JP2001108580A - Method for sampling data on gradient of road surface for use in road travel simulating test method using chassis dynamometer, and method for controlling chassis dynamometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for sampling data on the gradient of a road surface, for use in a road travel simulating test method using a chassis dynamometer, whereby the gradient of the road surface can be determined very easily. SOLUTION: An atmospheric pressure sensor 9 is mounted in a vehicle 1, which is made to travel on a road. A variation in height is calculated from short-term changes in atmospheric pressure during travel on the road, and the gradient of the road surface 18 relative to the traveled distance is measured from the variation in height in every traveled distance, to sample data on the gradient of the road surface 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for collecting road surface gradient data and a method for controlling a chassis dynamometer used in a road running simulation test method using a chassis dynamometer.

[0002]

2. Description of the Related Art Conventionally, in order to test the dynamic running performance of a vehicle such as an automobile, a real vehicle running simulation operation is performed by a chassis dynamometer. In order to simulate the above, conventionally, a plane movement amount and a height change are obtained from a map, a gradient with respect to a tilt movement distance is calculated, and this is input to a torque control circuit together with a torque command.

[0003]

However, in the above-mentioned method, it is very complicated to calculate the gradient with respect to the inclination moving distance, and it is necessary to prepare data every time a new course is set. There is a point.

[0004] On the other hand, it is conceivable to mount a gradient measuring device on a vehicle. However, in the conventional gradient measuring device, vibration due to unevenness of a road surface or horizontal G (acceleration of gravity) during traveling on a curve. It is difficult to accurately measure the inclination of the road surface due to the influence of the road surface.

[0005] When a vehicle is traveling on a road surface, the atmospheric pressure during traveling varies depending on the altitude of the road surface. The atmospheric pressure fluctuates even when the vehicle is stopped,
The variation within the time for traveling the distance for measuring the inclination is negligibly small (except in unusual weather).
The measurement of the atmospheric pressure is easy.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned matters, and a first object of the present invention is to provide a road surface simulation test method using a chassis dynamometer which can extremely easily determine the gradient of the road surface. A second object is to control a chassis dynamometer capable of performing a simulated operation in accordance with actual road surface traveling. Is to provide a way.

[0007]

In order to achieve the first object, according to the present invention (first invention), a vehicle is equipped with an atmospheric pressure sensor and travels on a road, and the vehicle travels on the road for a short time. The amount of change in altitude is calculated from the change in atmospheric pressure, and the gradient of the road surface with respect to the travel distance is measured from the amount of change in altitude for each travel distance so as to collect the gradient data of the road surface.

[0008] In order to achieve the second object,
According to the present invention (second invention), a gradient command for the traveling distance on the chassis dynamometer is generated using the road gradient data for the traveling distance obtained when the vehicle is traveling on the road surface, and this is referred to as a traveling resistance value. In addition to the above, it is input to a torque control circuit to perform gradient control (claim 2).

[0009]

Embodiments of the present invention will be described with reference to the drawings. First, the first invention will be described with reference to FIGS. 1 and 2, reference numeral 1 denotes an automobile used for collecting gradient data, for example, a gasoline-powered automobile. Reference numeral 2 denotes an engine of the automobile 1, reference numeral 3 denotes an exhaust pipe connected to the engine 2, and reference numeral 4 denotes a muffler provided in the exhaust pipe 3. Reference numeral 5 denotes a vehicle speed sensor, and reference numeral 6 denotes an interface to which an output of the speed sensor 5 is input, and is composed of a pulse generator 7 for generating a vehicle speed pulse and a pulse counter 8 (see FIG. 2).

In FIG. 1, reference numeral 9 denotes an atmospheric pressure sensor which is provided in a vehicle, for example, near a driver's seat. Also, 1
Reference numerals 0 and 11 denote an outside air temperature sensor for measuring the outside air temperature and an outside air humidity sensor for measuring the outside air humidity.
Reference numerals 0 and 11 are provided on the intake side of the engine 2 near the outside. Reference numeral 12 denotes an interface to which the outputs of the sensors 9 to 11 are input.
And an A / D conversion circuit 16 for performing an A / D conversion on the output of.

In FIG. 1, reference numeral 17 denotes a microcomputer (microcomputer) as a data collection device, which is mounted at an appropriate place in the vehicle. This data collection device 1
Reference numeral 7 appropriately performs calculations based on the interfaces 6, 12 and other input signals.

In FIG. 1, reference numeral 18 denotes a road surface.

Next, a method of collecting gradient data is shown in FIG.
This will be described with reference to FIGS. In order to simulate a road running state, the vehicle 1 configured as described above is driven, and data such as a running distance, an atmospheric pressure, an outside air temperature, and an outside air humidity are collected in time series with time. That is, the travel distance is obtained by counting the pulses generated by the pulse generator 7 attached to the speed sensor 5 by the pulse counter 8. The atmospheric pressure, the outside air temperature, and the outside air humidity are measured by the atmospheric pressure sensor 9, the outside air temperature sensor 10, and the outside air humidity sensor 11. Each of these data is input to the microcomputer 17.

By the way, at time T₀, T (= T₀+ ΔT)
Is the atmospheric pressure at each of P (T ₀), P (T) (Single
Position is hPa), the absolute pressure of the atmosphere will be
Change in the measured atmospheric pressure
Is probably due to altitude change.

Now, let the temperatures of the atmosphere (outside air) at times T ₀ and T be t (T ₀ ) and t (T), respectively.
Assuming that the atmospheric (outside air) humidity at time T is R (T) and the traveling distance is D (T), from the scientific chronological table, as a height measurement formula, h = h ₀ + 0.0036610t _v · h ₀ (1) h ₀ = 18410.0 log ₁₀ (P ₀ /P)=184100.0{log ₁₀ P (T ₀ ) −log ₁₀ P (T)} (2) t _v = {t (T ₀ ) + t (T) )｝ / 2 + C (t) ｛R (T ₀ ) + R (T)｝ / (2 × 100) (3) In the above formula, h is the height (unit is m), _tv is the average temporary temperature (unit is ° C.) of the column of height h,
P ₀ and P are the atmospheric pressures (unit: hPa) at times T ₀ and T.

In the above, h is the time between T ₀ and T
, The inclination angle (θ) of the road surface 18 is expressed by the following equation using the moving distance D (T) −D (T ₀ ) and h during this time. sin θ (T) = h / {D (T) −D (T ₀ )} (4)

FIG. 3 shows an example of a change in altitude according to the distance measured while the automobile 1 is traveling. The horizontal axis indicates the distance D (km), and the vertical axis indicates the height (m). . FIG. 4 shows an example of the gradient with respect to the traveling distance calculated from the altitude change shown in FIG. 3, and is obtained by differentiating the data shown in FIG. 3 with the distance. In this figure, the horizontal axis represents the distance D (km), and the vertical axis represents the gradient (%). Further, in this figure, the minus (−) sign on the vertical axis indicates a downward slope.

As described above, according to the first aspect of the present invention, the vehicle 1 is mounted with the atmospheric pressure sensor 9 and travels on the road, and a change in altitude is calculated from a short-time change in atmospheric pressure during traveling on the road. Since the gradient data of the road surface is collected by measuring the gradient of the road surface with respect to the traveling distance from the change in altitude for each traveling distance, the gradient of the road surface 18 can be obtained extremely easily.

In the above-described embodiment, the atmospheric humidity is measured and _tv is corrected. However, the altitude can be obtained by assuming that the atmospheric humidity is constant. The altitude h in this case is given by the following equation (5). h = {P (T ₀ ) −P (T)} × 13.6 / 293 × 1.205 × P (T) / {273 + t (T)} × 760 (5)

Next, the second invention will be described with reference to FIG. FIG. 5 shows an example of a dynamometer control circuit. In this figure, reference numeral 20 denotes a chassis dynamometer, which includes a roller 21 on which a driving wheel of an automobile is mounted, a flywheel 22 as an inertia generating unit, and a power absorbing unit 23. . A speed sensor 25 and a torque sensor 26 are provided on a rotation shaft 24 of the roller 21. The power absorbing portion 23 is made of, for example, an AC generator, and its drive shaft 27 is connected to the rotary shaft 24 and a joint member (not shown).
Is connected mechanically so as to be able to be separated and coupled, and generates electric power to convert the absorbed torque into electric energy.

In FIG. 5, reference numeral 28 denotes a torque control circuit, and 29 denotes a power converter. Reference numeral 30 denotes a circuit for calculating the running resistance RL, and a speed signal V from the speed sensor 25,
Input device constants entered by (not shown) A, B, with C, and outputs a running resistance RL represented by A + BV + CV ^2. The output RL is at the point 3
1 is output.

Reference numeral 32 denotes a calculation route provided in parallel with the running resistance calculation unit 30, and this route 32 is configured as follows. That is, an integrator 33 integrates the speed signal V from the speed sensor 25 and outputs the product distance D as an output signal. Reference numeral 34 denotes a gradient signal generator provided on the output side of the integrator 31. The gradient data obtained in the first aspect of the invention, that is, the gradient data of the road surface 18 with respect to the traveling distance obtained when the automobile 1 travels on the road surface. It outputs the gradient at that distance while reading the distance in the gradient data, and outputs sinθ as the gradient command. Further, 35 is a multiplier provided on the output side of the gradient signal generator 34, and sin θ from the gradient signal generator 34
Is multiplied by a set inertia amount _Iset input by the input device, and the output is a gradient command signal _Iset
is output to the abutting point 31 as sin θ.

At the abutting point 31, the running resistance signal RL and the gradient command signal _Iset · sinθ are added, and the added output RL + _Iset · sinθ is input to the torque control circuit 28 as a torque command.

In the dynamometer control circuit configured as described above, the chassis dynamometer 20 is controlled so that the torque output detected by the torque sensor 26 matches the torque command.

In the dynamometer control circuit, the value of sin θ calculated using the amount of change in altitude and the traveling distance is given as a gradient input of the chassis dynamometer, so that the vehicle travels on the road on the chassis dynamometer. Can be accurately and easily reproduced not only on a flat surface (horizontal surface) but also on an inclined road surface.

As described above, in the second invention, the gradient command for the travel distance on the chassis dynamometer is obtained by using the gradient data of the road surface 18 with respect to the travel distance obtained when the vehicle 1 travels on the road surface. This is input to the torque control circuit 28 together with the running resistance value RL and the like, and the slope control is performed. Therefore, it is possible to perform the simulated driving according to the state of the sloping road in the actual road running. .

The second invention can also be applied to an electric inertia type chassis dynamometer, and the dynamometer control circuit is as shown in FIG. In this figure, reference numeral 36 denotes a calculation route for calculating the torque based on the electric inertia amount, which is a differentiator 37 for differentiating the speed signal V, and a multiplier 38 for multiplying the output of the differentiator 37 by the electric inertia amount _IE . The output of the multiplier 38 and the running resistance calculation unit 30 are added at a matching point 39, and the added output is added to the output of the multiplier 35.

[0028]

As described above, in the first aspect of the present invention, the vehicle is mounted on the road with an atmospheric pressure sensor and travels on the road. Since the slope data of the road surface is collected by measuring the slope of the road surface with respect to the travel distance from the change in altitude for each travel distance, the slope of the road surface can be obtained extremely easily.

In the second invention, a gradient command for the traveling distance on the chassis dynamometer is generated by using the road gradient data for the traveling distance obtained when the vehicle is traveling on the road, and this is used for traveling. Since the input is input to the torque control circuit together with the resistance value and the like to perform the gradient control, it is possible to accurately and easily perform the simulated operation in accordance with the state of the sloping road in the actual road running.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a vehicle for implementing a first invention.

FIG. 2 is a diagram showing an example of a configuration for collecting data in the vehicle.

FIG. 3 is a diagram illustrating an example of a change in altitude measured during traveling of a vehicle with distance.

4 is a diagram illustrating an example of a gradient with respect to a traveling distance calculated from the altitude change illustrated in FIG. 3;

FIG. 5 is a diagram schematically showing an example of a configuration for implementing the second invention.

FIG. 6 is a diagram schematically showing another example of the configuration for carrying out the second invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Vehicle, 9 ... Atmospheric pressure sensor, 18 ... Road surface, 20 ... Chassis dynamometer, 28 ... Torque control circuit.

Claims (2)

[Claims] 1. A vehicle having an atmospheric pressure sensor mounted thereon is made to travel on a road, a change in altitude is calculated from a short-time change in atmospheric pressure during traveling on the road, and a change in altitude is calculated based on the change in altitude for each travel distance. A method for collecting road slope data used in a road running simulation test method using a chassis dynamometer, wherein a slope is measured. 2. A gradient command for a traveling distance on a chassis dynamometer is generated using road gradient data for a traveling distance obtained when the vehicle is traveling on a road surface, and the gradient command is generated together with a traveling resistance value and torque control. Input to the circuit,
A method for controlling a chassis dynamometer, wherein gradient control is performed.