CN113883318A

CN113883318A - PWM driving method and system of AMT electromagnetic valve

Info

Publication number: CN113883318A
Application number: CN202111173721.9A
Authority: CN
Inventors: 刘福伟; 姚元吉; 杨钢
Original assignee: Dongfeng Commercial Vehicle Co Ltd
Current assignee: Dongfeng Commercial Vehicle Co Ltd
Priority date: 2021-09-30
Filing date: 2021-09-30
Publication date: 2022-01-04
Anticipated expiration: 2041-09-30
Also published as: CN113883318B

Abstract

The invention discloses a PWM driving method and a PWM driving system for an AMT electromagnetic valve, which comprise the following steps: setting a plurality of PWM sequences, and selecting one or more PWM sequences; an output command of a high level or a low level according to the duration of the selected PWM sequence output in the initial output period; the main control chip outputs a high level or a low level of duration time to the electromagnetic valve according to the output command, and sends a level switching trigger command through internal peripheral interruption after the output time is over; and controlling the main control chip to switch the output high and low levels according to the level switching trigger command and the PWM sequence. The invention can realize the level switching rapidly in real time, can control the delay error to be microsecond level or even smaller, and greatly reduces the larger delay response caused by the increase of the periodic task load in the prior art scheme.

Description

PWM driving method and system of AMT electromagnetic valve

Technical Field

The invention belongs to the technical field of electromagnetic valve driving, and particularly relates to a PWM driving method and system of an AMT electromagnetic valve.

Background

The control of the AMT gear selecting and shifting actuating mechanism and the clutch of the commercial vehicle is realized by controlling the action of the mechanism by controlling the air source pressure or the engine oil pressure through a series of electromagnetic valves. Most of the existing design schemes of the solenoid valve PWM driving software are to set the solenoid valve opening time (or closing time) in the 5ms periodic scheduling task of the operating system, the solenoid valve is closed (or opened) after the opening time (or closing time) is over, then the solenoid valve opening time (or opening and closing time) is continuously set in the next periodic task, and so on, by setting different opening/closing times of the solenoid valves in a plurality of periodic scheduling tasks and splicing together, finally the purpose of outputting the PWM driving waveform with the preset frequency and duty ratio is achieved, and the application example is explained with reference to fig. 1.

In fig. 1, the expected output period is 16ms, wherein the PWM waveform with high level 6ms and low level 10ms can be completed by splicing 4 tasks with 5ms without considering the task load, wherein the first task is to set the continuous output high level, the second task is to set the continuous output high level for 1ms and then output the low level for 6ms, the third task is to output the continuous output low level, and the fourth task is to output the low level for 1ms and then output the high level. However, since the load rate of the second task is high, the setting command is issued after delaying for 1ms (delay1ms), so that the waveforms of high level 7ms and low level 9ms are output by splicing the final 4 tasks, and the error from the expectation is large.

Under the existing technical scheme, the output of the PWM waveform of the electromagnetic valve is formed by splicing a plurality of opening/closing times set in 5ms periodic scheduling tasks, and the setting time of the opening/closing time of the electromagnetic valve in a specific certain task depends on the sending time of a set instruction in the task. Since the task load may be different in different task periods and the time when the command is issued is also different, the PWM waveform of the solenoid valve may not be consistent with the expected result, and in an extreme case, the error may reach several milliseconds, and the error may eventually cause the control system to perform an uncontrolled motion.

Disclosure of Invention

The present invention aims to solve the above-mentioned drawbacks of the background art, and provides a PWM driving method and system for an AMT solenoid valve, which can realize the level switching rapidly in real time and control the delay error at microsecond level or even smaller.

The technical scheme adopted by the invention is as follows: a PWM driving method of AMT electromagnetic valve sets a plurality of PWM sequences, selects one or a plurality of PWM sequences;

an output command of a high level or a low level according to the duration of the selected PWM sequence output in the initial output period;

the main control chip outputs a high level or a low level of duration time to the electromagnetic valve according to the output command, and sends a level switching trigger command through internal peripheral interruption after the output time is over;

and controlling the main control chip to switch the output high and low levels according to the level switching trigger command and the PWM sequence.

Further, the PWM sequence includes a sequence number, a duty cycle, a PWM waveform pattern, and an output period.

Further, the PWM waveform pattern includes a duty ratio and an output order of a high level and a low level within one output period.

Further, when a plurality of PWM sequences are selected, the main control chip sends out a sequence switching trigger command through internal peripheral interruption, and controls the main control chip to switch the PWM sequences according to the sequence switching trigger command and the next PWM sequence to be switched.

Further, the selected plurality of PWM sequences are switched sequentially or alternately.

A PWM driving system of AMT electromagnetic valve comprises

The sequence setting module is used for setting a plurality of PWM sequences and outputting one or more PWM sequences to the control module;

a control module for outputting a high-level or low-level output command with a duration time to the main control chip according to the received PWM sequence in the initial output period, and for outputting a high-level or low-level output command with a duration time to the main control chip according to the level switching trigger command

And the main control chip is used for outputting a high level or a low level of the duration time to the electromagnetic valve according to the output command, and sending a level switching trigger command to the control module through internal peripheral interrupt after the output time is finished.

Furthermore, when the sequence setting module outputs a plurality of PWM sequences, the main control chip sends out a sequence switching trigger command through internal peripheral interruption, and the control module controls the main control chip to switch the PWM sequences according to the sequence switching trigger command and the next PWM sequence to be switched.

Further, the output multiple PWM sequences are switched sequentially or alternately.

The invention has the beneficial effects that:

1. a sequence mode of PWM control is added, namely a series of PWM sequences are predefined according to the actual application requirements of a control system, so that most application scenes can be covered, and the universality is high.

2. The application layer software only needs to send a command once in a periodic task as required to enter a sequence mode, the bottom layer software can control to repeatedly output a specified PWM sequence according to the command, and the response speed is high.

3. The switching of high and low levels in the PWM waveform is carried out in the interruption of the PWM peripheral of the main control chip, thereby greatly reducing the larger delay response caused by the increase of the periodic task load in the prior art scheme.

Drawings

Fig. 1 is a schematic diagram of a prior art PWM driving waveform.

Fig. 2 is a schematic diagram of the drive system of the present invention.

FIG. 3 is a schematic diagram of a repetitive output sequence PWM waveform according to the present invention.

FIG. 4 is a diagram illustrating switching between different sequences according to the present invention.

Detailed Description

The following further describes embodiments of the present invention with reference to the drawings. It should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.

Where the terms "comprising", "having" and "including" are used in this specification, there may be another part or parts unless otherwise stated, and the terms used may generally be in the singular but may also be in the plural.

It should be noted that although the terms "first," "second," "top," "bottom," "side," "other," "end," "other end," and the like may be used and used in this specification to describe various components, these components and parts should not be limited by these terms. These terms are only used to distinguish one element or section from another element or section. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, with the top and bottom elements being interchangeable or switchable with one another, where appropriate, without departing from the scope of the present description; the components at one end and the other end may be of the same or different properties to each other.

Further, in constituting the component, although it is not explicitly described, it is understood that a certain error region is necessarily included.

In describing positional relationships, for example, when positional sequences are described as being "on.. above", "over.. below", "below", and "next", unless such words or terms are used as "exactly" or "directly", they may include cases where there is no contact or contact therebetween. If a first element is referred to as being "on" a second element, that does not mean that the first element must be above the second element in the figures. The upper and lower portions of the member will change depending on the angle of view and the change in orientation. Thus, in the drawings or in actual construction, if a first element is referred to as being "on" a second element, it can be said that the first element is "under" the second element and the first element is "over" the second element. In describing temporal relationships, unless "exactly" or "directly" is used, the description of "after", "subsequently", and "before" may include instances where there is no discontinuity between steps.

The features of the various embodiments of the present invention may be partially or fully combined or spliced with each other and performed in a variety of different configurations as would be well understood by those skilled in the art. Embodiments of the invention may be performed independently of each other or may be performed together in an interdependent relationship.

As shown in FIG. 2, the present invention provides a PWM driving system of AMT electromagnetic valve, comprising

The sequence setting module (namely application software) is used for setting a plurality of PWM sequences and outputting one or more PWM sequences to the control module; the PWM sequence includes a sequence number, a task period, a PWM waveform pattern, and an output period. As shown in table 1 below, the PWM waveform pattern includes a duty ratio and an output order of a high level and a low level within one output period.

TABLE 1 PWM waveform patterns in predefined PWM sequences

A control module (i.e. bottom layer software) for outputting the output command with duration of high level or low level to the main control chip according to the received PWM sequence in the initial output period, and for outputting the output command with duration of high level or low level to the main control chip according to the level switching trigger command

And the main control chip (comprising PWM peripheral interrupt) is used for outputting a high level or a low level of the duration time to the electromagnetic valve according to the output command, and sending a level switching trigger command to the control module through the internal peripheral interrupt after the output time is finished.

When the sequence setting module outputs a plurality of PWM sequences, the main control chip sends out a sequence switching trigger command through internal peripheral interruption, and the control module controls the main control chip to switch the PWM sequences according to the sequence switching trigger command and the next PWM sequence to be switched. The output multiple PWM sequences are switched sequentially or alternately.

Based on the PWM driving system, the invention also provides a PWM driving method of the AMT electromagnetic valve, and the process is

The sequence setting module sets a plurality of PWM sequences, and selects one or more PWM sequences to output to the control module; the PWM sequence includes a sequence number, a task period, a PWM waveform pattern, and an output period. The PWM waveform form includes a duty ratio and an output order of a high level and a low level within one output period.

The control module outputs a high-level or low-level output command with duration in the initial output period according to the selected PWM sequence; and controlling the main control chip to switch the output high and low levels according to the level switching trigger command and the PWM sequence.

when a plurality of PWM sequences are selected, the main control chip sends out a sequence switching trigger command through internal peripheral interruption, and controls the main control chip to switch the PWM sequences according to the sequence switching trigger command and the next PWM sequence to be switched. The selected plurality of PWM sequences are switched sequentially or alternately.

The invention takes the PWM sequence mode as the main control mode, because in practical application, most of the PWM waveform is switched among a limited plurality of sequences, and once the sequence is selected, the PWM waveform is repeatedly output according to the sequence most of the time, and in a few cases, a plurality of sequences are needed to be spliced to output the expected waveform. In order to deal with the scene, a 'sequence mode' of PWM driving is newly added, limited commonly used PWM sequences are predefined in bottom layer software, the attributes of the sequences comprise periods, duty ratios, high and low level sequences and the like, application layer software only needs to send a sequence selection command once in a periodic task, and then the bottom layer software can control a main control chip to repeatedly output the specified PWM sequences after receiving the command; when different sequences are required to be switched or spliced into a new waveform, the application layer software can send out the next sequence to be switched within a 5ms scheduling period, then the bottom layer software receives a switching command sent by the application layer software, and the switching is carried out to the output of the new sequence after the ongoing sequence output is finished. In the scheme, the switching of the high and low levels of the PWM waveform in one sequence and the switching between different sequences are completely triggered by the interruption of the PWM peripheral of the main control chip, the interruption belongs to the function of chip hardware, and the response real-time performance is far higher than that of software, so that the level switching can be realized rapidly in real time, the delay error is controlled at microsecond level or even smaller (determined by the performance of the main control chip), the influence on the control precision of a control system can be ignored, and the larger delay response caused by the increase of the periodic task load in the prior art is greatly reduced.

In addition, the scheme adopts the predefined PWM sequence, so that the control algorithm of application layer software is greatly simplified. In the original scheme, the duration of high and low levels needs to be calculated and updated in each 5ms periodic task, and the scheme can be realized only by inputting a specified serial number.

Example 1: repeatedly outputting a specified sequence of PWM waveforms

Firstly, according to the requirements of a control system, a limited number of PWM waveform sequences are predefined, wherein the attributes of the sequences include period, duty ratio, high and low level sequence and switching time, for example, 8 sequences are predefined in this example (the definition of the sequences refers to table 1).

The PWM waveform control timing for repeating the output sequence 4(6ms high, 10ms low) in the "sequence mode" is explained as follows (refer to fig. 3):

(1) the application layer software sets a PWM output control mode as a sequence mode in a 5ms periodic task according to control requirements, and simultaneously specifies a sequence number of 4(16ms period, 6ms high level and 10ms low level);

(2) the bottom layer software controls the PWM peripheral of the main control chip to start and output a specified PWM waveform sequence according to the sequence mode command and the corresponding sequence number of the application layer software;

(3) in the example, firstly, the main control chip outputs a high level for 6ms, after 6ms is finished, the interruption of the PWM peripheral of the main control chip triggers a PWM interrupt service program located in bottom layer software, the switching of the high level and the low level is executed in the interrupt service program, namely, the output level is switched from the low level to the high level, and meanwhile, the high level output duration is set to be 10 ms;

(4) and when the duration of the high level reaches 10ms, triggering the PWM peripheral of the main control chip to interrupt again, detecting a sequence mode of an application layer and whether the sequence number is updated in an interrupt service program, and if the sequence mode is not updated, continuously repeating the sequence mode according to the current sequence, namely, starting to output the high level of 6ms and the low level of 10ms again. If there is an update, it is executed according to the new mode and sequence.

In the above step (3) and step (4), the switching of the level between the 6ms high level and the 10ms low level is triggered by the PWM peripheral interrupt of the main control chip, and then the duration of the new level is set in the interrupt service program, since the interrupt belongs to a hardware behavior, the interrupt service program has a feature of high real-time performance, and runs a short program instruction, and finally shows that the switching of the level is realized without delay in a single sequence. In addition, as long as the serial number command sent by the application layer is not updated, the repeated output of the PWM waveform of the specified sequence can be realized completely through interruption, and the real-time property is further ensured.

Example 2: switching between different sequences

First, a limited number of PWM waveform sequences are predefined as in example 1, in this example, it is set that sequence 4(6ms high level, 10ms low level) is output first, and then sequence 5(4ms high level, 16ms low level) is output, and the control timing is described as follows (refer to fig. 4):

(1) the application layer software sets a PWM output control mode as a sequence mode in a 5ms periodic task, and simultaneously appoints a sequence number as 4(6ms high level and 10ms low level);

(2) the bottom layer software controls the PWM peripheral of the main control chip to start and output 6ms high level according to the sequence number set by the application layer software, and simultaneously sets a 'start new sequence output flag bit' as 1, and the flag bit is read by the application layer software in a 5ms periodic task in a circulating way;

(3) consistent with the step (3) in the example 1, when the duration time of the high level reaches 6ms, the PWM peripheral of the main control chip is triggered to be interrupted, and the high level of 10ms is started and output in the interrupt service routine;

(4) in the process of the above steps, the application layer software will continuously read the "start new sequence output flag bit" in step (2) in a 5ms periodic task, and once the flag bit is 1, set a new sequence number, which is 5 in this example, and clear the flag bit at the same time;

(5) after the 10ms high level duration of the sequence 4 is finished, the PWM peripheral of the main control chip is triggered to be interrupted again, a new serial number 5(4ms high level and 16ms low level) set by application layer software is detected in an interruption service program, and then 4ms high level is started to be output;

(6) and (5) repeating the steps (2) to (5) in the subsequent control sequence, and setting a new sequence by the application layer software according to the step (4).

Consistent with example (1), in this example, the switching of high and low levels in a single sequence and the switching between different sequences are also realized by interrupts, thus ensuring the real-time property of the PWM waveform output.

It should be understood that the specific order or hierarchy of steps in the processes disclosed is an example of exemplary approaches. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the processes may be rearranged without departing from the scope of the present disclosure. The accompanying method claims present elements of the various steps in a sample order, and are not intended to be limited to the specific order or hierarchy presented.

The foregoing description of the embodiments and specific examples of the invention have been presented for purposes of illustration and description; it is not intended to be the only form in which the embodiments of the invention may be practiced or utilized. The embodiments are intended to cover the features of the various embodiments as well as the method steps and sequences for constructing and operating the embodiments. However, other embodiments may be utilized to achieve the same or equivalent functions and step sequences.

In the foregoing detailed description, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments of the subject matter require more features than are expressly recited in each claim. Rather, as the following claims reflect, invention lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. To those skilled in the art; various modifications to these embodiments will be readily apparent, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

What has been described above includes examples of one or more embodiments. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the aforementioned embodiments, but one of ordinary skill in the art may recognize that many further combinations and permutations of various embodiments are possible. Accordingly, the embodiments described herein are intended to embrace all such alterations, modifications and variations that fall within the scope of the appended claims. Furthermore, to the extent that the term "includes" is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term "comprising" as "comprising" is interpreted when employed as a transitional word in a claim. Furthermore, any use of the term "or" in the specification of the claims is intended to mean a "non-exclusive or".

Those of skill in the art will further appreciate that the various illustrative logical blocks, units, and steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate the interchangeability of hardware and software, various illustrative components, elements, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design requirements of the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present embodiments.

The various illustrative logical blocks, or elements, described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose processor, a digital signal processor, an Application Specific Integrated Circuit (ASIC), a field programmable gate array or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a digital signal processor core, or any other similar configuration.

The foregoing is considered as illustrative of the preferred embodiments of the invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious modifications, rearrangements, combinations and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A PWM driving method of an AMT electromagnetic valve is characterized in that:

setting a plurality of PWM sequences, and selecting one or more PWM sequences;

2. The PWM driving method of an AMT solenoid valve according to claim 1, characterized in that: the PWM sequence includes a sequence number, a task period, a PWM waveform pattern, and an output period.

3. The PWM driving method of an AMT solenoid valve according to claim 2, characterized in that: the PWM waveform pattern includes a duty cycle and an output order of a high level and a low level within one output period.

4. The PWM driving method of an AMT solenoid valve according to claim 1, characterized in that: when a plurality of PWM sequences are selected, the main control chip sends out a sequence switching trigger command through internal peripheral interruption, and controls the main control chip to switch the PWM sequences according to the sequence switching trigger command and the next PWM sequence to be switched.

5. The PWM driving method of an AMT solenoid valve according to claim 4, characterized in that: the selected plurality of PWM sequences are switched sequentially or alternately.

6. The PWM driving system of the AMT electromagnetic valve is characterized in that: comprises that

7. The PWM drive system for an AMT solenoid according to claim 6, wherein: the PWM sequence includes a sequence number, a task period, a PWM waveform pattern, and an output period.

8. The PWM drive system of an AMT solenoid according to claim 7, characterized in that: the PWM waveform pattern includes a duty cycle and an output order of a high level and a low level within one output period.

9. The PWM drive system for an AMT solenoid according to claim 6, wherein: when the sequence setting module outputs a plurality of PWM sequences, the main control chip sends out a sequence switching trigger command through internal peripheral interruption, and the control module controls the main control chip to switch the PWM sequences according to the sequence switching trigger command and the next PWM sequence to be switched.

10. The PWM drive system of an AMT solenoid valve according to claim 9, characterized in that: the output multiple PWM sequences are switched sequentially or alternately.