阅读说明：本技术 一种基于低频正弦微波算法实现快速精确控制比例继动阀的策略 (Strategy for realizing rapid and accurate control of proportional relay valve based on low-frequency sine microwave algorithm ) 是由 张林灿 董钊志 宋罡 刘树全 于 2020-05-07 设计创作，主要内容包括：本发明公开了一种基于低频正弦微波算法实现快速精确控制比例继动阀的策略,采用2000hz的PWM主控制频率和70hz的叠加震颤控制频率,主控制PWM的占空比控制范围在0-30％之间,叠加震颤控制的振幅在主控制占空比基础上增加7％,即震颤PWM是以70hz的频率以及7％的振幅叠加在主控制PWM之上的。本发明有效解决了在没有cpu输出震颤信号控制比例继动阀的情况下,采用软件实现多路PWM波叠加控制输出信号,实现对比例继动阀的快速精确控制,使得对于气刹制动的车辆制动控制得到快速响应,满足上层决策控制需求。(The invention discloses a strategy for realizing rapid and accurate control of a proportional relay valve based on a low-frequency sine microwave algorithm, which adopts a PWM (pulse-width modulation) main control frequency of 2000hz and a superposition chattering control frequency of 70hz, wherein the duty ratio control range of the main control PWM is between 0 and 30 percent, and the amplitude of superposition chattering control is increased by 7 percent on the basis of the main control duty ratio, namely chattering PWM is formed by superposing the frequency of 70hz and the amplitude of 7 percent on the main control PWM. The invention effectively solves the problems that under the condition that no CPU outputs a tremor signal to control the proportional relay valve, software is adopted to realize multi-path PWM wave superposition control output signals, and the rapid and accurate control of the proportional relay valve is realized, so that the vehicle brake control of air brake braking is rapidly responded, and the upper-layer decision control requirement is met.)

1. A strategy for realizing rapid and accurate control of a proportional relay valve based on a low-frequency sine microwave algorithm is characterized in that: the PWM main control frequency of 2000hz and the superposition chattering control frequency of 70hz are adopted, the duty ratio control range of the main control PWM is 0-30%, the amplitude of the superposition chattering control is increased by 7% on the basis of the main control duty ratio, namely the chattering PWM is superposed on the main control PWM by the frequency of 70hz and the amplitude of 7%.

2. The strategy for implementing a fast and accurate control of a proportional relay valve based on a low frequency sinusoidal microwave algorithm as claimed in claim 1, wherein: the response physical expression of the PWM step signal is expressed as:

rising edge:

falling edge:

wherein: i is₀Is the initial current; u: is the output voltage of the PWM; r: is the resistance of the coil; L/R is the time constant of the resistance inductance loop; l is the inductance of the coil; t is time.

The technical field is as follows:

the invention relates to a strategy for realizing rapid and accurate control of a proportional relay valve based on a low-frequency sine microwave algorithm, and belongs to the technical field of intelligent driving of electric automobiles.

Background art:

the problem of front collision early warning and emergency braking is essential to intelligent driving technology, air brake is mostly adopted on buses and trucks, in order to realize brake control, a proportional relay valve is often adopted to control the brake air pressure output to each tire by an air pump, and the control of the proportional relay valve is realized by controlling the current in a coil to control the motion of a valve core as shown in figure 1.

Wherein, 1 port normally enters air, the movable iron core moves downwards when the coil is electrified to close the valve a, and under enough current, the valve b is jacked open by overcoming the spring force and the pressure difference force, so that the air pressure of the 1 port flows into the relay piston upper cavity through the valve b, and the relay piston upper cavity moves downwards to open the valve c, thereby leading the 2 port to have air pressure output; when the air pressure in the upper cavity of the piston rises to a certain value, the proportional valve is pushed to rise so as to close the valve b, after constant current is input, the air pressure in each cavity reaches balance and stability, and the valves a, b and c are all in a closed state.

In engineering, the magnitude of input current is controlled by controlling the duty ratio of a PWM wave so as to control the opening and closing degree of the proportional relay valve; however, in practical applications, there is a potential problem that the control of the spool lags behind the control of the PWM wave because the spool needs to overcome the counter electromotive force generated by static friction and changing current during the transition from static to moving, and the counter electromotive force always exists during the PWM change, so a technology is needed to overcome the counter electromotive force, so that the proportional relay valve has higher response accuracy.

The invention content is as follows:

the invention aims to solve the problems in the prior art and provides a strategy for realizing the rapid and accurate control of the proportional relay valve based on a low-frequency sine microwave algorithm, which can realize the precise and rapid control of a pneumatic braking vehicle and ensure the safety and danger defense of the vehicle in running.

The technical scheme adopted by the invention is as follows: a strategy for realizing rapid and accurate control of a proportional relay valve based on a low-frequency sine microwave algorithm is characterized in that a PWM main control frequency of 2000hz and a superposition chattering control frequency of 70hz are adopted, the duty ratio control range of the main control PWM is 0-30%, the amplitude of the superposition chattering control is increased by 7% on the basis of the main control duty ratio, namely the chattering PWM is superposed on the main control PWM by the frequency of 70hz and the amplitude of 7%.

Further, the response physical expression of the PWM step signal is expressed as:

rising edge:

falling edge:

wherein: i is₀Is the initial current; u: is the output voltage of the PWM; r: is the resistance of the coil; L/R is the time constant of the resistance inductance loop; l is the inductance of the coil; t is time.

The invention has the following beneficial effects: the invention effectively solves the problems that under the condition that no CPU outputs a tremor signal to control the proportional relay valve, software is adopted to realize multi-path PWM wave superposition control output signals, and the rapid and accurate control of the proportional relay valve is realized, so that the vehicle brake control of air brake braking is rapidly responded, and the upper-layer decision control requirement is met.

Description of the drawings:

FIG. 1 is a schematic diagram of a prior art proportional relay valve.

The specific implementation mode is as follows:

the invention will be further described with reference to the accompanying drawings.

Aiming at the control hysteresis phenomenon in the control process of the proportional relay valve, the invention adopts a tremor algorithm based on low-frequency sine microwaves to overcome the counter electromotive force generated by static friction and changed current in the process of converting a valve core from static to motion from a software layer, so that the quick and accurate control requirement of an upper layer is met when the proportional relay valve is used as a control execution mechanism for a vehicle braked by an air brake.

The invention discloses a strategy for realizing rapid and accurate control of a proportional relay valve based on a low-frequency sine microwave algorithm, which adopts 2000hz PWM main control frequency and 70hz superposition chattering control frequency, the duty ratio control range of the main control PWM is between 0 and 30 percent, and the amplitude of the superposition chattering control is increased by 7 percent on the basis of the main control duty ratio, namely the chattering PWM is superposed on the main control PWM by the frequency of 70hz and the amplitude of 7 percent.

The invention overcomes the counter electromotive force generated by static friction and changed current in the process of converting the valve core from static to moving based on the chattering algorithm of low-frequency sine microwaves.

The coil of the proportional relay valve can be simplified in engineering and is composed of a series circuit of a resistor and an inductor, and a response physical expression of the PWM step signal can be represented as follows:

rising edge:

falling edge:

wherein: i is₀Is the initial current; u: is the output voltage of the PWM; r: is the resistance of the coil; L/R is the time constant of the resistance inductance loop; l is the inductance of the coil; t is time.

By superimposing a sine oscillation duty ratio on the inherent PWM wave, the triangular wave can be adopted for approximate substitution in engineering, and the verification shows that the actual effects are basically consistent and the difference is very small.

The invention effectively solves the problems that under the condition that no CPU outputs a tremor signal to control the proportional relay valve, software is adopted to realize multi-path PWM wave superposition control output signals, and the rapid and accurate control of the proportional relay valve is realized, so that the vehicle brake control of air brake braking is rapidly responded, and the upper-layer decision control requirement is met.

The foregoing is only a preferred embodiment of this invention and it should be noted that modifications can be made by those skilled in the art without departing from the principle of the invention and these modifications should also be considered as the protection scope of the invention.