JPH04303028A - Grade detector - Google Patents

Abstract

PURPOSE:To detect the grade of a road surface on which a vehicle is traveling, automatically. CONSTITUTION:A vehicle's load capacity is detected by a car level sensor 1, and on the basis of a car speed signal by a car speed sensor 4 and a throttle opening signal and a shift position signal of a throttle sensor 7, if a shift position is at low speed, the speed/acceleration of a vehicle is set to a positive direction but at high speed to a negative direction, respectively, and when the load capacity being detected by a loadage detecting sensor is light in weight, it is set to the positive direction but heavy in weight to the negative direction, respectively, and furthermore when a throttle of the throttle sensor is closed, it is set to the negative direction but opened, to the positive direction respectively. Thus it is inferred by a fuzzy inference inferring the grade of a road surface on which a vehicle is traveling as in a fact that when car speed in the car sensor is high speed, it is set to the negative direction but low speed, to the positive direction respectively, whereby the grade of the traveling road surface is detected in this way.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slope detection device for detecting the slope of a road surface on which a vehicle is running.

0002

2. Description of the Related Art Conventional vehicles are equipped with various electronic control devices for controlling the driving system and the interior environment. For example, as shown in FIG. 7, an automatic transmission device is known that automatically selects the gear position of a clutch based on the throttle opening and rotation speed of an engine 100, or a signal from a vehicle speed sensor 101. In this device, the throttle opening and rotation speed of the engine, as well as signals from the vehicle speed sensor 101 are applied to an AT control unit 102 to switch the transmission 103 in a predetermined pattern, and the switching mode is indicated by an AT mode indicator 10.
It is displayed by 4. This automatic transmission device may be provided with an AT mode switch 105, etc., which changes the mode to select powerful driving by shifting up late or to improve fuel efficiency by shifting up early. be.

[0003] Also, constant speed running devices are used which automatically control the throttle opening so that the vehicle speed is always set at a set speed while the vehicle is running. FIG. 8(a) is a schematic block diagram showing an example of a constant speed traveling device, in which the throttle valve is controlled by the cruise control unit 112 so that the speed of the vehicle becomes constant according to the signal from the vehicle speed sensor 101 and the signal from the vehicle speed setting switch 111. 113, and lights up a cruise lamp 114 when the vehicle is running at a constant speed. When the brakes are applied, the constant speed traveling is stopped by a signal from the brake switch 115, and the vehicle is switched to normal traveling.

0004

[Problems to be Solved by the Invention] However, in such conventional automatic transmission devices,
Since it is not possible to detect whether the road the vehicle is traveling on is flat or sloped, it is not possible to perform controls such as shifting up late or opening the throttle too quickly when going uphill, as drivers do. Ta. Furthermore, even when using a constant-speed traveling device that allows the vehicle to travel at a constant speed, as shown by the solid line in FIG. The problem was that the speed would fluctuate as the vehicle approached the uphill slope. In order to detect the slope of the road surface, it is possible to use a slope sensor that detects the slope of the vehicle, but in this case, it is not possible to distinguish between the output due to the slope of the road surface and the acceleration of the vehicle.

The present invention has been made in view of the problems of conventional vehicle control devices, and a technical problem is to enable accurate detection of the inclination of the road surface while the vehicle is running. do.

[0006]

[Means for Solving the Problems] The present invention is a slope detection device for detecting the slope of a road surface on which a vehicle is running, which includes a load detection sensor for detecting the load of the vehicle, and a vehicle speed for detecting the speed of the vehicle. a sensor, a throttle sensor that detects the throttle opening of the engine, a shift position detection means that detects the shift position of the transmission, and a shift position detected by the shift position detection means that is set in a positive direction at low speeds and in a negative direction at high speeds; When the load detected by the load detection sensor is light, the direction is positive;
If the load is heavy, the direction is negative, if the throttle of the throttle sensor is closed, it is negative, if it is open, it is positive, and if the vehicle speed of the vehicle speed sensor is high, it is negative, and if it is slow, it is positive. The present invention is characterized by comprising a fuzzy inference section that performs fuzzy inference to estimate the slope of the road surface on which the vehicle is running and obtains a non-fuzzy determined value.

[0007]

[Operation] According to the present invention having such characteristics, the shift position detected by the load detection sensor, vehicle speed sensor, throttle sensor, and shift position detection means provided on the vehicle is in the forward direction at low speeds and in the forward direction at high speeds. The direction is negative, when the load detected by the load detection sensor is light, the direction is positive, when the load is heavy, the direction is negative, if the throttle of the throttle sensor is closed, it is negative, and when it is open, it is positive. Fuzzy inference is used to estimate the gradient of the road surface on which the vehicle is traveling so that the vehicle speed sensor indicates a negative direction if the vehicle speed is high, and a positive direction if the vehicle speed is low. In this way, the gradient of the road surface on which the vehicle is traveling is estimated and output.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing the configuration of a slope detection device according to an embodiment of the present invention. In this figure, a detection means for detecting the amount of load carried on the vehicle is used in the vehicle, and in this embodiment, a vehicle height sensor 1 is used. The vehicle height sensor 1 is a sensor that detects the vehicle height based on the positional relationship between the vehicle body and the wheels using, for example, a magnetic potentiometer using a Hall element or a magnetic resistance element, and its output is sent to the A/D converter 2. The signal is converted into a digital signal at a predetermined timing, and is provided to a sample and hold (S/H) circuit 3. Further, this slope detection device is provided with a vehicle speed sensor 4 as a sensor. The vehicle speed sensor 4 has a magnet attached to one end of a cable having a rotational speed corresponding to the running speed of the vehicle, and a reed switch or the like is installed near the magnet to obtain a pulse signal corresponding to the rotational speed, and the output is sent to a counter. given to 5. The counter 5 counts and clears the pulses of the vehicle speed sensor at a predetermined timing, and its output is given to a sample and hold circuit 6. Further, this slope detection device has a throttle sensor 7 that detects the opening degree of the throttle, the output of which is converted into a digital signal via an A/D converter 8 and provided to a sample and hold circuit 9. Furthermore, if the vehicle is equipped with means for detecting the gear position, in this embodiment an automatic transmission (AT) device, a shift position signal is obtained from the automatic transmission computer 10. Signals of sample and hold circuits 3, 6, 9 and A
A shift position signal from the T-computer 10 is given to a fuzzy inference section 11. The fuzzy inference unit 11 performs fuzzy inference according to a plurality of fuzzy rules stored in the rule storage unit 12, and outputs a slope angle signal δ of the road surface on which the vehicle is running as the inference result.

The fuzzy rules stored in the rule storage section 12 are rules for the slope of the road on which the vehicle is traveling based on the vehicle height sensor 1, vehicle speed sensor 2, throttle sensor 3, and shift position signal 4. Yes, i
It is expressed in the form of f, then rules (if, then). Here, the output of the vehicle height sensor 1 is X1, the output of the vehicle speed sensor 4 is X2, the output of the throttle sensor 7 is X3, and the shift position signal X4 are membership functions as shown in FIGS. 2(a) to 2(d). It is evaluated as. Here, S indicates a small positive value, M indicates a medium positive value, and L indicates a large positive value. In addition, the gradient δ of the road is also NL~ as shown in Figure 3.
It is expressed in seven states of PL. Here, NL is a large negative value, NM is a medium negative value, NS is a small negative value, Z is a value near zero, PS is a small positive value, PM is a medium positive value, and PL is a medium positive value. Each shows a large positive value.

The fuzzy inference unit 11 uses these inputs to perform fuzzy inference based on the following inference rules. The fuzzy inference rules are: positive direction when the shift position is low, negative direction when high speed, positive direction when the load is light, negative direction when the load is heavy, negative direction if the throttle sensor throttle is closed, positive direction if it is open. , the gradient of the road surface on which the vehicle is traveling is estimated so that if the vehicle speed detected by the vehicle speed sensor is high, it will be in the negative direction, and if the vehicle speed is low, it will be in the positive direction. (Rule 1) If the output X1 of the vehicle height sensor is L and the output X3 of the throttle sensor 3 is NL, then the tilt angle E is NL.
Let it be. This rule 1 is simplified and expressed as follows. if X1=L and X3=SL and
X2=Lthen E=NL Similarly, other rules are expressed by the table shown in FIG. This rule shows the rule for one shift position, but when the shift position is on the low speed side, all the slope angles are changed in the positive direction, and when the shift position is on the high speed side, all the slope angles are changed in the negative direction, and the slope angle is changed in the same pattern. I am trying to estimate.

Now, the relationship between vehicle speed and throttle opening is shown in Figure 5 (
It is expressed as shown in a) or (b). In other words, on flat land, when the shift position is from 1st to 4th gear as shown in Figure 5(a), and the vehicle load is light, the vehicle speed is high relative to the throttle opening as shown by the solid line, and the load is small. If it is heavy, the vehicle speed will decrease as shown by the broken line in the figure. In addition, as shown in Fig. 5(b), in the case of the same shift position and the same load capacity, if the solid line A in Fig. 5(b) is a flat area, the broken line will change for the same throttle opening on an uphill slope. As shown by A1, the vehicle speed decreases, and when going downhill, the vehicle speed increases as shown by broken line A2. Therefore, the gradient is estimated based on the above-mentioned rules based on such characteristics.

Next, the operation of this embodiment will be explained with reference to the flowchart of FIG. When the operation starts, the sample and hold circuit 3 first converts the outputs of the vehicle height sensor 1, vehicle speed sensor 4, and throttle sensor 7 into A/D converters.
, 6, and 9. And these outputs X1
, X2, X3 and the shift position signal of the AT computer 10 are given to the fuzzy inference section 11. When these signals are input in the antecedent part (step 21), the degree to which they match the corresponding membership function of this fuzzy rule is determined (steps 22 to 25).
. Then, the one with the lowest degree of fitness is selected and given to the consequent. The consequent part of the fuzzy inference unit 11 limits the membership function of the output E1 based on the selected fitness to obtain, for example, a trapezoidal membership function. These membership functions are superimposed by a MAX synthesis process to produce a synthesis output, and fuzzy inference is performed (routine 26). Next, in step 27, the center of gravity of this composite output is calculated as a definitive output by a defuzzifier. The slope angle signal δ is output as a signal indicating the slope angle of the road surface on which the vehicle travels.

Now, this gradient signal is used as an input signal in an automatic transmission device to select the gear ratio and rotation speed, and change the switching between economy mode and power mode as appropriate depending on whether the road is flat or on a slope. Can be controlled. That is, by shifting up late when going uphill, you can drive more powerfully, and by shifting down earlier when going downhill, engine braking is more likely to be applied, making driving safer. Furthermore, by using the slope signal as one input of the constant speed traveling device described above, it is also possible to control the throttle opening so that when the vehicle reaches an uphill slope, the throttle opening is almost opened. In this way, there is no speed dip as shown by the broken lines in FIGS. 8(b) and 8(c), and the vehicle speed can be controlled to always be constant. The slope signal can also be used to reduce the air conditioner's capacity and reduce the engine load when going uphill.

In this embodiment, a microcomputer is used to execute the fuzzy inference processing, but dedicated hardware such as a fuzzy computer or a fuzzy controller as disclosed in Japanese Patent Application Laid-Open No. 63-123177 may also be used. Fuzzy inference may be executed using software to output a road surface slope signal. Further, in this embodiment, a vehicle height sensor is used to detect the vehicle speed and the load amount, but other devices may be used to detect the vehicle load amount. Furthermore, in this embodiment, the shift position signal is obtained from the automatic transmission computer in the case of a vehicle equipped with an automatic transmission device, but in the case of a manual transmission type vehicle, a detection means for detecting the position of the shift lever is provided to obtain the shift position signal. It goes without saying that you can.

[0015]

[Effects of the Invention] As explained in detail above, according to the present invention, it is possible to use an inclination sensor, etc. by performing fuzzy inference based on signals of the vehicle speed, load capacity, vehicle speed, throttle opening, and shift position. It is possible to accurately estimate the slope of the road surface while driving. Therefore, by using this signal as an input to various electronic control devices, it is possible to improve the performance of these devices.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the overall configuration of a slope detection device according to an embodiment of the present invention.

FIG. 2 is a diagram showing membership functions of a vehicle height sensor, a vehicle speed sensor, a throttle sensor, and a shift position signal according to an embodiment of the present invention.

FIG. 3 is a diagram showing a membership function indicating a slope angle of a road surface according to the present embodiment.

FIG. 4 is a diagram showing fuzzy inference rules of this embodiment.

FIG. 5 is a graph showing the vehicle speed and throttle opening of a typical vehicle.

FIG. 6 is a flowchart showing fuzzy inference processing according to the present embodiment.

FIG. 7 is a block diagram schematically showing a conventional automatic transmission device.

FIG. 8(a) is a block diagram schematically showing a conventional constant speed traveling device, and FIG. 8(b) is a graph showing the relationship between vehicle speed and road surface of a vehicle using this device.

[Explanation of symbols]

1 Vehicle height sensor 2,8　A/D converter 3, 6, 7 Sample and hold circuit 4 Vehicle speed sensor 5 Counter 7 Throttle sensor 10 AT computer 11 Fuzzy reasoning part 12 Rule storage section

Claims (1)

[Claims] 1. A slope detection device that detects the slope of a road surface on which a vehicle is running, comprising a load detection sensor that detects the load amount of the vehicle, a vehicle speed sensor that detects the speed of the vehicle, and an engine throttle opening sensor. a throttle sensor that detects the speed, a shift position detection means that detects the shift position of the transmission, and a shift position detected by the shift position detection means that is positive at low speeds and negative at high speeds; If the detected load is light, the direction is positive; if the detected load is heavy, the direction is negative; if the throttle of the throttle sensor is closed, the direction is negative; if the throttle is open, the direction is positive; and if the vehicle speed detected by the vehicle speed sensor is high. A fuzzy inference unit that performs fuzzy inference to estimate the gradient of the road surface on which the vehicle is running so that if the vehicle is traveling in the negative direction and if the vehicle is traveling in the positive direction, the vehicle obtains a non-fuzzy definite value. gradient detection device.