JP5217830B2 - Chassis dynamometer and synchronous control method for 4WD vehicle - Google Patents

Description

  The present invention relates to a chassis dynamometer that performs various tests on a 4WD vehicle or its power transmission system, and more particularly, to synchronous control that makes front and rear driving wheels or front and rear left and right driving wheels constant speed.

  The 4WD vehicle has a front-rear separation system in which power transmission to the front wheels and the rear wheels is separated, and a front-rear left-right separation system. The drive train (power transmission system) includes a transaxle that integrates a transmission and a differential gear, and a transfer that transmits power transmitted from the transmission to the front and rear wheels.

  Chassis dynamometers that can be adapted to differences in the drive systems of 4WD vehicles or power transmission systems having these various structures are prepared, enabling various performance tests. For example, fuel consumption / exhaust gas / performance evaluation and durability performance test of a 4WD vehicle separated front and rear, and fuel consumption / exhaust gas / performance evaluation and durability performance test of a 4WD vehicle separated front / rear and left / right are made possible.

  For power transmission system tests, (a) a drive train tester with two motors such as an engine driven and a transaxle, and (b) four motors such as an engine driven, a transaxle and a transfer. Arranged drivetrain testing machine, (c) Drive train instead of engine, transaxle, etc. Drivetrain tester arranged with 2 motors, (d) Motor driven instead of engine, transaxle, transfer, etc. There is a drive train testing machine with four motors.

In a 4WD vehicle chassis dynamo in which power transmission is separated between the front and rear wheels, the roller speed is synchronously controlled so that the front and rear drive wheels are at a constant speed. Furthermore, the chassis dynamometer controls the four-wheel synchronous control of the front, rear, left, and right drive wheels to simulate the road surface so that the vehicle is traveling on the actual road as in the case of mechanical direct connection. To enable tests such as exhaust gas, fuel consumption, and power performance of the vehicle (see, for example, Patent Document 1).
Japanese Patent No. 3019478

  Some 4WD vehicles have different driving force distributions depending on the vehicle structure. There are also a wide variety of transmissions such as A / T and M / T. Furthermore, there are various operation modes such as a 10-15 mode and an LA4 mode during a running test. For any vehicle having a wide variety of structures and test conditions, the constant speed of the front and rear rollers is important for a test that accurately simulates running on an actual road.

  Conventionally, synchronous control and test performance are evaluated by subtracting the rear roller speed from the front roller speed and monitoring the differential speed before and after in time series.

  However, the evaluation by this method is difficult to quantitatively evaluate because the accuracy of the collected differential velocity data is affected by the amount of sampling and noise.

  Further, the control state of the test vehicle may vary depending on the driving mode difference and the driving driver skill. In this case, proper evaluation cannot be performed. Further, since the differential speed performance cannot be grasped quantitatively and the quality of the control system cannot be judged, there is a problem that the control performance varies.

  An object of the present invention is to provide a 4WD vehicle chassis dynamometer and a drive wheel synchronization control method that enhance the synchronization control performance of a 4WD vehicle or a drive wheel of a power transmission system thereof, and perform various performance tests with this synchronization control. There is to do.

  In order to solve the above problems, the present invention statistically processes the differential speed of the front and rear drive wheels or the front and rear left and right drive wheels, and adjusts the differential speed control sensitivity in the synchronous control with 3σ of the differential speed (σ is a standard deviation), The control matching amount in the synchronous control is adjusted by the magnitude of the average value ΔVave of the differential speed, and is characterized by the following apparatus and synchronous control method.

(1) For a 4WD vehicle equipped with a synchronous control means for making the differential speed of the front and rear driving wheels driven by the 4WD vehicle or its power transmission system constant, or a synchronous control means for making the differential speed of the front and rear left and right driving wheels constant. A chassis dynamometer,
The differential speed control sensitivity of the synchronous control means is adjusted by the magnitude of 3σ (σ is a standard deviation) of the differential speed of the front and rear drive wheels or the front and rear left and right drive wheels when the 4WD vehicle or its power transmission system is operated according to the test mode. Means,
And a means for adjusting the amount of control matching in the synchronous control means by the magnitude of the average value ΔVave of the differential speed.

(2) For 4WD vehicles or 4WD vehicles equipped with synchronous control means for making the differential speed of front and rear drive wheels driven by its power transmission system constant speed or synchronous control means for making the differential speed of front and rear left and right drive wheels constant speed A method for synchronous control of a chassis dynamometer,
The differential speed control sensitivity of the synchronous control means is adjusted by the magnitude of 3σ (σ is a standard deviation) of the differential speed of the front and rear drive wheels or the front and rear left and right drive wheels when the 4WD vehicle or its power transmission system is operated according to the test mode. Steps,
Adjusting the amount of control matching in the synchronous control means according to the average value ΔVave of the differential speed.

  As described above, according to the present invention, the differential speed of the front and rear drive wheels or the front and rear left and right drive wheels is statistically processed, and the differential speed control sensitivity in the synchronous control is adjusted by the difference speed of 3σ (σ is the standard deviation). Because the amount of average value ΔVave is adjusted to adjust the amount of control matching in the synchronous control, the synchronous control performance of the drive wheel of the 4WD vehicle or its power transmission system can be enhanced, and various performance tests can be performed accurately by this synchronous control. .

  FIG. 1 is a configuration diagram of a chassis dynamometer for a 4WD vehicle showing an embodiment of the present invention.

  The test vehicle 1 is a 4WD vehicle in which power transmission is separated from the front and rear wheels. The front and rear wheels 1F and 1R are placed on rollers 2F and 2R, respectively. The inertia of the test vehicle 1 is also performed by electric inertia control), and the torque and speed of the dynamometers 3F and 3R are controlled by inverters (power converters) 4F and 4R.

The automatic driving device 5 controls the vehicle speed Vave ^* according to a test pattern such as the 10-15 mode or the LA4 mode, and operates the transmission and the clutch by a robot or a driving driver.

  The torque and speed control of the dynamometers 3F and 3R is performed by giving a current command corresponding to the running resistance value and the braking speed of the test vehicle 1 to the inverters 4F and 4R and controlling their output currents. The control device that performs these controls includes the following sensors and calculation blocks.

  The speed sensors 6F and 6R detect the speed of the front and rear rollers (drive wheel speed) from the rotational speeds of the dynamometers 3F and 3R. Torque sensors (torque meters) 7F and 7R detect torque generated by the dynamometers 3F and 3R.

  The speed calculation unit 8 obtains the average longitudinal speed Vave of the test vehicle by calculating the average value ((Vf + Vr) / 2) of the speeds Vf and Vr of the front and rear rollers detected by the speed sensors 6F and 6R. The running resistance command calculation unit 9 obtains a running resistance R at the average longitudinal speed Vave of the test vehicle. The running resistance R is composed of rolling resistance, gradient resistance, air resistance, and inertial resistance, and is obtained by calculation based on the following equation.

R = A + Wsin θ + BV ² + C · dV / dt
However, A, B, and C are constants determined by the structure of the automobile, W is the vehicle weight, θ is the road gradient angle, V is the velocity (Vave), and dV / dt is the acceleration.

  The torque control unit 10 uses the total value of the torque command based on the running resistance R and the detected torque of the front and rear drive wheels as a feedback value, and performs automatic torque control calculation from the deviation between the torque command and the detected torque value. Is given to the inverters 4F and 4R as a current command having the same value.

  The front and rear wheel synchronization control unit 11 corrects the current command to be applied to the inverters 4F and 4R according to the differential speed between the front and rear rollers Vf and Vr detected by the speed sensors 6F and 6R and the polarity (positive / negative). Synchronous control is performed to make the speed constant.

  The above configuration is a mechanism and a control device that constitute a conventional chassis dynamometer. In the present embodiment, as pre-processing for various performance tests, the 4WD vehicle or its power transmission system is operated according to the test mode, and the differential speed control sensitivity and the control butt amount in the front and rear wheel synchronous control unit 11 at this time are adjusted, This adjustment improves the synchronous control performance of the front and rear drive wheels. The adjustment of the sensitivity and the amount of matching is based on applying a statistical method to the differential speed to quantitatively grasp the differential speed, judge the quality of the synchronous control system, and optimally tune the synchronous control system. It is.

  The differential speed statistics unit 12 samples and collects time-series data of differential speeds of front and rear drive wheels (front and rear rollers) when mode running, for example, 10-15 mode running is performed in the front and rear wheel synchronous control state, and the statistics are collected. Take. This statistical result shows a normal distribution when the front roller speed Vf, the rear roller speed Vr, and the front / rear roller differential speed ΔV = Vf−Vr. 2A and 2B show distribution examples of front and rear wheel differential speeds.

  The differential speed evaluation unit 13 evaluates the synchronous control performance with 3σ (σ is a standard deviation) for the front / rear roller differential speed ΔV. 3σ means that almost all values are included in the differential speed ΔV within ± 3σ, and mathematically, about 99.7% of all samples fall within ± 3σ. become. In this evaluation, when 3σ (degree of variation) is larger than a certain value B, the control sensitivity G of the front-rear synchronization control unit 11 is sequentially increased from a low value that is initially set. That is, the control sensitivity of the front-rear synchronization control unit 11 is sequentially increased according to the rule “if 3σ> B then G + ΔG”. As a result, tuning of the front-rear synchronization control is performed, and the synchronization control performance is improved.

  Further, the differential speed evaluation unit 13 evaluates the deviation amount from the setting such as the offset in the synchronous control by the average value ΔVave of the front and rear roller differential speed ΔV. That is, according to the rule “if ΔVave> A then F + ΔF” and the rule “if ΔVave <A then F−ΔF”, the control matching amount F of the front-rear synchronization control unit 11 is adjusted depending on whether ΔVave is higher or lower than the set value A. As a result, the offset of the front-rear synchronization control is maintained at a constant amount, and the synchronization control performance is improved.

  In addition, although the case where it applies to the running test by the front-and-rear wheel synchronous control of 4WD vehicle is shown in the embodiment, it can be applied to the running test by the front-rear and left-right wheel synchronous control. In this case, a control device is provided for controlling torque and speed by placing four wheels on four independent rollers and connecting each roller to four dynamometers.

  Moreover, in the structure of embodiment, it can apply to the drive train test of the power transmission system of 4WD vehicle, and can obtain an equivalent effect.

The block diagram of the chassis dynamometer for 4WD vehicles which shows embodiment of this invention. Distribution example of front and rear wheel differential speed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Test vehicle 2F, 2R Roller 3F, 3R Dynamometer 4F, 4R Inverter 5 Automatic driving device 11 Front-rear synchronous control part 12 Differential speed statistics part 13 Differential speed evaluation part

Claims (2)

A chassis dynamometer for 4WD vehicles provided with synchronous control means for making the differential speed of the front and rear drive wheels driven by the 4WD vehicle or its power transmission system constant, or synchronous control means for making the differential speed of the front and rear left and right drive wheels constant. Because
The differential speed control sensitivity in the synchronous control means is adjusted by the magnitude of 3σ (σ is a standard deviation) of the differential speed of the front and rear drive wheels or the front and rear left and right drive wheels when the 4WD vehicle or its power transmission system is operated according to the test mode. Means,
A chassis dynamometer for a 4WD vehicle, comprising: means for adjusting a control matching amount in the synchronous control means based on a magnitude of the average value ΔVave of the differential speed. A chassis dynamometer for 4WD vehicles provided with synchronous control means for making the differential speed of the front and rear drive wheels driven by the 4WD vehicle or its power transmission system constant, or synchronous control means for making the differential speed of the front and rear left and right drive wheels constant. The synchronous control method of
The differential speed control sensitivity of the synchronous control means is adjusted by the magnitude of 3σ (σ is a standard deviation) of the differential speed of the front and rear drive wheels or the front and rear left and right drive wheels when the 4WD vehicle or its power transmission system is operated according to the test mode. Steps,
Adjusting the amount of control matching in the synchronous control means by the magnitude of the average value ΔVave of the differential speed, and a synchronous control method for a chassis dynamometer for a 4WD vehicle.

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