CN112937628A - Train brake cylinder pressure control method and system - Google Patents
Train brake cylinder pressure control method and system Download PDFInfo
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- CN112937628A CN112937628A CN202110267440.3A CN202110267440A CN112937628A CN 112937628 A CN112937628 A CN 112937628A CN 202110267440 A CN202110267440 A CN 202110267440A CN 112937628 A CN112937628 A CN 112937628A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B61—RAILWAYS
- B61H—BRAKES OR OTHER RETARDING DEVICES SPECIALLY ADAPTED FOR RAIL VEHICLES; ARRANGEMENT OR DISPOSITION THEREOF IN RAIL VEHICLES
- B61H11/00—Applications or arrangements of braking or retarding apparatus not otherwise provided for; Combinations of apparatus of different kinds or types
- B61H11/06—Applications or arrangements of braking or retarding apparatus not otherwise provided for; Combinations of apparatus of different kinds or types of hydrostatic, hydrodynamic, or aerodynamic brakes
- B61H11/10—Aerodynamic brakes with control flaps, e.g. spoilers, attached to the vehicles
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
- B60T13/66—Electrical control in fluid-pressure brake systems
- B60T13/68—Electrical control in fluid-pressure brake systems by electrically-controlled valves
- B60T13/683—Electrical control in fluid-pressure brake systems by electrically-controlled valves in pneumatic systems or parts thereof
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M17/00—Testing of vehicles
- G01M17/08—Railway vehicles
Abstract
The invention provides a method and a system for controlling the pressure of a train brake cylinder, wherein the method comprises the following steps: before the train is delivered out of the warehouse, acquiring a Cv pressure value output by an electromagnetic valve under a control strategy of an emergency braking test; calculating electromagnetic valve parameters according to the Cv pressure value; when the train is on-line operated, updating a C-Cv linear fitting function of the relay valve according to the collected multiple groups of C-Cv pressure values; calculating to obtain a Cv pressure target value according to a preset C pressure target value and the C-Cv linear fitting function; and outputting a control signal according to the Cv pressure target value and the electromagnetic valve parameter, and controlling the electromagnetic valve to act so as to output the corresponding Cv pressure. According to the invention, by estimating the parameters of the electromagnetic valve and the relay valve and controlling the pressure of the brake cylinder according to the parameters, the accuracy is higher, the control speed is higher, the action times of the electromagnetic valve are less, and the service life of the valve is greatly prolonged.
Description
Technical Field
The invention relates to the urban rail transit vehicle technology, in particular to a train brake cylinder pressure control method and system applicable to a motor train unit.
Background
In the air brake of a motor train unit or an urban rail transit train operated in China at present, a pair of electromagnetic valves and a relay valve are generally adopted for controlling the pressure of a brake cylinder as main actuating mechanisms. The electronic system controls the air charging/exhausting action of the electromagnetic valve, flow amplification is carried out through the relay valve, after the pressure of the brake cylinder reaches a set value, the brake clamp is driven, a certain friction force is formed between the brake pad and the brake shoe, and therefore air braking of the train is achieved.
Fig. 1 is a pneumatic connection diagram of a solenoid valve and a relay valve. As shown in the figure, the relay valve 3 uses the total reservoir air of the R port as a source, and performs numerical adjustment and flow amplification on the brake cylinder pressure output from the C port according to the input pressure of the Cv port. When the electromagnetic valve 1 and the electromagnetic valve 2 are electrified to act, air is filled in the main air cylinder, and the input pressure of the Cv port of the relay valve 3 is increased; when both solenoid valve 1 and solenoid valve 2 lose power, air is discharged and the Cv port input pressure of relay valve 3 decreases. When the T port of the relay valve 3 has pressure input, the C port outputs low pressure so as to ensure that the braking force of the train does not exceed the adhesion limit when the train runs at high speed. The traditional brake cylinder pressure control process is realized by performing linear fitting on the C-Cv characteristic of a relay valve under the conditions of pressure increase and reduction/high and low speeds before delivery, calculating a Cv pressure set value according to the C pressure set value based on the fitting result, performing open-close control on an electromagnetic valve based on PWM (pulse width modulation), and performing closed-loop control on the Cv pressure. In the control of the Cv pressure based on PWM, although the control accuracy can be ensured, the control error and the current Cv pressure interval are used as inputs, so that when the Cv pressure approaches a target value, the control system outputs a change value of the PWM signal duty ratio less than 100%, causing frequent operations of the solenoid valve 1 and the solenoid valve 2. In addition, due to the individual difference and different operating environments of the relay valves in mass production, the difference exists between the linear fitting of the C-Cv and the actual condition, and the difference between the pressure of the brake cylinder C and the set value is large after the Cv pressure reaches the target value.
The conventional brake cylinder pressure control method shown in fig. 2 does not consider the characteristic changes and the action times of the solenoid valve and the relay valve, is open-loop for pressure control at the position C of the relay valve 3, and needs to readjust the control parameters according to the pressure interval in actual use, thereby causing more workload and deviation of the controlled brake cylinder pressure from the target, which will have negative effects on the braking performance of the train and the service life of the valve. For example, in the control based on PWM, when the pressure is adjusted by adopting a PID method and other methods according to the Cv error, when the Cv pressure approaches a target value, the electromagnetic valve frequently carries out air charging/discharging actions, and the service life of the electromagnetic valve is greatly reduced; in addition, due to the use in different environments and conditions for a long time and the aging of the valve, key parameters in the control algorithm are as follows: for example, the maximum variation value of the single-period pressure under the conditions of the opening and closing response time of the electromagnetic valve and the 100% duty ratio, and the C-Cv characteristic of the relay valve under the working conditions of high speed, low speed and lifting and pressing can be changed, so that the output C pressure deviates from the target value.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a train brake cylinder pressure control method, which comprises the following steps:
before the train is delivered out of the warehouse, a pressure control strategy is output to control an electromagnetic valve, and a plurality of Cv pressure values in the process that the Cv pressure changes to the redundant emergency braking pressure are collected;
calculating electromagnetic valve parameters according to the plurality of Cv pressure values;
when the train is on-line operated, updating a C-Cv linear fitting function of the relay valve according to the collected multiple groups of C-Cv pressure values;
calculating to obtain a Cv pressure target value according to a preset C pressure target value and the C-Cv linear fitting function;
and outputting a control signal according to the Cv pressure target value and the electromagnetic valve parameter, and controlling the electromagnetic valve to act so as to output the corresponding Cv pressure.
In one embodiment, the train brake cylinder pressure control method further includes:
calculating the solenoid valve output duty ratio in the next opening and closing control period according to the Cv pressure actual value, the Cv pressure target value and the solenoid valve parameter which are collected in the current opening and closing control period;
and when the output duty ratio of the electromagnetic valve is 100%, updating the Cv pressure change sequence of the electromagnetic valve according to a preset first updating function.
In one embodiment, the train brake cylinder pressure control method further includes:
continuously collecting input R pressure of a relay valve;
and if the absolute difference value of the R pressure value at the current moment and the R pressure value at the previous moment exceeds the change threshold, updating the Cv pressure change sequence of the electromagnetic valve at the current moment according to a preset second updating function.
In an embodiment, the updating the C-Cv linear fitting function of the relay valve according to the collected multiple sets of C-Cv pressure values includes:
dividing a preset Cv pressure value interval into m continuous intervals;
continuously collecting two groups of C-Cv pressure values in each interval respectively;
and respectively calculating the slope and the intercept of the interval at the current moment according to the two groups of C-Cv pressure values of each interval and the slope and the intercept of the interval at the previous moment so as to update the corresponding C-Cv linear fitting function of the interval.
In one embodiment, the train brake cylinder pressure control method further includes:
acquiring a C pressure actual value and a Cv pressure actual value output at the current moment;
calculating a Cv pressure compensation value according to the C pressure actual value, the Cv pressure actual value and the slope and intercept of the corresponding C-Cv linear fitting function of the interval;
and compensating the Cv pressure target value according to the Cv pressure compensation value.
The invention also provides a train brake cylinder pressure control system, which comprises:
the first pressure controller is used for outputting a pressure control strategy control electromagnetic valve before the train is delivered out of a warehouse and acquiring a plurality of Cv pressure values in the process that the Cv pressure changes to the redundant emergency braking pressure;
the electromagnetic valve parameter estimation module is used for calculating electromagnetic valve parameters according to the plurality of Cv pressure values;
the relay valve parameter estimation module is used for updating a C-Cv linear fitting function of the relay valve according to a plurality of groups of collected C-Cv pressure values when the train is in on-line operation;
the linear fitting module is used for calculating to obtain a first Cv pressure target value according to a preset C pressure target value and the C-Cv linear fitting function;
and the second pressure controller is used for outputting a control signal according to the first Cv pressure target value and the electromagnetic valve parameter, and controlling the electromagnetic valve to act so as to output the corresponding Cv pressure.
In one embodiment, the second pressure controller includes:
the duty ratio calculation unit is used for calculating the solenoid valve output duty ratio in the next opening and closing control period according to the acquired Cv pressure actual value in the current opening and closing control period, the first Cv pressure target value and the solenoid valve parameter;
and the first pressure change sequence updating unit is used for updating the Cv pressure change sequence of the solenoid valve according to a preset first updating function when the output duty ratio of the solenoid valve is 100%.
In one embodiment, the second pressure controller includes:
the R pressure acquisition unit is used for continuously acquiring input R pressure of the relay valve;
and the second pressure change sequence updating unit is used for updating the Cv pressure change sequence of the electromagnetic valve at the current moment according to a preset second updating function if the absolute difference value of the R pressure value at the current moment and the R pressure value at the previous moment exceeds a change threshold value.
In one embodiment, the relay valve parameter estimation module comprises:
the pressure value segmentation unit is used for segmenting a preset Cv pressure value interval into m continuous intervals;
the first acquisition unit is used for continuously acquiring two groups of C-Cv pressure values in each interval respectively;
and the first calculation unit is used for calculating the slope and the intercept of the interval at the current moment according to the two groups of C-Cv pressure values of each interval and the slope and the intercept of the interval at the previous moment so as to update the corresponding C-Cv linear fitting function of the interval.
In one embodiment, the train brake cylinder pressure control system further comprises a pressure compensation module comprising:
the second acquisition unit is used for acquiring the actual value of the C pressure and the actual value of the Cv pressure output at the current moment;
the second calculation unit is used for calculating a Cv pressure compensation value according to the C pressure actual value, the Cv pressure actual value and the slope and intercept of the corresponding C-Cv linear fitting function of the interval;
and the pressure compensation unit is used for compensating the Cv pressure target value according to the Cv pressure compensation value.
The method and the system for controlling the pressure of the train brake cylinder adopt the estimated electromagnetic valve and the relay valve parameters and control the pressure of the brake cylinder according to the estimated electromagnetic valve and the relay valve parameters, compared with the traditional control method, the method and the system have the advantages of higher accuracy, quicker control time and fewer electromagnetic valve action times, greatly prolong the service life of the valve and save a large amount of manual calibration work by real-time parameter estimation. Through preliminary verification, the control effect of the pressure control method and the system can realize that the brake cylinder pressure reaches the target value within the range of +/-5 kpa after the solenoid valve acts for 1-2 times.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a gas circuit connection diagram of the solenoid valve and the relay valve.
Fig. 2 is a schematic diagram of a conventional brake cylinder pressure control process.
FIG. 3 is a schematic diagram of a brake cylinder pressure control method of the present invention.
FIG. 4 is a schematic diagram of a brake cylinder pressure control system of the present invention.
FIG. 5 is a schematic diagram of another brake cylinder pressure control system of the present invention.
Fig. 6 is a schematic structural diagram of an electronic device according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 3, the present invention provides a train brake cylinder pressure control method, including:
and S101, before the train is delivered out of the warehouse, outputting a pressure control strategy control electromagnetic valve, and collecting a plurality of Cv pressure values in the process that the Cv pressure changes to the redundant emergency braking pressure.
And step S102, calculating electromagnetic valve parameters according to the plurality of Cv pressure values.
It will be appreciated that during non-operational periods when the train is parked in a garage, the train will have to perform a number of braking tests, including an emergency braking test (UB test), before each departure from the garage. The braking of the train is realized by the corresponding action of the electromagnetic valve through the control signal output by the controller, the formation of the control signal is closely related to the parameter of the electromagnetic valve, and when the parameter of the electromagnetic valve changes, if the parameter is not updated in time, the problems of frequent action of the electromagnetic valve, reduction of the control accuracy and the like are caused. The solenoid valve outputs redundant Cv pressure in the emergency braking test, so that the control process can be used for estimating the solenoid valve parameters. The solenoid valve parameters in step S102 include: maximum pressure change capability Cvmax-cAnd Cvmax-vOpening response time ton_delayAnd Cv pressure variation value Cv in opening response timec_onClosing response time toff_delayAnd Cv pressure variation value Cv in closing response timec_off。
Referring to fig. 1, the solenoid valve 1 and the solenoid valve 2 may be solenoid valves of the same type, and the solenoid valve 1 is responsible for charging air and the solenoid valve 2 is responsible for discharging air. Parameter maximum pressure variation Capacity Cvmax-cThe calculation of (a) is specifically: under the pressure control strategy of the emergency braking test, the electromagnetic valve 1 is controlled to be fully opened, and the electromagnetic valve 2 is controlled to be closed. At each opening and closing control period c of the solenoid valvet(unit: ms) the actual value of Cv pressure is collected once, assuming pnRepresenting the actual value of Cv pressure, p, acquired during the n-th on-off control cycleeIs a preset emergency brake pressure, and pnAnd peSatisfies pn＜0.528peThen parameter Cvmax-cExpressed as: cvmax-c＝pn/n。
Parameter optimizationLarge pressure change capacity Cvmax-vThe calculation of (a) is specifically: under the pressure control strategy of the emergency braking test, the electromagnetic valve 2 is controlled to be fully opened, and the electromagnetic valve 1 is controlled to be closed. Collecting the actual value Cv of the Cv pressure in the first opening and closing control period after the electromagnetic valve 2 starts to exhaustv1And the actual value Cv of the Cv pressure of the second opening/closing control periodv2Then parameter Cvmax-vExpressed as: cvmax-v＝max(Cvv1，Cvv2)。
Parameter ton_delay、toff_delay、Cvc_onAnd Cvc_offThe calculation of (a) is specifically: the solenoid valves 1 and 2 are controlled in each opening/closing control period ctAnd (unit: ms) alternately opening and closing, namely, the electromagnetic valve 1 is fully opened and the electromagnetic valve 2 is closed in the first opening and closing control period, the electromagnetic valve 2 is fully opened and the electromagnetic valve 1 is closed in the second opening and closing control period, the electromagnetic valve 1 is fully opened and the electromagnetic valve 2 is closed in the third opening and closing control period, and the like. 2k Cv pressure values are collected according to the maximum sampling capacity, and if the maximum sampling capacity is 1ms, the Cv pressure values are collected once, 2k Cv pressure values are collected by taking 1ms as a pressure sampling period, and a Cv pressure value sequence P can be obtainedrecord＝[p1,p2,...,p2k]Wherein p ism(m is 1,2, …, 2k) represents the Cv pressure value collected in the mth pressure sampling period and satisfies pm＜0.528pe，peIs a preset emergency brake pressure. For Cv pressure value sequence PrecordCarrying out second-order difference operation to obtain a Cv pressure difference sequence Drecord＝[d1,d2,...,d2k-2]Wherein d isn＝pn+2-pn+1-(pn+1-pn)＝pn+2+pn-2pn+1And n is 1,2, …,2 k-2. For Cv pressure difference sequence DrecordScreening for values of (1), assuming do1，do2，...,dokIs a slave sequence DrecordK screened in the medium satisfies doi≠0,doi+10 (1. ltoreq. i.ltoreq.k), dc1，dc2，...,dckTo be driven from DrecordK screened in the medium satisfies dcj＝0,dcj+1≠0(1≤jK) or less, then the parameter ton_delay、toff_delay、Cvc_onAnd Cvc_offRespectively calculated by the following formula:
and S103, updating the C-Cv linear fitting function of the relay valve according to the collected multiple groups of C-Cv pressure values when the train is on line.
Wherein the C-Cv linear fit function refers to a linear fit function of the C pressure and the Cv pressure of the relay valve. Referring to fig. 1, the pressure C is the brake pressure output from port C of the relay valve 3; the pre-control pressure input by a Cv port of the Cv pressure relay valve 3 is provided by the electromagnetic valve 1 or the electromagnetic valve 2; the R pressure is a brake wind source pressure input to the R port of the relay valve 3. When the pilot control pressure (Cv pressure) of the relay valve and the brake wind source pressure (R pressure) are simultaneously supplied, the relay valve is opened, generating the brake pressure (C pressure).
And step S104, calculating to obtain a Cv pressure target value according to a preset C pressure target value and the C-Cv linear fitting function.
It will be appreciated that a C-Cv linear fit function is used to represent a linear relationship between C pressure and Cv pressure. Therefore, after a C pressure target value is input, a corresponding Cv pressure target value can be calculated according to the C-Cv linear fitting function.
And step S105, outputting a control signal according to the Cv pressure target value and the electromagnetic valve parameter, and controlling the electromagnetic valve to act so as to output the corresponding Cv pressure.
Specifically, with reference to fig. 1, the solenoid valve 1 and the solenoid valve 2 act to output a Cv pressure value, and when the solenoid valve 1 is fully opened and the solenoid valve 2 is closed, air enters a Cv port of the relay valve 3; when solenoid valve 2 is fully open and solenoid valve 1 is closed, air is vented to atmosphere from relay valve 3. The pressure of the Cv port of the relay valve 3 can be adjusted by controlling the opening and closing of the solenoid valves 1 and 2. The opening and closing control of the solenoid valve 1 and the solenoid valve 2 can be implemented by a controller, and the controller can control the opening and closing of the solenoid valve 1 and the solenoid valve 2 by outputting a control signal, for example, assuming that the opening and closing control period of the solenoid valve is 100ms, the control action in a certain opening and closing control period is that the solenoid valve 1 is opened for 68ms, and the controller can send a control signal "68" to the solenoid valve 1. The method of determining the control action of the solenoid valve can be implemented with reference to the prior art, and the present invention is not described in detail herein.
In the above embodiment, before the train is delivered from the depot, the six core control parameters Cv of the solenoid valve are estimated in real time through step S102max-c、Cvmax-v、ton_delay、toff_delay、Cvc_onAnd Cvc_offThe method can solve the problem of parameter change caused by the increase of action times, characteristic change and the like of the electromagnetic valve in the long-term use process based on the parameters, saves a large amount of manual calibration work, and simultaneously accurately calculates the action form of the electromagnetic valve when the current C pressure is adjusted to the C pressure target value, thereby realizing the accurate control of the brake cylinder pressure.
In one embodiment, in order to obtain a pressure change curve of a train during charging/discharging in real time during train operation, when the train performs service brake control, the train brake cylinder pressure control method further includes:
step S201, calculating an electromagnetic valve output duty ratio in the next opening and closing control period according to the acquired Cv pressure actual value in the current opening and closing control period, the Cv pressure target value and the electromagnetic valve parameter;
and step S202, when the output duty ratio of the electromagnetic valve is 100%, updating the Cv pressure change sequence of the electromagnetic valve according to a preset first updating function.
The Cv pressure variation sequence dCv is used to approximate a pressure variation curve during charging/discharging at the current R pressure, and is generated in advance according to a theoretical charging/discharging curve before the brake cylinder pressure is controlled. The sequence of Cv pressure changes may be represented as
peFor emergency brake pressure, Ess is control error, dCvi 
Indicating that the Cv pressure value is in the interval [ (i-1) Ess, iEss]The slope of the change in internal pressure. For example, suppose pe297kpa, Ess 5kpa, then
dCv50Is shown in the interval [245,250]The slope of the change in internal pressure.
In step S201, calculating the output duty ratio of the solenoid valve in the next on/off control period specifically includes: suppose that the actual value of the Cv pressure acquired in the current open-close control period is represented as CvcThe Cv pressure target value is expressed as CvsetControl error is Ess and the current measured slope of pressure change is shown as dCvcWherein the current measured pressure change slope dCvcThe change slope is calculated according to the Cv pressure actual value collected in the current open-close control period and the Cv pressure actual value collected in the previous open-close control period, for example, the Cv pressure actual value collected in the current open-close control period is piThe actual value of the Cv pressure collected in the previous opening and closing control period is pi-1The acquisition time differs by an on-off control period ctThen the slope of the currently measured pressure change is
At this time, the output duty ratio v of the solenoid valve in the next opening/closing control periodcThe following formula can be used for calculation:
per＝per1+per2+per3
wherein v isc-1For the solenoid valve output duty ratio, t, in the current on-off control periodoff_delayTo turn off the response time, Cvc_offTo the value of the change in Cv pressure over the closing response time, ton_delayTo turn on the response time, Cvc_onIs the Cv pressure change value in the opening response time.
In step S202, when the output duty ratio of the solenoid valve is 100%, updating the Cv pressure variation sequence of the solenoid valve according to a preset first update function specifically includes: a slope dCv of change in pressure based on the current measured pressurecUpdating the Cv pressure change sequence dCv by using a first-order filter, and assuming that the current switching control period is the jth period, the actual value of the Cv pressure collected in the jth period is represented as CvjThe next opening and closing control period is the j +1 th period, and the actual value of the Cv pressure acquired in the j +1 th period after the control signal is output is represented as Cvj+1And Cvj+1And CvjWith n Ess, the Cv pressure change sequence dCv of the j periodjThere are n corresponding slopes of pressure change dCvj k,dCvj k+1,...,dCvj k+n]Then the Cv pressure variation sequence dCv according to the current open/close control cycle (jth cycle)jCv pressure variation sequence dCv for the next opening and closing control cycle (j +1 th cycle)j+1Update, the first update function is as follows:
wherein r isoThe number of updates r of the dCv sequence is calibrated before the actual use of the solenoid valve (before leaving the factory)uThe number of times of dCv sequence updates in actual use (after shipment).
It should be noted that, in step S202, only the Cv pressure actual value Cv collected in the j-th cycle is updatedjN pressure change slopes [ dCv ] from the actual value of Cv pressure collected during the j +1 th cyclej k,dCvj k+1,...,dCvj k+n]Rather than the entire Cv pressure variation sequence
All pressure change slopes in (1).
In the embodiment, the core control parameters of the electromagnetic valve estimated in real time in the foregoing embodiment are adopted, the duty ratio of the control period to be output can be accurately calculated when the core control parameters have different deviations from the target pressure value, the duty ratio to be adjusted can be accurately estimated when the core control parameters are closer to the target pressure value, and in the pressure control process, the electromagnetic valve only needs to act once (open-close), and the pressure can reach the target pressure value within the range of ± Ess.
In one embodiment, in order to obtain a pressure change curve of a train during charging/discharging in real time during train operation, when the train performs service brake control, the train brake cylinder pressure control method further includes:
step S301, continuously collecting input R pressure of a relay valve;
step S302, if the absolute difference between the R pressure value at the current time and the R pressure value at the previous time exceeds the change threshold, updating the Cv pressure change sequence of the solenoid valve at the current time according to a preset second update function.
In particular, set upThe variation threshold of R pressure is EsrAssuming that the collected R pressure value at the time t before the previous time is prtThe R pressure value at the current moment v is prvAnd the sequence of the Cv pressure change at the time t is
If the absolute difference value between the R pressure value at the current moment v and the R pressure value at the previous moment t exceeds the change threshold value, namely when prv-prt≥EssrAccording to the Cv pressure variation sequence dCv at the previous time ttSequence of Cv pressure changes for the current time v
The update is performed as follows:
wherein the content of the first and second substances,
cv pressure variation sequence dCv representing the current time vvThe ith of
And (4) elements.
It is to be noted that all the values of the Cv pressure change sequence are updated in step S302.
The Cv pressure closed-loop control provided by the embodiment considers the change of the R pressure, and updates the pressure change sequence after obtaining the pressure change value every time, thereby effectively ensuring that the pressure control method is adjusted in real time following the system change, and improving the control precision.
In an embodiment, in step S103, updating the C-Cv linear fitting function of the relay valve according to the collected multiple sets of C-Cv pressure values includes:
in step S1031, the preset Cv pressure value section is divided into m continuous sections. In practical application, the Cv pressure value intervals of different trains may have slight differences.
And S1032, continuously collecting two groups of C-Cv pressure values in each interval respectively.
And step S1033, calculating the slope and the intercept of the interval at the current moment according to the two groups of C-Cv pressure values of each interval and the slope and the intercept of the interval at the previous moment so as to update the corresponding C-Cv linear fitting function of the interval.
Specifically, it is assumed that at the time of factory shipment, the C-Cv linear fitting function of the relay valve 3 in fig. 1 is represented by C ═ ki0·Cv+bi0Wherein k isi0And bi0Respectively is a linear fitting intercept and a slope measured at the delivery time of the relay valve. Step S1031 divides the actual Cv pressure value interval into m continuous intervals, wherein the C-Cv linear fitting function at the previous moment of the ith interval is Ci＝ki1·Cvi+bi1. In step S1032, two groups of C-Cv pressure values continuously collected in the ith interval are respectively (C)i1,Cvi1) And (C)i2,Cvi2). Step S1033 adopts a first order filter to update k of the current time in real timei2And bi2The formula is as follows:
wherein n isoThe number of updates, n, to be calibrated before actual use (before leaving factory) of the relay valveuThe number of updates in actual use (after shipment). It is considered herein that the environment of factory test and the environment of the train in actual use may be different, and thus, used with the trainShould gradually increase the weight of the train in actual use to gradually approach the actual change of train operation.
In the embodiment, the C-Cv linear fitting functions of all the intervals are respectively updated in real time according to the actual change of the relay valve and the Cv pressure value intervals, so that the characteristic estimation of the relay valve is more accurate. It should be noted here that, due to the characteristics of the solenoid valve and the change of the operating environment, the C-Cv linear fitting function of the relay valve may also change, and considering that the relationship between the C pressure and the Cv pressure of the relay valve may no longer be a simple linear relationship, a large error may be generated by fitting all Cv target values in the subsequent braking process by using only the C-Cv linear fitting function at the time of factory shipment of the relay valve. By using the method for estimating the relay valve parameters in real time provided by the embodiment, the error can be greatly reduced.
In an embodiment, the step S104 of calculating the Cv pressure target value according to a preset C pressure target value and the C-Cv linear fitting function includes:
step S1041, determining the section where the C pressure target value is located and the section C-Cv linear fitting function corresponding to the section. It is understood that the Cv pressure value is divided into continuous intervals, and the C pressure value and the Cv pressure value have a linear relation in each interval, so that the interval where the C pressure value is located can be determined according to the C pressure value.
And step S1042, calculating to obtain a Cv pressure target value according to the C pressure target value and the interval C-Cv linear fitting function. The target value of the Cv pressure can be obtained by substituting the target value of the C pressure into a corresponding interval C-Cv linear fitting function.
In one embodiment, the actual variation relationship between the C pressure and the Cv pressure is changed by considering the difference between individual relay valves and possibly changing the characteristics of the relay valves during long-term operation under different environments. Since the update of the C-Cv linear fit function of the relay valve is delayed, that is, the next C-Cv linear fit function is updated according to the C pressure and the Cv pressure that have been output, and the C pressure is obtained according to the C-Cv linear fit function before the update and the Cv pressure target value, in order to eliminate the error due to the change of the solenoid valve characteristic, the Cv pressure target value needs to be compensated. Therefore, when the relay valve characteristic is changed, the train brake cylinder pressure control method further includes:
step S401, collecting the C pressure actual value C output at the current moment1And the actual value Cv of the Cv pressure1；
Step S402, according to the C pressure actual value C1Actual value Cv of Cv pressure1And the slope k of the corresponding interval C-Cv linear fitting function1And intercept b1Calculating the Cv pressure compensation value CvadjustWherein, the corresponding interval C-Cv linear fitting function is determined according to the Cv pressure actual value, and the specific formula is as follows:
and S403, compensating the Cv pressure target value according to the Cv pressure compensation value. Specifically, the original Cv pressure target value and the Cv pressure compensation value are added to obtain a compensated Cv pressure target value.
In the present embodiment, when the relay valve characteristic changes, an error still exists between the C pressure output value corresponding to the first Cv pressure target value obtained from the existing C-Cv linear fitting function and the C pressure target value, and the method of the present embodiment can further reduce the error and improve the accuracy.
It will be appreciated by those skilled in the art that in practice, the step of compensating the Cv pressure target value always exists, and when the relay valve characteristic changes, the Cv pressure target value is compensated by the method as described in the above embodiment, and the compensated Cv pressure target value is different from the Cv pressure target value before compensation; when the relay valve characteristic change does not cause the C pressure control error to exceed the preset range, the compensation value of the Cv pressure target value is 0, and at this time, the compensated Cv pressure target value coincides with the Cv pressure target value before compensation.
The present invention also provides a train brake cylinder pressure control system, which can be used to implement all the steps of the train brake cylinder pressure control method provided by the present invention, referring to fig. 4, the system includes:
the first pressure controller is used for outputting a pressure control strategy control electromagnetic valve before the train is delivered out of a warehouse and acquiring a plurality of Cv pressure values in the process that the Cv pressure changes to the redundant emergency braking pressure;
the electromagnetic valve parameter estimation module is used for calculating electromagnetic valve parameters according to the plurality of Cv pressure values;
the relay valve parameter estimation module is used for updating a C-Cv linear fitting function of the relay valve according to a plurality of groups of collected C-Cv pressure values when the train is in on-line operation;
the linear fitting module is used for calculating to obtain a first Cv pressure target value according to a preset C pressure target value and the C-Cv linear fitting function;
and the second pressure controller is used for outputting a control signal according to the first Cv pressure target value and the electromagnetic valve parameter, and controlling the electromagnetic valve to act so as to output the corresponding Cv pressure.
In one embodiment, the second pressure controller includes:
the duty ratio calculation unit is used for calculating the solenoid valve output duty ratio in the next opening and closing control period according to the acquired Cv pressure actual value in the current opening and closing control period, the first Cv pressure target value and the solenoid valve parameter;
and the first pressure change sequence updating unit is used for updating the Cv pressure change sequence of the solenoid valve according to a preset first updating function when the output duty ratio of the solenoid valve is 100%.
In one embodiment, the second pressure controller includes:
the R pressure acquisition unit is used for continuously acquiring input R pressure of the relay valve;
and the second pressure change sequence updating unit is used for updating the Cv pressure change sequence of the electromagnetic valve at the current moment according to a preset second updating function if the absolute difference value of the R pressure value at the current moment and the R pressure value at the previous moment exceeds a change threshold value.
In one embodiment, the relay valve parameter estimation module comprises:
the pressure value segmentation unit is used for segmenting a preset Cv pressure value interval into m continuous intervals;
the first acquisition unit is used for continuously acquiring two groups of C-Cv pressure values in each interval respectively;
and the first calculation unit is used for calculating the slope and the intercept of the interval at the current moment according to the two groups of C-Cv pressure values of each interval and the slope and the intercept of the interval at the previous moment so as to update the corresponding C-Cv linear fitting function of the interval.
In an embodiment, the train brake cylinder pressure control system further comprises a pressure compensation module, see fig. 5, comprising:
the second acquisition unit is used for acquiring the actual value of the C pressure and the actual value of the Cv pressure output at the current moment;
the second calculation unit is used for calculating a Cv pressure compensation value according to the C pressure actual value, the Cv pressure actual value and the slope and intercept of the corresponding C-Cv linear fitting function of the interval; wherein the corresponding interval C-Cv linear fitting function is determined according to the Cv pressure actual value.
And the pressure compensation unit is used for compensating the Cv pressure target value according to the Cv pressure compensation value.
It will be appreciated by those skilled in the art that in practice, the pressure compensation module is always present, and when the relay valve characteristic changes, the Cv pressure compensation as described in the above embodiments is performed, with the target value of the Cv pressure after compensation being different from the target value of the Cv pressure before compensation; when the relay valve characteristic change does not cause the C pressure control error to exceed the preset range, the pressure compensation value of the pressure compensation module is 0, where the compensated Cv pressure target value is consistent with the Cv pressure target value before compensation. For ease of understanding, the "pressure compensation module" is not shown in fig. 4 when the compensation value is 0.
In one embodiment, the linear fitting module comprises:
the second function determining unit is used for determining a section where the C pressure target value is located and a section C-Cv linear fitting function corresponding to the section;
and the third calculating unit is used for calculating the Cv pressure target value according to the C pressure target value and the interval C-Cv linear fitting function.
The train brake cylinder pressure control system provided by the invention adopts the estimation of the parameters of the electromagnetic valve and the relay valve, and performs brake cylinder pressure control according to the parameters, compared with the traditional control method, the train brake cylinder pressure control system has higher accuracy, faster control time and fewer electromagnetic valve action times, greatly prolongs the service life of the valve, and saves a large amount of manual calibration work through real-time parameter estimation. Through preliminary verification, the control effect of the pressure control method and the system can realize that the brake cylinder pressure reaches the target value within the range of +/-5 kpa after the solenoid valve acts for 1-2 times.
The invention also provides electronic equipment which can be used for realizing all the steps of the train brake cylinder pressure control method provided by the invention. Referring to fig. 6, the electronic device 600 specifically includes:
a central processing unit (processor)610, a memory 620, a communication module (Communications)630, an input unit 640, an output unit 650, and a power supply 660.
The memory (memory)620, the communication module (Communications)630, the input unit 640, the output unit 650 and the power supply 660 are respectively connected to the central processing unit (processor) 610. The central processing unit 610 may call up a computer program stored in the memory 620, and the central processing unit 610, when executing the computer program, implements all the steps of the train brake cylinder pressure control method in the above-described embodiment.
Embodiments of the present application also provide a computer storage medium for storing a computer program executable by a processor. The computer program, when executed by a processor, implements any of the train brake cylinder pressure control methods provided by the present invention.
As will be appreciated by one skilled in the art, embodiments of the present description may be provided as a method, system, or computer program product. Accordingly, embodiments of the present description may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, embodiments of the present description may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and so forth) having computer-usable program code embodied therein. The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the system embodiment, since it is substantially similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment. In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of an embodiment of the specification.
In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction. The above description is only an example of the embodiments of the present disclosure, and is not intended to limit the embodiments of the present disclosure. Various modifications and variations to the embodiments described herein will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiments of the present specification should be included in the scope of the claims of the embodiments of the present specification.
Claims (12)
1. A method of controlling train brake cylinder pressure, comprising:
before the train is delivered out of the warehouse, a pressure control strategy is output to control an electromagnetic valve, and a plurality of Cv pressure values in the process that the Cv pressure changes to the redundant emergency braking pressure are collected;
calculating electromagnetic valve parameters according to the plurality of Cv pressure values;
when the train is on-line operated, updating a C-Cv linear fitting function of the relay valve according to the collected multiple groups of C-Cv pressure values;
calculating to obtain a Cv pressure target value according to a preset C pressure target value and the C-Cv linear fitting function;
and outputting a control signal according to the Cv pressure target value and the electromagnetic valve parameter, and controlling the electromagnetic valve to act so as to output the corresponding Cv pressure.
2. The method of controlling train brake cylinder pressure according to claim 1, further comprising:
calculating the solenoid valve output duty ratio in the next opening and closing control period according to the Cv pressure actual value, the Cv pressure target value and the solenoid valve parameter which are collected in the current opening and closing control period;
and when the output duty ratio of the electromagnetic valve is 100%, updating the Cv pressure change sequence of the electromagnetic valve according to a preset first updating function.
3. The method of controlling train brake cylinder pressure according to claim 1, further comprising:
continuously collecting input R pressure of a relay valve;
and if the absolute difference value of the R pressure value at the current moment and the R pressure value at the previous moment exceeds the change threshold, updating the Cv pressure change sequence of the electromagnetic valve at the current moment according to a preset second updating function.
4. The method for controlling train brake cylinder pressure according to any one of claims 1 to 3, characterized in that the updating of the C-Cv linear fit function of the relay valve according to the collected sets of C-Cv pressure values comprises:
dividing a preset Cv pressure value interval into m continuous intervals;
continuously collecting two groups of C-Cv pressure values in each interval respectively;
and respectively calculating the slope and the intercept of the interval at the current moment according to the two groups of C-Cv pressure values of each interval and the slope and the intercept of the interval at the previous moment so as to update the corresponding C-Cv linear fitting function of the interval.
5. The method of controlling train brake cylinder pressure according to claim 4, further comprising:
acquiring a C pressure actual value and a Cv pressure actual value output at the current moment;
calculating a Cv pressure compensation value according to the C pressure actual value, the Cv pressure actual value and the slope and intercept of the corresponding C-Cv linear fitting function of the interval;
and compensating the Cv pressure target value according to the Cv pressure compensation value.
6. A train brake cylinder pressure control system, comprising:
the first pressure controller is used for outputting a pressure control strategy control electromagnetic valve before the train is delivered out of a warehouse and acquiring a plurality of Cv pressure values in the process that the Cv pressure changes to the redundant emergency braking pressure;
the electromagnetic valve parameter estimation module is used for calculating electromagnetic valve parameters according to the plurality of Cv pressure values;
the relay valve parameter estimation module is used for updating a C-Cv linear fitting function of the relay valve according to a plurality of groups of collected C-Cv pressure values when the train is in on-line operation;
the linear fitting module is used for calculating to obtain a first Cv pressure target value according to a preset C pressure target value and the C-Cv linear fitting function;
and the second pressure controller is used for outputting a control signal according to the first Cv pressure target value and the electromagnetic valve parameter, and controlling the electromagnetic valve to act so as to output the corresponding Cv pressure.
7. The train brake cylinder pressure control system according to claim 6, wherein the second pressure controller comprises:
the duty ratio calculation unit is used for calculating the solenoid valve output duty ratio in the next opening and closing control period according to the acquired Cv pressure actual value in the current opening and closing control period, the first Cv pressure target value and the solenoid valve parameter;
and the first pressure change sequence updating unit is used for updating the Cv pressure change sequence of the solenoid valve according to a preset first updating function when the output duty ratio of the solenoid valve is 100%.
8. The train brake cylinder pressure control system according to claim 6, wherein the second pressure controller comprises:
the R pressure acquisition unit is used for continuously acquiring input R pressure of the relay valve;
and the second pressure change sequence updating unit is used for updating the Cv pressure change sequence of the electromagnetic valve at the current moment according to a preset second updating function if the absolute difference value of the R pressure value at the current moment and the R pressure value at the previous moment exceeds a change threshold value.
9. The train brake cylinder pressure control system according to any one of claims 6 to 8, characterized in that the relay valve parameter estimation module comprises:
the pressure value segmentation unit is used for segmenting a preset Cv pressure value interval into m continuous intervals;
the first acquisition unit is used for continuously acquiring two groups of C-Cv pressure values in each interval respectively;
and the first calculation unit is used for calculating the slope and the intercept of the interval at the current moment according to the two groups of C-Cv pressure values of each interval and the slope and the intercept of the interval at the previous moment so as to update the corresponding C-Cv linear fitting function of the interval.
10. The train brake cylinder pressure control system according to claim 9, further comprising a pressure compensation module, the pressure compensation module comprising:
the second acquisition unit is used for acquiring the actual value of the C pressure and the actual value of the Cv pressure output at the current moment;
the second calculation unit is used for calculating a Cv pressure compensation value according to the C pressure actual value, the Cv pressure actual value and the slope and intercept of the corresponding C-Cv linear fitting function of the interval;
and the pressure compensation unit is used for compensating the Cv pressure target value according to the Cv pressure compensation value.
11. An electronic device, comprising: a central processing unit, a memory, and a communication module, wherein the memory stores a computer program that can be called by the central processing unit, and the central processing unit implements the train brake cylinder pressure control method according to any one of claims 1 to 5 when executing the computer program.
12. A computer storage medium for storing a computer program, characterized in that the computer program, when being executed by a processor, implements the train brake cylinder pressure control method according to any one of claims 1 to 5.
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