CN102305715A

CN102305715A - Dynamic load simulating device and method for automobile power system test

Info

Publication number: CN102305715A
Application number: CN201110132440A
Authority: CN
Inventors: 叶晓; 金振华; 卢青春
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2011-05-20
Filing date: 2011-05-20
Publication date: 2012-01-04

Abstract

The invention relates to a dynamic load simulation device and method for testing a vehicle power system, and belongs to the technical field of vehicle power system testing. The dynamic load simulation device includes a control computer, a dynamometer controller, a frequency converter, an AC power dynamometer and a torque flange with a controller; the virtual vehicle model is driven by the measured torque using a control algorithm based on the virtual vehicle model, Realize the simulation of vehicle rolling resistance, wind resistance and inertial resistance without calculating the angular acceleration of the dynamometer. The dynamic load simulation device and method of the present invention have good stability and high simulation accuracy, which is beneficial to shorten the development cycle of the automobile power system, and provides a convenient test environment for the development of the power system; in the calculation process, the speed of the automobile power system is avoided. The process of obtaining the vehicle acceleration by differentiation prevents the difficulty in obtaining an accurate differential value due to the large noise brought about in the process of differentiating the rotational speed.

Description

A kind of dynamic load analogue means and method that is used for the automobile dynamic system test

Technical field

The present invention relates to a kind of dynamic load analogue means and method that is used for the automobile dynamic system test, belong to the automotive power technical field of measurement and test.

Technical background

Bench test is the important means of carrying out automobile dynamic system exploitation, in the test of the power system of carrying out engine test or integrated engine and wheel box, all need utilize dynamometer machine to carry out the simulation and the control of load.Development along with automobile dynamic system; Requirement to test macro load simulation precision and response speed is also more and more higher; Traditional measurement of power equipment has hydraulic dynamometer, electric eddy current dynamometer etc.; But the hydraulic dynamometer control accuracy is low; Electric eddy current dynamometer can not the towing astern power system, and it is used and all receives certain limitation.This year, electric A.C. dynamometer obtained widespread use along with the development of electric machines control technology.The ultimate principle of electric A.C. dynamometer is to use ac three-phase asynchronous motor as loading equipemtn, and frequency converter is the driving power that asynchronous machine provides variable frequency, and accurately controls its torque and rotating speed.Compare with other dynamometer machine technology; Ac dynamometer has torque and the rotating speed control accuracy is high, dynamic response time is short, structure is versatile and flexible and characteristics such as energy-efficient and high reliability; The demand that meets dynamic control; All right towing astern power system is used to simulate the hybrid power system braking energy feedback.

Utilize dynamometer machine to carry out dynamic load, the dynamic load when simulated automotive moves on road, and the fuel consume of recording engine and discharging can be realized car load emission test and fuel economy test on stand.The resistance F of automobile in operational process _Vehicle=F _a+ F _w+ F _f, F wherein _a, F _w, F _fRepresent acceleration resistance respectively, the windage and the frictional resistance that travels.Because the variation of frictional resistance and windage is slower, simulate than being easier to, and acceleration resistance changes and changes along with pickup, change comparatively fast difficulty simulation.

Generally in the conventional dynamic load simulation method, adopt flywheel sets to come the inertia of simulated automotive, but flywheel sets exist volume bigger, shortcomings such as adjustment and use inconvenience.If the direct use

to calculate the resistance of inertia of the vehicle, and the computing power necessary to measure the differential value of the angular velocity of the system, and is difficult to accurately measure the differential speed, often accompanied by large noise, and if the feedback control cycle longer, easily cause system oscillation.Therefore, this method requires all higher to the precision of test macro and the cycle period of control loop.

Summary of the invention

The objective of the invention is in order to overcome the defective of prior art, propose a kind of dynamic load analogue means and method that is used for the automobile dynamic system test.

The present invention realizes through following technical scheme.

A kind of dynamic load analogue means that is used for automobile dynamic system test of the present invention comprises the moment of torsion flange of control computer, Dynamometer Control device, frequency converter, electric A.C. dynamometer and tape controller, and its peripherals is automobile dynamic system to be measured;

The core component of automobile dynamic system to be measured comprises engine, clutch coupling, variator, can expand other equipment relevant with automobile dynamic system according to field requirement, such as power accumulator in the hybrid power automobile power system and drive motor;

The power output shaft of automobile dynamic system to be measured links to each other through the moment of torsion flange of tape controller and the power spindle of electric A.C. dynamometer; Frequency converter links to each other through the three-phase alternating current control line with electric A.C. dynamometer; Frequency converter links to each other through the CAN bus with the moment of torsion flange three of Dynamometer Control device, tape controller; Control computer links to each other through Ethernet with the Dynamometer Control device; The analog quantity output port that is used to simulate throttle in the automobile dynamic system to be measured in the throttle signal acquisition interface of engine and the Dynamometer Control device links to each other.

A kind of dynamic load analogue means that is used for the automobile dynamic system test of the present invention, the step of its dynamic load analogy method is:

1) start by sequence control computer, frequency converter, Dynamometer Control device, electric A.C. dynamometer and automobile dynamic system to be measured, whole automobile dynamic system and dynamometer machine entered system and all got into operational mode this moment;

2) on control computer, set the corresponding car load vehicle parameter of automobile dynamic system to be measured, the road grade parameter of the car load vehicle parameter that control computer sets to the transmission of Dynamometer Control device through the CAN bus, dynamic load simulation loop operating mode, setting;

3) control computer is sent the throttle parameter of RG/P mode command and setting to the Dynamometer Control device through the CAN bus;

4) the Dynamometer Control device instructs through analog output interface circuit the setting throttle parameter that obtains in the step 3) to automobile dynamic system simulation output throttle to be measured; This moment, automobile dynamic system to be measured began according to this throttle instruction operation, and corresponding moment of torsion under the output current working;

5) the moment of torsion flange of tape controller detects the moment of torsion of automobile dynamic system output to be measured, and this torque value is uploaded to the Dynamometer Control device through the CAN bus;

6) the Dynamometer Control device calls speed of a motor vehicle computation model and calculates current vehicle velocity simulate value, and detailed process is:

6.1 according to the current simulated condition of dynamic load; And according to the car load vehicle parameter of control computer setting and the road grade calculation of parameter current vehicle resistance simulation value of setting; This vehicle drag analogue value comprises the vehicle windage analogue value and vehicles roll resistance simulation value two parts, calculates vehicle windage analogue value F with following formula _w

F_{w} = \frac{C_{d} {Au}^{2}}{21.15}

Calculate vehicles roll resistance simulation value F with following formula _f

F _f＝m _vgf

M wherein _vBe car weight, f is a coefficient of rolling resistance, and A is equivalent windage area, C _dBe coefficient of air resistance, g is an acceleration of gravity;

6.2, calculate the current vehicle driving force analogue value with the moment of torsion input of the torque value that obtains in the step 5) as the dynamic load of being simulated:

F _d＝T _mi ₀/R

T wherein _mBe the moment of torsion that automobile dynamic system to be measured sends, i ₀Main reducing gear speed ratio for vehicle to be simulated.

6.3 the current vehicle driving force analogue value is deducted current vehicle resistance simulation value, and combine the car load vehicle parameter to calculate current vehicle velocity simulate value, its computing formula does

v (t) = {&Integral;}_{0}^{t} \frac{F_{d} - F_{f} - F_{w}}{m_{v}} dτ

In the following formula, t representes current point in time, and v (t) is a current vehicle velocity simulate value, F _dBe the current vehicle driving force analogue value, F _fBe the current vehicle resistance to rolling analogue value, F _wBe the current vehicle windage analogue value, m _vBe the complete vehicle quality in the car load vehicle parameter;

7) the Dynamometer Control device is according to current vehicle velocity simulate value; Utilize the speed ratio of radius of wheel and main reducing gear in the car load vehicle parameter; Calculate the rotating speed of automobile dynamic system power output shaft to be measured; And this tachometer value sent to frequency converter through the CAN bus; By the Frequency Converter Control electric A.C. dynamometer under the speed closed loop pattern; Provide the dynamometer machine torque value through the PI controller, accomplish the simulation of vehicle dynamic response.

Step 3) in the above-mentioned method can be used following step 3) replacement:

3) control computer is sent the speed of a motor vehicle parameter of RG/V mode command and setting to the Dynamometer Control device through the CAN bus; The Dynamometer Control device calls pilot model, calculates setting throttle parameter according to the speed of a motor vehicle parameter of setting and a last round-robin car speed analogue value;

Above-mentioned RG/P pattern and RG/V pattern are respectively two kinds of control models of electric A.C. dynamometer, and electric A.C. dynamometer also comprises other 4 kinds of traditional control models in addition, is respectively N/P pattern, M/P pattern, N/M pattern and M/N pattern; In these patterns are expressed; The control model of dynamometer machine load represented in previous letter; The control model of power system represented in the letter in back; Wherein RG represents the road grade control model; P represents the Throttle Opening Control pattern; V represents speed of a motor vehicle closed loop control mode, and M represents the moment of torsion closed loop control mode, and N represents the speed closed loop control model of power system.

Under dynamic load simulation RG/P mode state and RG/V mode state; Adopt the output torque of the moment of torsion flange test power system of tape controller; With this torque arithmetic vehicle drag model; Obtain the simulation speed of a motor vehicle of vehicle under this driving force; And calculate the simulation rotating speed of power system; This rotating speed is set to ac dynamometer as rotating speed of target, reached the function of vehicle dynamic load simulation.In this process, avoid the differential value of operating speed, can improve the dynamic stability of system preferably.

Beneficial effect

Method of the present invention realizes the dynamic similation of vehicle running resistance on road; This method good stability; Simulation precision is high; Dynamic load modeling algorithm through controller; Can be implemented in simulation road vehicle driving cycle on the stand; Help shortening the construction cycle of automobile dynamic system, the experimental enviroment that facilitates for the exploitation of power system.Adopt method of the present invention, avoided the rotating speed of automobile dynamic system is carried out the process that differential obtains vehicle acceleration, thereby prevented owing to bringing bigger noise to be difficult to obtain differential value accurately in the process of rotating speed being made differential.

Description of drawings

Fig. 1 is the structural representation of dynamic load analogue means of the present invention;

Fig. 2 is the synoptic diagram of data transfer between each parts among the embodiment 1;

Fig. 3 is the synoptic diagram of data transfer between each parts among the embodiment 2;

Fig. 4 is the actual measurement torque of dynamometer machine among the embodiment 1 and the simulating vehicle torque contrast synoptic diagram that calculates;

Fig. 5 is the speed tracking curve that dynamometer machine moves Chinese typical urban operating mode among the embodiment 2 under the RG/V pattern;

Fig. 6 is the throttle curve of output that dynamometer machine moves the driver of Chinese typical urban operating mode among the embodiment 2 under the RG/V pattern.

Embodiment

Below in conjunction with accompanying drawing and embodiment the present invention is further specified.

Embodiment 1

A kind of dynamic load analogue means that is used for the automobile dynamic system test as shown in Figure 1, comprises the moment of torsion flange of control computer, Dynamometer Control device, frequency converter, electric A.C. dynamometer and tape controller, and its peripherals is automobile dynamic system to be measured;

Automobile dynamic system to be measured comprises engine, clutch coupling, variator;

The power output shaft of automobile dynamic system to be measured links to each other through the moment of torsion flange of tape controller and the power spindle of electric A.C. dynamometer; Frequency converter links to each other through the three-phase alternating current control line with electric A.C. dynamometer; Frequency converter links to each other through the CAN bus with the moment of torsion flange three of Dynamometer Control device, tape controller; Control computer links to each other through Ethernet with the Dynamometer Control device; The analog quantity output port that is used to simulate throttle in the automobile dynamic system to be measured in the throttle signal acquisition interface of engine and the Dynamometer Control device links to each other;

Above-mentioned dynamometer machine is the Siemens Alternating motor, and frequency converter is the ACS800 frequency converter.

A kind of dynamic load analogue means that is used for automobile dynamic system test, in its dynamic load simulation process between each parts the data transfer relation as shown in Figure 2, the step of dynamic load analogy method is:

6) the Dynamometer Control device is according to the current simulated condition of dynamic load; And according to the car load vehicle parameter of control computer setting and the road grade calculation of parameter current vehicle resistance simulation value of setting, this vehicle drag analogue value comprises the vehicle windage analogue value and vehicles roll resistance simulation value two parts;

The car load vehicle parameter that control computer is set comprises: car weight m _vBe 15500Kg, coefficient of rolling resistance f is 0.012, and equivalent windage area A is 6.73m ², coefficient of air resistance C _dBe 0.65, radius of wheel is 0.471m, and the main reducing gear speed ratio is 6.2;

Calculate vehicle windage analogue value F with following formula _w

F_{w} = \frac{C_{d} {Au}^{2}}{21.15}

Calculate vehicles roll resistance simulation value F with following formula _f

F _f＝m _vgf

With the moment of torsion input of the torque value that obtains in the step 5), calculate current vehicle driving force analogue value F as the dynamic load of being simulated _dThe current vehicle driving force analogue value is deducted current vehicle resistance simulation value, and combine the car load vehicle parameter to calculate current vehicle velocity simulate value, its computing formula does

v (t) = {&Integral;}_{0}^{t} \frac{F_{d} - F_{f} - F_{w}}{m_{v}} dτ

In the following formula, t representes current point in time, and v (t) is a current vehicle velocity simulate value;

7) the Dynamometer Control device is according to current vehicle velocity simulate value; Utilize the speed ratio of radius of wheel and main reducing gear in the car load vehicle parameter; Calculate the rotating speed of automobile dynamic system power output shaft to be measured; And this tachometer value sent to frequency converter through the CAN bus; By the Frequency Converter Control electric A.C. dynamometer, under the speed closed loop pattern, accomplish the dynamic load simulation of automobile dynamic system by the Frequency Converter Control electric A.C. dynamometer;

Fig. 4 is in acceleration and shift process, the contrast of the situation of change of the actual measurement torque of dynamometer machine and the simulating vehicle torque that calculates, and as can be seen from Figure 4, dynamometer machine can be followed the tracks of the variation of torque preferably.

Embodiment 2

A kind of dynamic load analogue means that is used for automobile dynamic system test, in its dynamic load simulation process between each parts the data transfer relation as shown in Figure 3, the step of its dynamic load analogy method is:

3) control computer is through the speed of a motor vehicle parameter of CAN bus to Dynamometer Control device transmission RG/V mode command and setting, and the Dynamometer Control device calculates setting throttle parameter according to the speed of a motor vehicle parameter of setting and a last round-robin car speed analogue value;

The car load vehicle parameter that control computer is set comprises: car weight m _vBe 15500Kg, coefficient of rolling resistance f is 0.012, and equivalent windage area A is 6.73m ², coefficient of air resistance C _dBe 0.65, radius of wheel r is 0.471m, the speed ratio i of main reducing gear ₀Be 6.2;

Calculate vehicle windage analogue value F with following formula _w

F_{w} = \frac{C_{d} {Au}^{2}}{21.15}

Calculate vehicles roll resistance simulation value F with following formula _f

F _f＝m _vgf

7) the Dynamometer Control device is according to current vehicle velocity simulate value, utilizes the speed ratio i of radius of wheel r and main reducing gear in the car load vehicle parameter ₀Calculate the rotating speed of automobile dynamic system power output shaft to be measured; And this tachometer value sent to frequency converter through the CAN bus, by the Frequency Converter Control electric A.C. dynamometer, under the speed closed loop pattern, accomplish the dynamic load simulation of automobile dynamic system by the Frequency Converter Control electric A.C. dynamometer;

Adopt the RG/V pattern; By host computer target setting operating mode is Chinese typical urban public transport operating mode; By pilot model control hybrid power system to be measured; The speed tracking curve as shown in Figure 5; Driver's throttle curve of output as shown in Figure 6; Can find out that by Fig. 5 and Fig. 6 pilot model can be controlled the preset speed of a motor vehicle curve of vehicle tracking preferably.The test value that obtains is as shown in table 1, three test result unanimities, good reproducibility.

Table 1

Project	For the first time	For the second time	For the third time	Mean value
					Distance travelled (km)	5.17	5.17	5.17	5.17
Total oil consumption (L)	1.49	1.49	1.48	1.49
					The initial soc of accumulator	41	41	41	41
The final soc of accumulator	41	41	41	41
					Rate of fuel consumption (L/100km)	28.8	28.84	28.7	28.8
Motor output energy (kJ)	3506	3489	3537	3511

Claims

1. a kind of dynamic load simulation device that is used for automobile power system test, its peripheral equipment is the automobile power system to be tested, and the core component of the vehicle power system to be tested comprises engine, clutch, speed changer, is characterized in that:

Including control computer, dynamometer controller, frequency converter, AC power dynamometer and torque flange with controller;

The power output shaft of the vehicle power system to be tested is connected to the power shaft of the AC power dynamometer through a torque flange with a controller; the inverter and the AC power dynamometer are connected through a three-phase AC control line; the frequency converter and the dynamometer The machine controller and the torque flange with the controller are connected through the CAN bus; the control computer and the dynamometer controller are connected through Ethernet; Connected to the analog output port used to simulate the throttle.

2. A dynamic load simulation method for automotive power system testing, characterized in that the steps are:

1) Start the control computer, frequency converter, dynamometer controller, AC power dynamometer and the vehicle power system to be tested in order, and at this time the entire vehicle power system and dynamometer system enter the running mode;

2) Set the vehicle parameters corresponding to the vehicle power system to be tested on the control computer, and the control computer sends the set vehicle parameters, dynamic load simulation cycle conditions, and setting parameters to the dynamometer controller through the CAN bus. The specified road slope parameters;

3) The control computer sends the RG/P mode command and the set throttle parameters to the dynamometer controller through the CAN bus;

4) The controller of the dynamometer simulates and outputs the throttle command to the power system of the vehicle under test through the analog output interface through the set throttle parameter obtained in step 3), and the power system of the vehicle to be tested starts to run according to the throttle command at this time. And output the corresponding torque under the current working condition;

5) The torque flange with the controller detects the output torque of the vehicle power system to be tested, and uploads the torque value to the dynamometer controller through the CAN bus;

6) The dynamometer controller calls the vehicle speed calculation model to calculate the current vehicle speed simulation value, the specific process is:

6.1 Calculate the current simulated vehicle resistance value according to the current simulated working condition of the dynamic load and according to the vehicle parameters set by the control computer and the set road gradient parameters. The simulated vehicle resistance value includes the simulated value of the vehicle wind resistance and the simulated vehicle rolling resistance There are two parts of the value, use the following formula to calculate the simulated value of vehicle wind resistance F _w

{F f}_{w w} = = \frac{{C C}_{d d} {Au Au}^{22}}{21.15 21.15}

Use the following formula to calculate the simulated value of vehicle rolling resistance F _f

F _f =m _v gf

Where m _v is the weight of the vehicle, f is the coefficient of rolling resistance, A is the equivalent wind resistance area, C _d is the coefficient of air resistance, and g is the acceleration of gravity;

6.2 Use the torque value obtained in step 5) as the torque input of the simulated dynamic load to calculate the current vehicle driving force simulation value:

F _d =T _m i ₀ /R

Where T _m is the torque sent by the vehicle power system to be tested, and _i0 is the speed ratio of the final drive of the vehicle to be simulated;

6.3 Subtract the current vehicle resistance simulation value from the current vehicle driving force simulation value, and combine the vehicle parameters to calculate the current vehicle speed simulation value. The calculation formula is

v v ((t t)) = = {&Integral; &Integral;}_{00}^{t t} \frac{{F f}_{d d} - - {F f}_{f f} - - {F f}_{w w}}{{m m}_{v v}} dτ dτ

In the above formula, t represents the current time point, v(t) is the simulated value of the current vehicle speed, F _d is the simulated value of the current vehicle driving force, F _f is the simulated value of the current vehicle rolling resistance, F _w is the simulated value of the current vehicle wind resistance, m _v is the mass of the vehicle in the vehicle parameters;

7) The dynamometer controller calculates the speed of the power output shaft of the vehicle power system to be tested by using the wheel radius and the speed ratio of the final drive in the vehicle parameters according to the current vehicle speed simulation value, and sends the speed value through the CAN The bus is sent to the frequency converter, and the frequency converter controls the AC power dynamometer to complete the simulation of the dynamic response of the vehicle in the speed closed-loop mode;

The above RG/P mode is a control mode of the AC power dynamometer, where RG means that the control mode of the dynamometer load is the road gradient control mode, and P means that the control mode of the power system is the throttle control mode.

3. A kind of dynamic load simulation method for automotive power system test according to claim 2, is characterized in that:

Step 3) in the method is replaced with the following step 3):

3) The control computer sends the RG/V mode command and the set vehicle speed parameters to the dynamometer controller through the CAN bus, and the dynamometer controller invokes the driver model to simulate The value is calculated to obtain the set throttle parameter;

The above RG/V mode is a control mode of the AC power dynamometer, where RG represents the control mode of the dynamometer load is the road gradient control mode, and V represents the control mode of the power system is the vehicle speed closed-loop control mode.

4. A kind of dynamic load simulation device for automobile power system test according to claim 1, it is characterized in that:

The dynamometer is a Siemens AC motor, and the frequency converter is an ACS800 frequency converter.