CN1808093A - Damping matching test method and system based on magneto-rheological technology for automobile suspension system - Google Patents

Abstract

The invention discloses a method and a system for testing vehicle suspension damp match based on a magnetic flow variation technology. The system comprises: testing vehicle, an exciting platform, a magnetic flow variation damper, a power sensor, an offset sensor, a testing system constructed by an analog switch of external peak value testing module and a feedback controller. The method comprises: before testing, setting needed magnetic flow variation damper recovering damp value, compressing damp value and getting corresponding voltage signal; exciting the system by the up and down actions of the exciting platform; detecting piston relative offset signal peak by the offset sensor; switching the analog switch to input the voltage signal of the recovering damp value and the compressing damp value to the feedback controller as constant value; controlling the magnetic flow variation damper via the feedback controller to reach the set recovering damp and compressing damp value and get the optimum matching.

Description

Automobile suspension system car load damping matching test method and system based on magnetic converting technique

Technical field

The invention belongs to car load damping matching test technology in the automobile suspension system design.

Background technology

The damping coupling is the key link of automotive suspension design, and the new model of each automobile main frame maker all must carry out damping matching test before going into operation.The method that present each factory's damping matching test is adopted is to design one group (nearly ten kinds in advance, even tens of kinds) damper of different damping value is at the damping matching test that carries out on the experimental stand under the different parameters, till selecting a kind of damper of thinking optimum matching.This test replacing damper labour intensity is big, and the test period is long, cost is high, and because damping force is determined by structural parameters and damping oil that in advance can't regulate continuously, the damping that this test findings is difficult to reach optimum is mated.

Summary of the invention

The objective of the invention is to above-mentioned defective, a kind of automotive suspension car load damping matching test method and system based on magnetic converting technique is provided, simplify the proof strength of damping coupling, shorten the test period, and reach the damping Optimum Matching at the prior art existence.

MR damper (MRD) based on magnetic converting technique, be to utilize magnetic flow liquid under the action of a magnetic field, apparent viscosity dullness is within the specific limits passed the stepless adjustable device of damping of the characteristics design of transferring reversible variation, can satisfy the testing requirements of automotive suspension car load damping Optimum Matching.

The method that the present invention adopts is as follows:

At first, test vehicle is put on the actuating vibration table that can carry out single-frequency excitation and road analogy test, with the conventional hydraulic damper in the suspension of MR damper (MRD) replacement test vehicle, installation position displacement sensor (LVDT) and force transducer on vehicle suspension, and displacement transducer, MR damper and force transducer are connected with feedback controller by the peak detection block switching analoging switch of signal wire with the periphery respectively, composition can carry out the vehicle complete vehicle damping matching test system of four-wheel excitation.

By control hardware and/or software required MR damper is set respectively before the test and restores damping value, compression damping value, obtain the correspondent voltage signal.

Controlling four start heads of actuating vibration table then moves up and down, four wheels are encouraged, displacement transducer output damper piston relative displacement signal, become by compression in damper direction of motion and to stretch or when becoming compression (summit of motion) by stretching, the relative displacement signal of damper piston is just reaching/is bearing maximal value, maximum constantly and export high level and trigger analog switch and switch by peak detection block detecting position shifting signal, the recovery damping value that will be provided with by switching analoging switch, compression damping value correspondent voltage signal inputs to controller and makes set-point, by the FEEDBACK CONTROL MR damper (MRD) of controller, make MR damper (MRD) reach set recovery damping value then, the compression damping value.Carry out many group experiments as long as change the damping force value of setting like this, just can realize the damping Optimum Matching.

The feedback control procedure of its middle controller is as follows:

Force feedback signal after damping force set-point and the conditioning relatively, controlled error E inputs to speed change integral PID control device, determine control signal U according to governing equation (1), U Control current driver is exported corresponding electric current I and is given MR damper (MRD) as exciting current, thereby regulate the damping force of MRD, finish Control Circulation one time.

$U\left(k\right)=K_{p}E\left(k\right)K_i\underset{j=0}{\overset{k}{\mathrm{\Σ}}}E\left(j\right)+K_p[E\left(k\right)-E(k-1)\}]----\left(1\right)$

K in the formula---sampling sequence number, k=0,1,2,

E (k)---the deviate of input during the k time sampling

E (k-1)---the deviate of (k-1) inferior sampling instant input

Ki---integral coefficient, Ki=KpT/T1

Kd---differential number system, Kd=KpTd/T1

U (k)---the k time sampling instant output valve

T1 is an integration time constant, and Td is a derivative time constant, and T is the sampling period

Above-mentioned feedback control algorithm can be used PID (proportional-integral-differential) control, but is not limited to PID control.Owing to adopt the Controlled by Microcomputer structure, the Control Software establishment has dirigibility, fuzzy control, and optimum control ANN (Artificial Neural Network) Control scheduling algorithm all can be used for native system.

For realizing that said method the present invention has designed following automotive suspension damping matching test system:

This system is made up of automobile (mainly using automotive suspension), actuating vibration table, MR damper, displacement transducer, force transducer, peak detection block, switching analoging switch and feedback controller, four wheels of automobile are placed on respectively on four action heads of actuating vibration table, the driving cycle of simulated automotive on the road surface, displacement transducer, spring and MR damper are connected on the automotive suspension, automotive suspension upper end installing force sensor.The signal wire of displacement transducer is connected to peak detection block, the output signal of peak detection block inserts switching analoging switch, the recovery damping value of the required MRD that switching analoging switch will set in advance and compression damping value are converted to voltage signal access feedback controller and do set-point, the control line of feedback controller connects MR damper, and the signal wire of force transducer inserts feedback controller.

Damping among the present invention coupling experimental technique not only can be used for bench test, remove device such as actuating vibration table after, also can directly MR damper (MRD) and controller be used for the test of real vehicle road matching.

Advantage of the present invention is to utilize the continuously adjustable characteristic of damping force and the FEEDBACK CONTROL of MR damper, can comparatively fast determine optimum damping coupling more exactly, simplified the proof strength of damping coupling greatly, shorten the test period, and utilize the designed method and system of the present invention, can accomplish that damper compression damping power and recovery damping force are provided with respectively, accurately regulate, reach the purpose of damping Optimum Matching.

Description of drawings

Fig. 1 is the structure principle chart of this pilot system.

Among Fig. 1,1. start 12～15 force transducer of displacement transducer (LVDT) 11. actuating vibration tables of ride comfort evaluation sensor 2～5 MR damper 6. controllers 7～10.

Fig. 2 is the control principle figure of native system.

Fig. 3 is the peak detection block block diagram.

Embodiment

The bench test system of damping coupling as shown in Figure 1, this system is by test vehicle, actuating vibration table, MR damper 2～5, displacement transducer 7～10, force transducer 12～15, peak detection block, switching analoging switch and feedback controller 6 are formed, four wheels of automobile are placed on respectively in four starts 11 of actuating vibration table, four start heads move up and down, the driving cycle of simulated automotive on the road surface, installing in the suspension of test vehicle is MR damper (MRD) 2-5, displacement transducer (LVDT) 7-10 and force transducer 12-15 also are installed on vehicle suspension, and make displacement transducer, MR damper and force transducer are respectively by signal wire and peripheral peak detection block, switching analoging switch is connected with feedback controller 6, and composition can carry out the vehicle complete vehicle damping matching test system of four-wheel excitation.Test method is: control actuating vibration table four starts 11 move up and down, four wheels are encouraged, displacement transducer 7-10 just exports the relative displacement signal of the piston of MR damper 2～5, become by compression in damper direction of motion and to stretch or when becoming compression (summit of motion) by stretching, the relative displacement signal of damper piston is just reaching/is bearing maximal value, maximum constantly and export high level and trigger analog switch and switch by peak detection block detecting position shifting signal, the recovery damping value that will be provided with by switching analoging switch, compression damping value correspondent voltage signal inputs to controller and makes set-point, displacement transducer is by FEEDBACK CONTROL shown in Figure 2 then, FEEDBACK CONTROL MR damper (MRD) 2-5 makes MR damper (MRD) reach set recovery damping value and compression damping value.Set different recovery damping values and compression damping value by potentiometer and carry out damping matching test under the different parameters, utilize ride comfort evaluation sensor 1 to detect the vehicle body vibration signal again and carry out the evaluation of damping matching effect, change the damping force value of setting like this and carry out many groups and test, till selecting one group of damping value of thinking optimum matching.

In conjunction with Fig. 2 as seen, feedback control procedure wherein: the force feedback signal after damping force set-point and the conditioning relatively, controlled error E is input to PID controller (proportional-integral derivative controller), pass through Kp, the setting of Ki and three parameters of Kd, processing the signal into required control signal U according to governing equation (1) is input in the current driver output and stablizes adjustable electric current I and give MR damper (MRD) as exciting current, the exciting current of different numerical value just can be regulated MRD and produce different damping forces, and damping force forms the damping force feedback signal by force transducer and signal conditioning circuit again and finishes Control Circulation one time.

In conjunction with Fig. 3 as seen, the course of work of peak detection block is: displacement signal is input to the data buffer of DSP again through after the low-pass filtering through the A/D sampling, the extremum search to sampled data is finished in utilization " maximum value process ", and the output peak value.The D/A module is input to controller with output stage value transform simulation trigger pip by analog switch, recovery damping value, compression damping value correspondent voltage signal that the while switching analoging switch will be provided with input to controller and do set-point, finish the whole process that peak value detects.

The technical requirement of the electric elements that adopted in the native system is as follows:

Analog switch: require the conducting resistance of analog switch little, leakage current is little, and interelectrode capacity is little and switch speed is fast.Has the low RON (+2.7V power supply) of 3.5 Ω as MAX4729 series analog switch; 0.45 Ω RON flatness (+2.7V power supply); 0.05 Ω interchannel RON matching degree (+2.7V power supply);-three dB bandwidth: 300MHz; Low conducting electric capacity: 19.5pF; 0.036% total harmonic distortion is hanged down source current: 1nA; + 1.8V is to the work of+5.5V single supply.

Signal conditioner: can provide and amplify and temperature compensation; Adapt to inductor output susceptibility from 5mV/V to 40mV/V; Complete analog signal path; 3.2KHZ fast frequency response etc.As MAX1455EUE, MAX1455AUE, MAX1455EAE, MAX1455AAE, MAX1455C/D etc. all is very practical automobile sensor signal conditioner.

Peak detection block: the peak value that can measure displacement signal accurately and timely.

Feedback controller: mainly the requirement oneself according to Fig. 2 designs or buys suitable controller.

Above-mentioned peak detection block, feedback controller etc. can be realized by a slice processor, as the dsp chip TMS320F240 of Texas Instruments's production.

Sensor: force transducer requires to measure the dynamic force of 10-4～104N; Displacement transducer measures-250～250mm; Sensor error scope 0.1%～0.01%; Frequency response 0.1～1kHz; Adaptability to complex environment is strong, can work under rugged surroundings, shock and vibration condition; As long as carry out the design of suitable structure and select suitable material for use, also can be under high temperature (or low temperature), deep-etching and nuclear radiation condition reliably working.

Claims (3)

1,, it is characterized in that test procedure is as follows based on the automotive suspension damping matching test method of magnetic converting technique:

(1) four wheels with test vehicle are placed on respectively on four action heads of actuating vibration table, in the suspension of test vehicle MR damper is installed, installation position displacement sensor and force transducer on vehicle suspension, and displacement transducer, MR damper and force transducer are connected by peak detection block, switching analoging switch and the feedback controller of signal wire with the periphery respectively, form pilot system;

(2) by control hardware and/or software required MR damper is set respectively before the test and restores damping value, compression damping value;

(3) four action heads of control actuating vibration table move up and down, Vehicular system is carried out single-frequency excitation or road excitation at random, the displacement transducer that is installed between the vehicle suspension detects the displacement peak signal, recovery damping value, the compression damping value correspondent voltage signal that will be provided with by switching analoging switch input to feedback controller and do set-point, then by feedback controller control MR damper, make MR damper reach set recovery damping value, compression damping value, thereby reach the damping Optimum Matching.

2, the automotive suspension damping matching test method based on magnetic converting technique according to claim 1, the control procedure of feedback controller is as follows:

With the force feedback signal after damping force set-point and the conditioning relatively, controlled error E is input to proportional-integral derivative controller, by the setting of Kp, integral coefficient Ki in the control program and three parameters of differential number system Kd, according to following governing equation

$U\left(k\right)=K_{p}E\left(k\right){+K}_i\underset{j=0}{\overset{k}{\mathrm{\Σ}}}E\left(j\right)+K_p[E\left(k\right)-E(k-1)\}]$

K in the formula---sampling sequence number, k=0,1,2 ...

E (k)---the deviate of input during the k time sampling

E (k-1)---the deviate of (k-1) inferior sampling instant input

Ki---integral coefficient, Ki=Kp*T/T1

Kd---differential number system, Kd=Kp*TD/T1

U (k)---the k time sampling instant output valve

T1 is an integration time constant, and TD is a derivative time constant, and T is the sampling period

Processing the signal into required control signal U is input in the current driver output and stablizes adjustable electric current I and give MR damper as exciting current, the exciting current of different numerical value just can be regulated MR damper and produce different damping forces, and damping force forms the damping force feedback signal by force transducer and signal conditioning circuit again and finishes Control Circulation one time.

3, automotive suspension damping matching test system based on magnetic converting technique, it is characterized in that, this system is by test vehicle, actuating vibration table, MR damper, displacement transducer, force transducer, peak detection block, switching analoging switch and feedback controller are formed, four wheels of automobile are placed on respectively on four action heads of actuating vibration table, in the suspension of test vehicle, MR damper is installed, installation position displacement sensor and force transducer on vehicle suspension, displacement transducer connects peak detection block by signal wire, the output signal of peak detection block inserts switching analoging switch, be connected to feedback controller through switching analoging switch again, the recovery damping value of the required MR damper that switching analoging switch will set in advance and compression damping value are converted to voltage signal access feedback controller and do set-point, the control line of feedback controller connects MR damper, and the signal wire of force transducer inserts feedback controller.

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