CN102540960A - Fuzzy control system and method for eddy current retarder on basis of programmable logic controller (PLC) - Google Patents

Abstract

The invention provides a fuzzy control method for an eddy current retarder on the basis of a programmable logic controller (PLC), which comprises analyzing the heat recession phenomenon generated during the braking process of the eddy current retarder in details and providing a stepped fuzzy control method specific to a multidimensional control model. The fuzzy control method for the eddy current retarder on the basis of the PLC has the advantages of utilizing mechanism of sectional adjustment and finally enabling exciting current output by the eddy current retarder to be adjusted according to the rotation speed and the temperature of a rotor disc in real time by changing adjustment factors in a rule in an online mode. Fuzzy control algorithm is combined with a PLC control system, characteristics of being reliable, flexible and strong in adaptability of the PLC are brought into play, and good control effects are obtained.

Description

Current vortex retarder Fuzzy control system and method based on PLC

Technical field

The invention belongs to intelligence control system, relate in particular to a kind of current vortex retarder intelligence control system and method thereof based on PLC.

Background technology

The automobile electrical eddy current retarder is a kind of complemental brake system, is widely used on large and medium bus and the medium and heavy truck.That current vortex retarder has is non-linear, strong coupling, multivariable characteristics, and traditional control mode is difficult to reach the control effect of expection.Characteristics such as fuzzy control is based on a kind of Based Intelligent Control of rule, does not rely on the accurate model of controlled device, and it is good to have robustness, and response speed is fast have the better controlling effect for the system that has hysteresis or random disturbance.Yet the rule of conventional fuzzy controller does not have the lasting ability that changes of the procedure of adaptation in case foundation has just immobilized.Most of adaptive fuzzy controllers will comprise performance test or identification of Model Parameters mechanism usually, and calculated amount is big, have influenced the real-time of controller, in response speed requires than higher Motor Vehicle Braking Procedure, do not possess actual operability.The inventor to multidimensional model, takes mechanism sectional-regulated, that thickness combines to adjust the adjustment factor in the control law according to the actual working characteristics of current vortex retarder, has realized the real-time regulated of exciting current according to rotating speed and rotor disk temperature.PLC has the reliability height, the characteristics that antijamming capability is strong, and can fuzzy controller be realized with software easily.We adopt the FX of Mitsubishi _2NSeries of PLC has been carried out simulation test and has been obtained good effect.

Summary of the invention

The objective of the invention is to non-linear, the strong coupling of current vortex retarder, multivariable characteristics; Adopt FUZZY ALGORITHMS FOR CONTROL, it is big to solve in the current vortex retarder control procedure disturbance, follows the tracks of inaccurate; Problems such as poor reliability are set up a kind of current vortex retarder Fuzzy control system based on PLC.

For solving the problems of the technologies described above, the technical scheme that the present invention adopts is:

The The Design of Fuzzy Logic Controller principle:

One, sets up the current vortex retarder mathematical model, confirm that this controller regulates output exciting current I based on the difference and the difference variable quantity of the difference of actual rotor rotating speed and ideal rotor rotating speed and variable quantity and ideal rotor dish temperature and actual temperature.

$x=\left[\begin{array}{c}\mathrm{\ω}\\ \mathrm{\θ}\end{array}\right],u=I$

Its equation is following:

This fuzzy controller is based on the actual rotor rotational speed omega _dWith the ideal rotor rotational speed omega _aDifference ω _eAnd variable quantity ω _Ce(wherein $\left\{\begin{array}{c}{\mathrm{\ω}}_e={\mathrm{\ω}}_d-{\mathrm{\ω}}_a\\ {\mathrm{\ω}}_{\mathrm{Ce}}=\frac{d{\mathrm{\ω}}_e}{\mathrm{Dt}}\end{array}\right.$ ) and ideal rotor dish temperature θ _aWith actual temperature θ _dDifference θ _eWith difference variable quantity θ _Ce(wherein $\left\{\begin{array}{c}{\mathrm{\ω}}_e={\mathrm{\ω}}_d-{\mathrm{\ω}}_a\\ {\mathrm{\ω}}_{\mathrm{Ce}}=\frac{d{\mathrm{\ω}}_e}{\mathrm{Dt}}\end{array}\right.$ ) regulate and export exciting current I.

Two, above-mentioned error originated from input amount is carried out obfuscation, select suitable quantizing factor

And above-mentioned description sum of errors error change amount is mapped in the corresponding universe of fuzzy sets by basic domain, correspond to E separately _ω, EC _ωAnd E _θ, EC _θ, and the fuzzy language variable of output quantity is defined as U respectively _ωAnd U _θThree fuzzy language class variables of E and EC and U are adopted 7 identical fuzzy quantization levels, be expressed as NB, NM, NS, ZE, PS, PM, PB}, and it is quantified as 6 ,-5 ,-4 ,-3 ,-2 ,-1,0,1,2,3,4,5,6}13 grade.Each variable membership function is like Fig. 1, shown in 2.Corresponding fuzzy control rule can be expressed as: If E _ωBe A _iAnd EC _ωBe B _iAnd E _θBe C _iAnd EC _θBe D _iThen U _iBe Z _iThis obviously is the fuzzy control rule of a four-dimension, and all control laws will reach 7 ⁴=2 401; This system that makes is difficult to realize, if but in control, adopt staircase structure, rule of simplification number greatly then; And the effect that is controlled effectively. this paper turns to two-stage with fuzzy control rule; Totally 3 two-dimensional fuzzy controllers make control law be reduced to 3 * 49=147. the while dynamically updates fuzzy control rule according to the operating condition of retarder in real time in control procedure, regulate the exciting current of retarder

Three, second level fuzzy control.The 2nd grade of rule set in the mould controller is according to the current vortex retarder practical work process, to the speed of a motor vehicle and the fuzzy final output U that goes weighting respectively and obtain that exports of rotor disk temperature ^*, in fact this is the integral body adjustment of controller to the output exciting current.Be expressed as with analytic expression:

U＝<αU _ω+(1-α)U _θ>，α∈[0，1](2)

Fuzzy control draws real-time α weights according to the real-time speed of a motor vehicle and retarder rotor disk temperature with the mode of tabling look-up, and its control law is as shown in Figure 7.

Four, first order fuzzy control.The speed of a motor vehicle and Fuzzy Control for Temperature rule set all are two-dimentional. for a two-dimensional fuzzy controller, fuzzy control rule can be summarized with analytic expression:

U＝<αE+(1-α)EC>，α∈[0，1](3)

Wherein the size of rule adjustment factor-alpha has reflected that error E and error amount EC are to controlled quentity controlled variable output U weighting degree; Adjustment α value is equivalent to adjust fuzzy control rule. in order to adapt to the needs of online adjusting; Through the modified value of adjustment α, α is adjusted simultaneously automatically according to the size of error E.Through type (6) is adjusted α.

$\mathrm{\&alpha;}=\frac{1}{N}({\mathrm{\&alpha;}}_{\mathrm{\&epsiv;}}-{\mathrm{\&alpha;}}_0)\left|E\right|+{\mathrm{\&alpha;}}_0---\left(4\right)$

0≤α in the formula ₀≤α _ε≤1, α ∈ [0,1].

Five, ambiguity solution.Try to achieve fuzzy control quantity U ^*After, adopt the Min-Max gravity model appoach to carry out ambiguity solution, the exact value of controlled amount.

$u=\frac{\underset{i=0}{\overset{13}{\mathrm{\&Sigma;}}}\mathrm{\&mu;}\left(u\left(i\right)\right)u\left(i\right)}{\mathrm{\&mu;}\left(u\left(i\right)\right)}---\left(5\right)$

Advantage and good effect that the present invention has are: owing to adopt technique scheme, control procedure is convenient; It is little to have disturbance, and it is accurate, quick to follow the tracks of, advantages such as strong robustness.

Description of drawings

Fig. 1 is the membership function figure of E and EC

Fig. 2 is the membership function of U

Fig. 3 Fuzzy control system hardware structure diagram

Fig. 4 main program flow chart

Fig. 5 reads temperature and rotating speed ladder diagram

Fig. 6 fuzzy control rule inquiry ladder diagram

Fig. 7 is second level α-U _θ-U _ωFuzzy control rule table

Wherein,

Among Fig. 3:

1, computing machine 2, PLC 3, FX _2N-2DA

4, single-phase bridge rectification module 5, current vortex retarder 6, rotary encoder

7, temperature sensor 8, FX _2N-4AD

Among Fig. 4:

21, beginning 22, parameter initialization 23, sampling time arrive

24, call FUZZY ALGORITHMS FOR CONTROL 25, according to result of calculation output control 26, finish

Embodiment

The course of work of this instance:

The first, hardware aspect.With reference to accompanying drawing 3, the hardware of control system is formed and is mainly comprised main control computer, RS232-RS485 converter, PLC, FX _2N-4AD module, FX _2N-2DA module, rotary encoder, temperature sensor, single-phase bridge rectification module, current vortex retarder etc.Main control computer through the RS232-RS485 converter, adopts two-wire system RS485 serial communication to link to each other with PLC through COM port.Temperature sensor and FX2N-4AD-TC analog quantity load module coupling, the temperature range of demarcation is 0 ℃-600 ℃, and scrambler also matees with FX2N-4AD-TC analog quantity load module, and the angular velocity range of demarcation is 0-300rpm, and digital output area is 0-3000.PLC reads eddy current retarder rotor dish temperature, calculation deviation and deviation variation rate through FX2N-4AD-TC and temperature sensor; Through FX2N-4AD-TC and rotary encoder, read the eddy current retarder rotor rotating speed, calculation deviation and deviation variation rate simultaneously.Through the controlled amount of inquiry fuzzy control list procedure, through analog output module FX2N-2DA output 0-5V voltage, as the control signal of single-phase bridge rectification module.Control the moment of torsion of current vortex retarder with the output voltage of single-phase bridge rectification module.

The second, PLC software aspect.

1.PLC control system program circuit.PLC temperature control system program flow diagram is as shown in Figure 4, and at first each initial parameter value is set in start, with the offline fuzzy control question blank of setting up, according to certain rules it is left in 169 registers that D200 begins.When timing arrives, begin to call the fuzzy control subroutine, controlled amount deposits among the D180, through FX2N-2DA output 0-5V magnitude of voltage.

2. the PLC of fuzzy control realizes.D130～D133 storage temperature deviation preset value, D134～D137 storage temperature deviation variation rate preset value; D140～D143 deposits rotating speed deviation preset value, and D144～D147 deposits rotating speed deviation variation rate preset value.Arrive when the timing sampling time, adopt the FX2N-4AD-TC module, open wireless tunnel 1 fits into trip temperature with J type thermopair and reads, and reads temperature value and deposits D100 in.The error of calculation, error rate and the rotor disk temperature adjustment factor

Deposit in respectively among D110, D111 and the D112, utilize comparison order and preset value to compare and set, thereby obtain the domain of temperature error and error rate, calculate U by formula (3) _θ, deposit among the D114; 2 open wireless tunnel 2 read the rate signal that rotary encoder transmits simultaneously, deposit among the D102.Read temperature and the rotating speed program is as shown in Figure 5.The error of calculation, error rate reach

Deposit D120 respectively in, among D121 and the D122, utilize comparison order to compare and set, thereby obtain the domain of velocity error and error rate, calculate U by formula (3) _ω, deposit among the D124.

Elder generation is U in program _θAnd U _ωDomain be converted into [0,13], promptly, adopt plot+offset address method for addressing then, with α=U quantizing to add 6 respectively on the later numerical value _ω* 13+U _θThis formula realizes tabling look-up.Read the question blank respective value and obtain the α value, deposit among the D170, through type (2) calculates U, multiply by scale factor again and obtains output quantity, deposits among the D180, through passage 1 output of FX2N-2DA.The fuzzy control polling routine is as shown in Figure 6.

More than one embodiment of the present of invention are specified, but said content is merely preferred embodiment of the present invention, can not be considered to be used to limit practical range of the present invention.All equalizations of doing according to application range of the present invention change and improve etc., all should still belong within the patent covering scope of the present invention.

Claims (4)

1. based on the current vortex retarder Fuzzy control system of PLC; Comprise main control computer, RS232-RS485 converter, PLC, analog quantity load module, analog output module, rotary encoder, temperature sensor, single-phase bridge rectification module, current vortex retarder; It is characterized in that: main control computer through the RS232-RS485 converter, adopts two-wire system RS485 serial communication to link to each other with PLC through COM port; Temperature sensor and rotary encoder all mate with the analog quantity load module; PLC reads the rotor disk temperature of current vortex retarder through analog quantity load module and temperature sensor; Simultaneously through analog quantity load module and rotary encoder; Read the rotor speed of current vortex retarder; Through the controlled amount of inquiry fuzzy control list procedure; Through the voltage of analog output module output,, control the moment of torsion of current vortex retarder with the output voltage of single-phase bridge rectification module as the control signal of single-phase bridge rectification module; Said analog quantity load module adopts FX2N-4AD-TC, and said analog output module adopts FX2N-2DA.

2. control system according to claim 1; It is characterized in that: the temperature range of temperature sensor and analog quantity load module matching and calibration is 0 ℃-600 ℃; Scrambler is 0-300rpm with the angular velocity range of analog quantity load module matching and calibration also, and digital output area is 0-3000; Analog output module FX2N-2DA output voltage is 0-5V.

3. use the method for the current vortex retarder Fuzzy control system based on PLC as claimed in claim 1, it is characterized in that:

At first each initial parameter value is set in start, with the offline fuzzy control question blank of setting up according to certain rules with its leave in PLC from 169 registers that D200 begins;

When timing arrives, begin to call the fuzzy control subroutine among the PLC, controlled amount deposits among the D180, through FX2N-2DA output 0-5V magnitude of voltage.

4. method according to claim 3 is characterized in that:

D130～D133 storage temperature deviation preset value, D134～D137 storage temperature deviation variation rate preset value; D140～D143 deposits rotating speed deviation preset value, and D144～D147 deposits rotating speed deviation variation rate preset value;

Arrive when the timing sampling time, adopt the FX2N-4AD-TC module, open wireless tunnel one fits into trip temperature with J type thermopair and reads, and reads temperature value and deposits D100 in;

The error of calculation, error rate and the rotor disk temperature adjustment factor

deposit in respectively among D110, D111 and the D112; Utilize comparison order and preset value to compare and set; Thereby obtain the domain of temperature error and error rate, by formula (3)

U＝＜αE+(1-α)EC＞，α∈[0，1]

Calculate U _θ, deposit among the D114; Open wireless tunnel two reads the rate signal that rotary encoder transmits simultaneously, deposits among the D102;

Read temperature and rotating speed program, the error of calculation, error rate and the rotor disk rotating speed adjustment factor

Deposit D120 respectively in, among D121 and the D122, utilize comparison order to compare and set, thereby obtain the domain of velocity error and error rate, calculate U by formula (3) _ω, deposit among the D124;

Elder generation is U in program _θAnd U _ωDomain be converted into [0,13], promptly, adopt plot+offset address method for addressing then, with α=U quantizing to add 6 respectively on the later numerical value _ω* 13+U _θThis formula realizes tabling look-up; Read the question blank respective value and obtain the α value, deposit among the D170, through type (2)

U＝＜αU _ω+(1-α)U _θ＞，α∈[0，1]

Calculate U, multiply by scale factor again and obtain output quantity, deposit among the D180, through passage one output of FX2N-2DA.

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