π / 2)+0.5 is obtained.

[0043] In the above embodiment, the function Y3 is combined with the output PWM wave to output a PWM waveform with a dither frequency, that is, D1=(0.5sin(2πx×65-π / 2)+0.5)*D2, where D1 is the output value of the PWM wave after adjustment, and D2 is the standard output PWM duty cycle value.

[0044] It should be noted that this algorithm obtains the PWM duty cycle of the current period by timing and counting trigonometric functions, and then controls the PWM peripheral of the microprocessor to output the corresponding PWM waveform to control the valve body of the proportional valve to maintain a flutter state to improve the control effect.

[0045] It should also be noted that in order to ensure the real-time performance of the PWM waveform, when the PWM frequency is set to 1KHZ, the duty cycle calculation frequency should be calculated after no PWM wave output cycle is executed, to ensure that each square wave of the PWM output is output after adjustment.

[0046] Working principle: Through the functional analysis of the valve body, the control of the valve body introduces the flutter control mode. That is, the current size of the valve core is controlled to change periodically near the given current, so that the valve core produces a certain frequency of jitter. When the valve core is in the flutter state, its mechanical friction is in the dynamic friction mode, and it can overcome the hysteresis effect of the valve body. When the control current changes, it can act very quickly and has a certain control accuracy.

[0047] The above are only preferred embodiments of the present invention, and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the contents of the specification of the present invention should be included in the protection scope of the present invention.

Claims

1. A dither waveform generation algorithm for a proportional valve controller, characterized in that: The following steps are involved: S1. Determine the basis function Y; S2. Based on actual needs, modify and adjust the basic function Y to obtain function Y1; S3, compressing the function Y1 to obtain the function Y2; S4, based on engineering application calculations, the function waveform needs to be calculated from parameter 0, and the waveform is translated to obtain function Y3; S5. Combine the function Y3 with the output PWM wave to finally output a PWM waveform with a dither frequency.

2. The dither waveform generation algorithm for a proportional valve controller according to claim 1, characterized in that: The basic function Y is a trigonometric function Y=sin(x).

3. The dither waveform generation algorithm for a proportional valve controller according to claim 2, characterized in that: The step S2 also includes: S21, correct the basic function so that its frequency is corrected to B, and obtain function Y0; S22. Based on actual conditions, determine the adjustment frequency C, and obtain the function Y1 based on the adjustment frequency C.

4. The dither waveform generation algorithm for a proportional valve controller according to claim 3, characterized in that: In the step S21, the value of B is 1, the frequency of the basic function is corrected to 1, and the function Y0=sin(2πx) is obtained.

5. The dither waveform generation algorithm for a proportional valve controller according to claim 4, characterized in that: The adjustment frequency C is 65 Hz, and the function Y0 is adjusted to a function of 65 Hz, obtaining the function Y1 = sin(2πx×65).

6. The dither waveform generation algorithm for a proportional valve controller according to claim 5, characterized in that: The function Y1 is compressed between 0 and 1 to obtain the function Y2 = 0.5sin(2πx×65)+0.

5.

7. The dither waveform generation algorithm for a proportional valve controller according to claim 6, characterized in that: According to the waveform of the function Y2, it can be known that the waveform is shifted by π / 2 so that the waveform of the function Y2 starts from 0, and the function Y3=0.5sin(2πx×65-π / 2)+0.5 is obtained.

8. The dither waveform generation algorithm for a proportional valve controller according to claim 7, characterized in that: The function Y3 is combined with the output PWM wave to output a PWM waveform with a dither frequency, that is, D1=(0.5sin(2πx×65-π / 2)+0.5)*D2, where D1 is the output value of the PWM wave after adjustment, and D2 is the standard output PWM duty cycle value.

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