JPS645224Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is designed to improve the running characteristics of automobiles, such as driving force characteristics, hill climbing force characteristics, braking force characteristics, lift characteristics, cornering force characteristics, rolling resistance characteristics, etc. The present invention relates to a driving characteristic detection device for detecting driving characteristics.

[Conventional technology]

It is generally known that the above-mentioned driving characteristics can be detected by measuring the drag, lateral force, and lift of the vehicle. However, conventionally,
It has been impossible to measure these three elements simultaneously and easily.

Conventionally, when measuring drag on the actual road, a torque meter is inserted midway through the propulsion shaft to measure the torsional force and amount of twist on the drive shaft, or a wheel torque meter is attached to measure tire driving force. In addition, when measuring lateral force on the actual road, a wheel dynamometer was used to measure it. These methods allow relatively high-precision measurement values to be obtained, but because it is necessary to install each measuring device in the car, a large amount of process and cost is required from the design of the measuring device to the instrumentation. There's a problem. Furthermore, if a wheel torque meter is installed, for example, the inertial mass of the rotating parts increases significantly, making it difficult to maintain the original condition of the vehicle itself.

The only way to measure lift force is to use a scale model and measure it in a wind tunnel, and it was previously impossible to measure lift force using an actual vehicle.

The conventional method for measuring drag is to measure it on a bench using a chassis dynamometer, but this method does not correlate well with actual road measurements and has large mechanical loss fluctuations in the chassis dynamometer itself. For these reasons, the measurement accuracy was poor.

[Problem that the invention attempts to solve]

In any case, with conventional technology, it is not possible to measure drag, lateral force, and lift all at once;
In addition to the above, there were many other problems with individual measurements.

Therefore, the present invention solves the above-mentioned problems of the prior art, and the purpose of the present invention is to reduce the drag force of the automobile,
It is an object of the present invention to provide a device that can detect running characteristics by measuring lateral force and lift force extremely easily, in a short time, and with high precision.

[Means for solving problems]

The features of the present invention that achieve the above-mentioned object include a plurality of measurement face plates embedded in the road surface of the vehicle along the running direction so as to measure the tire road reaction force of the vehicle, and each of the measurement face plates. The present invention is equipped with a pressure detector that detects the force acting on the aus plate as component forces in three mutually orthogonal directions.

[Effect]

When a car is driven on a road surface so that the car's tires sequentially pass over each measurement face plate, the force applied to the pressure detector installed below the face plate the tires are passing over. is equal to the combined force of drag, lateral force, and lift. Therefore, the force applied to the pressure sensor can be divided into three directions: one in the direction opposite to the direction of travel of the car, one in the direction opposite to the vertical direction, and one in the direction orthogonal to both of the two directions. The force divided in the first direction is a drag force, the force divided in the second direction is a lift force, and the force divided in the third direction is a lateral force. These three types of forces can be measured extremely easily, in a short time, and with high precision.

〔Example〕

The present invention will be explained in detail below using the drawings.

Fig. 1 is a partial cross-sectional view of an embodiment of the present invention as viewed from the lateral direction with respect to the direction of travel of the automobile, and Fig. 2 is a partial cross-sectional view of the embodiment of Fig. 1 as viewed from the direction of travel of the car. It is. In both figures, 10 is the test vehicle,
Reference numeral 12 indicates an asphalt test course paved with tarmac, and reference numeral 14 indicates a tire road surface reaction force detection device buried in the middle of the test course 12.
The detection device 14 includes a plurality of measurement face plates 16 arranged along the traveling direction of the automobile 10;
a support member 18 supporting each measurement force plate 16 and a pressure sensor 20 receiving the support member 18;
and a floor plate 22 on which the pressure detector 20 is fixedly mounted. The measurement face plate 16 has a special surface processed so that its surface has the same coefficient of friction as the test course 12, and is supported by a support member 18 so that its surface is flush with the test course surface. There is. In this embodiment, the support member 18 has four legs, each of which is supported by a pressure detector 20. In this embodiment, therefore, four pressure detectors are provided for each measuring faceplate. If the number of pressure detectors is increased, it is possible to accurately measure the road reaction force regardless of the tire passing position, and the measurement accuracy itself is improved. However, the invention can be achieved if at least one pressure detector is provided for each measuring faceplate.

The individual pressure detectors 20 are as shown in FIG.
It consists of a ring-shaped piezoelectric element, and its hole 20
A cylindrical projection 18b provided at the tip of the leg 18a of the support member 18 is inserted into the support member 18 without a gap.
Thereby, the pressure detector 20 separately and simultaneously detects the pressures applied to the measurement face plate 16 in the X, Y, and Z axis directions, and outputs electric power corresponding to each of the detected pressures. This type of three-component force pressure detector is already commercially available. In addition to this, the pressure detector 20 of the present invention can also be constructed from three piezoelectric elements that respectively detect pressure in the X, Y, and Z axis directions.

When the automobile 10 approaches the detection device 14, the road reaction force of its tires acts on the measurement face plate 16, and this is applied to each pressure detector 20 via the support member 18, so that the X
Three component forces in the axial, Y-axis, and Z-axis directions are detected simultaneously. These three component forces acting on the measuring face plate 16 are shown in FIG.
They represent F _A , lateral force F _Y , and lift force F _{N ,} respectively.
These will be detected simultaneously by the pressure detector 20.

In FIGS. 1 and 2, 24 is a road gap filling member provided between the measurement face plates 16, and its upper surface is configured to be flush with the test course 12. A special surface treatment similar to that of the measurement face plate 16 has been applied. Moreover, inside this member 24,
A signal cable 26 for transmitting a detection signal from the pressure detector 20, a signal induction device 28 for generating a vehicle position signal from a position sensor mounted in the automobile 10, and the like are provided.

FIG. 5 is a block diagram of a processing circuit for a detection signal obtained from the tire road reaction force detection device 14 described above. In the figure, numeral 30 is the aforementioned three-component force pressure detector group, each block forming one pressure detector (pressure sensor). Three types of detection signals obtained from each pressure detector are sent via a charge amplifier 32 to an A/D converter 34 having an analog multiplexer function and sequentially converted into binary signals. The information is stored directly in a high-speed memory device 36, which may include a core memory device or the like. On the other hand, the automobile 10 has a position sensor 38 that recognizes which face plate the front wheels and rear wheels are passing over and generates a vehicle position signal for detecting the traveling speed of the automobile 10. , a steering sensor 4 that detects the steering angle of the automobile 10
0, a brake sensor 42 that detects the depression force on the brake pedal or brake oil pressure, a rotation speed sensor 44 that detects the rotation speed of the crankshaft or drive shaft, a shift position sensor 46 that detects the shift position of the transmission, etc. are installed. Furthermore, a transmitter 48 for transmitting the detection signals of these sensors in the form of FM waves is mounted. The detection signal of the above-mentioned in-vehicle sensor transmitted as an FM wave from the transmitter 48 is transmitted to a receiver 50 provided on the ground side.
After being received by and demodulated into a binary signal,
Stored directly in memory device 36.

Memory device 36 and CPU (central processing unit) 52
As mentioned above, the digital computer (minicomputer) mainly composed of the above has a DMA (direct memory access) function to directly store input data in the memory device 36 in a short period of time. This digital computer further includes a CRT display device 54 as a peripheral device.
and a hard copy device 56, which is configured to allow online processing of input information. Furthermore, this digital computer is equipped with an interrupt function and an operating system function so that input data can be sent to the host computer in the calculation center and final measurement data processing can be performed. In some cases, a data recorder 58 may be provided, and input data temporarily stored in the high-speed memory device 36 may be transferred to the data recorder 58 and temporarily stored, and the CPU 5 may
It is also possible to use the idle time in step 2 more effectively to perform online processing. In this way, in this example, a huge amount of data obtained from a large number of sensors is processed by a digital computer with a DMA function, so reading errors and simple mistakes by the measurer are avoided. This makes it possible to process a large amount of data in a short period of time with almost no occurrences.

FIG. 6 typically shows how the measurement face plate 16 is mounted on a test course. In the same figure, A is used to detect the driving characteristics in the starting, braking, and straight driving modes, B is used to detect the driving characteristics in the left-right cornering driving mode, and C is used when driving in the uphill and downhill driving modes. Used to detect characteristics.

Next, an example will be described in which the apparatus of this embodiment is used to detect the front-rear braking force distribution characteristic of an automobile.

Front axle control is determined based on the drag force F _A and lift force F _N detected by the pressure detector via the measurement face plate 16, the signal from the on-board position sensor 38, the signal from the on-board brake sensor 42, etc. The relationship between power Ff and rear shaft braking force Fr can be detected,
When this is expressed on the horizontal and vertical axes, it is possible to obtain the front-rear braking force distribution characteristic as shown by straight line a in FIG.
Curve b in the figure is the ideal distribution characteristic of braking force, which can be calculated as follows.

As shown in Fig. 1, a car 1 with a gross vehicle weight W
0 applies the brakes and the total braking force F (F=Ff+
Fr, where Ff is front axle braking force and Fr is rear axle braking force)
is generated, this car 10 has f
= A deceleration of F・g/W occurs, and this deceleration f causes an inertial force of W/g・f to be generated forward at the center of gravity of the vehicle body (however, if the equivalent weight of the rotating parts is ignored) be). That is, the ground contact portion of the tire is pulled backward by the braking force F, and the center of gravity of the vehicle body is pushed forward by the inertial force F. Therefore, a rotational moment F and H is generated in the automobile 10, which causes the automobile 10 to rotate forward. The front wheels prevent the automobile 10 from rotating due to this rotational moment, and the balance of rotational forces in this case is expressed by the following equation.

For the front axle, Ff/Wf+H/L・F For the rear axle, Ff/Wr−H/L・F Where, Wf is the front axle weight, Wr is the rear axle weight, H is the height of the center of gravity, and L is the wheel base. ing.

If the coefficient of friction between the tires and the road surface is μ, then for the front axle, Ff=μ(Wf+H/L・μ・W) For the rear axle, the relational expression is Fr=μ(Wr−H/L・μ・W). can get. By determining the braking force distribution between the front and rear axles so that the front axle braking force Ff is equal to the rear axle braking force Fr, the front and rear axles can obtain the maximum braking force on a road surface with a friction coefficient μ during actual road driving. From this, when Ff and Fr are calculated and expressed from μ=0.1 to μ=1.0, the results are as shown in FIG. 7b.

By displaying the ideal distribution characteristic b and the actual distribution characteristic a shown in FIG. It is easy to set it so that it approaches .

FIG. 8 shows the driving performance characteristics of an automobile detected using the device of this embodiment. Drag force F _A obtained from pressure detector and on-vehicle rotational speed sensor 44
The vertical axis represents the rotational speed from position sensor 3.
The horizontal axis represents the vehicle speed calculated from the detection signal from 8, and the shift position from the vehicle-mounted shift position sensor 46 is used as a parameter.

FIG. 9 shows the cornering force characteristics of an automobile detected using the device of this embodiment. The centripetal acceleration on the horizontal axis can be calculated from the vehicle speed and the radius of curvature of the test course, and the moving load on the vertical axis can be calculated from the signal from the pressure detector.

FIG. 10 shows the steering characteristics detected using the device of this embodiment. The centripetal acceleration on the horizontal axis is obtained in the same manner as described above, and the steering angle on the vertical axis is obtained from the output of the vehicle-mounted steering sensor 40.

The various characteristics described above are obtained by various processing programs that are preset in the digital computer including the CPU 52, but the details of these processing programs are not directly related to the present invention and are therefore not covered herein. Description will be omitted in the specification.

[Effect of idea]

As explained in detail above, the device of the present invention is
Multiple measuring face plates are buried in the road surface of the car, and the forces acting on the measuring face plates through the tires are detected by pressure detectors that detect force components in three directions orthogonal to each other. Since the drag, lateral force, and lift of the vehicle are obtained from the output, these drag, lateral, and lift forces can be detected with high precision, extremely easily, and in a short time. Therefore, according to the device of the present invention, when detecting the driving characteristics of an automobile, it is possible to achieve significant labor savings, time savings, and high accuracy.

[Brief explanation of the drawing]

1 and 2 are partial cross-sectional views of an embodiment of the present invention, FIG. 3 is a structural diagram of the pressure detector portion, FIG. 4 is a diagram showing the force applied to the measurement force plate, and FIG. Figure 5 is a block diagram of the signal processing circuit of the above-mentioned embodiment, Figure 6 is a diagram showing the installation status of the measurement faceplate for various test courses, and Figure 7 is a diagram showing the installation status of the measurement faceplate for various test courses.
8, 9, and 10 are diagrams showing examples of detection of driving characteristics according to the above-described embodiment. 10...Car, 12...Test course, 14...
...Tire road reaction force detection device, 16...Measurement face plate, 20...Pressure detector.

Claims (1)

[Scope of utility model registration request] A plurality of measurement face plates are embedded in the road surface of the car along the driving direction so as to measure the tire road reaction force of the car, and the force acting on each of the measurement face plates is measured in three directions orthogonal to each other. A pressure detector that detects component forces; a receiving means installed in the vehicle that receives signals indicating driving state parameters; component forces in three directions detected by the pressure detector and signals received by the receiving means. Combine,
A driving characteristic detecting device for a motor vehicle, comprising a driving characteristic calculation means for obtaining the driving characteristics of the automobile through calculation processing.