JPS5839360B2 - Current position display device for automobiles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention calculates the current position of a vehicle on its travel route from a detected yaw rate value and a detected travel distance,
The present invention relates to a current position display device for an automobile that displays the result on a position display section.

Generally, this type of current position display device for a vehicle directly detects the vehicle's yaw rate, that is, the rate of declination with respect to the target course using, for example, a rate-type gyroscope, and then outputs an electrical signal proportional to the declination via an angle potentiometer or the like. The current direction is obtained by amplifying the output signal using a gyro amplification circuit, sampling it every unit time, and adding it to the initial value from time to time.

Conventionally, when such a gyroscope was used to detect yaw rate, that is, to continuously detect changes in the declination angle along the vehicle's travel path, the gyroscope constantly vibrated slightly due to vibrations caused by the vehicle's running or disturbances such as wind. Therefore, simply adding the gyroscope output signals as described above will not only calculate the drift value while the car is running, but also the actual value when the car is stopped due to waiting at a traffic light. Even when no rate is being generated, the drift values of the gyroscope and the gyro amplification circuit are accumulated over time, and the cumulative error of this drift value has the drawback that the current direction determined by calculation and the actual direction are largely incorrect.

Therefore, in the past, in order to eliminate the influence of drift of the gyroscope and gyro amplification circuit, for example, RC
Separate circuits such as arithmetic circuits are provided, but the response is poor and the overall structure of the device is complicated.

The present invention has been made in consideration of the above points, and when determining the current direction of a car using a gyroscope or the like,
An object of the present invention is to provide a current position display device for an automobile that can correct the cumulative error caused by the aforementioned drift with a simple configuration without adversely affecting responsiveness.

The current position display device for a car according to the present invention uses a microcomputer to perform necessary calculations to determine the current position of the car based on the yaw rate detected by a gyroscope or the like and the number of traveled distances detected by a travel distance detector. In addition, a circuit is provided to detect whether the vehicle is stopped or running depending on the presence or absence of an output signal from the mileage detector, and when the vehicle is stopped, the above calculation is stopped, and when the vehicle is running, the yaw rate detection value at that time and the yaw rate detection when the vehicle is stopped is provided. The difference between the values (corresponding to the drift of the gyroscope and the gyro amplifier) is processed by the microcomputer as a calculation input.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the current position display device for an automobile according to the present invention includes, for example, a rate-type gyroscope 1, a gyro amplification circuit 2 that amplifies the output signal of the gyroscope 1, and an amplification output thereof. A to convert into a digital signal
-D conversion circuit 3, a mileage detector 4 that digitally detects the mileage of a car, a waveform shaping circuit 5 that shapes the detected output, and a unit mileage counting circuit that counts the pulse-shaped output. 6, a frequency detection circuit 7 that detects the output frequency of the waveform shaping circuit 5, a predetermined calculation based on the outputs of the A-D conversion circuit 3, the unit mileage counting circuit 6, and the frequency detection circuit 7. It is composed of a microcomputer 8 and a position display section 9 driven by the control output of this microcomputer 80.

The operation of the current position display device for an automobile according to the present invention configured as described above will be explained below.

First, the gyroscope 1 continuously detects changes in the declination angle with respect to the target course of the car, and the detection output (
As mentioned above, gyroscope 1 generates electrical signals using an angle potentiometer, etc.)
is amplified by the gyro amplification circuit 2, and converted into a digital signal by the A-D conversion circuit 3 to produce an argument signal A.
The signal is sent to the first input terminal of the microcomputer 8 as θ.

At the same time, the mileage of the car is continuously detected by the mileage detector 4, and the detected pulse output is waveform-shaped by the waveform shaping circuit 5 to generate a unit mileage signal AL.
is sent to the second input terminal of the microcomputer 8, and the output frequency of the mileage detector 4 is detected by the frequency detection circuit 7, and the detection signal is sent to the third input terminal of the microcomputer 8.

The microcomputer 8 has its first, second and third
A predetermined calculation, which will be described below, is performed based on the signals sent from each input terminal, and the position display section 9 is driven according to the calculation result to display the current position of the automobile.

As the position display section 9, a general one can be used, such as one that displays the current position of the vehicle on the road set in advance at the intersection point on the orthogonal coordinates of the X and Y axes. .

The microcomputer 8 first samples the declination signal Aθ sent from its first input terminal every unit time, and detects the traveling distance sent from the frequency detection circuit 7 to its third input terminal. The current direction θ of the vehicle is calculated by adding the declination signal lθ sampled as described above according to the frequency detection signal of the device 40.
Calculations are performed according to the flowchart shown in FIG.

That is, the sampling time of the argument signal lθ is (1,
The detection rate of the declination signal Aθ is Wx(Aθ−Wx−1t
), and let Wd be the rate drift preset in this microcomputer 8 (the outputs of the gyroscope 1 and the gyro amplification circuit 2 are stored in advance as the drift amount when the car is stopped), then the To sample the argument signal Aθ sent to the input terminal of 1, the sampling signal WX-At
), then it is determined whether or not the unit mileage lL of the car is zero based on the frequency detection signal sent from the third input terminal, that is, when the frequency output is zero, the car is in a stopped state, and it is not. Sometimes it is determined that the vehicle is in a running state.

At this time, when the car is in a running state and JL is not zero, drift correction is performed by subtracting the rate drift) Wd from the detection rate WX, and the drift-corrected deflection angle θ' per unit time is gradually changed to the initial value. The current direction θ of the vehicle is calculated by adding the value to the current direction θ.

In addition, when the car is in a stopped state and (L is zero, the drift angle Aθ' per unit time that is drift-corrected as Wd = Wx is set to zero, and the gyroscope 1 and the gyro amplification circuit 20 drift when the car is stopped. Prevent minutes from being added.

Next, the current direction θ of the vehicle obtained in this manner and the unit mileage counting circuit 6 sent to the second input terminal.
Based on the output signal JL of , the current position of the vehicle is calculated by collateral integral calculation.

In this case, to find the current position at the intersection on the rectangular coordinates of the X-Y axes, the following equation is used (see FIG. 3).

It should be noted that the current display device for a car according to the present invention is not limited to that of the above-described embodiment; for example, when the car is stopped, the frequency detection circuit 7 detects that the output frequency of the mileage detector 4 becomes zero. Instead, a voltage detector or the like may be used to detect that the output voltage of the mileage detector 4 becomes zero when the vehicle is stopped.

It goes without saying that the current position can be determined not only by integral calculation of the current direction θ of the vehicle and the detected distance number, but also by various other calculations.

As described above, in the current position display device for a car according to the present invention, the current position is calculated from the detected yaw rate value and the detected travel distance of the car, and the result is displayed on the position display section, which uses a microcomputer. When the current direction of the vehicle is determined, the microcomputer corrects the drift of the gyroscope and the gyro amplification circuit from the declination signal corresponding to the detection signal of the gyroscope.
The drift-corrected argument signal is added to the initial value every moment.

At the same time, the present invention includes a circuit for detecting a stopped state of the automobile, and according to the output of this detection circuit, the microcomputer generates a declination signal due to the drift of the gyroscope and the gyro amplification circuit when the automobile is stopped. This is set to zero so that the addition is not performed.

Therefore, it has the excellent advantage of being able to display the current position of the vehicle with a simple configuration, good coordination, and high precision without accumulated errors due to drift.

[Brief explanation of drawings]

FIG. 1 shows the block composition of a vehicle driving position display device according to an embodiment of the present invention, FIG. 2 is a flowchart of a microcomputer in the same embodiment, and FIG. 3 shows a vehicle on X-Y coordinates in the same embodiment. It is a diagram showing the current position of. 1... Gyroscope, 2... Gyro amplification circuit, 3... A-D conversion circuit, 4...
... Mileage detector, 5... Waveform shaping circuit, 6... Unit mileage counting circuit, 7...
- Frequency detection circuit, 8... microcomputer, 9... position display unit.

Claims (1)

[Claims] 1. A device that calculates the current position from the vehicle's yaw rate detection value and travel distance detection value and displays the result on a position display unit, which detects the stopped or running state of the vehicle depending on the presence or absence of a travel distance detection signal. A current position display device for an automobile, characterized in that a circuit is provided to stop the calculation when the vehicle is stopped, and to process the difference between the detected yaw rate value at that time and the detected yaw rate value when the vehicle is stopped as a calculation input when the vehicle is running. .